"North Pacific Groundfish Stock Assessments"

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 spiny dogfish (Squalus suckleyi), and the salmon shark (Lamna ditropis).

Forty-eight species of sculpins have been identified in the Bering Sea Aleutian Islands (BSAI) region (Families Cottidae, Hemitripteridae, Psychrolutidae, and Rhamphocottidae; Table 1). These species are managed as a complex, and biomass estimates are based on the six most abundant sculpins in the BSAI: bigmouth (Hemitripterus bolini), great (Myoxocephalus polyacanthocephalus), plain (Myoxocephalus jaok), threaded (Gymnocanthus pistilliger), warty (Myoxocephalus verrucosus), and yellow Irish lord (Hemilepidotus jordani). This non-target species complex is assessed biennially, to coincide with the frequency of trawl surveys in the Bering Sea and Aleutian Islands, with full assessments in even years. The 2013 executive summary can be found at http://www.afsc.noaa.gov/REFM/Docs/2013/BSAIsculpin.pdf. BSAI sculpins are managed as a Tier 5 stock, and a weighted average of species-specific natural mortality rates (M) is applied to the aggregate sculpin biomass to estimate standard reference points.

Sablefish (Anoplopoma fimbria) inhabit the northeastern Pacific Ocean from northern Mexico to the Gulf of Alaska (GOA), westward to the Aleutian Islands (AI), and into the Bering Sea (BS) (Wolotira et al. 1993). Adult sablefish occur along the continental slope, shelf gullies, and in deep fjords, generally at depths greater than 200 m. Sablefish observed from a manned submersible were found on or within 1 m of the bottom (Krieger 1997). In contrast to the adult distribution, juvenile sablefish spend their first two to three years on the continental shelf of the GOA, and occasionally on the shelf of the southeast BS. The BS shelf is utilized significantly in some years and seldom used during other years (Shotwell et al. 2012).

Rougheye rockfish (Sebastes aleutianus) have historically been managed within various stock complexes within 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.

Pacific ocean perch (Sebastes alutus) inhabit the outer continental shelf and upper slope regions of the North Pacific Ocean and Bering Sea. Pacific ocean perch, and four other associated species of rockfish (northern rockfish, S. polyspinis; rougheye rockfish, S. aleutianus; shortraker rockfish, S. borealis; and sharpchin rockfish, S. zacentrus) were managed as a complex in the two distinct areas from 1979 to 1990. Known as the POP complex, these five species were managed as a single entity with a single TAC (total allowable catch). In 1991, the North Pacific Fishery Management Council separated POP from the other red rockfish in order to provide protection from possible overfishing. Of the five species in the former POP complex, S. alutus has historically been the most abundant rockfish in this region and has contributed most to the commercial rockfish catch.

Alaska plaice (Pleuronectes quadrituberculatus) are primarily distributed on the Eastern Bering Sea continental shelf, with only small amounts found in the Aleutian Islands region. In particular, the summer distribution of Alaska plaice is generally confined to depths < 110 m, with larger fish predominately in deep waters and smaller juveniles (

The Bering Sea/Aleutian Islands (BSAI) Other Rockfish complex is defined by what it excludes rather than by what it includes. The Other Rockfish complex includes all species of Sebastes and Sebastolobus, other than Pacific ocean perch (POP, Sebastes alutus), northern rockfish rougheye rockfish (S. aleutianus), and shortraker rockfish (S. borealis). Current definitions of the complex do not specifically exclude blackspotted rockfish (S. melanostictus), a recently recognized species (Orr and Hawkins 2008) that had historically been identified as rougheye rockfish in research surveys. However, blackspotted is currently not distinguished from rougheye rockfish in the fishery catches, and is thus currently managed under the BSAI blackspotted/rougheye complex.

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.

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. However, due to recent increased 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 was accepted and used for 2013 and 2014. The consumption estimate has not been revised from 2012; the authors recommend that this calculation be revisited once every five years.