Contact Information

Department of Environmental Sciences
P.O. Box 65 (Viikinkaari 1)
00014 University of Helsinki

Niemenkatu 73
15140 Lahti

Invasion of New Fish Species in Arctic Lakes – Impacts on Ecosystem Functioning and Services


One of the study sites, Lake Kilpisjärvi

Project summary

The importance of Arctic region is increasing progressively along the global climate change. The invasion of new fish species is especially evident in Arctic region, where temperatures have previously restricted cool and warm water species establishment.The general aim of project is to detect and quantify the impacts of new fish species invasion on ecosystem functioning and to provide the most suitable adaptation strategies to change in ecosystem services. The proposed multidisciplinary project combines several modern methods (stable isotopes, fatty acids, vitamin D, mercury) to achieve objectives. The key findings of the project will give direct knowledge how the invasion of non-native fish species will influence on the supply of essential fatty acids (omega-3 and 6) and vitamin D as well as exposure of toxic mercury. Results will give direct instructions which species should be preferred and which should be maximum consumption of fish in future. The project is financed by Academy of Finland during 2013-2017.


Thomas, Stephen; Kiljunen, Mikko; Malinen, Tommi; Eloranta, Antti; Amundsen, Per-Arne; Lodenius, Martin; Kahilainen, Kimmo K. (2016) Food-web structure and mercury dynamics in a large subarctic lake following multiple species introductions. Freshwater Biology 61, 500–517. ISSN 0046-5070.s doi: 10.1111/fwb.12723.



New invading species ruffe at top and native whitefish below



Research area


Composition of research team

This project will be conducted in collaboration with large multidisciplinary research team briefly presented below.

Kick-off meeting October 2013


Project leader, Hannu Lehtonen, professor in fish biology, Department of Environmental Sciences, University of Helsinki, Finland. Key experience in fish biology and fisheries management.

Kimmo Kahilainen, PhD, Department of Environmental Sciences, University of Helsinki, Finland. Key research experience of food web structure and ecosystem functioning in the Arctic. Long-term experience in extensive sampling, analysing and publishing in the study area.

Per-Arne Amundsen, Professor, University of Tromsø, Norway. Key experience in long-term datasets of ecosystem change along species introduction in study region as well as accumulation of heavy metals in fish and invertebrates.

Roger Jones, Professor in limnology, University of Jyväskylä, Finland. Key experience in aquatic ecosystem ecology in boreal and arctic lakes using stable isotopes and fatty acids.

Chris Harrod, assistant professor, School of Biological and Chemical Sciences, Queen Mary University of London, UK. Key experience in the utilization of stable isotopes in ecosystem ecology in lakes, rivers and oceans.

Mikko Kiljunen, post-doc, University of Jyväskylä, Finland. Key experience in stable isotopes, mixing models, bioaccumulation and fisheries management.

Brian Hayden, post-doc, University of Helsinki, Finland. Key experience in the stable isotopes, ecological and evolutionary interactions especially with invasive species.

Martin Kainz, PhD, researcher scientist, Inter-University Center for Aquatic Ecosystem Research Wassercluster Lunz, Austria. Key experience in food web structure studies using fatty acids, stable isotopes and mercury.

Sami Taipale, post-doc, University of Jyväskylä, Finland. Key experience in energy flows and food web structure using fatty acids.

Tommi Malinen, MSc, Univ. Helsinki, Finland. Key experience in fish population density estimation and food web studies.

Martin Lodenius, PhD, docent, University of Helsinki, Finland. Key experience in heavy metal accumulation in ecosystems.

Pirjo Mattila, PhD, principal research scientist, MTT Agrifood Research, Finland. Key experience in vitamin D research including fish foods and various fish species.