1 4 I Ml RIStniRCKS 



Stocks and logging in their ilepcmlont watersheds, and 

 the recent successes in rebuilding salmon slocks in 

 Alaska by ensuring higher escapements, all support the 

 conclusion that the depletion of salmon stocks can usu- 

 ally be traced to the same cause as the declines in other 

 valuable hsh in Canada; namely, overfishing. The impli- 

 cation o( all this evidence is inescapable: to rebuild our 

 natural stocks we must allow larger escapements. 



However, the importance of increased escapements 

 does not diminish the ultimate importance of habitat pro- 

 tection since the productive capacity of the habitat will 

 limit the scope for increased fish production. While 

 overfishing is now the main constraint on slock recovery, 

 if the habitat is degraded, any rebuilding of the stocks 

 will quickly press on its reduced carrying capacity. The 

 following chapter, devoted to habitat management, draws 

 attention to the devastating and lasting impact that 

 slides, dams and diversions of watercourses have had on 

 stocks in the past, and the widespread threat of logging, 

 mining and pollution. 



So the findings should be interpreted as follows. The 

 capacity to produce fish is limited by the quality of the 

 habitat, which in turn is determined by the vigilance of 

 the habitat protection effort. But to take advantage of 

 whatever capacity exists, enough fish must be allowed to 

 spawn. The available evidence suggests that this is not 

 being done. In short, those responsible for managing 

 catches and escapements have not been as successful as 

 those responsible for habitat protection. 



Finally, it should be pointed out that these pressures 

 on stocks are not independent; those who study popula- 

 tion dynamics emphasize that one aggravates another. A 

 population of fish already weakened by overfishing is 

 more vulnerable to habitat degradation and vice versa. 



Natural predators Concern was also expressed at the 

 hearings about predation on the salmon stocks, in partic- 

 ular by seals and sea lions. Numerous reports indicate 

 that populations of these species are increasing, and they 

 are widely accused of taking large numbers of salmon 

 and of having a significant impact on some stocks. 



Eight species of marine mammals off the Pacific coast 

 are known to be predators on salmon: the northern fur 

 seal, the harbour seal, the northern sea lion and Califor- 

 nia sea lion, killer whale, Dall's porpoise and harbour 

 porpoise, and the Pacific white-sided dolphin. Several of 

 these species occur largely in offshore waters and little is 

 known about their abundance or the quantities of salmon 

 they consume. Others, such as northern sea lions, har- 

 bour seals, and killer whales occur throughout inshore 

 waters and we have more information about these. 



Estimates indicate that northern sea lions may con- 

 sume about 2.6 million pounds of salmon per year, har- 



bour seals some 1.3 million pounds,''' and killer whales 

 perhaps 5 million pounds." The question as to whether 

 fewer marine mammals would mean more salmon avail- 

 able for the fisheries is complex, however, since marine 

 mammals als() consume a number of other salmon preda- 

 tors. Moreover, the presence of some of these species, in 

 particular the killer whale, which is thought to number 

 only 300 in British Columbia waters, is regarded as desir- 

 able, and they are protected under federal statute. 



Some have recommended a return to the kinds of 

 predator control programs sponsored by fisheries depart- 

 ments in earlier decades; these involved annua! hunts, 

 bounties, and encouraging commercial utilization. I am 

 not prepared to recommend that these be reinstated at 

 present. Policy, in my opinion, should aim first at pre- 

 serving a viable population of all species; and this is par- 

 ticularly important for marine mammals because of their 

 scientific and aesthetic value. Beyond thi.s, if their popu- 

 lations expand, if they impose heavy costs of predation 

 and if they have commercial value, they should be man- 

 aged as one of the interdependent components of the 

 marine ecosystem. 



Prospects 



A number of conclusions can be drawn from our inves- 

 tigations of salmon stocks, the pressures on them, and 

 their potential yields. First, in the aggregate our salmon 

 stocks are well below their original levels of abundance. 

 Second, while in the last two decades the overall dechne 

 has been arrested and for many stocks declines have been 

 reversed (due mainly to improved fishery management), 

 some stocks appear to be declining still. I am particularly 

 apprehensive about the condition of many chinook and 

 coho stocks. Third, the immediate cause of continuing 

 declines and low levels of abundance is overfishing. And 

 finally, salmon stocks can undoubtedly be rebuilt sub- 

 stantially through better management, more careful regu- 

 lation of catches and enhancement. 



HERRING 



Herring have been exploited off the coast of British 

 Columbia since 1877, but harvests were small until early 

 in this century when a market for dry salted heriing 

 opened in the Orient. Annual catches rose to as high as 

 85 thousand short tons in the 1920s, then declined to 30 

 thousand tons in the Great Depression. Reduction of her- 

 iing into meal and oil was not permitted, except as a by- 

 product of food, until the pilchard reduction fishery col- 

 lapsed in the 1930s. Then a new herring reduction indus- 

 try was established, and consequently catches increased 

 sharply. In the 1950s herring landings averaged around 

 200 thousand short tons per year. Catches in the early 

 1960s were even larger, reaching the record of 264 thou- 

 sand tons in the 1962-63 season and 260 thousand tons 



