Science Advisory Report 2010/057

Assessment of Spiny Dogfish (Squalus acanthias) in British Columbia in 2010

Summary

• The fishery for spiny dogfish in BC occurs primarily in the Strait of Georgia and off the southwest coast of Vancouver Island. In British Columbia, this species has a long history of commercial exploitation dating back to the 1870’s, with maximum exploitation (5,000-32,000 tonnes) occurring from 1937-1950, to supply shark livers for Vitamin A production. A smaller food fish fishery (100-5,000 tonnes) has been conducted since 1974.
• In British Columbia, there are two discrete stocks of spiny dogfish; an outside stock that extends from Baja California to Alaska and an inside stock, in the Strait of Georgia. Spiny dogfish, like most shark species grow slowly, mature late (35-36 years for females) and produce between 2 and 17 offspring (pups) per year resulting in very low intrinsic rates of population increase. These life history features make them highly susceptible to overexploitation and stock depletion.
• The current assessment concluded that there is no immediate conservation concern for either the inside or outside stocks of Pacific spiny dogfish and that, given the perceptions of the current stock status, it is unlikely that deleterious or irreversible declines in stock abundance are likely to occur over the five year time frame established for the next assessment at the current (2000-2009) level of removals.
• For the Strait of Georgia, the use of the average long-term yield between 1978 and 2009 (the period of the modern food fish fishery) was recommended as the basis for establishing yield recommendations. This approach results in a yield recommendation of 1,579 mt.  While, the current TAC is 3000 mt, total landings (long line and trawl) have averaged approximately 1,000 mt, since 2000, exceeding this 1,579 mt marginally in one year.
• For the outside fishery, there was no consensus reached on a scientifically valid approach on which to base yield recommendations.
• Given the uncertainties in the current assessment, it is recommended that an updated stock assessment be conducted at the earliest date possible and that the harvest advice provided herein should stand for a period of no more than five years.  It is acknowledged that it may take five years to accrue sufficient new data to update the assessment.
• Overall, given the perceptions of the current stock status and nature of the fishery, it is unlikely that deleterious or irreversible declines in stock abundance are likely to occur over the five year time frame established for the next assessment.

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