THE RESOURCES 13 



reflects the present uncertainty about current information 

 on resource capabilities. Some observers believe that 

 salmon stocks were once capable of yielding catches of 

 300 to 360 million pounds per year, so that potential 

 yields could well be more than double the harvests of 

 recent years. The suggestion that salmon production 

 could be returned to historic levels apparently originated 

 with the eminent fisheries biologist Dr. W.E. Ricker.' His 

 estimate relied on a few special opportunities, notably 

 rehabilitating Eraser River sockeye stocks to pre- 191 3 

 levels, restoring chum stocks coastwide and improving 

 pink production on the south and central coasts. The 

 analyses conducted for this report support Ricker's con- 

 clusions, as does a recent report on Fraser River sockeye 

 stocks.'" 



Table 2-3 Potential harvests from existing salmon 

 stocks 



present optimum 

 (average annual catches in millions of fish) 



sockeye 7.0 11.1 



chum 1.5 3.2 



pink 10.5 18.5 



Chinook .9 1.1 



coho J^ J32 



total 22.4 37.1 



Pressures on the Stocks 



A wide variety of factors afi'ect the survival and pro- 

 ductivity of our salmon stocks: in addition to recorded 

 harvests in the commercial, sport and Indian fisheries, 

 some additional fish are killed and unrecovered; natural 

 predation accounts for more; habitat is altered by human 

 and natural causes; oceanographic conditions affect food 

 supplies, and so on. 



Overfishing and habitat damage Where stocks have 

 declined historically, the main causes are widely agreed 

 to be overfishing and environmental damage. However, 

 much controversy surrounds the relative impact of these 

 two pressures. In my Preliminary Report, I tentatively 

 concluded that the main cause of decline and low abun- 

 dance of many stocks has been overfishing. That conclu- 

 sion was based on analysis of the available evidence on 

 historical catches and escapements and the productivity 

 of spawning fish. The available data is limited mainly to 

 the large river systems, so the runs in the hundreds of 

 small streams that account for most coho production and 

 altogether about half of all salmon production could not 

 be analyzed. These smaller streams are undoubtedly the 

 most vulnerable to habitat damage. I also noted in my 

 Preliminary Report that even though overfishing has 



been the main cause of stock declines, habitat damage 

 has undoubtedly reduced the potential productive capac- 

 ity of the environment. Nonetheless, the conclusion that 

 the main cause of decline in many stocks is overfishing 

 has been bolstered by subsequent investigations. This 

 should not be surprising since a number of earlier studies 

 investigating the relationship between fishing pressure 

 and stock trends came to a similar conclusion. 



For example, a report of the International North 

 Pacific Fisheries Commission pointed out that when 

 fishing pressure was severely curtailed the affected fish 

 stocks responded, showing "gratifying increases over the 

 rather low levels of the early 1960s."" It also observed 

 that when several populations are mixed in a fishery, the 

 less productive stocks may be depleted before the overall 

 level of maximum sustainable yield from the fishery is 

 reached. We have reason to believe that this happened 

 with numerous small stocks as the commercial fishery 

 developed throughout this century. 



The submission to this Commission by the American 

 Fisheries Society also supports this general conclusion: 



Today as in the past it is a popular practice to 

 blame pollution, bad logging practice, stream 

 blockage, the Japanese fishery and all manner 

 of other villains for our lack of fish. It is true 

 that most of man's activities in and near 

 watercourses have some deleterious effects on 

 salmonid production as do natural disasters 

 such as floods and droughts. However, our 

 professional opinion based on extensive 

 observations in salmon and steelhead streams 

 in recent years is that the principal reason for 

 declining abundance has often been over- 

 fishing. In spite of logging and other insults to 

 some watercourses there currently exist many 

 miles of excellent stream habitat practically 

 unoccupied by juvenile salmon and steelhead 

 as a result of insufficient spawning escape- 

 ment.'^ 



A recent study of Fraser River sockeye has come to a 

 similar conclusion: 



. . . present levels of abundance are just over 

 one half those of the 1894-1913 period and 

 very considerable scope for further rehabilita- 

 tion is indicated. . . . While the losses and 

 gains are impossible to estimate numerically, 

 it is judged that well over 90 f)ercent of the 

 original Fraser River capacity to produce 

 sockeye remains intact today. '^ 



Other evidence presented at this Commission's hear- 

 ings regarding the devastating fishing practices of earlier 

 years, the lack of correlation between declines in fish 



