2014 Assessment of the Other Rockfish Stock Complex in the Bering Sea and Aleutian Islands
March 04, 2014
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.
Rockfish are long-lived species which do not attain reproductive maturity until 5-20 years of age. They are viviparous; they mate and fertilize the eggs internally. Embryos develop within the female, and thousands or millions of tiny larvae are released after several months. Juveniles settle in kelp, eelgrass, or rocky habitat and move to deeper water as they mature.
An analysis was conducted in the 2001 Other Rockfish SAFE report to distinguish species expected to occur in the BSAI Other Rockfish complex from rarely observed and potentially misidentified species (Reuter and Spencer 2001, http://www.afsc.noaa.gov/REFM/docs/2010/BSAIshortraker.pdf). The criteria used for the analysis was occurrence in at least one haul of the BSAI surveys and/or occurrence in at least 1% of observed fishery hauls. Using data from 1999-2001, 7 species (shortspine thornyhead; Sebastolobus alascanus, dusky rockfish; Sebastes variabilis, redbanded rockfish; Sebastes babcocki, redstripe rockfish; Sebastes proriger, yelloweye rockfish; Sebastes ruberrimus, harlequin rockfish; Sebastes variegatus, and sharpchin rockfish; Sebastes zacentrus) were identified as meeting these criteria (Table 2). Dark rockfish also met the criteria, but have since been removed from the Other Rockfish complex and is now managed by the State of Alaska.
The two most abundant species for Other Rockfish complex are dusky rockfish and shortspine thornyheads (SST). In the Aleutian Islands (AI) and eastern Bering Sea (EBS) slope, shortspine thornyheads occur between 200 m and 500 m (Reuter and Spencer 2001). In contrast, dusky rockfish are typically captured between 125-200 m in the AI, and are rarely encountered on the EBS slope in either survey or fishery catches.