The IUCN/SSC Shark Specialist Group
Shark News 9: June 1997
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British Columbian Spiny Dogfish Stocks are Doing Fine
Ramon Bonfil, Fisheries Centre, University of British Columbia,
Vancouver, BC, and Mark W. Saunders, Pacific Biological Station,
Department of Fisheries and Oceans, Nanaimo, BC, Canada
Two recent notes in Shark News (issues No. 7, p. 13, and No. 8, p. 8)
raised some concern over the status of the spiny dogfish fisheries in the
Pacific Northwest, by highlighting a supposed crash in the landings of
this species in British Columbia, Canada. According to the Canadian
Department of Fisheries and Oceans, reported landings of Squalus
acanthias in BC during 1994 totalled 1,739 t. Moreover, the total
catch of spiny dogfish in BC, including additional catches by joint
venture and other fisheries and the discards of trawl fisheries, amounted
to a grand total of 4,416 t during 1994.
When discussing fisheries status, it is important not to confuse
landing crashes with population crashes; equating both terms can be
misleading. A population crash is a decrease in the size of a population
relative to the historic or virgin population level. In some cases a
decline in landings is associated with a decline in population size, but
in others, including spiny dogfish in BC, a decline in landings can be
driven by a host of market and management factors. In the spiny
dogfish fishery of the Pacific Northwest, the dynamics of the fish
landings are largely determined by market forces. The present spiny
dogfish fishery of British Columbia is a marginal fishery that is
primarily serving the US export market of dogfish meat to Europe, as
there has been no substantial demand for dogfish in Canada for many
decades. The majority of spiny dogfish caught in BC are processed by
companies in the Puget Sound area of Washington in the USA and it
is the dynamics of price and demand in Europe, together with the
production costs and ex-vessel prices, that govern how much of BC's
spiny dogfish is caught and landed in a given year. Furthermore, Puget
Sound facilities processing some of this dogfish were limited in recent
years due to a fire damage at a major processor (Thomson, in press).
Thus, the ups and downs in spiny dogfish landings are currently not a
function of stock size but rather determined by the whims of the market.
Finally, it should be noted that stocks of spiny dogfish in BC are
currently at a very healthy level. Total abundance estimates for the
different stocks of spiny dogfish in BC range between 210,000 and
260,000 t for 1995. While the total catch of 4,416 t in 1994 represented
87% of the 1979-1993 catch average, it did not come close to the
recommended total allowable catch (TAC) for spiny dogfish in BC for
that year, which was 3,000 t for the Straight of Georgia and 15,000 t
offshore. Clearly, current levels of exploitation are much below any
level that could raise conservation concerns and it is actually expected
that the stocks of S. acanthias in this region continue to increase in size
due to limited exploitation (Thomson, B.L. In press. Groundfish stock
assessments for the west coast of Canada in 1995 and recommended
yield options for 1996. Can. Tech. Rep. Fish. Aquat. Sci.).
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