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 in the Gulf of Alaska 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. Catches of rex sole occur primarily in the Western and Central management areas in the gulf (statistical areas 610 and 620 + 630, respectively). Recruitment to the fishery begins at about age 5 (Stockhausen et al 2009).