Rm. Peterman et al., Patterns of covariation in survival rates of British Columbian and Alaskansockeye salmon (Oncorhynchus nerka) stocks, CAN J FISH, 55(11), 1998, pp. 2503-2517
Citations number
42
Categorie Soggetti
Aquatic Sciences
Journal title
CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES
We used a multi-stock comparison to identify spatial and temporal character
istics of environmentally driven sources of variability across four decades
in the productivity of 29 sockeye salmon (Oncorhynchus nerka) stocks from
British Columbia (B.C.) and Alaska. We examined patterns of covariation amo
ng indices of survival rate (residuals from the best-fit stock-recruitment
curve) and found positive covariation among Fraser River sockeye stocks (so
uthern B.C.) and, to a greater extent, among Bristol Bay stocks (western Al
aska) but no evidence of covariation between these two regions or with stoc
ks of other regions in B.C. and Alaska. This indicates that important envir
onmental processes affecting variation in sockeye survival rate from spawne
rs to recruits operate at regional spatial scales, rather than at the large
r, ocean-basin scale. The observed covariation in survival rates of Bristol
Bay stocks appears to be due to a combination of both freshwater and, to a
greater degree, marine processes. Bristol Bay sockeye stocks showed a dram
atic and persistent increase in survival rates coinciding with the abrupt c
hanges in the North Pacific environment in the mid-1970s; however, there wa
s little evidence of a similar response for Fraser River stocks.