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Assessment of the octopus stock complex in the Gulf of Alaska

At least seven species of octopus are found in the Gulf of Alaska (GOA). For management purposes, all octopus species are grouped into a single assemblage. Neither the relative abundances of the various species or the species composition of the commercial catch are well documented, but research indicates that the giant Pacific octopus Enteroctopus dofleini is the most abundant octopus species in shelf waters and makes up the bulk of octopus catches in commercial fisheries. Octopuses are taken as incidental catch in trawl, longline, and pot fisheries throughout the GOA; a portion of the catch is retained or sold for human consumption or bait. The highest octopus catch rates are from Pacific cod pot fisheries in the central and western GOA (NMFS statistical areas 610 and 630). Through 2010, octopuses were managed as part of the "other species" complex, with catch reported only in the aggregate along with sharks, squids, and sculpins. In 2011, the GOA Fishery Management Plan was amended to provide separate management for sharks, sculpins, squids, and octopuses. In compliance with the reauthorized Magnuson-Stevens Act, each complex has its own annual catch limit. Harvest recommendations for the octopus complex are made using a modified Tier 6 approach, where the overfishing level (OFL) is calculated by multiplying the best available estimate of octopus biomass by the best estimate of natural mortality for E. dofleini. Catch limits for octopus for 2011-2014 were set using the average biomass from the last 3 surveys. Beginning in 2015, a random-effects (RE) model is used to provide a minimum biomass estimate.

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