APPENDIX D 285 



The findings on the status of fish stocks presented in 

 the accompanying tables are in large part a result of 

 investigations sponsored by the Commission and con- 

 ducted by a team of biologists at the University of British 

 Columbia, who were asked to make an independent 

 assessment of the data relating to existing natural stock 

 conditions, trends and yield capabilities.- They have 



assembled the available historical data on total catches, 

 escapements and other variables and, with the coop)era- 

 tion of biologists from the Department of Fisheries and 

 Oceans, have analyzed them to infer as much as possible 

 about fish populations and their potentials. It should be 

 noted that the catch and escapement estimates in these 

 tables relate only to stocks originating in Canadian rivers. 



Sockeye 

 Table D-1 



Current and optimum catch and escapement of sockeye salmon originating in Canadian rivers estimated by 

 major production area 



catch escapement 



area 



Nass River 



Skeena River 



Central coast 



Rivers/Smith Inlets 



Johnstone Strait 



Fraser River 



S.W. Vancouver Island 



total: 



civrent 



317 



834 

 280 

 480 

 44 

 4.460 

 600 



7.015 



optnnum 



current 



estimate 



350 



800 



283 



1.200 



unknown 



8,000 



500 



11.133 + 



(range)' 



(thousands of fish) 



(240-360) 

 (750- 1,000) 

 (220 - 350) 

 (1,000- 1.500) 

 unknown 

 (7,000- 11.000) 

 (150- 1.000) 



(9.360 -H - 15.2 10 H-) 



195 

 820 

 100 

 390 

 unknown 

 1.370 

 260 



3.135-t- 



estiniate 



181 

 868 

 200 

 500 

 unknown 

 4,000 

 300 



6,049 -t- 



optiniun 



(range)" 



(120-360) 

 (600- 1,500) 

 (100-400) 

 (400 - 2.000) 

 unknown 

 (2,000 - 8.000) 

 (100- 1,000) 



(3.320 -t- - 13.260-t-) 



Because of uncertainties regarding early escapement counts, stocks being exploited in mixed-stock fisheries and difficulties in treating substocks 

 separately, the estimated ranges are quite wide. 



The wide range in the estimates of optimum escapement reflect the imprecise knowledge about spawner-recruitment relationships in the stocks and 

 uncertainty about the optimum rates of exploitation. 



Table D-l shows that the optimum average annual 

 sockeye catch is slightly in excess of 1 1 million fish, sub- 

 stantially more than the 7 million now taken. The current 

 and optimum escapement estimates indicate that in order 

 to achieve the optimum catch of over 1 1 million sockeye, 

 the annual escapement will have to be almost doubled 

 from present levels of 3. 1 million to slightly over 6.0 mil- 

 lion. 



In most areas the current and optimum catches are not 



badly out of balance, but there are two significant excep- 

 tions: Rjvers-Smith Inlets and Fraser River. In these two 

 areas, estimates indicate that catches could be increased 

 from current levels of about 4.9 million fish to approxi- 

 mately 9.2 million fish, a potential increase of 4.3 million 

 fish, representing some 60 percent of the current average 

 annual sockeye harvests. These estimates are generally 

 consistent with those of a recent independent study of 

 Fraser River sockeye production and potential.^ 



Chum 



Table D-2 Current and optimum catch and escapement of chum salmon originating in Canadian rivers estimated by 

 major production area 



catch escapement 



CJueen Charlotte, North 

 Queen Charlotte, South 

 Nass River 

 Central coast 

 Johnstone Strait 

 Strait of Georgia 

 Fraser River 

 S.W. Vancouver Island 

 N.W. Vancouver Island 



total: 



' The wide range in estimates reflects uncertainties about the optimum escapements, poor escapement data and anticipated difficulties in establishing 



terminal fisheries that could effectively harvest surpluses. 

 *• The wide range in the estimates, particularly in the Fraser system, reflects uncertainty about optimum exploitation rates and the spawner-recruitment 



relationships. 



