GROOT and QUINN: HOMING MIGRATION OF SOCKEYE SALMON 



the Strait of Juan de Fuca. We propose that the 

 coastal approach may be influenced by oceano- 

 graphic conditions in the eastern Gulf of Alaska 

 during the April-June period when the maturing 

 sockeye perform their homing migrations from 

 the high seas overwintering grounds to the 

 coastal areas (French et al. 1976). 



The following environmental factors were ana- 

 lyzed for correlation with diversion rates of 

 Fraser River sockeye via the north: 



1) Sea surface temperatures (SST) (average 

 April-June) measured daily at four lighthouse 

 stations along the British Columbia coast: Am- 

 phitrite Point, Kains Island, Cape Saint James, 

 and Langara Island (Fig. 6) (Dodimead 1984; 

 L. F. Giovando^). SSTs can be used as indications 



5L. F. Giovando, Institute of Ocean Sciences, Patricia Bay, 

 B.C. V8L 4B2, Canada, pers. commun. 1985. 



52°N 



52°N 



Figure 5. — The numbers of sockeye salmon tagged in northern British Columbia and southeastern Alaska and recovered that year 

 in waters around Vancouver Island. Tagging data are separated by location of tagging (inside vs. outside waters) and year (1982 

 vs. 1983). 



461 



