Monday, August 3, 2015

The Dogfish



Spiny dogfish are a remarkable fish Feeding on plankton as Pauly would wish. Gluttony is a sin that is not on their souls, And they grow so slowly they become very old. Babies arrive all ready to play After living in their moms for two years less a day. Peaceful in life, they avoided confrontation Until humans arrived with merciless exploitation. Stewardship and respect was not in our game As we fished and destroyed without any shame. It is amazing how people with advanced education Could plot or ignore attempts at extermination. But citizens’ concerns have given dogfish rights, So it is now up to us to finish this poem.
Beginning a scientific article with an amateur poem may be highly unusual, but it draws one’s attention to the highly unusual lack of attention paid to spiny dogfish Squalus acanthias by the stewards of our marine ecosystems. A general understanding of the biology of dogfish has been summarized in some excellent publications (Ford 1921; Bonham 1954; Ketchen 1975, 1986). Although the basic biology is known, there is no clear understanding of dogfish ecology. This is surprising considering the species’ current and historical importance to the commercial fisheries. In 2002, dogfish in the commercial fishery averaged Can$0.66/kg ($0.30/ lb); compare this to $1.29/kg ($0.59/lb) for Pacific cod Gadus macrocephalus, $0.34/kg ($0.15/lb) for pink salmon Oncorhynchus gorbuscha, or $1.93/kg ($0.88/lb) for lingcod Ophiodon elongatus. It is clear that the commercial value of spiny dogfish justifies more research to improve our understanding of the processes that regulate its production. Their long life, late maturity, 
   Their long life, late maturity, and slow growth mean that most spiny dogfish in the current commercial fishery were born before the mid-1970s and that individuals born now will be fished from about 2025 to 2050. (This also means that decisions we make today will be relevant through to the end of this century.) Consequently we must look back 20–50 years to understand the factors that produced the current exploitable biomass. Ketchen (1986) reviewed the history of spiny dogfish management, and in this report we review his summary. Our viewpoint is that history has not Beamish et al. 2 been respectful of dogfish either as a species or as an animal sharing a common ecosystem. The reader is referred to Ketchen (1986) for his detailed account of the dogfish fishery, which was the largest fishery in British Columbia in 1944 (Figure 1) and the fourth largest in Canada. Since 1986, the catch of spiny dogfish has been relatively stable at approximately 5,000 metric tons (mt) per year. Approximately 30% of this catch is from the Strait of Georgia. Dogfish quotas of 15,000 mt (offshore stock) and 3,000 mt (Strait of Georgia stock) for Canadian Pacific waters have remained unchanged since the early 1980s. In 2000, total landings averaged less than 5,000 mt, of which 1,200 mt came from the Strait of Georgia. Longline catches in the strait account for over 95% of the landings.

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