Bj. Pyper et Rm. Peterman, Relationship among adult body length, abundance, and ocean temperature forBritish Columbia and Alaska sockeye salmon (Oncorhynchus nerka), 1967-1997, CAN J FISH, 56(10), 1999, pp. 1716-1720
Citations number
12
Categorie Soggetti
Aquatic Sciences
Journal title
CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES
Body length of adult Pacific sockeye salmon (Oncorhynchus nerka) has decrea
sed significantly in recent years. We used 69 time series of age-specific b
ody-length data (1967-1997) for 30 sockeye salmon stocks from southern Brit
ish Columbia to western Alaska to test hypotheses about the effects of ocea
nographic conditions and competition on growth rate of sockeye salmon. Usin
g principal components analysis (PCA), we constructed a single time series
(PC1) that represented the dominant pattern of variability in length-at-age
shared among these stocks. Taking into account time trends and autocorrela
tion in residuals, we found that increases in total Gulf of Alaska sockeye
abundance and increases in sea-surface temperature (SST) across the Gulf of
Alaska were significantly associated with reduced adult body length. Abund
ance and SST together accounted for 71% of the variability in PC1. Although
researchers have documented increases in both abundance of sockeye salmon
and their food in the northeastern Pacific Ocean over the last few decades,
it is possible that increased food was more than offset by increased socke
ye abundance, leading to greater competition and reduced body size.