Assessing thermal ecology of Colorado River catostomids through stable isotopes (Á¤18O)

Authors: Barkalow, Adam L.*, Turner, Thomas F., Newsome, Seth D., McKinstry, Mark

Year: 2015 (xlvii)

Abstract

Knowledge of early life history strategies and ecological dynamics is invaluable for effectively managing and conserving common and endangered fish species. Isotopic analysis of otoliths from larval Colorado River catastomids could greatly facilitate understanding of thermally regulated growth rates, thermal preferences, and ontogenetic habitat use of these fishes. Isotope ratio mass spectrometry (IRMS) is a technique that reveals integral aspects of an individuals’ life history that are often difficult or impossible to assess with traditional sampling methods. Analysis of &#948¹⁸O data from larval fish otoliths may permit detailed reconstruction of water temperatures experienced by fish during early developmental phases. Development and substantiation of techniques for &#948¹⁸O analysis of larval otoliths is an important and emerging area of ecological research. While techniques have been validated for adult fish, applications for larval fish have been limited. To investigate the thermal ecology and ontogenetic habitat use of Colorado River catostomid larvae, including the federally endangered Razorback Sucker Xyrauchen texanus, we propose a method for obtaining &#948¹⁸O from larval fish otoliths.