2016 Assessment of the Octopus Stock Complex in the Bering Sea and Aleutian Islands
February 13, 2016
Through 2010, octopuses were managed as part of the BSAI “other species” complex, along with sharks, skates, and sculpins. Historically, catches of the other species complex were well below TAC and retention of other species was small. Due to increasing market values, retention of some of the other species complex members increased. Beginning in 2011, the BSAI fisheries management plan was amended to provide separate management for sharks, skates, sculpins, and octopus and set separate catch limits for each species group. Catch limits for octopus for 2011 were set using Tier 6 methods based on the maximum historical incidental catch rate. In 2012, a new methodology based on consumption of octopus by Pacific cod was introduced; this method has been in use since 2012 and is recommended for 2017 and 2018. The consumption estimates have been updated this year with additional diet data for 2007-2015. The new estimates show an increase in consumption of octopus in recent years, due to both an increasing cod population and increases in the proportion of octopus in cod diets.
In this assessment, all octopus species are grouped into one assemblage. At least seven species of octopus are found in the BSAI. The species composition of the octopus community is not well documented, but data indicate that the giant Pacific octopus Enteroctopus dofleini is most abundant in shelf waters and predominates in commercial catch. Octopuses are taken as incidental catch in trawl, longline, and pot fisheries throughout the BSAI; a portion of the catch is retained or sold for human consumption or bait. The highest octopus catch rates are from Pacific cod fisheries in the three reporting areas around Unimak Pass. The Bering Sea and Aleutian Island trawl surveys produce estimates of biomass for octopus, but these estimates are highly variable and do not reflect the same sizes of octopus caught by industry. Examination of size frequency from survey and fishery data shows that both commercial and survey trawls catch predominantly small animals (<5 kg), while commercial pot gear catches or retains only large animals (10-20 kg). In general, the state of knowledge about octopus in the BSAI is increasing, but there is still no reliable estimate of octopus biomass.