"Research in Alaska"

Alaska Fisheries Science Center (AFSC) surveys and fishery observer catch records provide biological information on shark species that occur in the Bering Sea and Aleutian Islands (BSAI) (Table 20.1 and Figure 20.1).  The three shark species most likely to be encountered in BSAI fisheries and surveys are the Pacific sleeper shark (Somniosus pacificus), the salmon shark (Lamna ditropis), and the spiny dogfish (Squalus suckleyi).

Sculpins are found in both freshwater and marine habitats; they are distributed throughout the BSAI and occupy all benthic habitats and depths. Forty-seven species of sculpins have been identified in the Bering Sea Aleutian Islands (BSAI) region.

New data included in the assessment model were relative abundance and length data from the 2016 longline survey, relative abundance and length data from the 2015 longline fishery, length data from the 2015 trawl fisheries, age data from the 2015 longline survey and 2015 fixed gear fishery, updated catch for 2015, and projected 2016 -2018 catches.

Rougheye rockfish (Sebastes aleutianus) have historically been managed within various stock complexes in the Bering Sea/Aleutian Islands (BSAI) region. For example, from 1991 to 2000 rougheye rockfish in the eastern Bering Sea (EBS) area were managed under the “other red rockfish” species complex, which consisted of shortraker (Sebastes borealis), rougheye (S. aleutianus), sharpchin (S. zacentrus), and northern rockfish (S. polyspinis), whereas in the Aleutian Islands (AI) area during this time rougheye rockfish were managed within the rougheye/shortraker complex. In 2001, the other red rockfish complex in the EBS was split into two groups, rougheye/shortraker and sharpchin/northern, matching the complexes used in the Aleutian Islands. Additionally, separate TACs were established for the EBS and AI management areas, but the overfishing level (OFL) pertained to the entire BSAI area. By 2004, rougheye, shortraker, and northern rockfish were managed with species-specific OFLs applied to the BSAI management area.

Northern rock sole (Lepidopsetta polyxystra n. sp.) are distributed primarily on the eastern Bering Sea continental shelf and in much lesser amounts in the Aleutian Islands region. Two species of rock sole are known to occur in the North Pacific Ocean, a northern rock sole (L. polyxystra) and a southern rock sole (L. bilineata) (Orr and Matarese 2000). These species have an overlapping distribution in the Gulf of Alaska, but the northern species comprise the majority of the Bering Sea and Aleutian Islands populations where they are managed as a single stock.

A summary of the 2016 assessment recommended ABCs relative to the 2015 recommendations is shown below. BSAI Pacific ocean perch are not overfished or approaching an overfished condition. The recommended 2017 ABC and OFL are 43,723 t and 53,152 t, which are 38% increases from the maximum ABC and OFL specified last year for 2017 of 31,724 t and 38,589 t. The 2016 AI survey biomass is large and consistent with the survey biomass estimates in 2010, 2012, and 2014, and the size composition data continue to show relatively strong recent cohorts. The mode is better able to fit the large AI survey biomass estimates since 2010, although the model total biomass is still lower the survey biomass estimates.

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, and Dover sole. A full list of the species in the other flatfish complex is shown in Table 11.1. Different areas and depths in the BSAI have different species compositions within the other flatfish complex (Figure 11.1). Starry flounder, longhead dab, butter sole, and Sakhalin sole occur primarily on the on the shallower continental shelf. Dover sole and deep sea sole are found at greater depth, and English sole and Dover sole are more abundant in the AI than in the EBS. Rex sole is common on the EBS shelf, the slope, and in the AI. 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 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, and Dover sole. A full list of the species in the other flatfish complex is shown in Table 11.1. Different areas and depths in the BSAI have different species compositions within the other flatfish complex (Figure 11.1). Starry flounder, longhead dab, butter sole, and Sakhalin sole occur primarily on the on the shallower continental shelf. Dover sole and deep sea sole are found at greater depth, and English sole and Dover sole are more abundant in the AI than in the EBS. Rex sole is common on the EBS shelf, the slope, and in the AI. 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.

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.

Northern rockfish (Sebastes polyspinus) inhabit the outer continental shelf and upper slope regions of the North Pacific Ocean and Bering Sea.  Northern rockfish (Sebastes polyspinus) in the Bering Sea/Aleutians Islands (BSAI) region were assessed under Tier 5 of Amendment 56 of the NPFMC BSAI Groundfish FMP until 2004.  The reading of archived otoliths from the Aleutian Islands (AI) surveysallowed the development of an age-structured model for northern rockfish beginning in 2003. Since 2004, BSAI northern rockfish have been assessed as a Tier 3 species in the BSAI Groundfish FMP.