Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2021
Erindi/veggspjald / Talk/poster V32
Höfundar / Authors: Sum Yi Lai (1,2), Jón S. Ólafsson (1), Arnar Pálsson (2), James Rosindell (3), Guðni Guðbergsson (1), Ingi Rúnar Jónsson (1), Hlynur Bárðarson (1)
Starfsvettvangur / Affiliations: 1. Marine and Freshwater Research Institute, 2. University of Iceland, 3. Imperial College London
Kynnir / Presenter: Sum Yi Lai
Freshwater ecosystems contain many species which depend on one another for survival. Therefore, studying food web dynamics of rivers spatially and temporally would improve our knowledge on the state of the ecosystem, how energy is transferred between level of organisms, and the potential future trends of population sizes and species composition. The drivers for survival and growth of Atlantic salmon (Salmo salar) populations at their northern limit needs to be further studied to better predict and manage the changes in population dynamics, especially as each population may respond differently. Therefore, the purpose of this study is to investigate whether the diet and food availability determine the growth and density of juvenile Atlantic salmon in the 4 rivers of Northeast Iceland. The trophic relationship within the river is analyzed using long-term data, collected annually, on density of juvenile fish, stomach content, and river invertebrate abundance, and algal biomass. The results showed that Chironomidae (Insect: Diptera) larvae took up most of the stomach content of juvenile salmon. The abundances of some invertebrates found in stomachs of salmon were significantly different between the age and length of the fish. The abundances and species of invertebrates found in fish stomachs varied spatially and temporally. There were significant differences in abundance of invertebrates within and between rivers in the Northeast of Iceland, and the invertebrate composition in the river also varied spatially. This would give a better indicator on the current feeding conditions and the population trend of Atlantic salmon in different rivers over time in Iceland, allowing for better river management.