Fish Communities & Climate Change

Last changed: 05 July 2021

Waters are getting warmer, darker (mainly in lakes) and less saline (in the Baltic Sea). How does this affect fish communities and fisheries? To resolve this, we study how the dynamics and responses of fish communities result from variation in individuals’ direct, physiological, responses and their interactions with other individuals in fish communities and aquatic food-webs.

Physiological responses in fish and interactions in food-webs

Species and individuals are affected in different ways by environmental changes resulting from climate change. Warming, for example, directly affects fish metabolism, but how varies between species. It even varies between individuals, often depending on how big they are.  But individuals also affect each other, e.g. by feeding on or competing with each other. The net effect of climate change on, for example, how individuals grow therefore depends both on their physiological responses to the environment and on these interactions in food-webs. The fate of fish individuals under climate change, in turn, determines – and is thus also affected by – the responses of the populations and communities they constitute. 

Field  experiments simulate climate

We study this by combining unique field-experiments that simulate climate change with mathematical models of environment-dependent physiologically based community- and food-web dynamics, currently in three related projects.

  • How trophic interactions mediate physiological responses to climate change in food-webs (lead A. Gårdmark; Vetenskapsrådet)

  • Darker and warmer lakes: from individual physiology to fish community responses and adaptive fisheries management (lead M. Huss; FORMAS)

  • Detecting and understanding climate change impacts on natural food-webs from monitoring data: a novel time series analysis method (lead A. Gårdmark; FORMAS)

Interested? Welcome to get in touch!  

Biotest basin from above
The Biotest, a heated artifical bay where we study effects of warming in the Baltic Sea (access thanks to collaboration with Forsmarks kraftgrupp AB). Photo: Göran Hansson.
We simulating climate change in the Baltic Sea using mesocosms. Photo: Fredrik Landfors.
Roe under water
Perch lay their eggs on vegetation, here we gave them Christmas trees! Photo: Fredrik Landfors.
Diver collecting roe
Collecting perch roe for hatching, for our climate change experiments. Photo: Fredrik Landfors.
Perch eggs are hatched in aquaria with different water temperatures. Photo: Fredrik Landfors (left), Anna Gårdmark (right).
See the eyes of perch eggs soon to hatch! Photo: Fredrik Landfors.
Three persons building test ramp
Fixing frames for mesocosms for warming experiments. Photo: Forsmarks Kraftgrupp AB Anna Ek.
Person filling up mesocosms
Fill up and soon all set for experiments! Photo: Anna Gårdmark
Hand pouring black water into test tank
Making water brown, to simulate altered water color and warming, both caused by climate change. Photo: Renee Van Dorst


Anna Gårdmark, Professor
Department of Aquatic Resources, SLU, +46 10-478 41 25                                    

Magnus Huss, Senior Lecturer, Director of Studies - postgraduate education
Department of Aquatic Resources, Institute of Coastal Research, SLU, +46 10 478 41 27