I study size-dependent interactions within and between fish species and effects of fishing and climate change on population dynamics and ecological processes.
My general research focus on size dependent predatory and competitive interactions within and between fish species and how these, together with abiotic factors, affect the size structure, density, production and dynamics of fish populations and fish communities. More specifically, present main research approaches focus on how fish populations, fish communities and ecosystems are affected by climate change and fisheries. The climate change research integrates studies of abiotic factors and its impact on biotic processes, focusing on identifying mechanisms and thresholds of climate change effects on fish production and ecosystem productivity. Key aspects of this research are how temperature, light availability and concentrations of terrestrial organic carbon affect productivity, resource use and energy pathways in aquatic food webs, from algae and bacteria at the base of the food web, through intermediate consumers (zooplankton and macroinvertebrates) to top consumers like fish.
The research on the effects of fishing focuses on how different types of fisheries and fishing mortality, size-dependent interactions between fish individuals and the variation in productivity between different habitats(and resources)affect the densities and size structure of fish populations. Another part of this research study the potential use of estimated concentrations of species-specific fish DNA in water samples as measures of fish abundance. The purpose of this research is to identify sustainable harvest regimes and to developed long-term monitoring methods and management strategies of lake fish top consumer populations.
Systems studied are mainly the Bothnian bay and Bothnian sea and boreal and arctic lakes and streams. The research includes comparative field studies along different climate gradients and experimental studies at different temporal and spatial scales from aquaria, to experimental pond ecosystems and whole lake experiments. Fish species mainly studied are three- and nine-spined sticklebacks, perch, brown trout and Arctic char.