Atlantic wolffish (Anarhichas lupus) COSEWIC assessment and status report 2012: chapter 11
Wolffish are caught primarily as bycatch in other fisheries, including outside Canadian waters. Landings statistics (including directed fishery and bycatch) are recorded for all wolffish species combined. However, the Northern Wolffish has usually been discarded at sea and, since 2003, the release of catches of threatened wolffish species (Spotted and Northern) has been mandatory. Therefore, landings statistics from 2003 to 2010 are nearly all for Atlantic Wolffish. The data in this report include all wolffish landings taken from NAFO (2010) (Figure 27).
Figure 27. Reported wolffish (unspecified species) landings in NAFO divisions located partly or entirely in Canadian waters.
Description of Figure 27
Chart presenting reported wolffish (unspecified species) landings from 1960 to about 2008 in Northwest Atlantic Fisheries Organization divisions located partly or entirely in Canadian waters. Source: NAFO (2010).
Reported wolffish catches were relatively high in the 1970s and declined in the 1990s. Since 2006, the lowest values since the start of the data series have been recorded, probably partly due to the requirement to release Northern and Spotted Wolffish under SARA. Although reported wolffish catches once exceeded 8000 t, current values are approximately 200 t annually.
Most catches come from Divisions 2J3KL (southern Labrador Sea and northeastern Newfoundland) and 4VWX (southern slope of the Laurentian Channel and Scotian Shelf) (Figure 27). Since the 1990s, a large proportion of catches have come from Divisions 3NOPs, namely southern Newfoundland and the Grand Banks, where there is a small directed fishery. In addition, records from Shrimp Fishing Areas 0-3 (from east of Baffin Island to waters around the Ungava Peninsula) show that 11-32% of sets catch one or more of this species (depending on the area and year) (Siferd 2010).
Commercial log data under-report wolffish catch rates (Kulka et al. 2007), and close to half of Atlantic Wolffish bycatch in Canada is believed to be discarded without being reported (Simpson and Kulka 2002). Landed values therefore underestimate actual catches. Wolffish caught by trawls are generally more vigorous than most other fish species and their survival rate following release may therefore be higher (Grant et al. 2005).
Effects on wolffish from disturbance or alteration of ocean bottoms by repeated use of mobile gear (primarily bottom trawls and dredges) are unknown. Bottom trawls rarely sample rocky bottoms due to the high risk of gear damage. This habitat is important to Atlantic Wolffish.
Due to the significant decline in Atlantic Wolffish catches and in fishing intensity in general, the fishery currently poses a much less serious threat than during the 1970s and 1980s (Kulka and Pitcher 2001). Fishing has been suggested to have been the main cause of the decline of wolffish species (O’Dea and Haedrich 2001) but this has been disputed by Kulka et al. (2004), who suggested wolffish declines in unfished areas were as great as or greater than those in heavily fished locations.
An episode of cold temperatures from the late 1980s to early 1990s (Colbourne et al. 2004) coincided with part of the period of decline in wolffish species, though declines preceded that temperature change. No cause-effect linkages have been shown between cold temperatures and wolffish population changes.
Climate change related to human activities could affect the distribution and abundance of marine species due to changes in the marine environment. Temperature increases are expected to become more pronounced in northern zones, where Atlantic Wolffish are found (Trenberth et al. 2007). As a general rule, movements will be towards the poles, increasing the range of warm-water species and decreasing the range of cold-water species (Perry et al. 2005, Cochrane et al. 2009). The distribution of boreal and subarctic species, such as wolffish, could shift northward (Gucinski et al. 1990).
Number of Locations
Following IUCN guidelines, COSEWIC defines the number of locations according to the threats. Since the main recognized threat is bycatch in fisheries, this species can be considered to occupy a large number of locations, as the different fisheries occur across a wide geographic area and are managed separately.
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