Atlantic wolffish (Anarhichas lupus) COSEWIC assessment and status report 2012: chapter 4
Anarhichas lupus
Atlantic (Striped) Wolffish
Range of occurrence in Canada: Eastern Arctic Ocean and the Atlantic Ocean (including the Bay of Fundy, Scotian Shelf, Grand Banks off Newfoundland, Gulf of St. Lawrence, northeastern Newfoundland and the Labrador Sea)
Demographic Information
Generation time (average age of parents in the population) | 15 |
Is there a continuing decline in the number of mature individuals? | No |
Estimated percent of continuing decline in the total number of mature individuals within 5 years or 2 generations | N/A |
Estimated percent change in the total number of mature individuals over the last 10 years, or 3 generations. Strong declines from the 1980s until the mid-1990s over much of the range. Numbers have been increasing in most areas since then, but they remain low compared to the start of the surveys. |
Variable, overall declines |
Projected percent change in the total number of mature individuals over the next 10 years or 3 generations. | Unknown |
Percent reduction or increase in the total number of mature individuals over any 10 year or 3 generation period, over a time period including both the past and the future. | Unknown |
Are the causes of the decline clearly reversible and understood and have they ceased? | Yes |
Are there extreme fluctuations in the number of mature individuals? | No |
Extent and occupancy information
Estimated extent of occurrence within Canada’s extent of jurisdiction 2.792 million km2 |
1.807 million km2 (excluding major land masses) |
Index of area of occupancy (IAO) [Using a 2 × 2 grid] | 37,332 km2 |
Is the total population severely fragmented? | No |
Number of locations* Threats include bycatch mortality in diverse fisheries over a large region. | Multiple, but exact number unclear |
Is there a continuing decline in the extent of occurrence? | No |
Is there a continuing decline in the index of area of occupancy? | No, increases in some but not all areas |
Is there a continuing decline in the number of populations? | No |
Is there a continuing decline in the number of locations*? | No |
Is there a continuing decline in the area, extent or quality of habitat? | No |
Are there extreme fluctuations in the number of populations? | No |
Are there extreme fluctuations in the number of locations*? | Probably not |
Are there extreme fluctuations in the extent of occurrence? | No |
Are there extreme fluctuations in the index of area of occupancy? | No |
* See definition of “location.”
Population | N mature individuals |
---|---|
Canadian Population | > 5 million |
Quantitative Analysis
Probability of extinction in the wild is at least 20% within 20 years or 5 generations, or 10% within 100 years. | Analysis not done |
Threats (actual or imminent, to populations or habitats)
Commercial fisheries (mainly bycatch), environmental fluctuations, climate change
Rescue Effect (immigration from outside Canada)
Status of outside populations
Large populations to the north and east, some declines but not strong trends
Is immigration known or possible?
Possible
Would immigrants be adapted to survive in Canada?
Yes
Is there sufficient habitat for immigrants in Canada?
Yes
Is rescue from outside populations likely?
Possible, but unlikely from south
Status History
Designated Special Concern in November 2000. Status re-examined and confirmed in November 2012.
Status and Reasons for Designation
Status:
Special Concern
Alpha-numeric code:
n/a
Reasons for designation:
This species underwent steep declines in both abundance and area of occupancy over much of its range from the 1980s until the mid-1990s, including its historical stronghold in waters east and north of Newfoundland. Since then it has been increasing in abundance and area of occupancy. While these recent increases are encouraging, the species remains at low abundance compared to the early 1980s. Population increases have probably been aided by reduced commercial fisheries, which take wolffish as bycatch. There have been continuing declines in abundance on the Scotian Shelf and in the Southern Gulf of St. Lawrence, where historically there were fewer individuals than areas to the east and north.
Applicability of Criteria
Criterion A:
Time series are too short to calculate trends over three generations, and inferences are hampered by changes in gear used by survey vessels. Criterion A1b could be used because fisheries bycatch mortality is reversible and reasonably well understood and no longer causing declines. Long-term population trends probably meet Threatened under criterion, but the species is designated Special Concern because there have been increases in abundance and area of occupancy since the mid-1990s, in parallel with a reduction in the threat due to fisheries bycatch.
Criterion B:
Does not apply because the extent of occurrence greatly exceeds 20,000 km2 and the area of occupancy greatly exceeds 2,000 km2.
Criterion C:
Does not apply because the number of mature individuals greatly exceeds 10,000.
Criterion D:
Does not apply because the number of mature individuals greatly exceeds 1,000 and the area of occupancy is very large.
Criterion E:
Not undertaken.
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