|Document Type:||Journal Article|
|Title:||Assessing marine pelagic ecosystems: Regional and inter-annual trends in marine growth rates of juvenile salmon off the British Columbia coast|
|Author:||Bridget E. Ferriss, Marc Trudel, Brian R. Beckman|
|Journal:||Marine Ecology Progress Series|
We measured insulin-like growth factor 1 (IGF1) concentrations (a proxy for growth rate) from juvenile coho (Oncorhynchus kisutch), sockeye (O. nerka), chum (O. keta), and Chinook salmon (O. tshawytscha) collected in eight regions of British Columbian coastal waters, in June of 2009, 2010, and 2011. We found annual differences in IGF1 for all four species of salmon, and species-specific regional differences in IGF1 concentrations in coho, chum and sockeye salmon. Sockeye and chum salmon had consistently higher values in the northern regions of the Dixon Entrance, Haida Gwaii, Hecate Strait, and lower values in Queen Charlotte Strait. Maximum differences in IGF1 levels ranged from 30.2 ng·ml-1 (chum salmon, 2009, South Vancouver Island) to 74.2 ng·ml-1 (coho salmon, 2011, Haida Gwaii). Regional differences in coho, chum and sockeye salmon were highly correlated (R2 = 0.61 - 0.75). These results demonstrate that salmon growth responds to local environmental variability on a scale of several hundred kilometers. IGF1 levels provide a mechanism linking local environmental conditions to variable salmon growth rates. Thus, IGF1 measures provide insight into fish performance on a relatively local regional and temporal scale and allow one to assess how habitats vary on this same scale.
|Theme:||Ecosystem Approach to Management for the California Current Large Marine Ecosystem|
Conduct integrated ecosystem assessments that produce metrics and criteria that will improve ecosystem forecasts and predictions.
Characterize ecological interactions (e.g. predation, competition, parasitism, disease, etc.) within and among species to support ecosystem approach to management.