Event Title

Comparison of muscle and scale isotope signatures for Pacific Herring (Clupea pallasii), and potential application in regional life history studies

Presentation Abstract

Carbon and nitrogen are found in two naturally occurring isotopic forms, differing in their number of neutrons: a light isotope (12C and 14N) and a heavy isotope (13Cand 15N). These stable C and N isotopes are taken up by the primary producers in a food web in ratios that reflect the interacting effects of temperature, elemental availability (e.g. nutrient concentrations), and productivity levels, among other factors. Subsequently, the baseline primary producer isotope ratio, or signature, is transferred through the food web with largely predictable increases between trophic levels resulting from organisms’ preferential metabolism of the lighter isotopes.

The carbon and nitrogen isotope ratios of an organism’s tissues therefore provide a powerful source of information on the environmental and feeding conditions experienced by that organism, as well as its trophic level. The isotope ratios of any tissue reflect a time integration that corresponds with the turnover rates of that tissue. In the case of fish, muscle tissue is expected to have relatively high turnover rates and thus reflect dietary information for the few months prior to capture. Conversely, hard body parts, such as scales and otoliths, are expected to reflect dietary information incorporated at the time the tissue was laid down, providing an incremental record of an individual’s feeding biology over time.

Here we present the results of a test study comparing muscle and scale C and N isotope ratios of Pacific herring from different management areas: the Strait of Georgia, West Coast of Vancouver Island, Central Coast, and Haida Gwaii. We specifically assess the utility of scale and muscle isotope data in reconstructing the life history feeding biology of Pacific Herring, and provide a preliminary comparison of regional feeding dynamics.

Session Title

Ecological and cultural context of Pacific herring in the Salish Sea

Conference Track

Species and Food Webs

Conference Name

Salish Sea Ecosystem Conference (2016 : Vancouver, B.C.)

Document Type

Event

Location

2016SSEC

Type of Presentation

Poster

Contributing Repository

Digital content made available by University Archives, Heritage Resources, Western Libraries, Western Washington University.

Rights

This resource is displayed for educational purposes only and may be subject to U.S. and international copyright laws. For more information about rights or obtaining copies of this resource, please contact University Archives, Heritage Resources, Western Libraries, Western Washington University, Bellingham, WA 98225-9103, USA (360-650-7534; heritage.resources@wwu.edu) and refer to the collection name and identifier. Any materials cited must be attributed to the Salish Sea Ecosystem Conference Records, University Archives, Heritage Resources, Western Libraries, Western Washington University.

Type

Text

Language

English

Format

application/pdf

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Comparison of muscle and scale isotope signatures for Pacific Herring (Clupea pallasii), and potential application in regional life history studies

2016SSEC

Carbon and nitrogen are found in two naturally occurring isotopic forms, differing in their number of neutrons: a light isotope (12C and 14N) and a heavy isotope (13Cand 15N). These stable C and N isotopes are taken up by the primary producers in a food web in ratios that reflect the interacting effects of temperature, elemental availability (e.g. nutrient concentrations), and productivity levels, among other factors. Subsequently, the baseline primary producer isotope ratio, or signature, is transferred through the food web with largely predictable increases between trophic levels resulting from organisms’ preferential metabolism of the lighter isotopes.

The carbon and nitrogen isotope ratios of an organism’s tissues therefore provide a powerful source of information on the environmental and feeding conditions experienced by that organism, as well as its trophic level. The isotope ratios of any tissue reflect a time integration that corresponds with the turnover rates of that tissue. In the case of fish, muscle tissue is expected to have relatively high turnover rates and thus reflect dietary information for the few months prior to capture. Conversely, hard body parts, such as scales and otoliths, are expected to reflect dietary information incorporated at the time the tissue was laid down, providing an incremental record of an individual’s feeding biology over time.

Here we present the results of a test study comparing muscle and scale C and N isotope ratios of Pacific herring from different management areas: the Strait of Georgia, West Coast of Vancouver Island, Central Coast, and Haida Gwaii. We specifically assess the utility of scale and muscle isotope data in reconstructing the life history feeding biology of Pacific Herring, and provide a preliminary comparison of regional feeding dynamics.