Thermal habitat segregation among morphotypes of whitefish ( Coregonus lavaretus: Salmonidae) and invasive vendace ( C. albula): a mechanism for co‐existence?

• Published in: Freshwater Biology
• Main Authors: Kelly, Brianne, Amundsen, Per‐Arne, Power, Michael
• Other Authors: EU InterReg ENPI project ‘Trilateral Cooperation on Environmental Challenges in the Joint Border Area’, NSERC Collaborative Research and Development Grant, Brookfield Renewable Energy, NSERC's HydroNet Strategic Network Grant, Strategic Network Enhancement Initiative Grant
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2015
• Subjects: Arctic; Norway; Pasvik; Northern Norway
• Online Access: http://dx.doi.org/10.1111/fwb.12660; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Ffwb.12660; https://onlinelibrary.wiley.com/doi/pdf/10.1111/fwb.12660

Summary Aquatic invasive species can have a variety of negative impacts on the ecosystems they invade. Carbon and nitrogen stable isotopes in the muscle tissue of aquatic organisms have proved useful for evaluating post‐invasion dietary shifts among species. However, oxygen and carbon stable isotopes in fish otoliths have the potential to provide additional data on thermal habitat, diet and metabolism, when investigating interactions among sympatric native and invasive fishes. We conducted oxygen and carbon stable isotope analysis on the otoliths of three morphotypes of native whitefish ( Coregonus lavaretus ) and invasive vendace ( Coregonus albula ) at two sites within the sub‐Arctic Pasvik watercourse in northern Norway. Mean temperature use among morphotypes and species over the course of the growing season ranged from 7.5 °C to 11.2 °C. Otolith δ 13 C was significantly positively correlated to fish muscle tissue δ 13 C ( P < 0.05, r 2 = 0.53). Significant differences in temperature use and δ 13 C among morphotypes and between species were found in the downstream site but not the upstream site. Complementary partitioning of thermal and dietary resource use in the downstream site coincides with a higher abundance of whitefish, enabling the coexistence of both species. In contrast, vendace were dominant in the upstream site where no differentiation in resource use among morphotypes and between species was evident. This study demonstrates the usefulness of stable oxygen and carbon otolith isotopes for characterising resource use and highlights the importance of investigating thermal habitat use as a factor influencing the success of invasive fishes.