2014 Assessment of the Other Flatfish Stock Complex in the Bering Sea and Aleutian Islands

March 04, 2014

The Bering Sea/Aleutian Islands “other flatfish” group have typically included those flatfish besides northern rock sole, yellowfin sole, arrowtooth flounder, Kamchatka flounder and Greenland turbot. Flathead sole (Hippoglossoides elassodon) were part of the other flatfish complex until they were removed in 1995, and Alaska plaice was removed from the complex in 2002, as sufficient biological data exists for these species to construct age-structured population models. In contrast, survey biomass estimates are the principal data source used to assess the remaining other flatfish. Although over a dozen
species of flatfish are found in the BSAI area, the other flatfish biomass consists primarily of starry
flounder, rex sole, longhead dab, Dover sole and butter sole. A full list of the species in the other flatfish
complex is shown in Table 11.1. At present, no evidence of stock structure is evident for these species in
the Bering Sea/Aleutian Islands region, although no formal genetic or tagging study has been conducted
on these species in this region.

The miscellaneous species of the other flatfish species category are listed in Table 11.1, and their catches from 1995-2014 are shown in Table 11.2 (with historical ABC and TAC). These species are not pursued as fishery targets but are captured in fisheries for other flatfish species and Pacific cod. Catch from 1995-2003 were obtained from the NMFS Regional Office “blend” data, and the catch for some species are reported by species and in an aggregate flatfish group. The catch estimates for these years were produced by applying the proportional catch, by species, from fishery observer data to the estimated total catch for the aggregate other flatfish group, and adding this total to the catch that was reported by species. In the current catch accounting system (in use since 2003), catches of other flatfish are reported only in an aggregate group, and the catch estimates for these years were produced by applying the proportional catch, by species, from fishery observer data to the estimated total catch of the aggregate group. In recent years, starry flounder (Platichthys stellatus) and rex sole (Glyptocephalus zachirus) account for most of the harvest of other flatfish, contributing 97% of the harvest of other flatfish in 2013. The 2014 catch of 4,385 t through late-October is well below the ABC of 13,300 t. Other flatfish fisheries are grouped with Alaska plaice, rock sole, and flathead sole in a single prohibited species group (PSC) classification, with seasonal and total annual allowances of prohibited bycatch applied to the group. In past years, this group of fisheries was closed due to the bycatch of halibut but since the implementation of Amendment 80 in 2008 there have been no closures.

Last updated by Alaska Fisheries Science Center on 04/02/2019

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