Northwest Fisheries Science Center

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Document Type: Chapter or Section
Center: NWFSC
Document ID: 9074
Type of Book: Technical
Section or Chapter Title: Stable isotope applications for understanding shark ecology in the Northeast Pacific Ocean
Book Title: Northeast Pacific Shark Biology, Research, and Conservation
Series Title: Advances in Marine Biology
Author: J. C. P. Reum, Greg Williams, C. J. Harvey
Editor: Dayv Lowry, Shawn Larson (Eds.)
Publication Year: 2017
Publisher: Elsevier
Volume: 77
Pages: 149-178

Stable isotopes are used to address a wide range of ecological questions and can help researchers and managers better understand the movement and trophic ecology of sharks. Here, we review how shark studies from the Northeast Pacific Ocean (NEP) have employed stable isotopes to estimate trophic level and diet composition and infer movement and habitat use patterns. To date, the number of NEP shark studies that have used stable isotopes is limited, suggesting the approach is underutilized. To aid shark researchers in understanding the strengths and limitations of the approach, we provide a brief overview of carbon and nitrogen stable isotope trophic discrimination properties (e.g., change in ¿15N between predator and prey), tissue sample preparation methods specific to elasmobranchs, and methodological considerations for the estimation of trophic level and diet composition. We suggest that stable isotopes are a potentially powerful tool for addressing basic questions about shark ecology and are perhaps most valuable when combined and analyzed with other data types (e.g., stomach contents, tagging data, or other intrinsic biogeochemical markers).

Theme: Ecosystem approach to improve management of marine resources
Foci: Characterize ecological interactions (e.g. predation, competition, parasitism, disease, etc.) within and among species.
Provide scientific support for the implementation of ecosystem-based management