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Proposed Management Plan for the Steller Sea Lion (Eumetopias jubatus) in Canada

Steller Sea Lion

About the Species at Risk Act Management Plan Series

What is the Species at Risk Act (SARA)?

SARA is the Act developed by the federal government as a key contribution to the common national effort to protect and conserve species at risk in Canada. SARA came into force in 2003, and one of its purposes is “to manage species of special concern to prevent them from becoming endangered or threatened.”

What is a species of special concern?

Under SARA, a species of special concern is a wildlife species that could become threatened or endangered because of a combination of biological characteristics and identified threats. Species of special concern are included in the SARA List of Wildlife Species at Risk.

What is a management plan?

Under SARA, a management plan is an action-oriented planning document that identifies the conservation activities and land use measures needed to ensure, at a minimum, that a species of special concern does not become threatened or endangered. For many species, the ultimate aim of the management plan will be to alleviate human threats and remove the species from the List of Wildlife Species at Risk. The plan sets goals and objectives, identifies threats, and indicates the main areas of activities to be undertaken to address those threats.

Management plan development is mandated under Sections 65–72 of SARA (http://www.sararegistry.gc.ca/approach/act/default_e.cfm).

A management plan has to be developed within three years after the species is added to the List of Wildlife Species at Risk. A period of five years is allowed for those species that were initially listed when SARA came into force.

What’s next?

Directions set in the management plan will enable jurisdictions, communities, land users, and conservationists to implement conservation activities that will have preventative or restorative benefits. Cost-effective measures to prevent the species from becoming further at risk should not be postponed for lack of full scientific certainty and may, in fact, result in significant cost savings in the future.

The series

This series presents the management plans prepared or adopted by the federal government under SARA. New documents will be added regularly as species get listed and as plans are updated.

To learn more

To learn more about the Species at Risk Act and conservation initiatives, please consult the SARA Public Registry (http://www.sararegistry.gc.ca).

Management Plan for the Steller Sea Lion (Eumetopias jubatus) in Canada
[PROPOSED]

October 2010

Recommended Citation:

Fisheries and Oceans Canada. 2010. Management Plan for the Steller Sea Lion (Eumetopias jubatus ) in Canada [Proposed]. Species at Risk Act Management Plan Series. Fisheries and Oceans Canada, Ottawa. vi + 69 pp.

Additional copies:

Additional copies can be downloaded from the SARA Public Registry, once posted (http://www.sararegistry.gc.ca/).

Cover illustration: M.A. Bigg.

Également disponible en français sous le titre
« Projet de plan de gestion des otaries de Steller (Eumetopias jubatus) au Canada »

© Her Majesty the Queen in Right of Canada, represented by the Minister of Fisheries and Oceans Canada, 2010. All rights reserved.
ISBN En3-5/8-2010E-PDF
Catalogue no. 978-1-100-16177-8

Content (excluding the illustrations) may be used without permission, with appropriate credit to the source.  

PREFACE

The Steller Sea Lion is a marine mammal, and is under the responsibility of the federal government. The Minister of Fisheries and Oceans is a “competent minister” for aquatic species under the Species at Risk Act (SARA).  Since Steller Sea Lion are located in the Gwaii Haanas National Park Reserve and Haida Heritage Site, Pacific Rim National Park Reserve, and Gulf Islands National Park Reserve, administered by the Parks Canada Agency, the Minister of Environment is also a “competent minister” under SARA for individuals occurring on lands and waters under the administration of the Parks Canada Agency.  The Species at Risk Act (SARA, Sections 65-66) requires the competent ministers to prepare management plans for species listed as special concern, in cooperation and consultation with affected and interested parties. The Steller Sea Lion was listed as a species of special concern under SARA in July 2005.  The development of this management plan was led by Fisheries and Oceans Canada – Pacific Region, in cooperation and consultation with many individuals, organizations and government agencies, including the Parks Canada Agency (Appendix III). 

Success in the conservation of this species depends on the commitment and cooperation of many different constituencies that will be involved in implementing the directions set out in this plan and will not be achieved by Fisheries and Oceans Canada and the Parks Canada Agency or any other party alone. This plan provides advice to jurisdictions and organizations that may be involved or wish to become involved in activities to conserve this species.  In the spirit of the Accord for the Protection of Species at Risk, the Minister of Fisheries and Oceans and the Minister of Environment invites all responsible jurisdictions and Canadians to join Fisheries and Oceans Canada and the Parks Canada Agency in supporting and implementing this plan for the benefit of the Steller Sea Lion and Canadian society as a whole. The competent ministers will report on progress within five years.

RESPONSIBLE AGENCIES AND JURISDICTIONS

Fisheries and Oceans Canada
Government of British Columbia
Environment Canada
Parks Canada Agency

AUTHOR

The DFO Technical Team prepared this document for Fisheries and Oceans Canada (DFO).

ACKNOWLEDGMENTS

The Team would like to thank Alana Phillips for input in development of initial drafts and for planning and coordination of the technical workshop.  Fisheries and Oceans Canada would like to acknowledge all participants who attended the Steller Sea Lion Management Planning Technical Workshop (listed in Appendix III).  The workshop proceedings provided valuable scientific and technical advice on Steller Sea Lion movements, distribution and abundance which supported the completion of this document.

STRATEGIC ENVIRONMENTAL ASSESSMENT

A strategic environmental assessment (SEA) is conducted on all SARA recovery planning documents, in accordance with the Cabinet Directive on the Environmental Assessment of Policy, Plan and Program Proposals. The purpose of a SEA is to incorporate environmental considerations into the development of public policies, plans, and program proposals to support environmentally sound decision-making.

Management planning is intended to benefit species at risk and biodiversity in general. However, it is recognized that management plans may also inadvertently lead to environmental effects beyond the intended benefits. The planning process based on national guidelines directly incorporates consideration of all environmental effects, with a particular focus on possible impacts on non-target species or habitats. The results of the SEA are incorporated directly into the management plan itself, but are also summarized below.

Through the development of this plan numerous factors that jeopardize or have potential to jeopardize the management of this population were evaluated and are presented. Principal among the anthropogenic factors or threats are competition with fisheries and chemical contaminants.  Environmental variability limiting prey availability is also of concern in terms of long-term impacts to population health.  In some cases these factors threaten the populations; in other cases they affect the designated habitat. It was concluded that some threats can be mitigated through the use of existing legislation, policies and programs and, in fact, there are numerous examples of mitigation measures that are currently employed. However, in other cases the threat and/or the potential mitigation measure(s) require further research or evaluation before recommendations on specific actions or activities can be formulated. The general type of research, evaluation and approaches for mitigation are presented in this management plan.

Through the course of implementing actions, specific activities for management, recovery and mitigation will be evaluated and detailed for these populations along with an evaluation of effects and costs for each activity or measure. Therefore, taking into account the general nature of the recommendations for new mitigation to manage this population and that many of the recommendations to protect habitat fall under existing legislation and policies, this plan will not entail any new significant adverse environmental effects.

EXECUTIVE SUMMARY

The Steller Sea Lion is the largest member of eared seals and a relatively long-lived and slow reproducing species. The scientific name (Eumetopias jubatus) means having a broad forehead and a mane, a reference to the prominent ruff of coarse hair that mature males develop on their necks and chests which resembles a lion’s mane.

All sea lions are remarkably agile on land due to their ability to rotate their hind flippers forward and prop themselves up on their foreflippers.  Steller Sea Lions can climb steep rocks and are often found many metres above the sea surface; they tend to be highly gregarious while on land and pack close together in dense breeding colonies (rookeries) or on non-breeding haulouts.  Steller Sea Lions typically haul out on a regular basis, they sometimes spend many days or several weeks at sea without coming ashore and can sleep in the water, usually in groups called rafts. 

This species is trans-boundary in its distribution and research and management are currently conducted by Canadian and U.S. governments, as well as private organizations and independent researchers.  There are four active breeding sites within British Columbia, one of which has recently been re-established after having been eradicated by predator control programs in the 1920s.  The Scott Islands rookery is now the second largest breeding aggregation in the world, and B.C. currently supports approximately 33% of the total Eastern Population of Steller Sea Lion.  Steller Sea Lions in B.C. are currently breeding at all known historic rookeries, and populations have grown well past known peak historic levels. 

Based on estimated pup production during the last range-wide survey in 2002, the total size of the Eastern Population is estimated to between 46,000 to 58,000 animals.  Abundance in Canadian waters was estimated to be 20,000-28,000 based on the most recent survey in 2006 (DFO 2008). During breeding season, the congregation of animals at the four Canadian breeding sites makes the B.C. population vulnerable to human disturbance and catastrophic events, which has the potential to affect a significant proportion of the population.

Limiting factors are the natural processes that limit population size or growth, whereas threats (both natural and anthropogenic) have caused, are causing, or may cause harm, death or behavioural changes to a species at risk or the destruction, degradation and/or impairment of its habitat to the extent that population-level effects occur.  Steller Sea Lions are limited by bottom-up processes that affect prey availability and accessibility, and by top-down processes that affect predation rates. The most significant threats identified for Steller Sea Lions are competition with fisheries, and environmental variability limiting prey availability.  Toxic spills and chronic chemical contamination are also of moderate concern for long-term impacts to population health.  Further research will assist in clarifying these threats.

Steller Sea Lions in Canada are listed under the Species at Risk Act as ‘special concern’ meaning they are considered a wildlife species that could become threatened or endangered because of a combination of biological characteristics and identified threats.  This management plan has two goals. First, to ensure that anthropogenic threats from Canadian sources do not cause unsustainable population declines, contraction of current range or number of breeding sites in Canada.  A second goal of this plan is to encourage support for, and contribution to an environment where research and monitoring of Steller Sea Lions in B.C. contributes to achieving an improved global knowledge of the Eastern Pacific Population.  Six high priority actions have been identified to address the threats of greatest concern (Table 3), and 20 ongoing actions beneficial to conservation and understanding of the species are also listed.  Six additional actions are listed to identify new efforts useful for management of the population.  Participation of interested parties in listed actions is encouraged and will contribute to implementation of this plan and conservation of this species in Canada.  Synchronization of activities recommended for protection, management and research will facilitate a multi-species approach to marine mammal conservation in B.C., and allow for effective use of available resources.

TABLE OF CONTENTS

LIST OF FIGURES

Figure 1. Worldwide range of the Steller Sea Lion.  Arrows denote breeding rookeries and shaded areas denote the approximate non-breeding range of the species.  The dashed line shows the separation between Asian, Eastern and Western stocks of Steller Sea Lions. (modified from Loughlin 1997 and Sease et al. 1999).
Figure 2. Geographic location of Steller Sea Lion rookeries (l), year-round haulout sites (¡) and major winter haulout sites (▲) in British Columbia. Also indicated is the major rookery on Forrester Island, Alaska.  Updated from Bigg (1985) (Olesiuk, DFO unpublished data).
Figure 3.  Historic trends in total numbers of Steller Sea Lions (pups, juveniles and adults) on breeding rookeries in B.C. (▲▬▲), Forrester Island, Alaska (●▬●), and other new rookeries in SE Alaska (■▬■).  The thin blue lines show the distribution of animals among main breeding areas in B.C. (modified from Bigg 1985 and Olesiuk et al. 2008).
Figure 4.  Total numbers of Steller Sea Lions reported to have been killed in B.C. as part of control programs and commercial harvests during 1913-70.  Data have been grouped and totalled into 5-year periods, and are colour-coded by major breeding area.  Comparison with Figure 3 shows the impact these kills had on populations.  (Data from Bigg 1984).
Figure 5. Recent trends in counts of Steller Sea Lion pups (○) and non-pups (●) on rookeries in a) southeast Alaska; b) British Columbia; and c) Oregon (updated from Pitcher et al. 2007).

LIST OF TABLES

Table 1.  Summary of Threat Classifications and Mitigation Potential for listed identified threats to the Eastern Pacific Steller Sea Lion population.  Mitigation potential refers to the likelihood that measures (future or existing) may mitigate or prevent negative effects to the population.  This assessment is a current view of the state of threats to the population, and as such assessment ratings may change over time. Asterisk (*) denotes naturally occurring threats to the population (i.e. limiting factors whose effects can be increased by human activities).
Table 2. The management actions outlined in this plan are to be carried out, where and when appropriate, in partnership with the following organizations.
Table 3. Proposed Implementation Schedule
Table 4. Details on Terms used for Assessment of Threats to the Eastern Pacific Steller Sea Lion Population.
Table 5.  Persistent Organic Pollutants that may pose a risk to Steller Sea Lions.  Table was obtained from the final Recovery Strategy for Resident Killer Whales in Canada (DFO 2008).

1. SPECIES INFORMATION

1.1. Species Assessment Information from COSEWIC

Date of Assessment: November 2003

Common Name (population): Steller Sea Lion
 
Scientific Name: Eumetopias jubatus

COSEWIC Status: Special Concern

Reason for Designation: There are only three1 breeding locations in British Columbia. Although the population is increasing, they are sensitive to human disturbance while on land. Threats include the possibility of acute oil spills. There are unexplained declines in other populations to the north and west of British Columbia.
 
Canadian Occurrence: British Columbia, Pacific Ocean

COSEWIC Status History: Designated Not at Risk in April 1987.  Status re-examined and designated special concern in November 2003.

1Since the 2003 COSEWIC designation, a fourth location has been re-classified as a breeding site.

1.2. Description and Biology

The Steller Sea Lion is the largest member of the eared seals, or sea lions and fur seals (Order Carnivora, Superfamily Pinnipedia, Family Otariidae; Rice 1998). Other common names used in Canada include Steller’s sea lion, northern sea lion and lion de mer de Steller.  Some First Nations names for sea lion include; tukuk or tukukw (tukwašt meaning dried sea lion) in Nuu-chah-nulth Barkley Sound dialects (BSDWG 2004), in Kwakiutl sea lion are referred to as tl’íx7en (Grubb 1977), and in the Haida language, kíit or kíidaay (Lawrence 1977).  The scientific name (Eumetopias jubatus) means having a broad forehead and a mane, a reference to the prominent ruff of coarse hair that mature males develop on their necks and chests, from which is also derived the name ‘lion’. 
Steller Sea Lions exhibit significant sexual dimorphism, with adult males (bulls) attaining a length of up to 3 m and weighing 400-800 kg, although at the start of the breeding season the largest males can weigh over 1,100 kg.  Mature males develop massive muscular necks and chests, and robust heads with flatter snouts than those of females.  Adult females (cows) are noticeably smaller, averaging 2.2 m and 200-300 kg (Mathisenet al.. 1962; Thorsteinson and Lensink 1962; Orr and Poulter 1967; Winshipet al.. 2001). 

When dry, the fur of adults and juveniles are pale yellow to light brown, darkening to chocolate brown on their hindquarters and near their flippers, which are black and bare-skinned.  Steller Sea Lions may appear greyish white when wet.  Steller Sea Lion fur is comprised of short coarse hairs, which is moulted annually between late June and early December, depending on the age class (Scheffer 1964).  Pups are born with a thick blackish-brown lanugo that is moulted between 3-6 months of age. 

All sea lions are remarkably agile on land due to their ability to rotate their hind flippers forward and prop themselves up on their foreflippers.  Steller Sea Lions can climb steep rocks and are often found many metres above the sea surface;  they tend to be highly gregarious while on land and generally pack close together in dense breeding colonies (rookeries) or non-breeding haulouts (Schusterman 1981; Loughlin et al. 1987).  Although Steller Sea Lions typically haul out on a regular basis, they sometimes spend many days or several weeks at sea without coming ashore (Olesiuk and Jeffries, unpublished data), and can sleep in the water, usually in groups called rafts. 

Breeding colonies (called rookeries) are used by sexually mature sea lions (along with a few dependent young with their mothers) during the summer months. Steller Sea Lions have a polygynous mating system, in which bulls compete to establish territories and gain access to females; the ratio of cows to territorial bulls is generally about 10-15:1 (Gisiner 1985; Merrick 1987).  Successful males will usually maintain their territory for an average of 40 days (range 20-68 days) without feeding (Gentry 1970).  Most territorial males are 9-13 years old (Thorsteinson and Lensink 1962) and may hold a territory for several years in succession (range 1-7 years) (Gisiner 1985). 

Females first ovulate at about 3-6 years of age.  Females begin returning to rookeries in late May and give birth to a single pup within a few days of their arrival; most pups are born by early July (Gentry 1970; Edie 1977; Bigg 1985).  Mothers nurse their pups on shore for about one week, before leaving on regular feeding trips that alternate one day at sea and one day on shore (Swain 1996).  By about four weeks of age, pups can swim in the open ocean and mothers start moving them to nearby haulouts.  Some pups continue to nurse into their third year, although most are weaned in their first or second years; some mothers may also nurse a newborn and yearling simultaneously (Sandegren 1970; Hood and Ono 1997; Milette and Trites 2003).

Use of breeding rookeries declines by late August and is at a minimum during January-April, although some animals continue to use them year-round as haulout sites (Bigg 1985).  Outside of the summer breeding season, Steller Sea Lions use year-round haulouts as well as winter-haulouts that may be considerable distances from rookeries.  Females with dependent young may stay at a single haulout or move their pups around between haulouts (Shusterman 1981; Loughlin et al. 1987).

1.3. Populations and Distribution

1.3.1. Global Range

Steller Sea Lions inhabit the cool-temperate and subarctic coastal waters of the North Pacific Ocean from the Channel Islands off southern California, north to the Bering Strait, and southwest along the Asian coast to Hokkaido, Japan (Fig. 1; Kenyon and Rice 1961; Loughlin et al. 1984; Loughlin et al. 1992).  They presently give birth on 61 rookeries and rest at >300 haulouts across this range.  Steller Sea Lions are non-migratory, but may disperse considerable distances from breeding sites (Fisher 1981; Calkins and Pitcher 1982; Loughlin 1997; Raum-Suryan et al. 2002). 

Worldwide, at least two populations of Steller Sea Lions are recognized based on genetic differentiation of mitochondrial DNA (which reflects maternal lineage): an Eastern Population (California to southeast Alaska) and a Western Population (Gulf of Alaska, Bering Sea, Aleutian Islands, and Russia) (Bickham et al. 1996).  Separation of the two populations in North America is further supported by a phylogeographic analysis that considers such ancillary information as population trends, distribution, movements, and morphology (York et al. 1996; Loughlin 1997).  However, recent genetic sampling indicates two newly established rookeries near the western edge of the Eastern Population may have been colonized by a mixture of Western and Eastern stock animals (O’Corry-Crowe et al. 2005).  Female Steller Sea Lions in Asian waters (Kamchatka Peninsula, Kuril Islands and Okhotsk Sea) appear to be genetically distinct from the other populations (Baker et al. 2005) but there is greater gene flow for males (Hoffman et al. 2006).  There is also some genetic evidence of geographic segregation among the shelf (Gulf of Alaska and Alaska Peninsula) and oceanic (Aleutian Islands) components of the western population (O’Corry-Crowe 2007).

Figure 1. Worldwide range of the Steller Sea Lion.  Arrows denote breeding rookeries and shaded areas denote the approximate non-breeding range of the species.  The dashed line shows the separation between Asian, Eastern and Western stocks of Steller Sea Lions. (modified from Loughlin 1997 and Sease et al. 1999).

Figure 1. Worldwide range of the Steller Sea Lion.  Arrows denote breeding rookeries and shaded areas denote the approximate non-breeding range of the species.  The dashed line shows the separation between Asian, Eastern and Western stocks of Steller Sea Lions. (modified from Loughlin 1997 and Sease et al. 1999).

1.3.2. Canadian Range

Within Canada, Steller Sea Lions occur only in British Columbia and constitute part of the Eastern Population (Bickham 2000).  There are four main breeding areas in B.C.: the Scott Islands off the northwest tip of Vancouver Island, with rookeries situated on Triangle Island and the small islets off Beresford and Sartine Islands; the second area at Cape St. James off the southern tip of the Queen Charlotte Islands, with rookeries situated on the Kerouard Islands; and a third area off Banks Island on the northern mainland coast, with rookeries situated on North Danger Rocks (Figure 2). 

Figure 2. Geographic location of Steller Sea Lion rookeries (), year-round haulout sites () and major winter haulout sites (▲) in British Columbia. Also indicated is the major rookery on Forrester Island, Alaska.  Updated from Bigg (1985) (DFO unpublished data).

Figure 2. Geographic location of Steller Sea Lion rookeries (•), year-round haulout sites (ο) and major winter haulout sites (▲) in British Columbia. Also indicated is the major rookery on Forrester Island, Alaska.  Updated from Bigg (1985) (DFO unpublished data). 

The fourth breeding area was historically located off the central mainland coast on the Sea Otter Group, with rookeries situated on Virgin, Pearl and possibly Watch Rocks, but this breeding aggregation was extirpated by intense predator control programs during the 1920s and 1930s and had subsequently been used as a haulout by non-breeding animals (Bigg 1985).  An increasing number of pups have been born on Virgin and Pearl Rocks in recent years and based on the 2006 abundance survey the site was reclassified as a rookery (Figure 2).  In addition to the four breeding sites, there are about twenty-three haulout sites distributed mainly along the exposed outer coast that are used continuously throughout the year, as well as numerous winter sites used on a seasonal or irregular basis.

The offshore distribution of Steller Sea Lions is not well defined.  In general, most Steller Sea Lions appear to feed within about 60 km of shore during summer, and can range over 200 km from shore in winter (Kenyon and Rice 1961; Merrick and Loughlin 1997).  They appear to feed over the continental shelf and along the shelf break (Kajimura and Loughlin 1988).  Steller Sea Lions captured in B.C. and fitted with satellite tags ranged widely along the B.C. coast, but rarely ventured more than 50 km from shore (Olesiuk and Jeffries, unpublished data). 

1.3.3. Global Population Trends

Between the late 1950s and 1970s, overall abundance of Steller Sea Lions in the North Pacific (range-wide: Japan to California) was believed to have been stable at about 250,000-300,000 individuals (Kenyon and Rice 1961; Loughlin et al. 1984).  Abundance subsequently declined to about 116,000 by 1989, 97,500 by 1994-95, and 95,000 by 1999-2002.

The drop in overall abundance of Steller Sea Lions was attributable to declines in the western part of their range.  Historically, the Western Population (Russia to Gulf of Alaska) was much larger than the Eastern Population (southeast (SE) Alaska to California), and accounted for roughly 90% of total abundance between the 1950s and 1970s (Kenyon and Rice 1961; Loughlin et al. 1984; Trites and Larkin 1996).  The decline appears to have begun in the eastern Aleutian Islands in the mid-1960s, and spread to the western Aleutian Islands and Gulf of Alaska in the late 1970s.  Numbers dropped precipitously during the 1980s, and continued at a much slower rate through the 1990s (York et al. 1996).  By 1999-2002, the Western Population was estimated to have numbered about 50,000 individuals (Burkanov 2000; Sease and Stinchcomb 2003), a decline of about 80% from levels present during the 1950s to 1970s.  The precipitous decline of the Western Population has made the Steller Sea Lion one of the most intensively studied marine mammals in the world (see NMFS 1992, 2008; Loughlin 1998; Hunter and Trites 2001; Dalton 2005).

Predator control programs in B.C., Washington, Oregon (Rowley 1929) and California (Pearson and Verts 1970) during most of the 20th century (1900 – 1970) resulted in the Eastern Population of Steller Sea Lions becoming severely depleted by the time the species was protected under the Fisheries Act in Canada in 1970 and under the Marine Mammal Protection Act in the U.S. in 1972. 

Steller Sea Lions were not known to breed in SE Alaska during the early 1900s and were not subjected to major control programs.  The first rookeries became established in SE Alaska during the 1930s or 40s when the intense killing had begun in southern parts of the range, and the species appears to have flourished in the 1950s and 60s even as breeding populations were reduced in B.C.  While predator control programs were underway, dispersal of breeding females from rookeries in B.C. may have contributed to the rapid expansion of new rookeries established in SE Alaska (Calkins et al. 1999; Pitcher et al. 2003, 2007), and dispersal patterns appear to have changed over time.  Forrester Island accounted for much of the growth until the early 1980s, but its growth rate has subsequently slowed, and newly established rookeries in central-northern SE Alaska as well as other rookeries in B.C. have accounted for much of the more recent growth (Pitcher et al. 2007).

In contrast to the Western Population, the Eastern Population has been growing in recent years (DFO 2008; Olesiuk unpublished data; Calkins et al. 1999; Pitcher et al. 2003, 2007).  In 2002, the Eastern Population was estimated to number about 46,000 – 58,000 individuals (Pitcher et al. 2007), compared with approximately 45,000 Steller Sea Lions in western Alaska (Angliss and Outlaw 2007) and 16,000 in Asia (Burkanov and Loughlin 2007). 

1.3.4. Canadian Population Trends

Historical counts of Steller Sea Lion rookeries in B.C. date back to the early 1900s, and provide an index of the size of the Canadian breeding population (Bigg 1984, 1985; DFO 2008).  It is estimated that about 14,000 animals (all ages, including pups) were present on rookeries in 1913-19 (Fig. 3), which was prior to any large-scale kills.  Steller Sea Lions in Canada and neighbouring waters were subjected to predator control programs during most of the 20th century. 

Prior to the species being protected in the 1970s, the Canadian government conducted intensive culls of Steller Sea Lions at rookeries, for the mandated purpose of protecting salmon fisheries (Figure 4).  Limited commercial harvests were also conducted for hides and for mink food.  Numbers on rookeries in B.C. had been reduced to 4,550 by 1961 and 3,390 animals (including 940 pups) by the time the first aerial survey was conducted in 1971.  Thus Steller Sea Lions in B.C. were depleted to about one-quarter of their historic size by predator control and commercial harvesting (Bigg 1985; DFO 2008).

Assessments of the abundance, distribution and status of Steller Sea Lions in B.C. were initiated in the 1970s and 1980s (Bigg 1984, 1985, 1988) and continue to the present day (DFO 2008; Olesiuk et al. unpublished data).  Province-wide aerial surveys have been conducted in B.C. at 4-5 year intervals since the species was protected under the Fisheries Act in 1970 from targeted harvest, or culling.  Surveys are conducted during a brief time window between late June and early July, representing the period by which most pups have been born, but most are still too young to have begun to disperse from rookeries (Bigg 1985; DFO 2008).

Figure 3.  Historic trends in total numbers of Steller Sea Lions (pups, juveniles and adults) on breeding rookeries in B.C. (▲▬▲), Forrester Island, Alaska (●▬●), and other new rookeries in SE Alaska (■▬■).  The thin blue lines show the distribution of animals among main breeding areas in B.C. (modified from Bigg 1985 and Olesiuk et al. 2008).

Figure 3.  Historic trends in total numbers of Steller Sea Lions (pups, juveniles and adults) on breeding rookeries in B.C. (▲▬▲), Forrester Island, Alaska (●▬●), and other new rookeries in SE Alaska (■▬■).  The thin blue lines show the distribution of animals among main breeding areas in B.C. (modified from Bigg 1985 and Olesiuk et al. 2008).

Figure 4.  Total numbers of Steller Sea Lions reported to have been killed in B.C. as part of control programs and commercial harvests during 1913-70.  Data have been grouped and totalled into 5-year periods, and are colour-coded by major breeding area.  Comparison with Figure 3 shows the impact these kills had on populations.  (Data from Bigg 1984).

Figure 4.  Total numbers of Steller Sea Lions reported to have been killed in B.C. as part of control programs and commercial harvests during 1913-70.  Data have been grouped and totalled into 5-year periods, and are colour-coded by major breeding area.  Comparison with Figure 3 shows the impact these kills had on populations.  (Data from Bigg 1984).

B.C. aerial surveys indicate that numbers of pups and non-pups on rookeries increased at a mean rate of 3.5% and 3.9% per annum respectively, which has resulted in a tripling in the size of the breeding population since the early 1970s (Figure 5) (DFO 2008).  Similar trends have been observed on neighbouring rookeries to the south in Oregon and to the north in SE Alaska (Figure 5), which combined constitute 90% of the Eastern Population (Brown and Reimer 1992; Calkins et al. 1999; Pitcher et al. 2007).  This indicates that the increase in Canada represented real population growth, and not merely a local shift in distribution (Pitcher et al. 2007). 
Based on estimated pup production during the last range-wide survey in 2002, the total size of the Eastern Population is estimated to be between 46,000 to 58,000 animals, with about one-third (33% of pups and 34% of non-pups) occurring in Canadian waters.  Abundance in Canadian waters was estimated to be 20,000-28,000 based on the most recent survey in 2006 (DFO 2008).

1.4. Requirements of the Steller Sea Lion

The needs of Steller Sea Lions can be partitioned between the time they spend on land when they come ashore to rest and reproduce, and the time they spend at sea where they travel and forage.  The species is gregarious while on land, and animals gather at traditional rookeries and haulout sites, some of which have been used for over a century.  Steller Sea Lions forage on a variety of prey items, primarily small or medium-sized schooling fish, and foraging habitat varies in relation to prey distribution and abundance.

1.4.1 Habitat and Biological Requirements

Terrestrial Habitat
The terrestrial sites used by Steller Sea Lions in British Columbia generally fall into three distinct categories: 1) rookeries where animals congregate during May-August to give birth, mate, and nurse pups; 2) year-round haulouts that are usually occupied continuously; and 3) winter haulout sites that are used less regularly, mainly during the non-breeding season (Bigg 1985).  Rookeries generally have peripheral haulout sites associated with them that are occupied mainly by non-breeding males and juveniles during the breeding season.  In most cases animals continue to use rookeries as haulout sites throughout the year, albeit in much reduced numbers.

Steller Sea Lions exhibit high site fidelity for breeding and birthing.  Studies of marked individuals indicate that most females tend to return to their rookeries of birth, and will return faithfully to a single rookery each year (Raum-Suryan et al. 2002).  The three main breeding colonies in B.C. were all well established when the first sea lion survey was conducted in 1970 (Newcombe and Newcombe 1914),  and  have been used continuously despite disturbances caused by predator control programs and commercial harvests (Pike and Maxwell 1958; Bigg 1985; Olesiuk unpublished data).  The fourth breeding site in the Sea Otter Group was eradicated by predator control programs, although sea lions continued to use the site as a non-breeding haulout.  Pupping has resumed at the site, and based on pup counts during the 2006 survey, the site was recently reclassified as a rookery.

Figure 5. Recent trends in counts of Steller Sea Lion pups (○) and non-pups (●) on rookeries in a) southeast Alaska; b) British Columbia; and c) Oregon (updated from Pitcher et al. 2007).

Figure 5. Recent trends in counts of Steller Sea Lion pups (○) and non-pups (●) on rookeries in a) southeast Alaska; b) British Columbia; and c) Oregon (updated from Pitcher et al. 2007).

Although Steller Sea Lions generally return to breed on their natal rookery, there may also be some exchange between neighbouring rookeries (Calkins and Pitcher 1982, 1996).  Of 31 females branded as pups on Forrester Island, several were observed to have given birth at other rookeries, including 400 km away at Cape St. James (Raum-Suryan and Pitcher 2000; Raum-Suryan et al. 2002). 

Terrestrial habitats for Steller Sea Lions comprise some of the most isolated, barren outcroppings in the North Pacific Ocean.  Haulouts are typically located in regions that have relatively high currents, high salinity, low surface temperatures and shallow waters, presumably reflecting high ocean productivity and hence optimum feeding areas (Ban et al., unpublished data).  Essential haulout features seem to include relatively flat terrain, accessibility, protection from swell and waves, and absence of terrestrial predators such as bears and wolves (Edie 1977).  Sea lions use protected areas during storms, and wet areas during extremely hot weather (Edie 1977).  Access to high ground is also important for whelping, although older animals that are capable of going to sea will use lower and more exposed areas.  Rocky ledges are preferred breeding substrate in B.C. rookeries, although increasing numbers of animals have recently begun breeding on the gravel beaches along the eastern (leeward) side of Triangle Island (Olesiuk, unpublished data).

The twenty-three year-round haulout sites in B.C. are generally situated in exposed areas along the outer coast, and are comprised of rocky islets and ledges.  Approximately half of the sites were noted to exist during the first surveys in 1913 (Newcombe and Newcombe 1914), while about one-quarter appear to have been colonized since aerial surveys were initiated in the early 1970s.  Year-round haulout sites are widely distributed in B.C., and provide sea lions with habitat for resting all along the outer coast.  Steller Sea Lions can also rest in the water during storms or heavy swells when haulouts are awash, or when they are near concentrations of prey without suitable nearby haulouts; this rafting behaviour often occurs in groups (Kenyon and Rice 1961; Olesiuk and Bigg 1988). 

Many winter haulouts are situated in protected areas, such as the Strait of Georgia, Strait of Juan de Fuca and Queen Charlotte Strait.  In addition to natural substrates, wintering haulouts include log booms, floats, jetties and docks.  In southern B.C., winter haulouts are often shared with subadult and adult male California sea lions (Zalophus californianus) (Hancock 1970; Brenton 1977; Bigg 1985).

Prey Requirements and Marine Habitat

Over 50 species of fish and invertebrates have been identified in the diets of Steller Sea Lions (Wilke and Kenyon 1952; Pike 1958; Spalding 1964; Pitcher 1981; Kastelein et al. 1990; Sinclair and Zeppelin 2002).  In British Columbia, preferred prey appears to include small or medium-sized schooling fishes, such as herring, hake, sandlance, salmon, dogfish, Eulachon and sardines, and bottom fish such as rockfish, flounder and skate (Pike 1958; Spalding 1964; Olesiuk and Bigg 1988, Trites and Olesiuk, unpublished data).  In addition to fish, squid and octopus are sometimes consumed, but their importance was likely exaggerated in earlier studies because cephalopod beaks likely accumulate in stomachs over extended periods (Bigg and Fawcett 1985).  Crabs, mussels, clams and other invertebrates are occasionally recovered in stomachs and scats, but these may represent secondary prey that had been consumed by the prey species eaten by sea lions.  Steller Sea Lions have also been observed to prey on gulls (O'Daniel and Schneeweis 1992) and other pinnipeds, including neonate fur seals (Gentry and Johnson 1981) and harbour seals (Pitcher and Fay 1982, E. Mathews, University of Alaska, Juneau AK, pers. comm.).  Predation on other pinnipeds seems quite uncommon, but may be locally significant.

Prey requirements of Steller Sea Lions vary seasonally and with age and sex, and depend on the type and quality of prey (Perez 1994; Rosen and Trites 1999, 2000b,c).  Bioenergetic models predict that daily food requirements for Steller Sea Lions in the wild are approximately 15-20 kg for mature females and 30-35 kg for mature males (Winship et al. 2002).  For females, these daily energy requirements represent about 14% of body weight for a 1 year old and 7% for a mature individual.  Mean consumption in the SE Alaska population was estimated at 17 kg per individual per day (Winship and Trites 2003).  Sea lions that consume more low fat fishes such as gadids require significantly more prey than those that consume fattier fishes such as herring (Trites and Donnelly 2003; Winship and Trites 2003).

There is relatively poor understanding of how Steller Sea Lions use their aquatic habitat  At sea, Steller Sea Lions are commonly seen alone, or in groups of several animals (Bonnell et al. 1983).  Animals feeding on small schooling fishes appear to feed co-operatively in groups of up to 100 animals that dive and surface in synchrony (Fiscus and Baines 1966; Loughlin et al. 1983; Loughlin and DeLong 1983; P. Olesiuk, Fisheries and Oceans Canada – Pacific Region, Science, pers. comm.).  Foraging appears to occur primarily at night based on satellite telemetry (Loughlin et al. 1998; Loughlin et al. 2003) and diurnal haul out patterns (Withrow 1982; Higgins 1984; Milette 1999), but can vary seasonally depending on the type of prey consumed (Olesiuk and Jeffries, unpublished data).  Steller Sea Lions can dive to depths of at least 310 m (Andrews 1999) and stay submerged for over 8 minutes (Swain and Calkins 1997), with most dives in the range of 15-50 m and lasting 1.5-2.5 min (Merrick and Loughlin 1997; Swain and Calkins 1997; Loughlin et al. 1998; Andrews 1999; Swain 1999). 

Animals are generally observed within 60 km of land and in water depths less than 400 m, but may venture several hundred kilometres offshore and occur off the continental shelf (Kenyon and Rice 1961; Merrick and Loughlin 1997).  Telemetry and branding studies have shown that animals are highly mobile, and may travel hundreds of kilometres and utilize numerous haulout sites over the course of a few weeks or months (Merrick and Loughlin 1997; Loughlin et al. 1997, 2003; Raum-Suryan et al. 2002).  Steller Sea Lions captured and tagged in B.C. have been subsequently tracked up to 1,700 km, ranging north to Alaska or south to California (Calkins 1981; Fisher 1981; Loughlin, pers. comm.; Olesiuk, unpublished data).  Steller Sea Lions also occasionally venture into freshwater (Jameson and Kenyon 1977; Roffe and Mate 1984; Beachet al. 1985).  In B.C., sea lions are occasionally seen rafting as far as 35 km upriver (Olesiuk, unpublished data).  Steller Sea Lions also congregate in estuaries during autumn to feed on pre-spawning salmon and at the mouth of the Fraser River in spring when Eulachon are running (Bigg 1985; Bigg et al. 1990, Olesiuk unpublished data).  Major wintering areas of sea lions off southern Vancouver Island have shifted, presumably in relation to changes in distribution of pre-spawning herring (P. Olesiuk, pers. comm.).

Foraging trips tend to be more localized during the summer breeding season (<20 km) than during other times of the year (60-160 km).  (Bonnell et al. 1983; Merrick and Loughlin 1997).  In summer, reproductive females are confined to foraging within commuting distance of rookeries, as they must regularly return to attend pups.  In contrast, non-breeding animals during summer and all animals during the non-breeding season (September-May) are more flexible and movements are likely related to the availability of forage fish.  Foraging ranges of immature non-breeding animals appear intermediate to the summer and winter foraging ranges of adults (Merrick and Loughlin 1997). 

1.4.2. Ecological Role

The Steller Sea Lion is the largest species of otariid and the only one that resides and breeds year-round in Canadian waters.  The species occupies a niche intermediate to the inshore distribution of harbour seals (Phoca vitulina) that generally occupy more protected waters, and the pelagic distribution of northern fur seals (Callorhinus ursinus) that generally occur over the continental shelf and along the shelf break.  The role of seals and sea lions in complex marine ecosystems remains poorly understood and studies are required to assess the contribution of the Steller Sea Lion in large and complex ecosystems (Beverton 1985; Bowen 1997; Merrick 1997; Trites 1997). 

Due to the recent declines in Alaska, the British Columbia rookeries at the Scott Islands and Cape St. James now represent the second and sixth largest breeding aggregations in the world.  Based on overall pup production in 2002, B.C. supports about 16% of the world’s population and about 33% of the Eastern stock (another 31% occurs in southeast Alaska within 50 km of the Canadian border). Steller Sea Lions are widely perceived to be an important component of the coastal marine ecosystem, and contribute to the eco-tourism industry.

Steller Sea Lions are top marine predators.  In SE Alaska, Steller Sea Lions are estimated to consume about 140 million kg of fish annually (Winship and Trites 2003); assuming a similar diet, the B.C. population would consume another 110 million kg annually.  In comparison, the total annual commercial fish landing in B.C. has averaged about 185 million kg over the last decade (DFO 2007).  Basic knowledge of seasonal and regional feeding habits of sea lions in B.C. are still lacking, and much of the information that does exist has been collected anecdotally as part of other studies.  As Steller Sea Lions recover from predator control programs and harvests, it is likely that prey resources will ultimately limit sea lion populations, but it remains unclear to what extent sea lions themselves might limit their prey populations. 

Steller Sea Lions also compete with other marine predators, including other species of pinnipeds, whales, seabirds, sharks and flatfish (Livingston 1991; Tamura and Ohsumi 2000; Wespestad et al. 2000; NMFS 2001; Gallucci et al. 2006).  Over the last century, competition with California sea lions (Zalophus californianus) has increased dramatically (Lowry and Maravilla-Chavez 2005), which could adversely affect Steller Sea Lions.  California sea lions appear to have displaced Steller Sea Lions from traditional rookeries in the Channel Islands off California, and have extended their non-breeding range north into B.C. (Bigg 1988; P. Olesiuk pers. comm.) and occasionally as far as Alaska (Maniscalco et al. 2004).  California sea lions migrating along the coast of Oregon appear to displace Steller Sea Lions (Mate 1975); the two species often share the same winter haulout sites (P. Olesiuk pers. comm.) and consume the same prey species (Olesiuk and Bigg 1988). 

Steller Sea Lions are an important prey species for Transient Killer Whales (also called transients), (Morton 1990; Baird and Dill 1995; Ford et al. 1998; Matkin et al. 2007; Wade et al. 2007), which may selectively prey on pups and juveniles (Barrett-Lennard et al. 1995).  Transient Killer Whales are listed under the Species at Risk Act [SARA] as threatened, and could be vulnerable to fluctuations in their prey species.  In B.C. and adjacent waters, Steller Sea Lions were found to be the second most important prey for transients (Ford et al. 1998), and a survey of the entire northeast Pacific Ocean reported Steller Sea Lions to be the sixth most commonly observed prey of these whales (Wade et al. 2007).  Large sharks may also prey on Steller Sea Lions in the southern part of their range (Stroud 1978; Ainley et al. 1981) and sleeper sharks are a potential sea lion predator in Alaska (Sigler et al. 2006). 

Steller Sea Lions may have the potential for serving as an indicator of the general status of coastal marine ecosystems.  The species is widely distributed in coastal waters, has a long life­span, congregates on rookeries where breeding populations can be readily censused, and occupies a position near the top of the marine food chain.  The recent declines in the Western Population of Steller Sea Lions in Alaska are now widely believed to be associated with broader ecosystem processes that are not well understood; this demonstrates that the ability to monitor Steller Sea Lion populations far exceeds our under­standing of the complex ecological processes that regulate these apex predators.  As populations in B.C. and neighbouring waters have now recovered past historic high levels, natural population regulatory mechanisms might become a factor governing the status of Steller Sea Lion populations.

1.4.3. Limiting Factors

Limiting factors are the natural processes that limit population size or growth.  Steller Sea Lions are inherently a relatively long-lived and slow-reproducing species.  The maximum productivity level has not been determined for this species, but it is likely low.  For U.S. stock assessments, a theoretical maximum growth rate of 12% is generally assumed for pinnipeds.  While this may be appropriate for phocids (e.g. Olesiuk et al. 1990; Olesiuk 1999; Bowen et al. 2003), otariids generally exhibit lower survival rates, and expanding populations have not attained that level of productivity.  For instance, severely depleted populations of California sea lions sustained exponential growth rates of only about 6.1% (Lowry and Maravilla-Chavez 2005) and northern fur seals about 8.6% per year (York, pers. comm. cited in Angliss and Outlaw 2007).  Recovering Steller Sea Lion populations along the west coast of North America have sustained growth recovery rates of only about 3.1% per annum and have exhibited no signs of density dependence as populations increased, but it is not known whether this represents the maximum intrinsic rate of increase for the species or whether some stressor has been inhibiting recovery throughout this region for the past 40 years (Pitcher et al. 2007).  Regardless, the productivity of Steller Sea Lions is probably lower than other pinnipeds, making it less resilient to perturbations and stresses, taking longer to recover from such impacts. 

The low productivity of Steller Sea Lions can be attributed to a combination of low reproductive potential and high mortality.  Most otariids, including California sea lions and northern fur seals, wean their young at a few months of age, and tend to reproduce annually.  In contrast, Steller Sea Lions often continue to nurse their young into the second or third year (Pitcher et al. 2003).  Since lactating females are less likely to carry fetuses to term, the extended period of parental care typically results in longer intervals between consecutive births and overall reduced reproductive performance (Pitcher et al. 1998). 

Mortality of newborn pups (< 1 month) is high (Pike and Maxwell 1958; Orr and Poulter 1967).  Juvenile mortality is difficult to estimate due to potential sampling biases, but appears to be high, with about 48% of females and 26% of males surviving to three years of age (Calkins and Pitcher 1982; York 1994).  The higher mortality rates for males’ results in a progressively skewed sex ratio favouring females.  Mortality rates are significantly lower for adults (~10-15% per year for females, and ~13-25% for males).  The principle cause of death for pups is drowning due to limited swimming abilities at this age preventing them from hauling out of the water or steering in strong tidal currents (Orr and Poulter 1967; Edie 1977).   Being bitten, tossed or trampled by older animals, and being abandoned or separated from their mothers also contributes to pup mortality (Orr and Poulter 1967; Gentry 1970; Sandegren 1970; Sandegren 1976).  In marine mammals, density dependence is generally thought to be expressed primarily in the parameters that affect reproductive rates, especially of younger animals (i.e., age at first reproduction, fecundity rates, and juvenile survival) (Eberhardt 1985; Fowler 1987).  Juvenile mortality has been implicated as the main driver in the steep declines of the Western Population in the 1980s (York 1994), with reduced adult female natality and survival playing a lesser role (Holmes and York 2003).  The slower decline in the 1990s may be attributable to improved juvenile and adult survival, although natality rates appear to have continued to drop (Holmes and York 2003).  The ratio of pups to non-pups provides an index of relative birth and survival rates.  The surprisingly high ratio of non-pups to pups observed in surveys along the west coast of North America suggests that increased juvenile survival (as opposed to increased natality rates) may have been an important factor influencing growth of the Eastern Population (Pitcher et al. 2007).
The factors that ultimately limit Steller Sea Lions and other marine predators can be broadly categorized as bottom-up processes mediated by the availability and quality of prey, and top-down processes mediated by predators (including direct kills by humans). 

Prey Availability and Quality

Steller Sea Lion populations are ultimately limited by the availability of suitable prey.  A shift in the quality of diets from fatty fishes (i.e. herring) to low-fat fishes (i.e. walleye pollock) has been implicated in the decline of Steller Sea Lions in the Gulf of Alaska and Aleutian Islands (Alverson 1992; Alaska Sea Grant 1993; DeMaster and Atkinson 2002; Trites and Donnelly 2003).  Controlled-feeding studies have shown that sea lions, particularly young animals, consuming large amounts of low-fat prey such as pollock, may be unable to maintain body mass (Rosen and Trites 2000c; Azana 2002). In the wild, these young animals would typically still be dependent on their mothers, who may have difficulty meeting the high energetic costs associated with lactation (Winship et al. 2002; Pitcher et al. 2003).  Therefore, availability of high quality prey near rookeries appears to be a potentially important limiting factor. 

Diversity of the diet has been shown to be inversely correlated with the severity of declines of the Western Population in the Gulf of Alaska, with the steepest declines occurring in areas with the least diverse diet (Merrick et al. 1997).  Diversity of the diet in the increasing Eastern Population appears to be high (Trites et al. unpublished data).  Reduced rates of body growth (Calkins et al. 1998), and a direct correlation between body condition and the proportion of animals maintaining late-term pregnancies (Pitcher et al. 1998) provides further evidence of nutritional stress during the steep declines in the Western Population observed during the 1980s (NMFS 2008). 

The acute impacts that reduced prey availability can have on pinnipeds is evident from the abrupt declines in California sea lion and northern fur seal pup production on San Miguel Island coinciding with El Niño events (DeLong and Antonelis 1991; Melin and DeLong 1994; Melin et al. 1996; Melin and DeLong 2000). 

Steller Sea Lions also consume many of the same prey resources sought by other predators, including humans (McAlister and Perez 1976; Kajimura and Loughlin 1988; Fritz et al. 1995; Wada 1998; Trites et al. 1999); selective-fishing by humans can cause changes in fish stocks (Pauly et al. 1998).

Predation

The question as to whether top-down forcing as a result of predation by Transient Killer Whales could also limit sea lion populations has garnered much attention in recent years.   In 1992, a killer whale stranded in Prince William Alaska had 14 flipper tags from Steller Sea Lion pups in its stomach.  While data on predation rates are lacking, simulation models have shown that Transient Killer Whales could potentially have a significant impact on Steller Sea Lion populations, and in particular could inhibit the recovery of depleted populations (Barrett-Lennard et al. 1995). 

Maniscalco et al. (2007) estimated that killer whales consumed 3-7% of the Steller Sea Lion population in Kenai Fjords annually, and 11% of pups born at their main study site on Chiswell Island, which could be significant for a species with such an inherently low rate of productivity.  Preliminary calculations indicate that even if killer whale predation accounted for all natural mortality, the net annual production of Steller Sea Lion populations in B.C. and the entire Eastern Population could only support roughly 26 and 77 killer whales respectively (Olesiuk, unpublished data).

1.5. Threats

There are several threats which may affect this population in British Columbia.  Threats (both natural and anthropogenic) have caused, or are causing, or may cause harm, death or behavioural changes to a species at risk or the destruction, degradation and/or impairment of its habitat to the extent that population-level effects occur.   

The effects of threats are often difficult to distinguish from one another, or from natural limiting factors.  For example, exposure to contaminants may render animals more susceptible to natural diseases, and disturbance of sea lions at haulout sites and rookeries may displace them into the water, making them more vulnerable to predation by killer whales.  In addition, because animals concentrate at a limited number of breeding sites, they may be more vulnerable to both catastrophic accidents, or localized threats affecting early survival (e.g. localized prey depletion from fishing or disturbance).

Section 1.5.1 provides a tabular summary of the risk assessment rating threats in terms of population-level impacts to Steller Sea Lions.  The ‘current level of concern’ and ‘mitigation potential’ for each threat is identified (Table 1).  These assessments allow for prioritisation of recommended management and other actions to prevent this population from becoming threatened or endangered, and provide an indication of the mitigation feasibility for a threat.  Definitions of the terms used for rankings are available in Appendix I (Table 4).

Section 1.5.2 provides detailed descriptions of twelve historic, current and potential threats to the Steller Sea Lion population in B.C., as well as the uncertainties surrounding population level effects.  This text provides the background information used to determine the overall level of concern for the impact of each threat to the Eastern Population (Table 1). 

Although there is considerable uncertainty regarding the total impact of threats on Steller Sea Lions in Canadian waters, the continued growth of the local Steller Sea Lion population suggests it is currently within sustainable limits.  However, with a population growth rate of about 4.5% per annum, a relatively small increase in human-induced mortality could become an important factor if conditions for Steller Sea Lions deteriorate, or if combined with other threats. 

1.5.1. Threat Classification

Threats were assessed based on their current likelihood of occurrence and severity of impact on the B.C. population.  In addition, the certainty of an effect on the B.C. population was incorporated into the assessment to provide a measure of confidence in the rating of current ‘level of concern’ and to provide an indication of areas where further monitoring or study may be useful in addressing uncertainties or knowledge gaps. Where certainty of effect on the population is not demonstrated, weight of scientific evidence for other pinnipeds or marine mammals may be deemed adequate to contribute to the assessment of the level of concern for a threat. 

The mitigation potential column (Table 1) refers to the likelihood that measures (future or existing) will adequately mitigate or prevent negative effects to the population. It should be noted that the current level of concern column reflects the concern for impacts from a threat at this time, and future assessments may result in levels of concern that differ from those presented here.  Therefore, the importance of long-term monitoring of the population cannot be overstated.

Table 1.  Summary of Threat Classifications and Mitigation Potential for listed identified threats to the Eastern Pacific Steller Sea Lion population.  Mitigation potential refers to the likelihood that measures (future or existing) may mitigate or prevent negative effects to the population.  This assessment is a current view of the state of threats to the population, and as such assessment ratings may change over time. Asterisk (*) denotes naturally occurring threats to the population (i.e. limiting factors whose effects can be increased by human activities).

ThreatMost vulnerable age classLimiting factors which are likely to be affectedSeverity of population-level impactUncertainty
of Effect
Current Level of ConcernMitigation Potential
  Juveniles
Reproductive Females
Prey availability
Direct impact: Survival
Chronic prey limitation may result in decreased reproductive rates
Potentially HighMediumModerate,
potentially High
High
 Juveniles
Reproductive Females
Prey availability
Potential for altered distribution Occurrence of natural diseases
Direct impact: Survival
Chronic prey limitation may result in decreased reproductive rates
Potentially HighMediumModerate,
potentially High
None, if due to natural fluctuation
Low, if due to anthropogenic effects on climate
Environmental contaminantsUn-regulated Persistent Organic Pollutants (POPs) 
e.g. PBDEs

Pups, Adult
Females

 

Prey quality
Increased susceptibility to disease
Impaired reproductive rates
ModerateMedium-HighModerateLow-Medium
Regulated POPs
e.g. DDT

Pups, Adult
Females

 

Prey quality
Increased susceptibility  to disease
Impaired reproductive rates
ModerateMedium-HighLow - ModerateLow -Medium
DisturbancePhysical disturbance when on terrestrial habitatPups on rookeriesPup survival
Territorial and breeding behaviours
Low, at haulouts
Moderate, at rookeries
Medium-HighLow -ModerateHigh
Acoustic disturbance when in aquatic habitatAllHabitat use (i.e. displacement from feeding areas)
Foraging success
Chronic prey limitation may result in decreased reproductive rates
Likely LowMediumLowHigh
Toxic SpillsPups
Adult
Females, at rookeries during breeding season
Habitat use
Direct impact: Survival
Low
Moderate for Scott Island and Cape St. James rookeries
Medium-HighLow -ModerateLow-Medium
Incidental take - fisheries and aquacultureUnknownDirect impact: SurvivalLowHighLowMedium
Entanglement in marine debrisJuveniles and Sub-adultsForaging success
Direct impact: Survival
Low, potentially severe effects on individual animalsMedium LowMedium
Illegal killsJuveniles and AdultsDirect impact: SurvivalUnknownHighLowMedium
Predation by Killer Whales*Pups, Juveniles and
Adults
Direct impact: SurvivalPotentially HighMediumLowNone
Predator control programsHistorically affected all age classes
Currently not applicable
Direct impact: SurvivalHistorically High
Currently Low
LowHistorically High
Currently Negligible
High
First Nations harvestAllDirect impact: SurvivalLowHighNegligibleHigh
Disease and Parasitism*AllEffects can be enhanced by synergistic effects of threats
Direct impact: Survival
Reduced reproductive rates
UnknownMedium-HighUnknownLow

1.5.2. Description of Threats

Prey Reduction - Fisheries Competition
Steller Sea Lions consume many of the same prey resources exploited by other predators, including humans (McAlister and Perez 1976; Kajimura and Loughlin 1988; Fritz et al. 1995; Wada 1998; Trites et al. 1999).  Commercial harvesting can deplete local abundance and availability of prey (Lowe and Fritz 1997; Fritz and Brown 2005), and harvesting surplus production on a continual basis could affect resilience and amplify the effects of natural prey fluctuations.   Because nursing females are restricted to foraging within commuting distance of rookeries during the first few months after giving birth, prey availability around rookeries may be critical in ensuring successful early survival of pups and their nursing mothers.

It is now widely acknowledged that the decline of the Western Population of Steller Sea Lions was, to at least some extent, driven by a change in diet resulting in reduced body growth, birth rates and ultimately survival (Calkins and Goodwin 1988; Calkins et al. 1998; Pitcher et al. 1998; see review by Trites and Donnelly 2003).  However, debate continues over the relative influence of fluctuations in environmental conditions and regime shifts that may be the result of global warming, as well as the effects of whaling and commercial fisheries (Pascual and Adkinson 1994; Fritz and Ferrero 1998; Pauly et al. 1998; Trites et al. 1999; Rosen and Trites 2000a; Shima et al. 2000; Benson and Trites 2002; Fritz and Hinkley 2005; Trites et al. 2006; Trites et al. 2007). For additional, prey information see “Environmental Change and Variability’.

There are several commercial fisheries that target important known summertime prey species of Steller Sea Lions in British Columbia: sardine, herring, hake, salmon and groundfish.  All are currently managed to prescribed catch levels, which are believed to be sustainable.  Steller Sea Lion are known to feed on a variety of prey species, and it is not known whether limitations in one prey species alone may limit population growth.  Overall prey availability and regional species composition may be altered by natural or anthropogenic factors, and fisheries management will need to balance the needs of a continually growing Steller Sea Lion population with that of fisheries. The non-summer diet of Steller Sea Lions is poorly understood, and as information becomes available, additional species may be identified as important components of the year-round diet of Steller Sea Lions in B.C. 

The potential for mitigation of this threat is high (Table 1) as fisheries extractions may be managed directly through Fisheries and Oceans Canada.  However, as Steller Sea Lions and their prey are trans-boundary species, adequate mitigation may require additional collaboration and cooperation with U.S. fisheries management.

Given the unrestrained, exponential growth of the Steller Sea Lion population during the last 45 years, competition for prey with commercial fisheries does not appear to have had an effect on the population, leaving moderate concern for impacts.  Reduced availability of a high quality prey supply has had a demonstrated negative effect on Steller Sea Lion in the Western Population (Calkins and Goodwin 1988; Calkins et al. 1998; Pitcher et al. 1998; see review by Trites and Donnelly 2003), and prey requirements will continue to  increase as the Eastern population continues to grow.  Therefore, there is some concern for potential population-level impacts in the future (Table 1).  This illustrates the importance of continued monitoring of fisheries, ocean conditions, and the clarification of seasonal prey requirements to forecast any increase in competition with fisheries for prey resources.  All of this may assist in development and application of appropriate management measures. 

Prey Reduction - Environmental Change and Variability
The degree of natural ecosystem change (which often occurs in discrete steps termed ‘regime shifts’) is dependent on a number of factors, many of which are poorly understood and the causes of which are not always apparent.  While regime shifts may be forced by global climate change affecting oceanographic processes (e.g. changes in ocean temperatures, or species distribution), shifts may also occur through processes such as decadal oscillations or El Niño events.  Fishing can also cause changes in fish stocks and functioning of marine food webs (Pauly et al. 1998).

As mentioned in ‘Limiting Factors’, climate change and large-scale regime shifts can affect biota throughout the North Pacific (Sinclair et al. 1994; Beamish and Bouillon 1993; Sinclair et al. 1996; Anderson et al. 1997; Anderson and Piatt 1999; Hare et al. 1999; McFarlane et al. 2000; Benson and Trites 2002), and such changes may affect Steller Sea Lion prey distribution within B.C. and range-wide (NMFS 2008).  Increases in ocean temperatures resulting from global climate change might be expected to shift the distribution of Steller Sea Lions northward (NMFS 2008), and indeed the species has been disappearing from the southernmost part of their breeding range on both the North American and Asian coasts (Pitcher et al. 2007; Burkanov and Loughlin 2007).  The centre of distribution of the breeding population on the west coast of North America has shifted northward from the Columbia River (46.0ºN) in the 1920s to central B.C. (51.5ºN) by 2002 (Pitcher et al. 2007).

The acute impacts that reduced prey availability can have on pinnipeds is evident from the abrupt declines in California sea lion and northern fur seal pup production on San Miguel Island coinciding with El Niño events (DeLong and Antonelis 1991; Melin and DeLong 1994; Melin et al. 1996; Melin and DeLong 2000).  A regime shift that alters prey abundance from a high to low energy prey species (e.g. herring to gadids) may affect sea lion vital life history parameters (Trenberth 1990; Springer 1998; Benson and Trites 2002; Trites et al. 2007), resulting in population decline.

Currently, the Steller Sea Lion population in B.C. has exceeded historic peak abundance levels.  As populations continue to grow, and prey requirements increase, Steller Sea Lions may become more susceptible to prey shortages.  The concern for impacts on population viability from regime shift or climate change is moderate.  However, should extreme ecosystem changes occur that result in decreased prey availability, there may be high concerns for population level effects.  The high uncertainty regarding occurrence and effects of single regime shift events, or the effects of chronic long-term alterations in ocean conditions (i.e. through global climate changes) indicates that monitoring of the population is prudent.  Clarification of seasonally important prey may assist in forecasting impacts to occurrence and distribution of prey species resulting from regime shift.

Environmental Contaminants – Persistent Organic Pollutants
Persistent environmental contaminants such as organochlorine pesticides (e.g. DDT), polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polybrominated diphenyl ethers (PBDEs) bioaccumulate in marine food chains.  The magnification of such chemicals with increasing position in the food web predisposes many marine mammals to becoming highly contaminated.
In some cases, levels of persistent environmental contaminants have been associated with adverse health effects in free-ranging pinnipeds. Field studies suggest linkages between contaminant levels and reproductive impairment (Helle 1976a,b; Addison 1989), premature births (DeLong et al. 1973; Gilmartin et al. 1976; Martin et al. 1976), birth defects (Arndt 1973), skeletal deformities (Bergman et al. 1992), suppression of the immune response (Mos et al., 2006) and disruption of vitamin A and thyroid hormone physiology (Tabuchi et al. 2006, Mos et al. 2007). Captive feeding studies of harbour seals have also demonstrated deleterious effects of persistent contaminants on the reproductive, immune and endocrine systems (Brouwer et al.. 1989; de Swart et al.. 1994; Ross et al. 1995; Reijnders et al. 1986; Ross et al. 1996) .  Results in many of these studies are consistent with the pattern of effects in PCB- or dioxin-exposed laboratory animals (Ross et al. 1997; Ross 2000).

Nursing pups are exposed to particularly high levels of contaminants because fat-soluble chemicals such as PCBs are readily transferred through their mothers’ lipid-rich milk (Hickie et al. 2005).  While most persistent contaminants are not likely to cause acute toxicity, they are considered to be endocrine disrupting compounds (‘hormone mimics’; Colborn et al. 1993). As such, they may alter the normal growth and development of exposed animals. In addition, effects may not be notable until a stressful co-factor is implicated, such as a fasting period or period of food shortage which may increase the mobilization of fat-soluble chemicals or add to the stress upon the immune system (Jepson et al. 2005). An additional example might be the introduction of a new virus to a naïve pinniped population, in which contaminant-associated toxicity may cause an increase in vulnerability, virus transmission, disease severity and/or mortality (Ross 2002).

As has been shown in other marine mammals, contaminant concentrations in Steller Sea Lions (predominantly organochlorines) are linked to age and gender.  The highest concentrations are found in old males, while females transfer much of their burden to their pups during lactation (Lee et al. 1996).  Barron et al. (2003) found that PCB levels in Steller Sea Lions appeared to be declining in the Gulf of Alaska in recent years and that current levels are not a threat, but concentrations of PCB in the 1980s were higher in Steller Sea Lions than in any other pinniped and could have posed a health risk. 

In B.C., there have been few systematic studies of contaminant levels in Steller Sea Lions, although studies have recently been initiated to evaluate PCBs and PBDEs. PCB, dioxins, furans and organochlorine pesticides are considered to be regulated, ‘legacy’ contaminants as a result of national and international restrictions on their use, production and/or by-production. However, many new, unregulated chemicals are considered as ‘emerging’ concerns. These include the flame retardant PBDEs, which are doubling every four years in the environment (Hites 2004; Ross 2006).  Because PBDEs resemble PCBs, it is likely that PBDEs will be increasingly recognized as a threat to the health of wildlife, including Steller Sea Lions. 

This weight of evidence regarding effects and persistence of regulated and unregulated pollutants on Steller Sea Lions leaves concern for effects to the population viability. As the environmental presence and overall usage of emerging, unregulated persistent organic pollutants (POPs) is increasing, the level of concern for this threat is moderate1, while concern for regulated, legacy contaminants is deemed low to moderate (Table 1).  However, one might expect the population to be more susceptible during periods of prey limitation and nutritional stress, when lipids with their high concentrations of contaminants are mobilized.  As uncertainties on the level of toxic loading in Steller Sea Lions in B.C. remain, monitoring of this threat and mitigation of sources of pollution are recommended. 

Though point sources of contamination can be regulated and monitored, potential to implement mitigation measures for this threat is rated low-medium, due to the difficulty in mitigating or managing non-point sources and long-range airborne transport of contaminants.  Additionally, sources of contamination that originate in Canada may be mitigated, whereas for contamination that may originate in international waters, the mitigation potential is very low from a Canadian management perspective. 

Disturbance on and around Terrestrial Habitat
Repeated disturbances of breeding or haulout sites by aircraft, boats, pedestrians, construction, or fishing activities (e.g. geoduck and urchin dive fisheries) can lead to animals temporarily leaving haulouts and rookeries (Sandegren 1970; Calkins and Curatolo 1980; Johnson et al. 1989; Brown 1997) and can eventually lead to permanent abandon­ment (Pike and Maxwell 1958; Kenyon 1962). 

Vessel disturbance of pinnipeds at haulouts can reflect a suite of influences, including vessel type and number, speed, and distance from animals (Henry and Hammill 2001; Szaniszlo 2005).  Interestingly, self propelled vessels (such as kayaks) are demonstrated to elicit behavioural responses from pinnipeds on haulouts (Henry and Hammill 2001), possibly due to these disturbance stimuli illustrating perceived predation risk (Deecke et al. 2002; Frid and Dill 2002).  Nonetheless, Steller Sea Lions at winter feeding sites often habituate to chronic disturbances, and some haulout sites are located in high traffic areas close to major urban centres such as Vancouver and Victoria (Bigg 1985; P. Olesiuk pers. comm.).  Acute noise disturbances, such as blasting or demolition, near haulouts may result in stampeding of Steller Sea Lions, resulting in pronounced, localized (as opposed to population-wide) disturbances. 

Although habituation to human activities may occur at haulouts, Steller Sea Lions are vulnerable to disturbances on rookeries.  Human intrusion onto rookeries during breeding season (e.g. to census animals, capture pups for tagging or branding) appears to be highly disruptive and often causes animals to escape into the water or to nearby haulouts (Lewis 1987; Scordino 2006; Olesiuk, unpublished data).  Disturbances can result in increased pup mortality due to drowning, trampling or separation of pups from mothers.  Recovery times of haulout sites from disturbances such as scat collections is highly variable, ranging from as little as a few hours to as much as a couple of weeks (Kucey 2005; J. Etzkorn, Carmanah Lighthouse, B.C., pers. comm.), but disturbance of rookeries may persist over a number of years (Olesiuk, unpublished data).  Additionally, disturbance may have energetic costs for both pups and mothers, should feeding or nursing opportunities be disrupted. 

Breeding site fidelity is another factor in disturbance of rookeries.  During the control programs conducted prior to 1970, some breeding animals were likely displaced to other rookeries, but the majority of sea lions continued to return to sites that had been heavily disturbed for many consecutive years.  At the Sea Otter Group rookery, in spite of intense annual culls, animals continued to use the rookery for 17 years before the colony was completely eradicated.  Thus, Steller Sea Lion reproductive biology may not have the plasticity to adapt to disturbances near breeding colonies.

As mentioned above, severity of population level impact is low for haulouts, but moderate for disturbance to rookeries due to site fidelity, potential energetic costs for mothers and pups, and pup survival (Table 1).  The mitigation potential for management of this threat is high.  At present, access to rookeries is strictly monitored and permits are required for entry onto a known rookery site.  Vessel disturbance of pinnipeds is managed via guidelines for viewing marine mammals.  Based on the criteria listed above, level of concern for disturbance is rated low to moderate.  It should be noted that U.S. regulation maintains a 3 mile no-entry zone surrounding rookeries (in western Alaska), further illustrating the sensitive nature of rookery disturbance.

Acoustic Disturbance in Aquatic Habitat
Operations related to oil and gas exploration, alternative energy development (e.g. wind and wave energy), and other resource extraction (e.g. methyl hydrates) have the potential to disturb animals as they produce both chronic (i.e. from vessel or construction activities) and acute (i.e. seismic surveys) underwater noise. 

Acoustic disturbance such as explosions, seismic or military tactical sonar noise may cause displacement of animals from feeding areas, and disrupt foraging behaviour.  Canadian seismic surveying standards assist in mitigation of this threat. The Statement of Canadian Practice with respect to the Mitigation of Seismic Sounds in the Marine Environment set out minimum standards that must be met during marine seismic surveys in all non-ice covered marine waters in Canada (http://www.dfo-mpo.gc.ca/oceans-habitat/oceans/im-gi/seismic-sismique/statement-enonce_e.asp).  As Steller Sea Lions are able to surface or exit the water to avoid acute noise stress, the concern for acute noise disturbance at feeding sites is low.  However, there is currently interest in expansion of offshore fossil fuel exploration and extraction activities, and as such, assessment of this threat should be ongoing as new information on occurrence and frequency of activities in relation to Steller Sea Lion rookeries and feeding areas becomes available. Continued review of development and exploration proposals will ensure that Steller Sea Lion habitat requirements are considered in sustainable development plans.

Chronic noise stress in important foraging areas and near rookeries could have a long-term effect on Steller Sea Lion vital rates and body conditions; however, given the remote locations of rookeries at present, concern remains low (Table 1).  Consideration for the placement of industrial developments near rookeries should assist in mitigation of this potential chronic threat.  General increase in vessel traffic (motorized and self-propelled) along the B.C. coast has increased the number and frequency of visits to haulout areas.  Such in-water acoustic (or visual) disturbance from vessel activity may contribute to increased energetic cost should foraging be disrupted on a long-term scale.  Mitigation potential for underwater acoustic disturbance, particularly surrounding rookeries, is high given the National Park Reserves protection surrounding two of the rookeries, and potential review and revision of guidelines and protocols for acute noise disturbance of marine mammals.

Toxic Spills
Sea lions may be impacted by catastrophic accidents such as toxic spills (St. Aubin 1990), although the impact on a population-wide scale has rarely been established.  The main threat is likely through contact with heavy oil accumulations when the source of the spill is near important habitats such as rookeries and haulout sites, and to a lesser degree from absorption through the skin, incidental ingestion of oil directly or through feeding, exposure to vapours, and partial fouling of pelage from fresh oil (Smith and Geraci 1975; Engelhardt et al. 1977; Engelhardt 1987; St. Aubin 1990).  Sea lions are insulated by a subcutaneous layer of blubber, so oiled fur does not interfere with thermoregulation.  Steller Sea Lions with tar lodged in their throats or around their lips, jaw and neck have been observed in Alaska (Calkins and Pitcher 1982). 

During the 1989 Exxon Valdez oil spill (EVOS) in Prince William Sound, oil did not persist on the coats of Steller Sea Lions for as long as it did on harbour seals (Calkins et al. 1994a), but sea lions were observed in the vicinity of the oil spill and metabolites in the blood showed they had been exposed to hydrocarbons.  Premature births were more common and pup production was somewhat lower in the year following the spill, but limited data prior to EVOS and the ongoing population decline in the area made it difficult to assess the statistical significance of the impact (Calkins et al. 1994b; Loughlin et al. 1996). 

Several Steller Sea Lions with small patches of oiled fur were observed during the Nestucca spill that spread along the west coast of Vancouver Island in 1988 (Harding and Englar 1989).  Because the population is widely dispersed along the entire B.C. coast, the potential threat of accidental spills is one of local depletion, as opposed to impacting the entire population.  However, a spill affecting a rookery during the breeding season could result in a significant population-level impact.  Considering that over 70% of pup production in B.C. occurs on the Scott Islands, an oil spill in that area during the breeding season could have a significant impact on breeding animals.

As a population-wide impact has been illustrated to be unlikely, concern for catastrophic spills affecting the population has been rated low (Table 1).  However, given that a spill near a rookery (e.g. Scott Islands) during breeding season might impact a large proportion of animals at once, an additional moderate concern is applied for impacts to rookeries during breeding season (Table 1).  As spills are accidental, the timing and locations of spill events are difficult to predict.  There are currently Canadian regulations and measures to minimize the risk of accidental spills (e.g. Transportation of Dangerous Goods Act) and mitigate effects through remediation of habitat and other measures.  The potential for mitigation of this threat is considered low to medium due to the inherent difficulty in, and low success of, post-spill clean-up measures (Graham 2004), particularly in isolated, remote areas.

Incidental Take in Fishing or Aquaculture Gear
Steller Sea Lions are killed incidentally in various fisheries (particularly drift gillnet fisheries for salmon), and there is incomplete fisheries observer coverage to adequately monitor by-catch levels.  Animals can get trapped in trawl nets or caught (entrapped) in drift and gill nets, and ultimately drown (Loughlin and Nelson 1986).  Unfortunately, once an animal is entangled the potential for rescue or rehabilitation is extremely low, from both a technical and practical standpoint.  Annual by-catch in U.S. waters in recent years has been estimated at about 25 animals per year (Loughlin and York 2000; Angliss and Outlaw 2007).  No such estimates are available for fisheries in B.C.

Rates of entrapment in finfish aquaculture installations are currently reported via voluntary means in the Pacific Region, which may limit the information regarding these types of interactions.  Information from voluntary reporting between 2004 and 2008 indicates only one animal was positively identified as a Steller Sea Lion (drowned as a result of entrapment) and another 12 pinnipeds could not be identified to species2
Accuracy in reporting of species identification has not been determined.  However voluntary industry-based training is conducted.  Implementation of standardized, voluntary reporting mechanisms is also being pursued to promote improved reporting and documentation of these occurrences.  This will result in future improvements regarding information on entrapment rates of Steller Sea Lions in aquaculture gear.  At present, there are no aquaculture facilities in Alaska, therefore there are no data available for comparison with incidental take of Steller Sea Lions elsewhere. 

Improved reporting on marine mammal entanglements and entrapments by aquaculture operators has led to increased reporting on incidences, however this does not necessarily reflect an increase in number of incidents overall.  The level of concern is rated low for this threat, based on the current population estimates for the Steller Sea Lion in B.C. (Table 1).  However, proactive measures including siting of aquaculture operations away from haulouts, gear modification (both fisheries and aquaculture), and all reasonable non-lethal means of control at aquaculture sites, to minimize risks of entanglement or entrapment is being used.   Methods should be continually reviewed and revised to minimize lethal interactions.

Entanglement in Marine Debris
The increasing prevalence of synthetic debris (net fragments, plastic bags and packing bands, etc.) is a growing problem worldwide and has been implicated in the declines of other species of pinnipeds (Fowler and Merrell 1986; Fowler 1988).  Debris such as net fragments and packing bands can get caught around the necks of sea lions, leading to abrasion or cutting deeply into tissue as animals grow.  Steller Sea Lions occasionally take fish from troll gear, and it is not uncommon to see animals that have swallowed hooks and are hooked internally with salmon flashers dangling from their mouths.  Unfortunately, rescue or rehabilitation of animals entangled in marine debris is usually neither technically, nor practically feasible.

Entanglement rates for Steller Sea Lions in Alaska have been estimated at about 0.07% for adults, with packing bands and net debris being the most common material (Calkins 1985; Mate 1985; Loughlin et al. 1986; Stewart and Yochem 1987; Fowler 1988).  On recent research surveys in B.C., approximately 0.2% of animals counted had either debris around their necks or fishing gear hooked in their mouths or throats (Olesiuk, unpublished data).  However, as Fowler (1988) noted, much of the debris found at sea or washed ashore may be too large for an animal to transport, so the observed rate of entanglement could represent a small fraction of numbers actually being entangled and drowned at sea.  Entanglement of pups and yearlings has not been observed, and it is unclear whether these age groups are able to avoid debris or whether entanglement of smaller animals results in 100% fatality.  The marine debris documented to cause entanglements results mainly from lost fishing gear.  Modifications to fishing gear may reduce the risk of harmful entanglements and should be considered a potential for successful mitigation of this threat. 

The severity of a population-wide impact on Steller Sea Lions as a result of entanglement in marine debris is unknown, however as entanglements have been recorded, it is evident that this threat affects some proportion of the population.  Further research may be necessary to address knowledge gaps on the rate of entanglements and their effect on a population-wide scale.  Currently, the level of concern regarding entanglement in marine debris is low (Table 1). 

Illegal Kills
Illegal and undocumented killing of Steller Sea Lions is likely to occur in B.C., particularly since the species is perceived to have a negative impact on fish stocks and is known to depredate fishing operations.  Several cases of illegal kills have been documented (DFO unpublished data), and mortality may also occur outside of the legal parameters assigned to permit holders (e.g. for predator control or subsistence harvest).  However, data on these activities are currently lacking, and incidents that occur in remote locations are inherently more difficult to document or monitor.  In some remote areas, fishing operations are located near rookeries and haulouts, and further exacerbating the interaction between fisheries and sea lions is the conditioning of pinnipeds to dumping sites for offal and other fish remnants. 

The extent of illegal killing of pinnipeds is poorly understood and the impact of such activity at a population-level is unknown.  However, given the recent abundance estimates for Steller Sea Lion in B.C. (DFO 2008), it is unlikely that this threat currently impacts population viability (Table 1).  Mitigation of this threat requires outreach and communication with affected parties, and education on modification of some practices (e.g. dumping offal, habituation of animals to fishing gear), and increased monitoring and enforcement around Steller Sea Lion haulouts and rookeries.  As such there is moderate potential for successful mitigation of this threat.

Predation by Killer Whales
As outlined in ‘Limiting Factors’, killer whales are an important predator having the potential to limit Steller Sea Lion populations.  Predation rate on Steller Sea Lion may be increased due to synergistic effects with other threats or limiting factors.  The potential for altering predation rate by killer whales due to environmental variability, changes in prey availability (i.e. increased distance required for foraging excursions), or increased incidence of disease may increase the impact of this natural threat on the population viability of Steller Sea Lions in B.C.  Impacts on other killer whale prey, such as harbour seals, could result in a shift in killer whale diet and increased predation on sea lions.  Disturbances that cause animals to enter the water or move to other sites could also increase exposure to killer whales.  Additionally, an increasing trend in population growth for Transient Killer Whales (Ford et al. 2007) indicates that there is potential for the predation rate to increase. Simulation models have shown that Transient Killer Whales could potentially have a significant impact on Steller Sea Lion populations, and in particular could inhibit the recovery of depleted populations (Barrett-Lennard et al. 1995).  Preliminary calculations indicate that even if killer whale predation accounted for all natural mortality of Steller Sea Lions, the net annual production of the Steller Sea Lion population in B.C., and the entire Eastern Population could only support roughly 26 and 77 killer whales respectively (P. Olesiuk, unpublished data).  This suggests there are also other sources of mortality for these sea lions.

As the Steller Sea Lion population is currently experiencing uninhibited population growth, and alternative prey such as harbour seals are also at high levels, concern for predation-induced population decline is at present minimal (Table 1).  Given that mitigation measures for predator-prey interactions are extremely unlikely, monitoring of both the Steller Sea Lion and Transient Killer Whale populations will assist in determining long-term trends in abundance and distribution of both of these species within B.C., and range-wide.

Predator Control Programs
For most of the 20th century, the main factor limiting Steller Sea Lions along the west coast of North America was predator control programs.  In B.C., government predator control programs eradicated a major rookery on the Sea Otter Group by the late 1930s, and numbers of sea lions breeding at the remaining rookeries had been reduced to about one-quarter of historic levels by the late 1960s (Bigg 1985).  In Washington, the state government offered a bounty payment for Steller Sea Lion kills, and abundance along the Washington coast fell from several thousand in the early 1900s to fewer than a hundred by the late 1940s.  Large bounty kills were also made in Oregon in the 1920s (Pearson and Verts 1970), and harassment and killing by bounty hunters and fisherman also reduced abundance of Steller Sea Lions and apparently eliminated several breeding sites in California (Rowly 1929).  The Eastern Population of Steller Sea Lions had been severely depleted by the time the species was protected under the Fisheries Act in Canada in 1970 and the Marine Mammal Protection Act in the U.S. in 1972.  The only portion of the Eastern Population range that escaped large culls was southeast Alaska, where there are no records of the species breeding or being abundant in the early 1900s. 

From 1990 to 2003, legal predator control at finfish aquaculture operations in B.C. constituted one of the largest known sources of human-induced mortality for Steller Sea Lions in the North Pacific (Angliss et al. 2001; Jamieson and Olesiuk 2001).  Quarterly reports filed by licence holders indicate that a total of 362 Steller Sea Lions plus 21 sea lions for which species could not be identified, were killed from 1990 (when the first permits were issued) up to 2003.  The number of Steller Sea Lions killed annually was initially low (averaging less than 10), but escalated in the late 1990s and peaked at 91 in 1999 (Jamieson and Olesiuk 2001), likely as a result of a shift in winter distribution of sea lions from Barkley to Clayoquot Sound (P. Olesiuk pers. comm.).  In 2004, license conditions were modified to remove Steller Sea Lions from the permits to eliminate the use of lethal control for this species due to the COSEWIC designation of this species as special concern.  However, many of the 100 or so salmon farms currently operating in B.C. waters possess permits to use lethal means of control for harbour seals and California sea lions, and it is possible that Steller Sea Lions could be shot as a result of being mis-identified as one of these species. Given the low level of current reported kills, the level of concern for this threat is currently assessed as negligible (Table 1).

First Nations Harvest
Traditionally, Steller Sea Lions were hunted by aboriginal peoples in B.C. for use as a food source (Bigg 1985), and whiskers continue to be used on some traditional ceremonial garb.  Use of sea lions by First Nations people appears to have declined during the 1800s and sea lion meat has not been an important dietary staple since the early 1900s (Bigg 1985). It is unknown whether subsistence harvesting prior to the 1900s regulated the Steller Sea Lion population in B.C. 

Aboriginal hunting of Steller Sea Lions for subsistence and cultural purposes does occasionally occur in Canada, but harvest levels are unknown.  First Nations people may hunt sea lions without a licence; nevertheless, Fisheries and Oceans Canada works with First Nations to encourage the use of Communal Licences with harvest limits to ensure removals do not exceed sustainable limits. Given that there are no commercial harvest licences issued for Steller Sea Lions in B.C., and there is very limited subsistence harvest of Steller Sea Lions, the level of concern associated with harvesting is rated as negligible (Table 1).  Continued communication with First Nations groups interested in harvesting pinnipeds will assist in assessing future level of concern for population-scale impacts due to harvest.

Disease and Parasitism
Steller Sea Lions in both B.C. and Alaska have exhibited positive screenings for several pathogens (Calkins and Goodwin 1988; Sheffield and Zarnke 1997; Burek et al.. 2003, 2005; Lambourn et al.. 2006), and in general parasites are common to the species (Dailey and Hill 1970, Dailey and Brownell 1972, Fay and Furman 1982, Shults 1986, Gerber et al.. 1993; all cited in NMFS 2008).  Although parasites and diseases may have little impact on otherwise healthy animals, effects could become significant if combined with other stresses (Haebler and Moeller 1993).  Anthropogenic stressors can also increase the incidence of disease, or introduce foreign pathogens into the population.
Pathogens and diseases from terrestrial sources or exotic species are a concern in terms of exposure of the population to new biological contaminants.  Sewage outflow, storm-water and agricultural runoff may play important roles as vectors for pathogens or disease, as do multi-species rehabilitation-reintroduction programs that include pinnipeds. 

Mitigation of terrestrial sources of pathogens and exposure to exotic species affecting marine mammals will assist in reducing the risk of transmission of foreign diseases to the Steller Sea Lion population in B.C.  Measures to minimize the risk of exposure of rehabilitated pinnipeds to pathogens carried by terrestrial mammals may decrease the likelihood of transmission of disease to pinniped populations.  Further, management of sources of outflow and runoff may assist in mitigating this threat.  However, given the high degree of uncertainty regarding disease effects, the primary action is to address knowledge gaps on terrestrial sources of pathogens and their potential effects on Steller Sea Lions. 

1.5.3. Cumulative or Synergistic Effects of Threats and/or Limiting Factors

The effects of threats and limiting factors can be difficult to distinguish from one another, making conclusions regarding causes of population decline often difficult to ascertain.  Although there is considerable uncertainty as to the total impact of threats on Steller Sea Lions in Canadian waters, the continued growth of the local Steller Sea Lion population suggests it is currently within sustainable limits, and individual or combined effects of threats and limiting factors are not prominent enough to force population decline, or to limit population growth.  Nevertheless, with a population growth rate of less than 5% per annum, a relatively small increase in human-induced mortality could become an important factor if conditions for Steller Sea Lions deteriorate, or if combined with other threats.  Therefore the importance of targeted research programs addressing knowledge gaps, and long-term monitoring of the population and of identified threats cannot be overemphasized. 

1.6. Actions Already Completed or Underway

1.6.1. Management

Harvest Controls
The conservation and management of Steller Sea Lions in Canada falls under the authority of the Fisheries Act (1985), more specifically the Marine Mammal Regulations (1993) of that Act.  With the exception of First Nations peoples, no person can fish for or disturb any marine mammal, unless explicitly authorized by a licence.  Under s.6, First Nations people may hunt sea lions without a licence for food, social or ceremonial purposes; however, the use of Communal Licences with harvest limits is common, to ensure removals do not exceed sustainable limits.

Since 1970, the management approach for pinnipeds in British Columbia has not provided for commercial harvest or culls.  The only licences issued that allow for killing of sea lions have been to protect stocks at fish farms and herring impoundments from predation. Limited harvests are permitted of “nuisance animals” as defined in the Marine Mammal Regulations (a licence is required under section 26.1(1)(c)), and harvests are monitored to ensure removals are within sustainable levels.  In response to Steller Sea Lions being COSEWIC-designated as special concern in 2003, predator control nuisance seal licences issued under section 26.1(1)(c)), since 2004 have prohibited the killing of Steller Sea Lions.

Protection from Disturbance
Section 7 of the Marine Mammal Regulations (Fisheries Act) prohibits the disturbance of marine mammals, unless authorized by a fishing licence or scientific licence. Proposed amendments to these regulations would also provide specific protection from some forms of disturbance such as swimming with, or feeding marine mammals.  In addition, guidelines (Be Whale Wise: Marine Mammal Viewing Guidelines for Boaters, Paddlers and Viewers, 2006) have been established to address disturbance from close approaches whether on land or sea, and are often followed for pinniped viewing.  Management and educational programs, for the purposes of achieving compliance with the guidelines, have been implemented for the ecotourism industry (e.g. Pacific Whale Watch Association Best Management Practices (http://pacificwhalewatch.org/ ) and the public).  Furthermore, the Statement of Canadian Practice with respect to the Mitigation of Seismic Sound in the Marine Environment was developed as a national code of conduct in response to public concerns over the potential impacts of seismic surveys on marine life. 

Protection of Habitat
The Fisheries Act (ss. 35, 36) contains provisions for habitat protection and prevention of pollution of marine mammal habitat.  The Steller Sea Lion breeding colonies at Triangle and Beresford Islands are located within Anne Vallee (Triangle Island) and Beresford Island Ecological Reserves, respectively.  These reserves were established in 1971 by the Province of British Columbia to protect biodiversity. Ecological reserves are closed to entry except as authorized by permit. Environment Canada (Canadian Wildlife Service) is leading a federal government initiative to establish a Marine Wildlife Area (MWA) in the Scott Islands, which will fulfill objectives of the Species at Risk Act by protecting habitat for several nationally listed species at risk, including Steller Sea Lions.

The Steller Sea Lion breeding colony at Cape St James is located within the Gwaii Haanas National Park Reserve and Haida Heritage Site, cooperatively administered by the Parks Canada Agency and the Council of the Haida Nation.  Gwaii Haanas National Marine Conservation Area (NMCA) in the southern Queen Charlotte Islands is proposed under the Canada National Parks Act and National Marine Conservation Areas Act to extend 10 km offshore from Gwaii Haanas National Park Reserve and Haida Heritage Site potentially protecting marine habitat for Steller Sea Lion in the area.  NMCAs are managed for sustainable use, and protected from industrial activities such as marine dumping, mining, and oil and gas exploration and development. 
                                                                
Numerous Steller Sea Lion haulouts around B.C. are also protected within National or Provincial Parks, such as Pacific Rim and Gulf Islands National Park Reserves, Race Rocks Ecological Reserve, and others.

Department of National Defence (DND) ‘Maritime command order: marine mammal mitigation procedures’ (DND 2007), mitigates disturbance from tactical sonar use by the Canadian military.  The Canadian Environmental Protection Act, Polybrominated Diphenyl Ethers Regulation (July 2008) has recently been passed in Parliament.  This regulatory tool restricts manufacture and use of several types of PBDEs in Canada, and is a first step toward long term reduction in environmental toxic effects from PBDEs.  Additionally, the Canada Shipping Act, Regulation for Prevention of Pollution from Ships and for Dangerous Chemicals addresses marine pollution and debris.  These codes of practice and regulatory tools may assist in mitigation of effects to Steller Sea Lion habitat.  
Following the coming into force of SARA in 2003, several marine recovery strategies and management plans for ‘at-risk’ marine mammals have been developed.  These documents include recommended actions for recovery, protection and management of listed marine mammal species.  In a larger context, these management actions may also benefit Eastern Pacific Steller Sea Lions in B.C.  Please refer to Section 4.0 ‘Associated Plans’ for specific recovery strategies and management plans with actions relevant to the protection and management of Steller Sea Lions in B.C.

1.6.2. Enforcement

Fisheries and Oceans Canada, Conservation and Protection Branch responds to, as necessary, and investigates reports of unauthorized lethal take (including attempts) and disturbance to all marine mammals, in the course of general operations.  Targeted enforcement of disturbance is focusing on whale oriented viewing, but also addresses the disturbance of pinnipeds, especially when hauled out near populated areas.  However, these activities do not significantly overlap with Steller Sea Lion distribution. 

Information to assist enforcement and response to incidents is collected by the Marine Mammal Response Program (1-800-465-4336).  These initiatives provide information on pinniped incidents, and provide capacity for response actions on a case-by-case basis.

1.6.3. Population Assessment

Given the trans-boundary distribution and high mobility of Steller Sea Lions, population assessments need to be coordinated among jurisdictions.  This is especially true for B.C. and southeast Alaska, as the largest breeding aggregation of Steller Sea Lions on Forrester Island is situated less than 50 km north of the international border. Following a recommendation of the National Marine Fisheries Service (NMFS) Steller Recovery Plan (NMFS 1992), effort has been made to standardize census techniques (Olesiuk et al. 2008) and coordinate survey schedules between each state and province (DFO 2008), culminating in the first comprehensive assessment of Eastern Population over its entire range (Pitcher et al. 2007). 

1.7. Knowledge Gaps

Key knowledge gaps for Steller Sea Lions in B.C. include diet composition and annual prey requirements, both by age class and by season.  The seasonal abundance and distribution of prey species is also poorly understood, as are potentially important foraging areas.  As such, the spatial and temporal distribution of fisheries may become increasingly important as these knowledge gaps are addressed and our understanding of Steller Sea Lion feeding ecology is expanded.

Several natural limiting factors are currently poorly understood.  In some cases, there are research programs addressing these uncertainties, but results are so far unavailable or inconclusive.  Information on key vital rates of Steller Sea Lions are required to determine age and sex specific fecundity and survival rates, age at weaning, and age of first reproduction that regulate population productivity.  Further genetic samples of the population within B.C. may foster an increased understanding of dispersal among rookeries, and the genetic makeup of individuals re-colonizing the rookery on the Sea Otter Group.

Seasonal changes in diet or prey requirements are at present unclear for the Steller Sea Lion population in B.C.  Of particular uncertainty is their diet outside of the breeding season.  Several studies on the summer diet of Steller Sea Lions have indicated that forage fish, such as herring,  sandlance and sardines, as well as other mid-sized schooling fishes such as salmon, hake and rockfish (see `Prey Requirements` section) may be important dietary components (Pike 1958; Spalding 1964; Olesiuk and Bigg 1988, Trites and Olesiuk, unpublished data).  Additionally studies to address the distribution of these prey will assist in identifying important geographic feeding areas (particularly adjacent to rookeries), and temporal or geographic areas having potential for fisheries interactions.

The importance of killer whale predation as a limiting factor remains somewhat uncertain.  While predation by transients is significant, the specific importance of different sex and age classes of sea lions in the diet of transients is unknown.  Increasing knowledge of the seasonal distribution of Transient Killer Whales and their diet will assist in determining the degree to which predation regulates Steller sea lion population growth in B.C.

Anthropogenic threats affecting sea lions in North America that require further clarification include:

  • The effects of research activities such as disturbances at haulouts and especially rookeries and hot-branding on pup survivorship
  • Baseline levels of chemical and biological pollutants in the B.C. population
  • The significance of specific fishing and aquaculture gear types (e.g. troll vs. seine nets) in terms of risk of entanglements
  • The spatial and temporal distribution of fisheries with respect to important sea lion haulouts and rookeries, as well as the frequency of fisheries interactions, illegal kills or entanglement incidents

2. MANAGEMENT

2.1. Goal

There are two goals of this management plan.    

  1. To ensure that anthropogenic threats from Canadian sources do not cause unsustainable population declines, or a contraction of the current range or number of breeding sites in Canada.

  2. Support for, and contribution to, an environment where research and monitoring of Steller Sea Lions in B.C., contributes to achieving an improved global knowledge of the Eastern Pacific Population

The Eastern Pacific Steller Sea Lion population continues to exhibit population growth, with no evidence of having reached carrying capacity.  It can be expected that at some point the population growth of this prey-dependent species will level and fluctuate in response to natural changes in prey abundance.  The role of Canadian management of this species is to protect the population within Canada from anthropogenic sources of mortality that are unsustainable.  As there are gaps in our understanding of this species’ ecology and population dynamics, along with impacts of identified threats, a key component of achieving the first goal will be to address knowledge gaps. 

This species is trans-boundary in its distribution, and research and management are currently conducted by Canadian and U.S. governments, as well as private organizations and independent researchers.  The second goal of this management plan recognizes that management initiatives and research are most effectively conducted in a coordinated and collaborative manner with all parties, where feasible.

2.2. Objectives

Population Objectives

P1   Maintain a viable population and prevent the population from declining to levels at which it would be considered at risk of extinction.

Distribution Objectives        

D1  Maintain the annual usage of all three main rookeries and support the establishment of the fourth breeding site as a permanent rookery.  

D2  Maintain the number and utilization of existing haul-outs in British Columbia to ensure a widespread distribution along the B.C. coast.

Maintenance of the abundance and distribution of Steller Sea Lions in B.C. over the next three generations will ensure that this population is protected within Canada.  Protection for known haulout sites and rookeries will ensure that required terrestrial habitat is available throughout the coast.  As the population has sustained an increasing trend for over four decades and is currently above known historic peak levels, monitoring data will contribute to the detection of declining population trends, or significant contraction in distribution.

Research and Monitoring Objectives

Research and monitoring objectives for this management plan focus on priority needs as follows:

R1  Conduct range wide population assessments through coordinated Canadian and U.S. surveys, where feasible.

R2  Contribute to, and foster an improved understanding of Steller Sea Lion biology and habitat requirements in B.C.

R3 Support, foster and contribute to research addressing knowledge gaps regarding identified (Table 1) and unidentified threats to this population.

R4  Determine total cumulative levels of human-caused annual mortalities for Steller Sea Lions in B.C. that can be sustained.

Research should focus on key knowledge gaps for this species, listed in ‘Knowledge Gaps’, and those regarding the effects of the threats identified in this management plan. 

Presently, population surveys within B.C. are typically conducted every four years.  As Steller Sea Lions range across both the northern and southern Canadian-U.S. boundaries, an emphasis on coordination of these surveys is necessary to generate a total population estimate for the Eastern Pacific Steller Sea Lion population.  This in turn will increase our understanding of the relative importance of the Canadian component of this population.  More frequent monitoring, particularly at local breeding sites, will enhance our ability to detect and respond to population declines.

Research on foraging ecology is identified as a priority for research in Canada, including assessment for potential fisheries interactions.  Additionally, programs to clarify vital rates, habitat utilization and fine-scale genetic makeup will assist in directing management and protection of this population in B.C.

Steller Sea Lions are susceptible to a number of human-induced sources of mortality.  A better understanding of the current levels of human-induced mortality and their trends over time is necessary, and determination of sustainable thresholds of human-caused mortality (Obj. R4) will assist in monitoring population level effects.  Steller Sea Lion populations have been growing in recent years, indicating that current levels of human-induced mortality are sustainable.  However, this could change if conditions were to become less favourable for sea lions, in which case the mortalities could attenuate the rates of population growth or exasperate the magnitude of population fluctuations.   

Management Objectives

Table 1 summarizes the assessment of threats to Eastern Pacific Steller Sea Lions, and presents the perceived mitigation potential for each threat.  Analysis of severity, occurrence and causal certainty provided an overall level of concern for each threat in terms of impacts to this population’s viability. Over the next ten years, the following management objectives aim to ensure that the threats currently of greatest concern do not impact the population or distribution of Steller Sea Lions in B.C., and to contribute to the conservation of this population throughout its range.

M1 Promote international collaboration, independent research, education and outreach on management and conservation initiatives

M2 Minimize the exposure of Steller Sea Lions to pollutants

M3 Minimize the level of disturbance of Steller Sea Lions at rookeries during the breeding season  

M4 Reduce the risk of catastrophic spills impacting Steller Sea Lions or their habitat in Canada

M5 Minimize the exposure of Steller Sea Lions to acute sound levels known to cause behavioural or physical harm in pinnipeds

M6 Minimize the likelihood of prey limitation caused by anthropogenic factors

The population shows a continued increasing trend.  Management objectives addressing threats of greatest concern aim to prevent undesirable population decreases and prevent significant alterations in distribution of Steller Sea Lions in B.C.  Catastrophic spills, disturbance (i.e. at rookeries), and contaminants are considered to be the human-induced threats that require mitigation or management in order to meet the first goal of this management plan.  The limitation of prey species through anthropogenic means is of concern.  However specific information on Steller Sea Lion prey needs is lacking. Thus monitoring of prey supply and research will be the primary tool to assist in addressing the M6 objective.    

The threats assessed at a low or unknown level of concern do not have specific objectives or new recommendations for mitigation; instead, knowledge gaps will be filled by opportunistic or cost-effective means, where feasible.  Some threats impact individual sea lions, but do not constitute a population level effect.  Where potential for effective mitigation of a threat is high (Table 1) and resources are available, it is prudent to manage and mitigate these threats when feasible.

2.3. Actions

The following non-prioritized actions support the objectives outlined in Section 2.2.  Some of the actions listed below are currently underway (see Section 1.6 ‘Actions Already Completed, or Underway’), and have been identified in other recovery planning documents to date (See Section 4.0 ‘Associated Plans’).  The synchronization of these listed activities for protection, management and research will facilitate a multi-species approach to marine mammal conservation in B.C., and allow for effective use of resources available.  Actions have been recommended where implementation is deemed to be practical and feasible, and where they are most likely to result in successful protection of the Steller Sea Lion population in B.C.

Where responsibility for actions is determined to fall under the jurisdiction of Fisheries and Oceans Canada or the Parks Canada Agency, actions will be implemented directly as availability of funding and other resources permit.  However, collaboration with other responsible agencies and organizations will be necessary to complete some actions.  If responsibility for actions falls outside of the mandate or jurisdiction of Fisheries and Oceans Canada or the Parks Canada Agency, support for implementation of the action(s) and contribution to effort(s) will be a priority where feasible.  Potential participating agencies and organizations and implementation timelines for each of the listed actions are presented in Section 3 (Table 3).  Organizations currently involved in data collection on the Eastern Pacific population of Steller Sea Lions are listed in Appendix II. 

2.3.1. Protection

1.  To protect Steller Sea Lions from disturbance (physical and acoustic) at, or adjacent to, the four breeding sites, twenty-three year-round, and numerous winter haulouts in B.C.

  1. Continue to enforce the MMR and promote Be Whale Wise guidelines for marine mammal viewing, as well as relevant regulations for marine industrial development.

2.   Continue enforcement of regulations for discarding debris3, and develop new fishing gear standards for troll, seine and long line fisheries to reduce the risk of entanglement in marine debris and/or directly in fishing gear.

2.3.2 Management

3.  Continue to manage fish resources and fisheries where there is overlap with Steller Sea Lion diet.  Consider Steller Sea Lion dietary needs when changes to current fisheries management regimes occur for species known to be important to Steller Sea Lions in B.C.

4.  Continue to review project proposals that include activities with potential to generate disturbance at haulouts or at rookeries, and provide project-specific advice for mitigation or avoidance with respect to Steller Sea Lion habitat needs.

5.  While contaminants are listed as a threat to this population, the management of biological and chemical contamination falls under the jurisdiction of Environment Canada. The following actions are recommended to assist in reducing toxic loading of marine mammals and their habitat.

  1. Develop a DFO emergency response plan to identify marine mammal expertise required in spill response initiatives, when triggered.
  2. Develop a marine mammal-specific DFO operational manual to be included into existing catastrophic spill response plan(s)4 to identify response protocols and data collection required for mitigation and monitoring of short and long-term effects to marine mammals and important habitat.
  3. Review management of point-sources of toxic pollution within known Steller Sea Lion habitat, to assess compliance with federal, provincial, and regional guidelines regarding thresholds for environmental contamination for the specific toxins listed in Appendix I.

6.  Support low-impact research activities through permitting and range-wide coordination of trans-boundary research, as well as monitoring and assessment (Sections 2.3.3. and 2.3.4.) to address key knowledge gaps and clarify identified threats while minimizing the level of disturbance to animals.  This will also ensure uniform and standardized data collection for population- and range-wide assessments and comparisons.

7.  Strengthen measures to reduce the risk of entanglement of Steller Sea Lions in marine debris, aquaculture and fishing gear.

  1. Support the Marine Mammal Response Network (MMRN) to collect data in support of comprehensive understanding of the following threats: incidental by-catch, entanglement in marine debris, fishing and aquaculture gear.
  2. Strengthen, support and foster, where feasible, the continued development of fisheries observer reporting standards and guidelines for marine mammal species identification and data collection to clarify the extent of fisheries interactions in terms of entanglement, by-catch, or depredation and to gather samples, where possible, and when required. 
  3. Continue to develop solutions to predator interactions and quarterly reporting on marine mammal kills at aquaculture sites, and continue the development of reporting requirements for marine mammal interactions at aquaculture sites. Of particular importance are accurate species identification, data collection, and temporal requirements for reporting of incidents.
  4. Continue to work with the aquaculture industry to evaluate and develop best management practices for mitigating Steller Sea Lion depredation and subsequent entanglements (e.g. more effective predator net infrastructure).
  5. Suggest alternative gear types to proactively minimize likelihood of entanglements in marine debris, and fishing and aquaculture gear. Of particular importance is the consideration of entanglement risk for predator nets, packing bands, and ingestion of hooks from trolling and long line gear.  This action will assist in the continued evolution of guidelines, best management practices, regulations and standards.

8.  Evaluate the risk to Steller Sea Lions in B.C. from catastrophic spills and acoustic and vessel disturbance that might result from lifting the moratorium on offshore fossil fuel exploration and extraction in B.C.  Of particular concern are impacts to at-sea foraging success near year-round haulout and breeding sites in B.C.

2.3.3. Research on Steller Sea Lion Biology

The following areas are those that have been identified as a priority for research actions to address knowledge gaps surrounding species biology.  Other potential areas for research efforts have been listed in previous sections of this management plan and should also be considered in the context of supporting those topics listed below.

9.  Fisheries and Oceans Canada will support, contribute to and foster Steller Sea Lion research, by management of samples and data collected by non-governmental organizations and the public, including:

  1. Tissue samples from the B.C. Steller Sea Lion population for potential future genetic, pathogen and fatty acid research.  This will assist in collection of genetics, and pathogen data to better understand the requirements and health of the B.C. population, and to facilitate range-wide comparisons. 
  2. Brand re-sighting efforts and photographs of branded animals, where and when opportunity presents itself, to assist in addressing uncertainties in vital rates, movements of individuals and other knowledge gaps.

10.  Fisheries and Oceans Canada and the Parks Canada Agency will support, contribute to, and foster, where feasible, the following directed research actions to address key knowledge gaps for Steller Sea Lions.

  1. Studies on foraging areas, and seasonal distribution of sea lions and their prey species to address uncertainties regarding prey availability near rookeries. 
  2. Studies addressing uncertainties regarding the diet of Steller Sea Lions outside of the breeding season.
  3. Maintenance of database for brand re-sight data, to facilitate organization of data collected, and data sharing between researchers.

2.3.4 Research to Clarify Identified Threats

Fisheries and Oceans Canada and the Parks Canada Agency will support, contribute to, and foster, where feasible, the following research actions to address knowledge gaps on threats to the population.

11.  Assess current levels and trends in annual human-caused mortality that can be sustained by Steller Sea Lions under various conditions (to achieve the population objective).

12.  Determine the diet of Steller Sea Lions (across all seasons) to assess the potential for fisheries competition for prey resources.

13.  Investigate seasonal variation in significance of impacts from research-related disturbance at haulouts and rookeries to clarify the magnitude of this identified threat.  

14.  Gather information on entanglement rates observed during Steller Sea Lion research in B.C. to compile information on entanglement rates, gear types, and severity of entanglements, and explore and develop methods for disentangling animals.

15.  Collect samples for analyses of toxin and pathogen loading in Steller Sea Lions, when feasible.

16.  Conduct assessments of current sources of biological pollutants within known Steller Sea Lion habitat to assess the potential for population-level impacts.  Of particular significance are agricultural sources of pollutants and rehabilitation programs. 

17.  Identification of significant non-point sources of toxic contamination within Steller Sea Lion habitat in B.C.  Of particular importance are emerging contaminants and those sources in close proximity to rookeries and year-round haulouts.

2.3.5. Monitoring Population Status

18.  Continue to support, and contribute to the coordination of range-wide aerial and vessel surveys, every four years. 

19.  Consider additional biennial rookery surveys to more closely monitor breeding populations.

2.3.6. Outreach and Communication

20.  Foster improved communication networks to increase awareness of initiatives for Steller Sea Lion conservation and research.

  1. Pro-actively build intra- and interagency networks for effective communication during catastrophic spill response to allow timely, effective and coordinated actions by responsible agencies and parties.
  2. Support and contribute, where feasible, to trans-boundary and inter-jurisdictional collaboration on conservation initiatives to ensure a coordinated response to conservation of this population.
  3. Ongoing media communications and promotion of the Marine Mammal Regulations and ‘Be Whale Wise: marine wildlife guidelines for boaters, paddlers and viewers’ to reduce physical and acoustic disturbance at haulouts.  This action will facilitate increased awareness of regulations and facilitate ease of enforcement measures.
  4. Support, where feasible, independent education and awareness programs on:
    • Significance of marine debris in entanglement of Steller Sea Lions. 
    • Measures to avoid or minimize depredation of commercial and sport fishing gear.
    • The importance of reporting marine mammal incidents involving Steller Sea Lions to the DFO Marine Mammal Response Program (1-800-465-4336). 
    • Mitigation measures available to reduce chemical and biological contamination of habitat.

3. PROPOSED IMPLEMENTATION SCHEDULE

Fisheries and Oceans Canada and the Parks Canada Agency encourage other agencies and organizations to participate in the conservation of Eastern Pacific Steller Sea Lion through the implementation of this management plan.  The agencies in Table 2 have been identified as potential partners for implementing the recommended actions. 

Table 3 summarizes those actions that are recommended to support the goals and objectives of this management plan.  The activities implemented by Fisheries and Oceans Canada and the Parks Canada Agency will be subject to the availability of funding and other required resources.  Where appropriate, partnerships with specific organizations and sectors will provide the necessary expertise and capacity to carry out the listed action.  However, this identification is intended to be advice to other agencies, and carrying out these actions will be subject to each agency’s priorities and budgetary constraints.  Organizations currently collecting data on Steller Sea Lion are listed in Appendix II.

Table 2. The management actions outlined in this plan are to be carried out, where and when appropriate, in partnership with the following organizations.

OrganizationAcronym
Fisheries and Oceans CanadaDFO
Parks Canada AgencyPCA
Marine Mammal Response NetworkMMRN
Department of National DefenceDND
Environment CanadaEC
Transport CanadaTC
Natural Resources CanadaNRCan
Canadian Coast Guard ServicesCCG
National Energy BoardNEB
First NationsFN
B.C. ProvinceB.C. Prov
Ministry of Agriculture and LandsMAL
Vancouver Aquarium Marine Science CentreVAMSC
B.C. Cetacean Sightings NetworkB.C. CSN
Pacific Salmon CommissionPSC
StraitwatchStraitwatch
Universities having relevant research programsUniversities
U.S. National Marine Fisheries ServiceNMFS
National Oceanic and Atmospheric Administration,
National Marine Mammal Lab
NOAA
Oregon Department of Fish and WildlifeODFW
Washington Department of Fish and WildlifeWDFW
Alaska Department of Fish and GameADFG
Pacific Whale Watch AssociationPWWA
Environmental non-Governmental OrganizationsENGOs
North Pacific Marine Mammal University ConsortiumNPMMUC
To be determinedTBD

Table 3. Proposed Implementation Schedule

ActionObj.PriorityThreats or concerns addressedParticipating Agencies5Timeline
Protection 
1. Protect Steller Sea Lions from disturbance at breeding sites and haulouts 
a. Continue enforcement of MMR, promote regional guidelinesD1, D2,
M3
LContinued protection from disturbance; habitat degradationCCG, DFO, PCAOngoing
2. Enforcement of regulations for discarding debris, develop new fishing standardsM2LReduce entanglement risksDFO, TC,
Fishing industry
Ongoing
Management
3. Consider dietary needs when changes to current fisheries management regimes occurP1, M6HPrey limitationDFO,
Fishing industry
As changes to fisheries management occur
4. Review proposals with potential for disturbance at haulouts and rookeries, and provide adviceD1, D2,
M3, M5
LAcoustic and physical disturbanceDFO, DND, Industry,
NRCan, NEB
Ongoing, enhance involvement where necessary 
5. Manage and reduce input of chemical toxins, reduce toxic loading
a. Develop DFO emergency response plan to identify marine mammal expertise required in toxic spill responseP1, M2,
M4
LMEffective, coordinated response for toxic spillsDFO, EC, CCG, PCA, B.C. Prov, TC4 years
b. Marine mammal-specific DFO operational manual for toxic spill responseM2, M4LMEffective, coordinated step-wise response to toxic spills; standardized data collection; monitoringDFO, EC, CCG, PCA, B.C. Prov, TC4 years
c. Review management of point-sources of toxins listed in Appendix IR3, M2LMRelevance of guidelines and thresholds for marine mammals, contaminant loadingEC, B.C. Prov, Municipalities,
Industry
Ongoing
6. Support low-impact researchR1 to R4, M1, M3HFostering independent/ non-DFO, low-impact research, trans-boundary collaboration, data sharingDFO, ENGOs,
NPMMUC, NMFS,
ADFG, WDFW, ODFW, TBD
Ongoing
7. Strengthen measures to reduce entanglement risk
a. Support MMRN initiativesR3, R4LBy-catch, entanglement (all types), incidental takeDFO, VAMSC, ENGOs, MAL, NPMMUC, PCA, CCG, TBDOngoing
b. Fisheries observer reporting standards and guidelinesR3, R4MClarify extent of fisheries interactionsDFO,
Fishing industry
3 years
c. Develop solutions to predator interactions, quarterly reportingP1, R3, R4LClarify extent of interactions at aquaculture sites; entanglement; predator controlDFO,
Aquaculture industry
Ongoing
d. Develop and evaluate best management practicesP1, M2LMitigate depredation and entanglementsDFO,
Aquaculture industry
Ongoing
e. Alternative gear types (fishing, aquaculture)P1, M2MReduce entanglement risk; incidental takeDFO, Fishing and Aquaculture industry, VAMSCOngoing as new information becomes available
8. Determine risk associated with lifting of moratorium on offshore fossil fuel extractionP1, D1,
D2, R3,
M2 to
M5
LMDetermine associated risk regarding toxic spills; disturbance; potential impacts to foragingDFO, EC, NEB,
 NRCan, B.C. Prov
Ongoing
Research on Steller Sea Lion Biology
9. Data collection:
a. Collection of tissue samplesR2, R3, M1LGenetic, pathogen and fatty acid analysisDFO, NMFS, ODFW, ADFG, WDFW, TBDOpportunistically
b. Brand re-sighting; photographs of branded animalsR1, R2, R3, M1MAssist range-wide research efforts to assess vital rates; movementsDFO, NMFS, ODFW, ADFG, WDFW,  TBDOngoing
10. Contribute, support, foster research on
a. Important foraging areas, seasonal distributionP1, R2, R3, M1,
M6
HPrey availability near rookeries during breeding seasonDFO, PSC, WDFW, ADFGW, NMFSOngoing  
b. Diet outside the breeding seasonP1, R2, R3, M1, M6HKnowledge gaps re: seasonally important prey species; nutritional needsDFO, PSC, WDFW, NPMMUC, NMFS, ODFW,TBDOngoing
c. Maintenance of brand re-sight databaseR2,
M1
MData sharing; data organizationDFO, ADFGW, ODFW, NMFS, NPMMUCOngoing
Research to clarify identified Threats
11. Assess sustainability of total human-caused mortalityP1, R4MHuman-caused mortality levelsDFO, TBDOngoing
12. Assess potential for fisheries competition for prey resourcesP1, R3,
M6
HPrey limitation; fisheries impactsDFO, PSC, WDFW, NPMMUCOngoing
13. Determine seasonal variation in significance of research disturbance at haulouts and rookeriesD1, D2,
R3, M3
LMSignificance of seasonal disturbancesNPMMUC, TBDOngoing
14. Gather information on entanglement rates observed by researchersP1, R3,
M1, M2
LEntanglement rates in B.C.; gear types; severity of incidentsDFO, NMFS, ODFW, ADFG, WDFW, VAMSC, NPMMUC, TBDOngoing
15. Analysis of toxin and pathogen loadingP1, R3,
M2
LMDetermine risk of impacts from toxins and diseaseDFO, EC, B.C. Prov,
MAL, TBD
Ongoing
16. Assess sources of biological pollutantsR3, M2LDetermine potential for biological pollutant loadingMunicipalities,  Industry, TBDOngoing
17. Identify significant non-point source toxic contaminationR3, M2LMEmerging contaminants; toxic loading near rookeries and year-round hauloutsTBDOngoing
Monitoring population status
18. Support, contribute to coordination of range-wide surveys, every four yearsP1, D1,
D2, R1, 
M1
HMonitoring range-wide trends; effective, efficient data collection; foster data sharingDFO, PCA, B.C. Prov, NMFS, ODFW, ADFG, WDFW, TBDOngoing
(next survey in 2010)
19. Consider biennial rookery surveysP1, D1,
D2, R1,
R2, M1
MMonitor breeding populationsDFO, PCA, B.C. Prov, NMFS, ODFW, ADFG, WDFW, TBDConducted in 2008, next survey is funding dependent
Outreach and Communication
20. Foster improved communication networks
a. Pro-actively build communication networksM1, M2MEffective intra- and inter-agency communication catastrophic spill responseDFO, EC, CCG,
B.C. Prov, VAMSC, Municipalities, ENGOs
3 years
b. Trans-boundary and inter-jurisdictional collaborationAllMCoordinated management and research effortsDFO,PCA, NOAA,
NMFS, NPMMUC,
ENGOs
3 years
c. Ongoing media communications and promotion of the MMR and ‘Be Whale WiseM1LAwareness of guidelines, regulations; enforcement measuresDFO, B.C. CSN,
VAMSC, Straitwatch, PWWA, TBD
Ongoing
d. Support, where feasible, independent education and awareness programsM1, M2LEntanglement; marine debris; depredation; incident reporting; contamination of habitatDFO, B.C. CSN,
VAMSC, Straitwatch, PWWA,  TBD
Ongoing

4. ASSOCIATED PLANS

The following are specific recovery plans and management plans that identify similar threats to marine mammals at-risk, and contain similar recommendations for mitigation of threats identified in this Management Plan for the Steller Sea Lion in Canada.  Implementation of actions listed in this, and other plans will provide a multi-species and multi-jurisdictional approach to conservation of marine mammals on the west coast of North America.

  • U.S. National Marine Fisheries Service. Recovery Plan for the Steller Sea Lion (Eumetopias jubatus). (NMFS 2008)
  • Management Plan for the Offshore Killer Whale (Orcinus orca) in Canada [Final] (DFO 2009)
  • Management Plan for the Eastern Pacific Grey Whale (Eschrichtius robustus) in Pacific Canadian Waters. [Draft] (DFO 2008b)
  • Management Plan for the Pacific Harbour Porpoise (Phocoena phocoena) in Canada [Final] (DFO 2009b)
  • Recovery Strategy for the Transient Killer Whale (Orcinus orca) in Canada [Final] (DFO 2007c)
  • Recovery Strategy for the Northern and Southern Resident Killer Whale (Orcinus orca) in Canada. [Final] (DFO 2008c)
  • Recovery Strategy for the Sea Otter (Enhydra lutris) in Canada [Final] (DFO 2007b)

5. REFERENCES

Addison, R.F. 1989. Organochlorines and marine mammal reproduction. Canadian Journal of Fisheries and Aquatic Sciences 46: 360-368.
Ainley, D.G., C.S. Strong, H.R. Huber, T.J. Lewis, and S.H. Morrell. 1981. Predation by sharks on pinnipeds at the Farallon Islands. Fishery Bulletin 78: 941-945.
Alaska Sea Grant. 1993. Is it food? Addressing marine mammal and sea bird declines. Alaska Sea Grant AK-SC-93-01. 65 pp.
Alverson, D. 1992. A review of commercial fisheries and the Steller sea lion (Eumetopias jubatus): the conflict arena. Reviews in Aquatic Sciences 6: 203-256.
Anderson, P.J., J.E. Blackburn, and B.A. Johnson. 1997. Declines in forage species in the Gulf of Alaska, 1972-95, as indicator of regime shift. pp 531-543. In: Forage Fishes in Marine Ecosystems. Alaska Sea Grant AK-SG-97-01. 816 pp
Anderson, P.J. and J.F. Piatt. 1999. Community reorganization in the Gulf of Alaska following ocean climate regime shift. Marine Ecology Progress Series 189:117-123.
Andrews, R.D. 1999. Preliminary progress report of Steller sea lion (SSL) foraging ecology studies. Presentation to the Steller Sea Lion Research Peer Review Feeding Ecology Workshop Seattle, WA, 11-12 Feb 1999. 40 pp.
Angliss, R.P., D.P. DeMaster, and A.L. Lopez. 2001. Alaska Marine Mammal Stock Assessments, 2001. NOAA Technical Memorandum. NMFS-AFSC-124. 206 pp.
Angliss, R.P., and R.B. Outlaw. 2007. Alaska Marine Mammal Stock Assessments, 2006. NOAA Technical Memorandum NMFS-AFSC–168. 244 pp.
Arndt, D.P. 1973. DDT and PCB levels in three Washington State harbor seal (Phoca vitulina richardsi) populations. M.Sc. thesis, University of Washington, Seattle, WA. 65 pp.
Azana, C.D.P. 2002. Seasonal variation in the nutrient composition of Alaskan walleye pollock (Theragra chalcogramma) and its effect on the nutritional status of Steller sea lions (Eumetopias jubatus). M.Sc. thesis, University of British Columbia, Vancouver, B.C. 104 pp.
Baird, R.W., and L.M. Dill. 1995. Occurrence and behaviour of transient killer whales: seasonal and pod-specific variability, foraging behaviour, and prey handling. Canadian Journal of Zoology 73:1300-1374.
Baker, C.S., T.R. Loughlin, V. Burkanov, C.W. Matson, R.G. Trujillo, D.G. Calkins, J.K. Wickliffe, J.W. Bickham. 2005. Variation of mitochondrial control region sequences of Steller sea lions: the three-stock hypothesis. Journal of Mammalogy 86(6): 1075-1084.
Barrett-Lennard, L.G., K. Heise, E. Saulitis, G. Ellis, and C. Matkin. 1995. The impact of killer whale predation on Steller sea lion populations in British Columbia and Alaska. Report for the North Pacific Universities Marine Mammal Research Consortium. University of British Columbia, Vancouver, B.C. 77 pp.
Barron, M.G., R. Heintz, and M.M. Krahn.  2003.  Contaminant exposure and effects in pinnipeds: implications for Steller sea lion declines in Alaska.  Science of the Total Environment 311: 111-133.
Beach, R.J., A.C. Geiger, S.J. Jeffries, S.D. Treacy, and B.L. Routman. 1985. Marine mammals and their interactions with fisheries of the Columbia River and adjacent waters, 1980-82. NMFS, NWAFC Processed Report. 85-04. 316 pp.
Beamish, R.J. and D.R. Bouillon. 1993. Pacific salmon production trends in relation to climate. Canadian Journal of Fisheries and Aquatic Sciences 50: 1002-1016.
Benson, A.J., and A.W. Trites. 2002. Ecological effects of regime shifts in the Bering Sea and eastern North Pacific Ocean. Fish and Fisheries 3:95-113.
Bergman, A.,M. Olsson, and S.Reiland. 1992. Skull-bone lesions in the Baltic grey seal (Halichoerus grypus). Ambio 21: 517-519.
Beverton, R.J.H. 1985. Analysis of marine mammal-fisheries interaction. pp. 3-33. In: J.R. Beddington, R. J. H. Beverton and D. M. Lavigne (Eds). Marine Mammals and Fisheries. George Allen and Unwin, London, UK.
Bickham, J.W. 2000. Variation in nuclear microsatellites and mtDNA of Steller sea lions taken from rookeries and native harvests. Unpublished report to National Marine Mammal Laboratory. Seattle, WA. 21 pp.
Bickham, J.W., J.C. Patton, and T.R. Loughlin. 1996. High variability for control-region sequences in a marine mammal: implications for conservation and biogeography of Steller sea lions (Eumetopias jubatus). Journal of Mammalogy 77:95-108.
Bigg, M.A. 1984. Sighting and kill data for the Steller sea lion (Eumetopias jubatus) and California sea lion (Zalophus californianus) in British Columbia, 1892-1982, with some records from Washington and southeastern Alaska. Canadian Data Report of Fisheries and Aquatic Sciences 460: 1-191.
Bigg, M.A. 1985. Status of Steller sea lion (Eumetopias jubatus) and California sea lion (Zalophus californianus) in British Columbia. Canadian Special Publication of Fisheries Aquatic Sciences 77: 1-20.
Bigg, M.A. 1988. Status of the Steller sea lion Eumetopias jubatus in Canada. Canadian Field-Naturalist 102: 315-336.
Bigg, M.A., G.M. Ellis, P. Cottrell, and L. Milette. 1990. Predation by harbour seals and sea lions on adult salmon in Comox Harbour and Cowichan Bay, British Columbia. Canadian Technical Report of Fisheries and Aquatic Sciences 1769: 1-31.
Bigg, M.A., and I. Fawcett. 1985. Two biases in diet determination of northern fur seals (Callorhinus ursinus). pp 284-291. In: J.R. Beddington, R. J. H. Beverton and D. M. Lavigne (eds). Marine Mammals and Fisheries. George Allen and Unwin, London, UK.
Bonnell, M.L., M.O. Pierson, and G.D. Farrens. 1983. Pinnipeds and sea otters of central and northern California, 1980-1983: status, abundance and distribution.  Final Report, Marine Mammal and Seabird Study, Contract No. 14-12-0001-29090. Prepared by Center for Marine Sciences, University of California, Santa Cruz, for the Pacific OCS Region, Minerals Management Service, OCS Study MMS 84-0044. 220 pp
Bowen, W.D. 1997. Role of marine mammals in aquatic ecosystems. Marine Ecology Progress Series 158:267-274.
Bowen, W.D., J.I. McMillan and R. Mohn. 2003. Sustained exponential population growth of the grey seal on Sable Island. ICES. Journal of Marine Sciences 60: 1265–1374.
Brenton, C.M. 1977. Inter and intraspecific behaviour of Eumetopias jubatus and Zalophus californianus on a winter haulout area. M.Sc. thesis, University of British Columbia, Vancouver, B.C. 131 pp.
Brouwer, A., P.J.H. Reijnders, and J.H. Koeman. 1989. Polychlorinated biphenyl (PCB)-contaminated fish induces vitamin A and thyroid hormone deficiency in the common seal (Phoca vitulina). Aquatic Toxicology 15: 99-106.
Brown, R.F. 1997. Pinnipeds in Oregon: status of populations and conflicts with fisheries, fish resources and human activities.  pp 124-134. In: G. Stone, J. Goebel and S. Webster (eds). Pinniped Populations, East North Pacific: Status, Trends and Issues. 127th Annual Meeting of the American Fisheries Society, 28 Aug 1997, Monterey, CA.
Brown, R.F., and S.D. Reimer. 1992. Steller sea lion counts in Oregon during June and July, 1975-1991. Unpublished Report. Nongame Wildlife Program, Oregon Department of Fish and Wildlife, Newport, OR. 12 pp.
BSDWG (Barkley Sound Dialect Working Group). 2004. Nuu-chah-nulth phrase book and dictionary: Barkley Sound dialect. Huu-ay-aht First Nation, Bamfield. 186 pp.
Burek, K.A., F.M.D. Gulland, G. Sheffield, K.B. Beckmen, E. Keyes, T.R. Spraker, A.W. Smith, D.E. Skilling, J.F. Evermann, J.L. Stott, J.T. Saliki, and A.W. Trites. 2005. Infectious disease and the decline of Steller sea lions (Eumetopias jubatus) in Alaska, USA: Insights from serologic data. Journal of Wildlife Diseases 41:512-524.
Burek, K. A., F.M.D. Gulland, G. Sheffield, E. Keyes, T.R. Spraker, A.W. Smith, D.E. Skilling, J. Evermann, J.L. Stott, and A.W. Trites. 2003. Disease agents in Steller sea lions in Alaska: a review and analysis of serology data from 1975-2000. UBC Fisheries Centre Research Reports. 11(4): 26 pp.
Burkanov, V.N. 2000. Steller's sea lion population status and dynamics in Russian waters in 1989-1999.  Marine Mammals of the Holarctic Regions: Materials from International Conference, Archangelsk, Russia 21-23 September, 2000. Pages 56-65 [in Russian].
Burkanov, V.N., and T.R. Loughlin. 2007. Historical distribution and abundance of Steller sea lions on the Asian coast. Marine Fisheries Review. 67: 1- 62.
Calkins, D.G. 1981. Distribution and Movements of Steller Sea Lions In The Gulf of Alaska.  Unpublished report. Alaska Department of Fish and Game, Anchorage, AK. 11 pp.
Calkins, D. 1985. Steller sea lion entanglement in marine debris. pp. 308-314. In: R.S. Shomura and H. O. Yoshida (eds). Proceedings of the Workshop on the Fate and Impact of Marine Debris. NOAA Technical Memorandum NMFS-SWFC-54.
Calkins, D.G., E.F. Becker, and K.W. Pitcher. 1998. Reduced body size of female Steller sea lions from a declining population in the Gulf of Alaska. Marine Mammal Science 14:232-244.
Calkins, D., E. Becker, T.R. Spraker, and T.R. Loughlin. 1994a. Impacts on Steller Sea Lions. pp. 119-139. In: T.R. Loughlin (ed.). Marine Mammals and the Exxon Valdez. Academic Press, San Diego.
Calkins, D.G., E. Becker, T.R. Spraker, and T.R. Loughlin. 1994b. Impacts on the distribution and abundance of Steller sea lions in Prince William Sound and the Gulf of Alaska. pp. 119-137. In: T.R. Loughlin (ed.). Marine Mammals and the Exxon Valdez. Academic Press, San Diego.
Calkins, D.G., and J.A. Curatolo. 1980. Marine mammals of Lower Cook Inlet and the potential for impact from outer continental shelf oil and gas exploration, development and transport. Unpublished report. Alaska Department of Fish and Game, Anchorage, AK. 81 pp.
Calkins, D.G., and E. Goodwin. 1988. Investigation of the declining sea lion population in the Gulf of Alaska. Unpublished report. Alaska Department of Fish and Game, Anchorage, AK. 76 pp.
Calkins, D.G., D.C. McAllister, K.W. Pitcher, and G.W. Pendleton. 1999. Steller sea lion status and trend in Southeast Alaska: 1979-1997. Marine Mammal Science 15: 462-477.
Calkins, D.G., and K.W. Pitcher. 1982. Population assessment, ecology and trophic relationships of Steller sea lions in the Gulf of Alaska. pp. 445-546. Final Report of the Outer Continental Shelf Environmental Assessment Program. NOAA, Juneau, AK.
Calkins, D.G., and K.W. Pitcher. 1996. Steller sea lion movements, emigration and survival. pp. 34-40. In: K.W. Pitcher (ed.). Steller Sea Lion Recovery Investigations in Alaska, 1992-1994. ADFandG Wildlife Technical Bulletin No. 13. Alaska Department of Fish and Game, Anchorage, AK.
Colborn, T., F.S.V. Saal and A.M. Soto. 1993. Developmental effects of endocrine-disrupting chemicals in wildlife and humans. Environmental Health Perspectives 101: 378-384.
Dailey, M. D., and R. L. Brownell, Jr. 1972. A checklist of marine mammal parasites. Pages 528-589 in: S. H. Ridgway (ed.), Mammals of the sea, biology and medicine. Charles C Thomas Publ., Springfield IL. 812 pp.
Dailey, M. D., and B. L. Hill. 1970. A survey of metazoan parasites infesting the California (Zalophus californianus) and Steller (Eumetopias jubatus) sea lion. Bull. S. Calif. Acad. Sci. 69:126-132.
Dalton, R. 2005. Is this any way to save a species? Nature 436: 14-16.
de Swart, R.L., P.S. Ross, L.J. Vedder, H.H. Timmerman, S.H. Heisterkamp, H. VanLoveren, J.G. Vos, P.J.H. Reijnders, and A.D.M.E. Osterhaus. 1994. Impairment of immune function in harbor seals (Phoca vitulina) feeding on fish from polluted waters. Ambio 23: 155-159.
Deecke, V.D., P.J.B. Slater and J.K.B. Ford. 2002. Selective habituation shapes acoustic predator recognition in harbour seals. Nature. 420: 171-173.
DeLong, R.L., and G.A. Antonelis. 1991. Impacts of the 1982-1983 El Niño on the northern fur seal population at San Miguel Island, California. pp. 75-83 In: F. Trillmich and K. Ono (eds). Pinnipeds and El Niño: Responses to Environmental Stress. University of California Press, Berkeley, CA.
DeLong, R.L., W.G. Gilmartin, and J.G. Simpson. 1973. Premature births in California sea lions: association with high organochlorine pollutant residue levels. Science 181:1168-1170.
DeMaster, D., and S. Atkinson. (Eds). 2002. Steller sea lion decline: is it food II? Alaska Sea Grant AK-SG-02-02. 80 pp.

DFO. 2007.  State of the Fisheries British Columbia, Trends in B.C.’s commercial Landings (1996-2005). Accessed on 28 Oct 2007 at: http://www.pac.dfo-mpo.gc.ca/ops/fm/reports/fisheries05/stats_e.htm
DFO. 2007b. Recovery strategy for the sea otter (Enhydra lutris) in Canada [Final]. Species at Risk Act Recovery Strategy Series.  Fisheries and Oceans Canada, Vancouver.  vii + 56pp. Available at http://sararegistry.gc.ca/default_e.cfm
DFO. 2007c. Recovery strategy for the transient killer whale (Orcinus orca) in Canada [Final]. Species at Risk Act Recovery Strategy Series.  Fisheries and Oceans Canada, Vancouver. Vi + 46pp.
DFO. 2008. Population Assessment: Steller Sea Lion (Eumetopias jubatus). DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2008/047.
DFO. 2008b. Management plan for the Eastern Pacific grey whales (Eschrichtius robustus) in
Canadian Pacific Waters [Proposed]. Species at Risk Act Management Plan Series. Fisheries and Oceans Canada, Nanaimo. Available at http://www-comm.pac.dfo-mpo.gc.ca/pages/consultations/consult_e.htm
DFO. 2008c. Recovery strategy for the northern and southern resident killer whales (Orcinus orca) in Canada [Final]. Species at Risk Act Recovery Strategy Series.   Fisheries and Oceans Canada, Ottawa. 76p +ix.  Available at http://sararegistry.gc.ca/default_e.cfm
DFO. 2009. Management plan for the offshore killer whale (Orcinus orca) in Canada [Final]. Species at Risk Act Management Plan Series. Fisheries and Oceans Canada, Nanaimo. ix + 51pp.  Available at www.sararegistry.gc.ca
DFO. 2009b. Management plan for the Pacific harbour porpoise (Phocoena phocoena) in Canada
[Final]. Species at Risk Act Management Plan Series. Fisheries and Oceans Canada, Nanaimo.  Available at www.sararegistry.gc.ca
Eberhardt, L.L. 1985. Assessing the dynamics of wild populations. Journal of Wildlife Management 49:997-1012.
Edie, A.G. 1977. Distribution and movements of Steller sea lion cows (Eumetopias jubatus) on a pupping colony. M.Sc. thesis, University of British Columbia, Vancouver, B.C.. 81 pp.
Engelhardt, F.R. 1987. Assessment of the vulnerability of marine mammals to oil pollution. pp. 101-115. In: J. Kuiper and W.J. Van den Brink (eds). Fate and Effects of Oil in Marine Ecosystems. Martinus Nijoff Publishers, Boston, MA.
Engelhardt, F.R., J.R. Geraci, and T.G. Smith. 1977. Uptake and clearance of petroleum hydrocarbons in the ringed seal, Phoca hispida. Journal of the Fisheries Research Board of Canada 34:1143-1147.
Fay, F. H., and D. P. Furman. 1982. Nasal mites (Acari: Halarachnidae) in the spotted seal, Phoca largha Pallas, and other pinnipeds of Alaskan waters. J. Wildl. Dis. 18:63-68.
Fiscus, C.H., and G.A. Baines. 1966. Food and feeding behaviour of Steller and California sea lions. Journal of Mammalogy 47: 195-200.
Fisher, D.H. 1981. Studies on the biology of sea lions in British Columbia. National Geographic Society Research Report 13: 215-219.
Ford, J.K.B., G.M. Ellis and J. W. Durban. 2007. Recovery potential assessment of west coast transient killer whales in British Columbia.  Canadian Science Advisory Council. Research Document 2007/088.
Ford, J.K.B., G.M. Ellis, L.G. Barrett-Lennard, A.B. Morton, R.S. Palm, and K.C. Balcomb III. 1998. Dietary specialization in two sympatric populations of killer whales (Orcinus orca) in coastal British Columbia and adjacent waters. Canadian Journal of Zoology 76: 1456-1471.
Fowler, C.W. 1987. A review of density dependence in populations of large mammals. Current Mammalogy 1: 401-441
Fowler, C.W. 1988. A review of seal and sea lion entanglement in marine fishing debris. pp. 16-63. In:  D.L. Alverson and J.A. June (Eds). Proceedings of the North Pacific Rim Fishermen’s Conference on Marine Debris, Kailua-Kona, HI, 13-16 Oct 1987.  Unpublished Report. National Marine Mammal Laboratory, Seattle, WA. 
Fowler, C.W., and T.R. Merrell. 1986. Victims of plastic technology. Alaska Fish Game 18: 34-37.
Frid, A. and L. Dill. 2002. Human-caused disturbance stimuli as a form of predation risk.  Conservation Ecology. 6(1): 11.
Fritz, L.W., and E.S. Brown . 2005. Survey- and fishery-derived estimates of Pacific cod (Gadus macrocephalus) biomass: implications for strategies to reduce interactions between groundfish fisheries and Steller sea lions (Eumetopias jubatus). Fishery Bulletin 103: 501-515.
Fritz, L.W., and R.C. Ferrero. 1998. Options in Steller sea lion recovery and groundfish fishery management. Biosphere Conservation 1: 7-19.
Fritz, L.W., R.C. Ferrero, and R.J. Berg. 1995. The threatened status of Steller sea lions, Eumetopias jubatus, under the Endangered Species Act: effects on Alaska groundfish fisheries management. Marine Fisheries Review 5: 14-27.
Fritz, L.W., and S. Hinckley. 2005. A critical review of the regime shift - "junk food" – nutritional stress hypothesis for the decline of the western stock of Steller sea lion. Marine Mammal Science 21(3): 476-518.
Gallucci, V., H. Nesse, I. Taylor, and J. Rice.  2006.  Competitive interactions among Steller sea lions, salmon sharks, and commercial fisheries.  Unpublished Manuscript. School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA.
Gentry, R.L. 1970. Social behaviour of the Steller sea lion. PhD thesis, University of California, Santa Cruz, CA. 113 pp.
Gentry, R.L., and J.H. Johnson. 1981. Predation by sea lions on northern fur seal neonates. Mammalia 45:423-430.
Gerber J. A., J. Roletto, L. E. Morgan, D. M. Smith, and L. J. Gage. 1993. Findings in pinnipeds stranded along the central and northern California coast, 1984-1990. J. Wild. Dis. 29:423-433.
Gilmartin, W.G., R.L. DeLong, A.W. Smith, J.C. Sweeney, B.W. DeLappe, R.W. Risebrough, L.A. Griner, and M.D.P. Dailey, and D.B. Peakall. 1976. Premature parturition in the California sea lion. Journal of Wildlife Diseases 12: 104-115.
Gisiner, R.C. 1985. Male territorial and reproductive behaviour in the Steller sea lion, Eumetopias jubatus. Ph.D. thesis, University of California, Santa Cruz, CA. 146 pp.
Graham, G. 2004. Expert systems for marine oil spill response operations. In: 2003 GeorgiaBasin/Puget Sound Research Conference Proceedings. Droscher T.W., Fraser, D.A. (eds). Puget Sound Action Team: Olympia, WA.
Grant, S.C.H. and P.S. Ross. 2002. Southern resident killer whales at risk: toxic chemicals in the British Columbia and Washington environment.  Canadian Technical Report of Fisheries and Aquatic Sciences. 2412. 111p.
Grubb, D. McC. 1977. A practical writing system and short dictionary of Kwakw’ala (Kwakiutl). Canadian Ethnology Service Paper No. 34. National Museum of Canada, Ottawa. 251 pp.
Haebler, R., and R.B. Moeller, Jr. 1993. Pathobiology of selected marine mammal diseases. pp 217-244. In: J.A Couch and J.W. Fournie (eds). Pathobiology of Marine and Estuarine Organisms. CRC Press, Boca Raton, FL.
Hall, A.J., O.I. Kalantzi, and G.O. Thomas. 2003. Polybrominated diphenyl ethers (PBDEs) in grey seals during the first year of life – are they thyroid hormone endocrine disrupters? Environmental Pollution 126: 29-37.
Hancock, D. 1970. California sea lion as a regular winter visitor off the British Columbia coast. Journal of Mammalogy 51:614.
Harding, L.E., and J.R. Englar. 1989. The Nestucca oil spill: fate and effects to May 31, 1989.  Environment Canada Regional Program Report 89-01. Vancouver, B.C.:
Hare, S.R., N.J. Mantua, and R.C. Francis. 1999. Inverse production regimes: Alaskan and West Coast Pacific salmon. Fisheries 24: 6-14.
Helle, E., M. Olsson and S. Jensen. 1976a. DDT and PCB levels and reproduction in ringed seal from the Bothnian Bay. Ambio 5: 188-189
Helle, E.,M. Olsson and S. Jensen. 1976b. PCB levels correlated with pathological changes in seal uteri. Ambio 5: 261-263.
Henry, E. and M.O. Hammill. 2001. Impact of small boats on the haulout activity of
harbour seals (Phoca vitulina) in Metis Bay, St. Lawrence Estuary, Quebec, Canada.
Aquatic Mammals. 27(2):140-148.
Hickie, B.E., D.C.G. Muir, R.F. Addison, and P. Hoekstra. 2005. Modelling the temporal trends of persistent organic pollutants in Arctic ringed seal (Phoca hispida) populations. Science of the Total Environment 351-352: 413-426.
Higgins, L. 1984. Maternal behaviour and attendance patterns of the Steller sea lion in  California. M.Sc. thesis, University of California, Santa Cruz, CA. 37 pp.
Hites, R. 2004. Polybrominated diphenyl ethers in the environment and in people: a meta-analysis of concentrations. Environmental Science and Technology 38:945-956.
Hoffman, J.I., C.W. Matson, W. Amos, T.R. Loughlin, and J.W. Bickham. 2006. Deep genetic subdivision within a continuously distributed and highly vagile marine mammal, the Steller’s sea lion (Eumatopias jubatus). Molecular Ecology 15: 2821-2832
Holmes, E.E., and A.E. York. 2003. Using age structure to detect impacts on threatened populations: a case study with Steller sea lions. Conservation Biology 17(6):1794-1806.
Hood, W.R., and K.A. Ono. 1997. Variation in maternal attendance patterns and pup behaviour in a declining population of Steller sea lions (Eumetopias jubatus). Canadian Journal of Zoology 75: 1241-1246.
Hooper, K. and T.A. McDonald. 2000. The PBDEs: an emerging environmental challenges and another reason for breast-milk monitoring programs. Environmental Health Perspectives 108: 387- 392.
Hunter, A.M.J., and A.W. Trites. 2001. An annotated bibliography of scientific literature (1751-2000) pertaining to Steller sea lions (Eumetopias jubatus) in Alaska. Fisheries Centre Research Reports 9(1): 45 pp.
Jameson, R.J., and K.W. Kenyon. 1977. Prey of sea lions in the Rogue River, Oregon. Journal of Mammalogy 58:672.
Jamieson, G.S., and P.F. Olesiuk. 2001. Salmon farm - pinniped interactions in British Columbia: an analysis of predator control, its justification and alternative approaches. Canadian Stock Assessment Secretariat Research Document 2001/142. 74 pp.
Jepson, P.D., P.M. Bennett, R. Deaville, C.R. Allchin, J.R. Baker, and R.J. Law. 2005. Relationships between polychlorinated biphenyls and health status in harbor porpoises (Phocoena phocoena) stranded in the United Kingdom. Environmental Toxicology and Chemistry 24: 238-248.
Johnson, S.R., J.J. Burns, C.I. Malme, and R.A. Davis. 1989. Synthesis of information on the effects of noise and disturbance on major haulout concentrations of the Bering Sea pinnipeds. Final Report to Mineral Management Service, U.S. Department of Interior, contract no. 14-12-0001-30361. LGL Alaska Research Associates, Anchorage, AK. 284 pp.
Kajimura, H., and T.R. Loughlin. 1988. Marine mammals in the oceanic food web of the eastern subarctic Pacific. Bulletin of the Ocean Research Institue, University of Tokyo 26:187-223.
Kannan, K., J. Koistinen, K. Beckmen, T. Evans, J.F. Gorzelany, K.J. Hansen, P.D. Jones, E. Helle, M. Nyman, and J.P. Giesy. 2001. Accumulation of perfluorooctane sulfonate in marine mammals. Environmental Science and Technology 35: 1593-1598.
Kastelein, R.A., N. Vaughan, and P.R. Wiepkema. 1990. The food consumption of Steller sea lions (Eumetopias jubatus). Aquatic Mammals 15:137-144.
Kenyon, K.W. 1962. History of the Steller sea lion at the Pribilof Islands, Alaska. Journal of Mammalogy 43:68-75.
Kenyon, K.W., and D.W. Rice. 1961. Abundance and distribution of the Steller sea lion. Journal of Mammalogy 42:223-234.
Kucey, L. 2005. Human disturbance and the hauling out behaviour of Steller sea lions (Eumetopias jubatus). M.Sc. thesis, University of British Columbia, Vancouver, B.C. 67 pp.
Lambourn, D.M., S.J. Jeffries, M.M. Lance, P.F. Olesiuk, S.A. Raverty, and A.W. Trites. 2006. Blood analysis on free ranging Steller sea lions (Eumetopias jubatus).  International Association for Aquatic Animal Medicine Conference, 6-10 May 2006. Nassau, Bahamas.
Lawrence, E. 1977. Haida dictionary. Edenso, C., Cogo, R. and N. Cogo (eds.). Society for the Preservation of Haida language and literature, Alaska Native Language Center.  University of Alaska, Fairbanks, AK. 464pp.
Lee, J.S., S. Tanabe, H. Umino, R. Tatsukawa, T.R. Loughlin, and D.C. Calkins. 1996. Persistent organochlorines in Steller sea lion (Eumetopias jubatus) from the bulk of Alaska and the Bering Sea, 1976-1981. Marine Pollution Bulletin 32: 535-544.
Lewis, J.P. 1987. An evaluation of a census-related disturbance of Steller sea lions. M.Sc. thesis. University of Alaska, Fairbanks, AK. 93 pp.
Lindstrom, G., H. Wingfors, M.Dam, and B. von Bavel. 1999. Identification of 19 polybrominated diphenyl ethers (PBDEs) in long-finned pilot whale (Globicephala melas) from the Atlantic. Archives of Environmental Contamination and Toxicology 36: 355-363.
Livingston, P.A. 1991. Groundfish food habits and predation on commercially important prey species in the eastern Bering Sea from 1984-1986. NOAA Technical Memorandum NMFS-NWFC-207.
Loughlin, T.R. 1997. Using the phylogeographic method to identify Steller sea lion stocks. pp. 159-171. In: A. Dizon, S.J. Chivers and W.F. Perrin (eds.). Molecular genetics of marine mammals. Special Publication #3 of the Society for Marine Mammalogy.
Loughlin, T.R. 1998. The Steller sea lion: A declining species. Biosphere Conservation 1: 91-98.
Loughlin, T.R., B.E. Ballachey, and B.A. Wright. 1996. Overview of studies to determine injury caused by the Exxon Valdez oil spill to marine mammals. American Fisheries Society Symposium 18: 798-808.
Loughlin, T.R., L. Consiglieri, R.L. DeLong, and A.T. Actor. 1983. Incidental catch of marine mammals by foreign fishing vessels, 1978-1981. Marine Fisheries Review 45: 44-49.
Loughlin, T.R., and R. L. DeLong. 1983. Incidental catch of sea lions during the 1982 and 1983 walleye pollock joint venture fishery in Shelikof Strait, Alaska. NWAFC Processed Report. 83-15. 37 pp.
Loughlin, T.R., P.J. Gearin, R.L. DeLong, and R.L. Merrick. 1986. Assessment of net entanglement on northern sea lions in the Aleutian Islands, 25 June-15 July 1985. NWAFC Processed Rep. 86-02. National Marine Mammal Laboratory, Seattle WA. 50 pp.
Loughlin, T.R., and R. Nelson, Jr. 1986. Incidental mortality of northern sea lions in Shelikof Strait, Alaska. Marine Mammal Science 2: 14-33.
Loughlin, T.R., M.A. Perez, and R.L. Merrick.  1987. Eumetopias jubatus. Mammalian Species 283: 1-7
Loughlin, T.R., A.S. Perlov, J.D. Baker, S.A. Blokhin, and A.G. Makhnyr. 1998. Diving behaviour of adult female Steller sea lions in the Kuril Islands, Russia. Biosphere Conservation 1: 21-31.
Loughlin, T.R., A.S. Perlov, and V.A. Vladimirov. 1992. Range-wide survey and estimation of total number of Steller sea lions in 1989. Marine Mammal Science 8: 220-239.
Loughlin, T.R., D.J. Rugh, and C.H. Fiscus. 1984. Northern sea lion distribution and abundance: 1956-1980. Journal of Wildlife Management 48: 729-740.
Loughlin, T.R., J T. Sterling, R.L. Merrick, J.L. Sease, and A.E. York. 2003. Diving behaviour of immature Steller sea lions (Eumetopias jubatus). Fishery Bulletin 101: 566-582.
Loughlin, T.R., and A.E. York. 2000. An accounting of the sources of Steller sea lion, Eumetopias jubatus, mortality. Marine Fisheries Review 62:40-45.
Lowe, S.A., and L.W. Fritz. 1997. Atka mackerel. Stock assessment and fishery evaluation report for the groundfish resources of the Bering Sea/Aleutian Islands regions for 1998. North Pacific Fisheries Management Council, Anchorage, AK.
Lowry, M. and O. Maravilla-Chavez. 2005. Recent abundance of California sea lions in western Baja California, Mexico and the United States. Proceedings of the 6th California Islands Symposium, Ventura, CA, 1-3 Dec 2003.  National Park Service Technical Publication CHIS-05-01, Institute for Wildlife Studies, Arcata, CA.
Maniscalco, J.M., C.O. Matkin, D. Maldini, D.G. Calkins, and S. Atkinson.  2007.  Assessing killer whale predation on Steller sea lions from field observations in Kenai Fjords, Alaska.  Marine Mammal Science. 23: 306-321.
Maniscalco, J.M., K. Wynne, K.W. Pitcher, M.B. Hanson, S.R. Melin, and S. Atkinson.  2004.  The occurrence of California sea lions (Zalophus californianus) in Alaska. Aquatic Mammals 30: 427-433.
Martin, J.H., P.D. Elliot, V.C. Anderlini, D. Girvin, S.A. Jacobs, R.W. Risebrough, R.L. DeLong, and W.G. Gilmartin. 1976. Mercury-selenium-bromine imbalance in premature parturient California sea lions. Marine Biology 35: 91-104.
Mate, B.R. 1975. Annual migration of the Steller sea lion and California sea lion along the coast of Oregon. Journal du Conseil International pour l’Exploration de le Mer 169:455-461.
Mate, B.R. 1985. Incidents of marine mammal encounters with debris and active fishing gear. pp. 453-457. In: R.S. Shomura and H. O. Yoshida (eds). Proceedings of the Workshop on the Fate and Impact of Marine Debris. NOAA Technical Memorandum NMFS-SWFC-54.
Mathisen, O.A., R.T. Baade, and R.J. Lopp. 1962. Breeding habits, growth, and stomach contents of the Steller sea lion in Alaska. Journal of Mammalogy 43:464-477.
Matkin, C.O., L.G. Barrett-Lennard, H. Yurk, D. Ellifrit, and A.W. Trites.  2007.  Ecotypic variation and predatory behaviour among killer whales (Orcinus orca) off the eastern Aleutian Islands, Alaska. Fishery Bulletin 105: 74-87.
McAlister, W.B., and M.A. Perez. 1976. Ecosystem dynamics, birds and marine mammals. Part I: Preliminary estimates of pinniped-finfish relationships in the Bering Sea. Final report for Environmental Assessment of the Alaskan Continental Shelf. Alaska Fisheries Science Center. Seattle, WA. pp 219-248.
McFarlane, G.A., J.R. King, and R.J. Beamish. 2000. Have there been recent changes in climate? Ask the fish. Progress in Oceanography 47:147-169.
Melin, S.R., and R.L. DeLong. 1994. Population monitoring of northern fur seals on San Miguel Island, California.  pp. 137-141. In: Sinclair, E.H. (ed.).  Fur Seal Investigations, 1992. NOAA Technical Memorandum NMFS-AFSC-45. 190 pp.
Melin, S.R., and R.L. DeLong. 2000. Population monitoring studies of northern fur seals at San Miguel Island, California. pp. 41-51. In: Robson, B.W. (ed.). Fur Seal Investigations, 1998. NOAA Technical Memorandum NMFS-AFSC-113. 101 pp.
Melin, S.R., R.L. DeLong, and J.R. Thomason. 1996. Population monitoring studies of northern fur seals at San Miguel Island, California. pp. 87-102. In: Sinclair, E.H. (ed.). Fur Seal Investigations, 1994. NOAA Technical Memorandum NMFS-AFSC-69. 144 pp.
Merrick, R.L. 1987. Behavioural and demographic characteristics of northern sea lion rookeries. M.Sc. thesis, Oregon State University, Corvallis, OR. 124 pp.
Merrick, R.L. 1997. Current and historical roles of apex predators in the Bering Sea ecosystem. Journal of Northwest Atlantic Fishery Science:343-356.
Merrick, R.L., M.K. Chumbley, and G.V. Byrd. 1997. Diet diversity of Steller sea lions (Eumetopias jubatus) and their population decline in Alaska: a potential relationship. Canadian Journal of Fisheries and Aquatic Sciences 54: 1342-1348.
Merrick, R.L., and T.R. Loughlin. 1997. Foraging behaviour of adult female and young-of-year Steller sea lions in Alaskan waters. Canadian Journal of Zoology 75: 776-786.
Milette, L.L. 1999. Behaviour of lactating Steller sea lions (Eumetopias jubatus) during the breeding season: A comparison between a declining and stable population in Alaska. M.Sc. thesis, University of British Columbia, Vancouver, B.C. 57 pp.
Milette, L.L., and A.W. Trites. 2003. Maternal attendance patterns of lactating Steller sea lions (Eumetopias jubatus)from a stable and a declining population in Alaska. Canadian Journal of Zoology 81:340-348.
Morton, A.B. 1990. A quantitative comparison of the behaviour of resident and transient forms of the killer whale off the central British Columbia coast. Report of the International Whaling Commission, Special Issue 12: 245-248.
Mos, L., B. Morsey, S.J. Jeffries, M.B. Yunker, S. Raverty, S. De Guise, and P.S. Ross. 2006. Chemical and biological pollution contribute to the immunological profiles of free-ranging harbor seals. Environmental Toxicology and Chemistry 25: 3110-3117
Mos, L., M. Tabuchi, N. Dangerfield, S.J. Jeffries, B.F. Koop, and P.S. Ross. 2007. Contaminant-associated disruption of vitamin A and its receptor (RARa) in free-ranging harbour seals (Phoca vitulina). Aquatic Toxicology 81: 319-328
Newcombe, C.F., and W.A. Newcombe. 1914. Sea-lions on the coast of British Columbia,  Report of the Commission of Fisheries for 1913. 131-139 pp.
NMFS (National Marine Fisheries Service). 1992. Recovery Plan for the Steller sea lion (Eumetopias jubatus). Prepared by the Steller Sea Lion Recovery Team for the Office of Protected Resources, National Marine Fisheries Service, Silver Spring, MD. 92 pp.
NMFS (National Marine Fisheries Service). 2001. Endangered Species Act, Section 7 Consultation Biological Opinion and Incidental Take Statement on the authorization of the Bering Sea/Aleutian Islands and Gulf of Alaska Groundfish Fishery Management Plan Amendments 61 and 70. NMFS Alaska Region, Protected Resources Division, Juneau, AK.  206 pp.
NMFS (National Marine Fisheries Service).  2008.  Steller sea lion recovery plan, eastern and western distinct population segments (Eumetopias jubatus).Revision.  Office of Protected Resources, National Marine Fisheries Service, Silver Spring, MD. 325 pages.
O’Corry-Crowe, G., T. Gelatt, K. Pitcher, and B. Taylor.  2005.  Crossing significant boundaries: evidence of mixed-stock origins of new Steller sea lion, Eumetopias jubatus, rookeries in southeast Alaska.  6th Biennial Conference on the Biology of Marine Mammals, 12-16 Dec 2005, San Diego, CA.
O’Corry-Crowe, G., B.L. Taylor, T. Gelatt, T.R. Loughlin, J. Bickman, M. Basterrretche, K.W. Pitcher, and D.P. DeMaster.  2007  Demographic independence along ecosystem boundaries in Steller sea lions revealed by mtDNA analysis: implications for management of an endangered species.  Canadian Journal of Zoology. 84: 1796-1809.
O'Daniel, D., and J.C. Schneeweis. 1992. Steller sea lion, Eumetopias jubatus, predation on Glaucous-winged gulls, Larus glaucescens. Canadian Field-Naturalist 106:268.
Olesiuk, P.F.  1999.  An assessment of the status of harbour seals (Phoca vitulina) in British Columbia.  Canadian Stock Assessment Secretariat Research Document. 1999/33. 71 pp.
Olesiuk, P.F. 2008. Abundance of Steller sea lions (Eumetopias jubatus) in British Columbia. Canadian Science Advisory Secretariat Research Document. 2007/063.
Olesiuk, P.F., Calkins, D.G., Pitcher, K.W., and Perryman,W.L.,C. Stinchcomb, and M. Lynn. 2008. An evaluation of Steller sea lion (Eumetopias jubatus) pup counts from 35mm oblique photographs. Canadian Science Advisory Secretariat Research Document.2007/064.
Olesiuk, P.F., and M.A. Bigg. 1988. Seals and sea lions in British Columbia. Department of Fisheries and Oceans Special Publication. Pacific Biological Station, Nanaimo, B.C. 12 pp.
Olesiuk, P.F., M.A. Bigg and G.M. Ellis.  1990.  Recent trends in the abundance of harbour seals, Phoca vitulina, in British Columbia.  Canadian Journal of Fisheries and Aquatic Science 47(5): 992-1003.
Orr, R. T., and T.C. Poulter. 1967. Some observations on reproduction, growth, and social behaviour in the Steller sea lion. Proceedings of the California Academy of Science 35: 193-226.
Pascual, M.A., and M.D. Adkinson. 1994. The decline of the Steller sea lion in the northeast Pacific: demography, harvest or environment? Ecological Applications 4:393-403.
Pauly, D., V. Christensen, J. Dalsgaard, R. Froese, and F. Torres Jr. 1998. Fishing down marine food webs. Science 279: 860-863.
Pearson, J.P., and J.P. Verts.  1970.  Abundance and distribution of harbor seals and northern sea lions in Oregon. Murrelet 51: 1-5.
Perez, M.A. 1994. Calorimetry measurements of energy value of some Alaskan fishes and squids. NOAA Technical Memorandum NMFS-AFSC-32. 32 pp.
Pike, G.C. 1958. Food of the northern sea lion. Fisheries Research Board of Canada, Progress Report of the Pacific Coast Biological Station. 112, 18-20 pp.
Pike, G.C., and B.E. Maxwell. 1958. The abundance and distribution of the northern sea lion (Eumetopias jubata) on the coast of British Columbia. Journal of the Fisheries Research Board of Canada 15: 5-17.
Pitcher, K.W. 1981. Prey of the Steller sea lion, Eumetopias jubatus, in the Gulf of Alaska. Fishery Bulletin 79: 467-472.
Pitcher, K.W., D.G. Calkins, and G. Pendleton. 1998. Reproductive performance of female Steller sea lions: an energetics-based reproductive strategy? Canadian Journal of Zoology 76: 2075-2083.
Pitcher, K.W., and F.H. Fay. 1982. Feeding by Steller sea lions on harbor seals. Murrelet 63: 70-71.
Pitcher, K.W., P.F. Olesiuk, R.F. Brown, M. Lowry, J. Sease, W. Perryman, C. Stinchcomb, and L. Lowry. 2003. Status and trend of the eastern population of Steller sea lions.  Marine Sciences in the Northeast Pacific Symposium, 13-17 Jan 2003, Anchorage, AK.
Pitcher, K.W., P.F. Olesiuk, R.F. Brown, M.S. Lowry, S.J. Jeffries, J.L. Sease, W.L. Perryman, C.E. Stinchcomb, and L.F. Lowry.  2007. Abundance and distribution of the eastern North Pacific Steller sea lion (Eumetopias jubatus) population.  Fishery Bulletin 105: 102-115.
Raum-Suryan, K., and K.W. Pitcher. 2000. Trip report: brand resights of Steller sea lions within Southeast Alaska and northern British Columbia from 19 June - 10 July, 2000.  Unpublished report. Alaska Department of Fish and Game, Anchorage, AK.
Raum-Suryan, K.L., K.W. Pitcher, D.G. Calkins, J.L. Sease, and T.R. Loughlin. 2002. Dispersal, rookery fidelity, and metapopulation structure of Steller sea lions (Eumetopias jubatus) in an increasing and a decreasing population in Alaska. Marine Mammal Science 18:746-764.
Rayne, S., M.G. Ikonomou, P.S. Ross, G. M. Ellis, and L.G. Barrett-Lennard. 2004. PBDEs, PBBs, and PCNs in three communities of free-ranging killer whales (Orcinus orca) from the northeastern Pacific Ocean. Environmental Science and Technology 38: 4293-4299.
Reijnders, P.J.H. 1986. Reproductive failure in common seals feeding on fish from polluted coastal waters. Nature 324: 456-457.
Rice, D.W. 1998. Marine mammals of the world: systematics and distribution. Special Publication of the Society of Marine Mammalogy. 231 pp.
Roffe, T.J., and B.R. Mate. 1984. Abundances and feeding habits of pinnipeds in the Rogue River, Oregon. Journal of Wildlife Management 48:1261-1274.
Rosen, D.A.S., and A.W. Trites. 1999. Metabolic effects of low-energy diet on Steller sea lions, Eumetopias jubatus. Physiological and Biochemical Zoology 72:723-731.
Rosen, D.A.S., and A.W. Trites. 2000a. Assessing the role of nutritional stress in the decline of wild populations: a Steller case of scientific sleuthing. pp. 182-186. In: C.L.K. Baer (ed.). Proceedings of the Third Comparative Nutrition Society Symposium, Pacific Grove, CA, 4-9 August 2000.
Rosen, D.A.S., and A.W. Trites. 2000b. Digestive efficiency and dry matter digestibility of Steller sea lions fed herring, pollock, squid, and salmon. Canadian Journal of Zoology 78:234-239.
Rosen, D.A.S., and A.W. Trites. 2000c. Pollock and the decline of Steller sea lions: testing the junk-food hypothesis. Canadian Journal of Zoology 78:1243-1258.
Ross, P.S. 2000. Marine mammals as sentinels in ecological risk assessment. Human and Ecological Risk Assessment 6: 29-46
Ross, P.S. 2002. The role of immunotoxic environmental contaminants in facilitating the emergence of infectious diseases in marine mammals. Human and Ecological Risk Assessment. 8(2): 277-292.
Ross, P.S. 2006. Fireproof killer whales (Orcinus orca): Flame retardant chemicals and the conservation imperative in the charismatic icon of British Columbia, Canada. Canadian Journal of Fisheries and Aquatic Sciences 63: 224-234.
Ross, P. S., R.L. de Swart, P.J.H. Reijnders, H.V. Loveren, J.G. Vos, and A D.M.E. Osterhaus. 1995. Contaminant-related suppression of delayed-type hypersensitivity and antibody responses in harbour seals fed herring from the Baltic Sea. Environmental Health Perspectives 103:162-167.
Ross, P.S., R.L. de Swart, H.H. Timmerman, H. van Loveren, J.G. Vos, and A.D.M.E. Osterhaus. 1996. Immunotoxicological studies in the harbour seal (Phoca vitulina). pp. 579-584. In: J.S. Stolen, T.C. Fletcher, C.J. Bayne, C.J. Secombes, J.T. Zelikoff, L.E. Twerdok and D.P. Anderson (eds). Modulators of Immune Responses: the Evolutionary Trail. SOS Publications, Fair Haven, NJ.
Ross, P.S., R.L. De Swart, H. Van der Vliet, L. Willemsen, A. De Klerk, G. Van Amerongen, J. Groen, A. Brouwer, I. Schipholt, D.C. Morse, H. Van Loveren, A.D.M.E. Osterhaus, and J.G. Vos. 1997. Impaired cellular immune response in rats exposed perinatally to Baltic Sea herring oil or 2,3,7,8-TCDD. Archives of Toxicology 17: 563-574
Rowley, J. 1929. Life history of sea lions on the California coast. Journal of Mammalogy 10:1-36.
Sandegren, F.E. 1970. Breeding and maternal behaviour of the Steller sea lion (Eumetopias jubatus) in Alaska. M.Sc. thesis, University of Alaska, Fairbanks, AK 138 pp.
Sandegren, F.E. 1976. Courtship display, agonistic behaviour and social dynamics in the Steller sea lion. Behaviour 57:136-158.
Scheffer, V.B. 1964. Hair patterns in seals (Pinnipedia). Journal of Morphology 115: 291-303.
Schusterman, R.J. 1981. Steller sea lion, Eumetopias jubatus (Schreber, 1776). pp. 119-141.  In: S.H. Ridgway and R.J. Harrison (eds). Handbook of Marine Mammals. Vol. 1. Walrus, Sea Lions, Fur Seals and Sea Otters. Academic Press, New York, NY.
Scordino, J.  2006. Steller sea lions (Eumetopias jubatus) of Oregon and northern California: seasonal haulout abundance patterns, movements of marked juveniles, and effects of hot-branding on apparent survival of pups at Rogue Reef.  M.Sc. Thesis, University of Oregon, Corvallis, OR.  93p.
Sease, J.L., R.F. Brown, V.N. Burkanov, D.G. Calkins, P.F. Olesiuk, and A.E. York. 1999. Range-wide survey of Steller sea lions in 1994.  Unpublished Report. National Marine Mammal Laboratory, Seattle, WA.
Sease, J.L., and C. Stinchcomb. 2003. 2002 Surveys of Steller Sea Lions in Alaska.  Marine Sciences in the Northeast Pacific Symposium, 13-17 Jan 2003, Anchorage, AK.
Sheffield, G. and R. Zarnke.  1997.  Summaries of serologic data collected from Steller sea lions in the Bering Sea and Gulf of Alaska, 1978-1996.  pp. 74-84. In: K.W. Pitcher (ed.).  Steller Sea Lion Recovery Investigations in Alaska, 1995-1996. NOAA Contract Report NA57FX0256.  Alaska Department of Fish and Game, Division of Wildlife Conservation, Anchorage, AK. 
Shima, M., A.B. Hollowed, and G.R. VanBlaricom. 2000. Response of pinniped populations to directed harvest, climate variability, and commercial fishery activity: a comparative analysis. Reviews in Fisheries Science 8:89-124.
Shults, L. M. 1986. Helminth parasites of the Steller sea lion, Eumetopias jubatus, in Alaska. Proc. Helminthol. Soc. Wash. 53:194-197.
Sigler, M.F., L.B. Hulbert, C.R. Lunsford, N.H. Thompson, K. Burek, G. O'Corry- Crowe, and A.C. Hirons. 2006. Diet of Pacific sleeper shark, a potential Steller sea lion predator, in the northeast Pacific Ocean. Journal of Fish Biology 69:392-405.
Sinclair, E., T.R. Loughlin, and W. Pearcy. 1994. Prey selection by northern fur seals (Callorhinus ursinus) in the eastern Bering Sea. Fishery Bulletin 92:144-156.
Sinclair, E.H., G.A. Antonelis, B.W. Robson, R.R. Ream, and T.R. Loughlin. 1996. Northern fur seal, Callorhinus ursinus, predation on juvenile walleye pollock, Theragra chalcogramma. pp 167-178. In: R.D. Brodeur, P.A. Livingston, T.R. Loughlin, and A.B. Hollowed (eds). Ecology of Juvenile Walleye Pollock, Theragra chalcogramma. NOAA Technical Report NMFS 126.
Sinclair, E.H., and T.K. Zeppelin. 2002. Seasonal and spatial differences in diet in the western stock of Steller sea lions (Eumetopias jubatus). Journal of Mammalogy 83:973-990.
Smith, T.G., and J.R. Geraci. 1975. The effect of contact and ingestion of crude oil on ringed seals in the Beaufort Sea. Beaufort Sea Technical Report No. 5. 66 pp.
Song, L., A. Seeger, and J. Santos-Such. 2005. On membrane motor activity and chloride flux in the outer hair cell: lessons learned from the environmental toxin tributyltin. Biophysical Journal 88 (3): 2350-2362.
Spalding, D.J. 1964. Comparative feeding habits of the fur seal, sea lion and harbour seal on the British Columbia coast. Fisheries Research Board of Canada Bulletin 146:1-47.
Springer, A.M. 1998. Is it all climate change? Why marine bird and mammal populations fluctuate in the North Pacific. pp 109-119. In: G. Holloway, P. Muller and D. Henderson (eds). Biotic Impacts of Extratropical Climate Variability in the Pacific. Proceedings of the 'Aha Huliko'a Hawaiian Winter Workshop. 26-29 Jan 1998. University of Hawaii, Honolulu, HI. 
St. Aubin, D.J. 1990. Physiologic and toxic effects on pinnipeds. pp. 103-127. In: J.R. Geraci and D.J. St. Aubin (eds). Sea Mammals and Oil: Confronting the Risks. Academic Press, San Diego, CA.
Stewart, B.S., and P.K. Yochem. 1987. Entanglement of pinnipeds in synthetic debris and fishing net and line fragments at San Nicolas and San Miguel Islands, California, 1978-1986. Marine Pollution Bulletin 18: 336-339.
Stroud, R.K. 1978. Causes of death and pathological findings in marine mammals along the Oregon coast. M.Sc. thesis, Oregon State University, Corvalis, OR. 65 pp.
Swain, U.G. 1996. Foraging behaviour of female Steller sea lions in Southeast Alaska and the eastern Gulf of Alaska. pp 135-166. Steller sea lion recovery investigations in Alaska, 1992-1994.  Wildlife Technical Bulletin 13, May 1996. Alaska Department of Fish and Game, Anchorage, AK.,
Swain, U.G. 1999. Steller sea lion foraging studies in Southeast Alaska during 1998. Steller Sea Lion Research Peer Review Feeding Ecology Workshop. 11-12 Feb 1999. Seattle, WA. 40 pp.
Swain, U., and D.G. Calkins. 1997. Foraging behaviour of juvenile Steller sea lions in the northeastern Gulf of Alaska: diving and foraging trip duration. pp. 92-106. Steller sea lion recovery investigations in Alaska, 1995-1996. Unpublished report. Alaska Department of Fish and Game, Anchorage, AK.
Szaniszlo, W. 2005. California sea lion (Zalophus californianus) and Steller sea lion (Eumetopias jubatus) interactions with vessels in Pacific Rim National Park Reserve: implications for marine mammal viewing management. M.Sc. Thesis. University of Victoria.
Tabuchi, M., N. Veldhoen, N. Dangerfield, S. J. Jeffries, C.C. Helbing, and P.S. Ross. 2006. PCB-related alteration of thyroid hormones and thyroid hormone receptor gene expression in free-ranging harbor seals (Phoca vitulina). Environmental Health Perspectives 114: 1024-1031
Tamura, T., and S. Ohsumi. 2000. Regional assessments of prey consumption by marine cetaceans in the world. International Whaling Commission, Scientific Committee Document SC/52/E6. 42 p.
Thorsteinson, F.V., and C.J. Lensink. 1962. Biological observations of Steller sea lions taken during an experimental harvest. Journal of Wildlife Management 26:353-359.
Trenberth, K.E. 1990. Recent observed interdecadal climate changes in the northern hemisphere. Bulletin of the American Meteorological Society 71:988-993.
Trites, A.W. 1997. The role of pinnipeds in the ecosystem. pp. 31-39. In: G. Stone, J. Goebel and S. Webster (eds). Pinniped populations, eastern north Pacific: status, trends and issues, New England Aquarium, Conservation Department, Boston, MA.
Trites, A.W., V. Christensen, and D. Pauly. 2006. Effects of fisheries on ecosystems: just another top predator? pp. 11-27. In: I.L. Boyd, K. Camphuysen and S. Wanless (eds). Top Predators in Marine Ecosystems: Their Role in Monitoring and Management. Cambridge University Press, Cambridge.
Trites, A.W., and C.P. Donnelly. 2003. The decline of Steller sea lions in Alaska: a review of the nutritional stress hypothesis. Mammal Review 33: 3-28.
Trites, A.W., and P.A. Larkin. 1996. Changes in the abundance of Steller sea lions (Eumetopias jubatus) in Alaska from 1956 to 1992: How many were there? Aquatic Mammals 22: 153-166.
Trites, A.W., P.A. Livingston, S. Mackinson, M.C. Vasconcellos, A.M. Springer, and D. Pauly. 1999. Ecosystem change and the decline of marine mammals in the eastern Bering Sea: testing the ecosystem shift and commercial whaling hypotheses. UBC Fisheries Centre Research Reports. 7(1): 106 pp.
Trites, A.W., A.J. Miller, H.D.G. Maschner, M.A. Alexander, S.J. Bograd, J.A. Calder, A. Capotondi, K.O. Coyle, E.D. Lorenzo, B.P. Finney, E.J. Gregr, C.E. Grosch, S.R. Hare, G.L. Hunt, J. Jahncke, N.B. Kachel, H.-J. Kim, C. Ladd, N.J. Mantua, C. Marzban, W. Maslowski, R. Mendelssohn, D.J. Neilson, S.R. Okkonen, J.E. Overland, K.L. Reedy-Maschner, T.C. Royer, F.B. Schwing, J.X.L. Wang, and A.J. Winship. 2007. Bottom-up forcing and the decline of Steller sea lions in Alaska: assessing the ocean climate hypothesis. Fisheries Oceanography: 16: 46-67.
Van de Vijver, K.I., P.T. Hoff, K. Das, W. Van Dongen, E. L Esmans, T. Jauniaux, J. Bouquegenau, R. Blust, and W. de Coen. 2003. Perfluorinated chemicals infiltrate ocean waters: link between exposure levels and stable isotope ratios in marine mammals. Environmental Science and Technology 37: 5545-5550.
Wada, K. 1998. Steller sea lions: present status of studies of migratory ecology, and conflict between fisheries and conservation in Japan. Biosphere Conservation 1: 1-6.
Wade, P., V.N. Burkanov, M.E. Dahlheim, N.A. Friday, L.W. Fritz, T.R. Loughlin, S.A. Mizroch, M.M. Muto, D.W. Rice, L.G. Barrett-Lennard, N.A. Black, A.M. Burdin, J. Calambokidis, S. Cerchio, J.K.B. Ford, J.K. Jacobsen, C.O. Matkin, D.R. Matkin, A.V. Mehta, R.J. Small, J.M. Straley, S.M. McCluskey, and G.R. VanBlaricom. 2007. Killer whales and marine mammal trends in the North Pacific – A re-examination of evidence for the sequential megafauna collapse and the prey-switching hypothesis.  Marine Mammal Science 23(4): 766-802
Wespestad, V.G., L.W. Fritz, W.J. Ingraham, and B.A. Megrey. 2000. On relationships between cannibalism, climate variability, physical transport, and recruitment success of Bering Sea walleye pollock (Theragra chalcogramma). ICES Journal of Marine Science 57: 272-278.
Wilke, F., and K.W. Kenyon. 1952. Notes on the food of fur seal, sea-lion, and harbor porpoise. Journal of Wildlife Management 16: 396-397.
Winship, A.J., and A.W. Trites. 2003. Prey consumption of Steller sea lions (Eumetopias jubatus) off Alaska: How much prey do they require? Fishery Bulletin 101: 147-167.
Winship, A.J., A.W. Trites, and D.G. Calkins. 2001. Growth in body size of the Steller sea lion (Eumetopias jubatus). Journal of Mammalogy 82: 500-519.
Winship, A.J., A.W. Trites, and D.A.S. Rosen. 2002. A bioenergetic model for estimating the food requirements of Steller sea lions (Eumetopias jubatus) in Alaska, USA. Marine Ecology Progress Series 229: 291-312.
Withrow, D.E. 1982. Using aerial surveys, ground truth methodology, and haul out behaviour to census Steller sea lions, Eumetopias jubatus. M.Sc. thesis, University of Washington, Seattle, WA. 102 pp.
York, A.E. 1994. The population dynamics of northern sea lions, 1975-1985. Marine Mammal Science 10: 38-51.
York, A.E., R.L. Merrick, and T.R. Loughlin. 1996. An analysis of the Steller sea lion metapopulation in Alaska. pp. 259-292. In: D.R. McCullough (ed.). Metapopulations and Wildlife Conservation. Island Press, Washington, DC.

6. Appendix I

Table 4. Details on Terms used for Assessment of Threats to the Eastern Pacific Steller Sea Lion Population .

TERMSRATINGDEFINITIONS
UncertaintyLowEffect of threat is causally linked with decreased population viability and likely will result in failure to meet management plan objectives
MediumEffect of threat is correlated with decreased population viability and negatively impacts management plan objectives
HighNegative effect of threat on population viability and/or management plan objectives is assumed or is plausible.
SeverityNegligibleThreat has no detectable effects on the population
LowEffects of threat are sublethal, potentially leading to short-term behavioural changes
ModerateEffects of the threat result in chronic physiological and/or behavioural changes (e.g. potential for long-term displacement from habitat)
HighEffects of the threat are lethal
UnknownAvailable information is insufficient to gauge the degree to which the threat may affect the population viability
Mitigation PotentialLowImplementation of measures to mitigate or prevent impacts on population viability, are not practical or are likely to be unsuccessful.
ModerateImplementation of measures to mitigate or prevent impacts on population viability are feasible, and are likely to be somewhat successful
HighImplementation of measures to mitigate or prevent impacts on population viability are currently in place and future measures are likely to be very easy to implement, and are likely to be very successful.
UnknownAvailable information is insufficient to gauge whether mitigation of effects from the threat is possible.

Table 5.  Persistent Organic Pollutants that may pose a risk to Steller Sea Lions.  Table was obtained from the final Recovery Strategy for Resident Killer Whales in Canada (DFO 2008c).

PollutantUse/SourcePersistentBio-accumulateRisk
DDT
Dichlorodi-phenyl trichloroethane
pesticide used in some countries, banned in North America, persists in terrestrial runoff 30 years post-ban, enters atmosphere from areas where still in useyesyesreproductive impairment, immunosuppression, adrenal and thyroid effects
PCBs
Polychlorinated Biphenyls
electrical transformer and capacitor fluid, limited use in North America but enters environment from runoff, spills and incinerationyesyesreproductive impairment, skeletal abnormalities, immunotoxicity and endocrine disruption
Dioxins and Furansby-product of chlorine bleaching, wood product processing and incomplete combustion. Mills less of a source now. Current sources include burning of salt-laden wood, municipal incinerators, and residential wood and wood waste combustion, in runoff from sewage sludge, wood treatmentyesyesthymus and liver damage, birth defects, reproductive impairment, endocrine disruption, immunotoxicity and cancer
PAHs
Persistent Polycyclic aromatic hydrocarbons
by-product of fuel combustion, aluminum smelting, wood treatment, oil spills, metallurgical and coking plants, pulp and paper millsyesnocarcinogenic
flame retardants, esp. PBBs and PBDEs
Polybrominated diphenyl ethers
flame retardants; in electrical components and backings of televisions and computers, in textiles and vehicle seats, ubiquitous in environment.  2/3  product PBDEs banned in Europe. Same two products withdrawn from North American marketplace in 2005, but one (deca) product still used globally.yesyesendocrine disruption, impairs liver and thyroid
PFOs
Perfluro-octane sulfonate
stain, water and oil repellent (included in Scotchgard until recently), fire fighting foam, fire retardants, insecticides and refrigerants, ubiquitous in environmentyesyes but in blood, liver, kidney and musclepromotes tumour growth
TBT, DBT
Tributyltin
Dibutyltin
antifoulant pesticide used on vesselsyesyesunknown but recently associated with hearing loss
PCPs
 (Polychlorinated paraffins)
flame retardants, plasticizers, paints, sealants and additives in lubricating oilsyesyesendocrine disruption
PCNs
Polychlorinated napthalenes
ship insulation, electrical wires and capacitors, engine oil additive, municipal waste incineration and chlor-alkali plants, contaminant in PCBsyesyesendocrine disruption
APEs
Alkyl-phenol ethoxylates
detergents, shampoos, paints, pesticides, plastics, pulp and paper mills, textile industry found in sewage effluent and sedimentsmoderatemoderateendocrine disruption
PCTs
Polychlorinated terphenyls
fire retardants, plasticizers, lubricants, inks and sealants, enters environment in runoffyesyesendocrine disruption and reproductive impairment
References: Primarily Grant and Ross 2002, but also Lindstrom et al. 1999, Hooper and MacDonald 2000, Kannan et al. 2001, Hall et al. 2003; Van deVijver et al. 2003, Rayne et al. 2004, Song et al. 2005.

7. Appendix II:

Organizations currently involved in research on Eastern Pacific Steller Sea Lions.

  • Fisheries and Oceans Canada, Nanaimo, B.C.
    • Science Branch
    • Marine Mammal Response Network
  • Parks Canada Agency
  • Vancouver Aquarium Marine Sciences Centre, Vancouver, B.C.
    • Veterinary Department
    • Marine Mammal Rescue and Rehabilitation Department
  • University of British Columbia
  • U.S. National Oceanographic and Atmospheric Administration, Seattle, WA
  • National Marine Fisheries Service
  • Oregon Department of Fish and Wildlife
  • Washington Department of Fish and Wildlife
  • Alaska Department of Fish and Game
  • Oregon State University
  • B.C. Ministry of Agriculture and Lands, Abbotsford, B.C.
  • Independent Researchers

8. Appendix III: Record Of Cooperation and Consultation

Eastern Pacific Steller Sea Lions are listed as a species of “special concern” on Schedule 1 of the Species at Risk Act (SARA).  As an aquatic species, they fall under federal jurisdiction, and are managed by Fisheries and Oceans Canada (DFO) Suite 200 - 401 Burrard Street, Vancouver, B.C, V6C 3S4.

DFO brought together a small internal working group of technical experts from science and management to develop an initial draft of this management plan.  A Steller Sea Lion Management Planning Technical Workshop was hosted in November of 2007 to provide a forum for the sharing of knowledge and expertise on Eastern Pacific Steller Sea Lions to support the drafting of the plan.  A group of scientific and technical experts including independent researchers, environmental non-governmental organizations, and other governmental (federal and provincial) staff from both Canada and the United States participated in the workshop. An invitation letter was also sent to all coastal First Nations soliciting their participation in development of the management plan and at the technical workshop.  This workshop was invaluable in assisting the DFO internal working group in drafting the Management Plan for Steller Sea Lions in Canada.  Given that the population considered in this management plan frequents both Canadian and United States (U.S.) waters, bilateral government and non-government input and collaboration was sought. 

A draft version of the management plan was posted to the DFO Pacific Region website for a 30-day public comment period from April 7 to May 12, 2008, and also included mail-outs to all coastal First Nations soliciting comments, follow-up emails were also sent.  Consultations were web-based, and included an initial draft of the management plan, discussion guide and feedback form available online. In addition, a message announcing the development of the management plan, was sent to a marine mammal list serve (MARMAM) with a broad local and international distribution to marine mammal researchers and interested parties, and to a distribution list of whale-related contacts provided to DFO in recent years from environmental groups, non-governmental organizations, government agencies, and the eco-tourism sector. 

Comments on the management plan were received from eight independent sources and from two government agencies: Environment Canada, and the Province of B.C.  Processes for coordination and consultation between the federal and provincial governments on management and protection of species at risk are outlined in the Canada-B.C. Agreement on Species at Risk (2005).   Natural Resources Canada, Department of National Defence, the Parks Canada Agency and Transport Canada provided no comments on the draft document.  The Parks Canada Agency provided input during the development of the management plan through active involvement in the technical workshops and ongoing representation, as a competent agency under SARA. This negated the need to provide input through the public consultation mechanism. No feedback was received from mail-outs to First Nations.  

Feedback from the public, government agencies and scientific experts has been carefully considered in the production of the final management plan. Peer review of the document was not considered necessary as applicable experts were in attendance at the Steller Sea Lion Management Planning Technical Workshop and were provided an opportunity to provide input through public consultation.

Fisheries and Oceans Canada Technical Team:

Paul Cottrell                            Fisheries and Oceans Canada
Marilyn Joyce                          Fisheries and Oceans Canada
Peter Olesiuk                           Fisheries and Oceans Canada
John Ford                                Fisheries and Oceans Canada
Graeme Ellis                            Fisheries and Oceans Canada
Jake Schweigert                      Fisheries and Oceans Canada
Peter Ross                               Fisheries and Oceans Canada
Larry Paike                              Fisheries and Oceans Canada
Tatiana Lee                             Fisheries and Oceans Canada
Joy Hillier                                Fisheries and Oceans Canada
Jeff Grout                               Fisheries and Oceans Canada
Linda Nichol                           Fisheries and Oceans Canada
Robin Abernethy                    Fisheries and Oceans Canada

Steller Sea Lion Management Planning Technical Workshop Participants:

Alana Phillips                          Vancouver Aquarium Marine Science Centre, B.C. Cetacean Sightings Network
Andrew Trites                          University of British Columbia
Annely Greene                          Fisheries and Oceans Canada, Fisheries Management
Brent Norberg                          National Oceanic and Atmospheric Administration
Brian Fadely                            National Oceanic and Atmospheric Administration
Courtney Druce                       Fisheries and Oceans Canada, Fisheries Management
Dave Rosen                             University of British Columbia, Marine Mammal Research Unit
Dominic Tollit                         University of British Columbia
Doug Bifford                           Province of B.C.
Graeme Ellis                            Fisheries and Oceans Canada– Pacific Region, Science
Jake Schweigert                        Fisheries and Oceans Canada – Pacific Region, Science
John Ford                                Fisheries and Oceans Canada– Pacific Region, Science
Joy Hillier                                Fisheries and Oceans Canada– Pacific Region, Habitat
Kaja Brix                                 National Oceanic and Atmospheric Administration, Juneau AK
Kim Raum-Suryan                   Alaska Department of Fish and Game, and Oregon State University
Larry Paike                              Fisheries and Oceans Canada, Conservation and Protection   
Louvi Nurse                             Fisheries and Oceans Canada, Treaty and Aboriginal Policy
Marilyn Joyce                          Fisheries and Oceans Canada, Fisheries Management
Marty Haulena                         Vancouver Aquarium Marine Sciences Centre
Norm Sloan                             Parks Canada Agency, Haida Gwaii
Pat Gearin                                National Oceanic and Atmospheric Administration
Peter Ross                                Fisheries and Oceans Canada– Pacific Region, Science
Robin Abernethy                     Fisheries and Oceans Canada – Pacific Region, Science
Robin Brown                           Oregon Department of Fish and Wildlife
Tatiana Lee                              Fisheries and Oceans Canada – Pacific Region
Wendy Szaniszlo                     Parks Canada Agency


1 Regulated and unregulated contaminants of concern are listed in Appendix II.

2 The vast number of pinniped entanglements (110 out of 170) can be attributed to shark guards used at one site, and these have since been removed (DFO unpublished data).

3 For example; Canada Shipping Act, Regulations for Prevention of Pollution from Ships and for Dangerous Chemicals.

4 Include in the operational manual, measures outlined in the Fisheries and Oceans Canada ‘Marine mammal incident response’ manual and ‘Sea otter oil spill response plan for Canada’s Pacific coast’ (draft).

5 Identification of government agencies and non-governmental organizations is intended to be advice and does not commit the agency or organization to implementing the listed action.  Implementing actions will be contingent upon each organization’s or agency’s priorities and budgetary constraints.