Rex sole (Glyptocephalus zachirus) is a right-eyed flatfish occurring from southern California to the Bering sea and ranging from shallow water (<100m) to about 800 meters depth. They are most abundant at depths between 100 and 200m and are found fairly uniformly throughout the Gulf of Alaska (GOA) (NOAA 2011).

Rex sole are caught in a directed fishery using bottom trawl gear. Fishing seasons are driven by seasonal halibut PSC apportionments, with approximately 7 months of fishing occurring between January and November. Recruitment to the fishery begins at about age 5 (Stockhausen et al 2009, 2010).

The rex sole population is made up of several stocks that are managed as four separate units: the U.S. West Coast stock which includes waters off the coasts of California, Oregon, and Washington; the British Columbia stock which is managed separately by the Canadian government; the Gulf of Alaska (GOA) stock; and the Bering Sea stock (NOAA 2011).