Environmental Monitoring of Pacific Halibut (Hippoglossus stenolepis) Habitat in the North Pacific Ocean and Bering Sea

In 2009, the International Pacific Halibut Commission (IPHC) began collecting oceanographic data at over 1200 stations during the IPHC annual setline survey. The survey spans the area from northern California to the Bering Sea and Aleutian Islands, and provides a snapshot of summertime conditions on the Pacific halibut (Hippoglossus stenolepis) grounds, i.e. near-bottom in depths to 500 m. Data collected include temperature, dissolved oxygen (DO), salinity, pH, and chlorophyll concentration. The first six years of environmental data have shown some clear differences among the major geographic areas relative to other areas spanned by the survey. The waters off the U.S. West Coast and British Columbia, Canada have higher temperatures except where there is upwelling, lower DO, lower pH, and moderate chlorophyll concentrations. Gulf of Alaska (GOA) shelf waters differ from east to west with the western GOA tending towards warmer temperatures, higher DO, and less acidic water than the eastern and central GOA.  The Bering Sea and Aleutian Islands is characterized by cooler temperatures, moderate primary production, a variety of pH conditions, and higher DO, except at very deep stations. Presented here is a summary of environmental conditions on the halibut grounds according to the survey conducted from 2009-2014.