APPENDIX D 287 



Coho 



Table D-4 



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

 major production area 



catch 



escapement 



Queen Charlotte. North 

 Queen Charlotte. South 

 Nass River 

 Skeena River 

 Central coast 

 Rivers/Struth Inlets 

 Johnstone Strait 

 Strait of Georgia 

 Fraser Rjver 

 S.W. Vancouver Island 

 N.W. Vancouver Island 



total: 



" The ranges around the estimate reflect lack of knowledge about spawner-recruitment relationships and uncertainty about optimal rates of exploita- 

 tion. 



Comparison of current and estimated optimum escape- 

 ment levels indicates that, except for the Queen Char- 

 lottes' northern area, escapement should be increased. 

 The required increase is not dramatic in any area, 

 although the relatively small numbers in the coho stocks 

 may tend to mask the fact that, for some stocks, the pro- 

 portionate increase is quite large. 



Table D-4 shows that current catches of 2.5 million 

 coho annually are below the estimated optimum of 3.2 

 million, indicating a possible expansion in catches of 0.7 

 million fish. Opportunities for increases appear to be 

 most significant in the central coast and northern areas, 

 with the catches from the southern areas generally being 

 close to the indicated optimum. 



Chinook 



Table D-5 Current and optimum catch and escapement of chinook salmon originating in Canadian rivers estimated by 

 major production area 



Nass River 

 Skeena River 

 Central coast 

 Rivers 'Smith Inlets 

 Johnstone Strait 

 Strait of Georgia 

 Fraser River 

 S.W. Vancouver Island 



total: 



879 



1.052-1- 



598 -I- ) 



(905-1- - 1.3%-!-) 180 3144- (175 



■' The ranges are wide because of uncertainty about rates of recruitment from various levels of spawner abundance and the optimal rates of 

 exploitation. 



Table D-5 shows that current catches of chinook are 

 estimated to be some 880 thousand annually, with the 

 optimum not significantly greater at about 1.1 million. 

 Compared to the other species, the size of the chinook 

 stocks is small, and the only substantial opportunity for 

 increase is in the Fraser River system where it is esti- 

 mated that current catches of some 578 thousand could 

 be increased to reach 788 thousand. The present Fraser 

 stocks will not support harvests of this level, however, 

 and they can only be achieved if the stocks are rebuilt 

 through increased escapements. Throughout the coast 



there is concern that exploitation rates may be excessive 

 and that catches must be curtailed until management 

 information is significantly improved and the stocks can 

 be managed with greater certainty. 



The estimates of current and optimum chinook escape- 

 ments appear deceptively simple, probably because the 

 numbers are so small by comparison with the other spe- 

 cies. The indicated optimum spawning requirements are 

 not far from the current levels in most areas, with the 

 notable exceptions being the Fraser system (200 thou- 

 sand versus 68 thousand) and the Strait of Georgia. 



