Assessing the relationship between diet and size-at-age in Pacific halibut (<em>Hippoglossus stenolepis</em>) using δ₁₃C and δ₁₅N analysis
Wolf, Nathan; Webster, Sarah R.; Welker, Jeffery M.; Harris, Bradley P. (2019-09-06)
Wolf, Nathan; Webster, Sarah R.; Welker, Jeffery M.; Harris, Bradley P. Assessing the relationship between diet and size-at-age in Pacific halibut (Hippoglossus stenolepis) using δ13C and δ15N analysis. Canadian Journal of Fisheries and Aquatic Sciences, 2019, 76(12): 2326-2331, https://doi.org/10.1139/cjfas-2018-0380
Copyright remains with the author(s) or their institution(s). The final authenticated version is available online at https://doi.org/10.1139/cjfas-2018-0380.
https://rightsstatements.org/vocab/InC/1.0/
https://urn.fi/URN:NBN:fi-fe202002135413
Tiivistelmä
Abstract
The ecological mechanisms driving an observed decline in the mean size-at-age of adult Pacific halibut (Hippoglossus stenolepis) in the eastern North Pacific Ocean have yet to be defined. Here, we present the results of a study designed to investigate the relationship between one potential mechanism — diet — and size-at-age using carbon and nitrogen stable isotope analysis. Our results indicate significant differences in the skeletal muscle δ₁₃C and δ₁₅N values between size-at-age categories for each sex, with larger-size-at-age fish consuming diets with higher δ₁₅N values, indicating higher trophic level feeding. Analysis of Bayesian standard ellipse areas showed that for females, intermediate size-at-age categories have the largest dietary range. For males, the largest dietary range was observed in the largest size-at-age category. Our results suggest a size-based stratification in dietary strategy for Pacific halibut with implications for observed declines in size-at-age.
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