Assessing regional patterns of juvenile salmon growth in the Salish Sea

• Main Authors: Journey, Meredith L., Trudel, Marc Jean, Neville, C. M., Sweeting, Ruston, Beckman, Brian R.
• Format: Text
• Language: English
• Published: Western CEDAR 2014
• Subjects: Terrestrial and Aquatic Ecology; Keta; Pacific; Queen Charlotte; Sockeye; Pink salmon
• Online Access: https://cedar.wwu.edu/ssec/2014ssec/Day1/10; https://cedar.wwu.edu/cgi/viewcontent.cgi?article=1009&context=ssec

Early marine juvenile growth in Pacific salmon is generally positively correlated with overall survival to reproductive age. In this study, regional patterns of juvenile salmon growth are being analyzed over a two-year period (2012-2013) in the Salish Sea and surrounding waters to better assess juvenile productivity, via growth, in the Salish Sea and surrounding waters to provide us insight into possible mechanisms regulating survival. Insulin-like growth factor-1 (IGF-1), a hormone used to assess instantaneous growth in fishes, including juvenile salmon, was measured in late June and early July of 2012 and 2013 in the Strait of Georgia, Johnstone Strait, Queen Charlotte Strait, and Puget Sound. Juvenile sockeye (Oncorhynchus nerka) and pink salmon (O. gorbuscha) were collected in 2012, whereas juvenile coho (O. kisutch), Chinook (O. tshawytscha), and chum salmon (O. keta) where obtained in both years. In 2012 IGF-1 levels were highest in pink salmon from the Gulf Islands and Puget Sound; this was a unique pattern among the 5 species of juvenile salmon sampled. Coho salmon IGF-1 levels were highest in samples from the Northern Strait of Georgia. Chinook salmon IGF-1 levels were significantly higher in the Strait of Georgia than Puget Sound. The only regions where IGF-1 values were consistently low for three of the four species were Queen Charlotte Strait and Johnstone Strait. Analyses of 2013 IGF-1 levels (juvenile coho, Chinook, chum and a low number of sockeye) are underway and scheduled plans to obtain samples in late June to early July of 2014 are in place.