ESR 42:83-93 (2020)  -  DOI: https://doi.org/10.3354/esr01040

ABSTRACT: Identifying the realized thermal habitat of animals is important for understanding life history and population processes, yet methods to estimate realized thermal use are lacking for many small-bodied organisms, including imperilled fishes. Analysis of oxygen isotopes provides one solution, but requires the development of species-specific fractionation equations. To date, such equations have generally been limited to commercial or game fish species. Here, we developed a field-based fractionation equation for the threatened silver shiner Notropis photogenis to better understand the thermal ecology of the species in an urban watershed. Archived otoliths were analyzed for oxygen isotope values (δ¹⁸O). There was a significant linear relationship between otolith isotope fractionation and water temperature, described by δ¹⁸O_{otolith(VPBD)} - δ¹⁸O_water(VPBD) = 32.03 - 0.21(°C). Results indicate that otolith isotope techniques can be used to identify the average relative temperature occupied by silver shiner, representing the first investigation of oxygen isotopes to understand thermal occupancy of the species. This field-based equation provides an opportunity to understand how silver shiner may respond to alterations in stream temperatures resulting from urbanization and climate effects and may be useful in identifying thermal refugia for the species. Field-based, species-specific fractionation equations can provide insights into the thermal ecology of many small-bodied fishes, which are increasingly imperilled due to thermal stressors.

KEY WORDS: Endangered species · Threatened fish · Otolith microchemistry · Thermal ecology · Stable isotopes · Minnows · Temperature

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Cite this article as: Burbank J, Drake DAR, Power M (2020) Field-based oxygen isotope fractionation for the conservation of imperilled fishes: an application with the threatened silver shiner Notropis photogenis. Endang Species Res 42:83-93. https://doi.org/10.3354/esr01040 Export citation Share:    Facebook - - linkedIn