Seasonal variation is an important regulating factor in aquatic ecosystems and is most pronounced in at extreme latitudes. In subarctic regions winters are long, cold (-30 to -40
0C) and dark, whereas summers are brief but comparatively warm (>15
0C) and 24 hour sunlight stimulates productivity. Lakes in this region are ice covered for 6 to 8 months per year and productivity is limited to the summer period. Due to the difficulties sampling in such inhospitable conditions, few investigations have explored the effects of this seasonal variation on resident fish communities. In an investigation funded by the Fisheries Society of the British Isles I am leading a collaboration with
Prof Kimmo Kahilainen and
Dr Chris Harrod to determine how resident cold water adapted and invasive warm water adapted fishes respond to seasonal variation in resource availability and water temperature. A review of this project was included in a recent
FSBI Newsletter. See publications for further details.