Using Pacific Halibut (Hippoglossus stenolepis) Distributional Response to Recent Environmental Anomalies as a Tool to Explore Possible Dispersal Effects Related to Climate Change in the Future

Pacific halibut (Hippoglossus stenolepis) are currently found in the North Pacific Ocean and Bering Sea. Although they tend to be habitat generalists that occupy a wide range of environmental conditions, the geographic range under which Pacific halibut most often occur is uncertain when considering a changing climate where environmental conditions may exceed the traditional spans of variability. In this study, oceanographic parameters are examined during three recent and significant environmental events: 1) episodic hypoxia off the U.S.A. West Coast; 2) anomalously warm water in the Gulf of Alaska in 2014-2016; and 3) lack of sea ice and resulting cold pool in the Bering Sea in 2018-2019. Changes in environmental conditions are described, and a spatio-temporal model is used to investigate Pacific halibut distribution during these events. Conditions like those observed during these anomalous incidents are predicted to become more frequent with global climate change and examination of Pacific halibut response in the present day may provide insight into future longer term distributional impacts of climate change on the population.