Polymorphism or Ecological Speciation?: Ecotype Variation in Charrs in the Canadian Arctic

Our research has shown that charrs in the Canadian Arctic such as lake char and Arctic charr have intra-specific ecotypes with distinct life cycles and substantial differences in vital rates.  Lake charrs in Great Bear Lake have 5 distinct morphs which appear to occupy different trophic niches.  Arctic charr show both anadromous and resident non-migratory forms as well as land locked populations.  We consider the ecological roles of these forms, their variation in productivity and whether they are indicative of a process of speciation or reflect only phenotypic plasticity. The term ecological speciation has been used to describe a process of intra-specific differentiation in the absence of geographical barriers.   Ecological speciation has significant implications for the management of fisheries in that production parameters such as growth and reproductive output could change during the process of differentiation.  We outline the importance of considering whether ecological speciation processes are occurring in harvested species.  Using examples from the Canadian Arctic and elsewhere we demonstrate how fisheries management decisions should take these processes into account and the potential consequences to conservation of resources when these principles are ignored.