Arctic freshwater fish productivity and colonization increase with climate warming

Climate warming at high latitudes has long been expected to exceed that predicted for tropical and temperate climes, but recent warming in the Arctic has exceeded even those expectations1. The geophysical consequences of this warming are reasonably well established2, but the impacts on freshwater fauna are poorly understood. Here we use a large-scale geospatial analysis of the population dynamics of one of the most abundant north temperate freshwater fish species to forecast increased demographic rates, productivity and colonization range in response to IPCC climate warming scenarios. Geospatial lake morphometry data were used to characterize 481,784 lakes in the Canadian Arctic capable of supporting lake trout (Salvelinus namaycush) populations. Lake trout productivity in existing habitat is projected to increase by 20% by 2050 due to climate change, but an expanded habitable zone may result in a 29% increase in harvestable biomass. Although many ecosystems are likely to be negatively impacted by climate warming, the phenotypic plasticity of fish will allow a rapid relaxation of the current environmental constraints on growth in the far north, as well as enhanced colonization of bodies of water in which there are few potential competitors. Arctic lakes and their resident fish species are warming rapidly. Geospatial analysis of Canadian Arctic lakes predicts a 20% increase in lake trout productivity by 2050 and a 29% increase in harvestable biomass across an expanded range.