TitleDiel Feeding Chronology, Gastric Evacuation, and Daily Food Consumption of Juvenile Chinook Salmon in Oregon Coastal Waters
Publication TypeJournal Article
Year of Publication2009
AuthorsBenkwitt, CE, Brodeur, RD, Hurst, TP, Daly, EA
JournalTransactions of the American Fisheries Society
Keywordsfish daily ration oncorhynchus-kisutch walbaum columbia river plume sockeye-salmon coho salmon meal size prey selectivity british-columbia lake washington multiple meals

The diel feeding periodicity of juvenile Chinook salmon Oncorhynchus tshawytscha was determined from stomachs collected in coastal waters off Oregon in 2000 and 2003. Juvenile Chinook salmon exhibited a diurnal feeding pattern with morning and evening feeding periods. There were differences in the duration and magnitude of the dawn and dusk peaks between the 2 years. Gastric evacuation rates of euphausiid meals were estimated from laboratory experiments at 9.3, 10.7, and 13.9 degrees C. Based oil air exponential model, the instantaneous evacuation rates at these three temperatures were 0.0407, 0.0589, and 0.0807 per hour, respectively. The daily ration of juvenile Chinook salmon in Oregon coastal waters in 2000 and 2003 was estimated using three models. Using laboratory-derived evacuation rates, tire Elliott and Persson and Eggers models produced daily ration estimates of 2.04% and 2.57% of body weight (BW). respectively, in 2000 and 2.93% and 2.46%BW in 2003. The MAXIMS model. which does not rely oil laboratory-derived evacuation rates, produced higher estimates of daily ration (3.84% and 4.28%BW). Our diet feeding chronology, gastric evacuation rate, and daily ration estimates for juvenile Chinook salmon were comparable to those of other juvenile salmonids.