Meeting Abstract
Arctic waters are home to a highly cold-adapted ichthyofauna. As these fishes have evolved for life in the cold, understanding their resilience to the expected rising water temperatures from global climate change is of increasing importance. Past work looking at heat tolerance has focused on only a few high-latitude northern species, and as a result it is unknown whether the diverse collection of nearshore, estuarine, and freshwater arctic and boreal fishes show a consistent reduction in heat tolerance. We began work to investigate the heat tolerance of this broader arctic ichthyofaunal by studying heat tolerance among key members of the fish fauna of Utqiaġvik (formally Barrow), Alaska. Situated on the Arctic coast, Utqiaġvik provides access to fishes that span the key ecological divisions of arctic waters. Organismal heat tolerance was measured for six species of local fishes using the critical thermal maximum methodology. This work aimed to put heat tolerance of these fishes into the context of previously studied polar, temperate, and tropical fishes, as well as the level of thermal variability seen in local waters. We found that these near shore fishes show high organismal heat tolerance, similar to what has been reported for a number of cold-temperate fishes. This high level of heat tolerance may reflect continued selective pressure on fishes inhabiting shallow coastal waters, as water temperatures rose above 11°C during our investigation. While generally heat tolerant, there was a notable split between species with lower tolerance such as least cisco and broad whitefish more commonly associated with freshwater habitats as compared to fourhorn sculpin and arctic flounder more commonly associated with brackish to marine habitats.
