Climate effects on an endangered stock of great Arctic charr
(English)Manuscript (preprint) (Other academic)
Climate affects species in many different ways and climate change represent an important and increasing threat to single populations as well as the structure and functioning of entire ecosystems. Studies have indicated that water temperature may affect plankton spring biomass abundance in temperate lakes but does not seem to have much effect on the timing of plankton peak abundance. If plankton peak abundance is not significantly affected by water temperature, while the development time of eggs and fry is, and thus the predicted time of strong demand for food, there is a strong possibility for a trophic mismatch effect. Our data and analysis show that this indeed seems to be the case for great Arctic charr in Lake Vättern. The date when the yolk sac is predicted to be consumed is positively correlated with the standardized catches of great Arctic charr six years later. This suggest that warm winters, which result in early hatching of eggs and early date for when the yolk sac is consumed, affect survival of fry and subsequent recruitment to older size classes negatively. This leads to lower than expected catches a few years later. In addition, we also show that ice winters have a positive effect on Arctic charr with a time lag of 3-4 years and that this effect increase with the duration of the ice-cover. These effects are probably not due to trophic mismatch effects. However, all these effects are the result of a changing climate and when combined these effects of increasing water temperature, decreasing frequency and duration of ice winters are predicted to affect the stock of great Arctic charr negatively.
IdentifiersURN: urn:nbn:se:liu:diva-77680OAI: oai:DiVA.org:liu-77680DiVA: diva2:528412