Effect of population abundance and climate on the growth of 2 populations of chum salmon (Oncorhynchus keta) in the eastern North Pacific Ocean

Seasonal and annual marine growth of chum salmon (Oncorhynchus keta) from Fish Creek, Alaska, during 1972-2004 and from Quilcene River, Washington., during 1973-2004 were examined in relation to abundances of chum salmon and pink salmon (O. gorbuscha) and climate indices from that period. Pink salmon abundance indices were included in the analysis because of evidence for density-dependent effects on chum salmon growth and survival. In linear regression models, growth was negatively related to abundance of chum salmon or to the combined abundance of pink and chum salmon during the middle juvenile (July-Sept), 1st immature, 2nd immature, and maturing stages for the Fish Creek chum salmon and the 1st immature, 2nd immature, and maturing stages for Quilcene River chum salmon, indicating possible density-dependent effects on growth. Mid-juvenile and maturing growth models for the Fish Creek chum salmon and the maturing growth model for Quilcene River chum salmon performed well in model validation, when model predictions were tested against 20% of the data that were not used for model specification, and provided insight into the effects of climate and abundance on growth of chum salmon from 1972 to 2004.