Stomach content analyses to investigate longterm changes in a pelagic ecosystem
(English)Manuscript (preprint) (Other academic)
This is the first serious step to describe a fish community food web of the off-shore ecosystem in Europe’s sixth largest lake, Lake Vättern. Stomach contents analyses from in total 777 fishes from nine different species were used to describe an updated off-shore food web of Lake Vättern. Furthermore, a comparison with earlier made stomach content analyses were done to see if observed changes in Lake Vättern in the last 30-40 years have led to any changes in the trophic interactions between the species. Our results indicate that diet shifts may have occurred for some species. For example, the diet during summer for great Arctic charr (Salvelinus umbla) and stocked Atlantic salmon (Salmo salar) in our study show a shift to a diet dominated by three-spined stickleback instead of smelt and vendace respectively. Still, we conclude that the investigated food web structure of Lake Vättern has remained largely intact and stable during the last 50 years even if there have been introductions of non-native species and environmental changes. The updated off-shore food web for Lake Vättern presented here could be a valuable tool for using an ecosystem based approach and to better identify management strategies.
IdentifiersURN: urn:nbn:se:liu:diva-77681OAI: oai:DiVA.org:liu-77681DiVA: diva2:528413