Black Rockfish Management and Research
More than 30 species of rockfish from the genera Sebastes and Sebastolobus are harvested in the U.S. Exclusive Economic Zone off Alaska. For management purposes rockfish in the Gulf of Alaska and Bering Sea Aleutian Islands are divided into management assemblages based on their habitat, habits, distribution and, in some cases, to reduce the possibility of overharvest of certain more economically valuable species. Rockfish inhabiting the Gulf of Alaska are separated into three ecological groups: demersal shelf, pelagic shelf, and slope rockfish. Black rockfish are categorized with pelagic shelf rockfish (Sebastes sp.); this assemblage includes dusky (S. variabilis), dark (S. ciliatus), widow (S. entomelas), yellowtail (S. flavidus), and blue rockfish (S. mystinus). Generally groundfish fisheries in the U. S. Exclusive Economic Zone (EEZ; 3–200 nm offshore) are federally managed; however in 1998 management jurisdiction for black and blue rockfish was transferred to the State of Alaska. In the pelagic shelf rockfish assemblage, management emphasis is placed on black rockfish as it is the only species in this group with directed fisheries in state waters.
Fisheries targeting pelagic shelf rockfish or black rockfish occur in Kodiak, Chignik and the South Alaska Peninsula in the Westward region, in Lower Cook Inlet in Central Region, and in Southeast Alaska. Pelagic shelf or black rockfish may be harvested with hand troll or mechanical jig in all regions, and in Southeast Alaska dinglebar is an additional legal gear type. The directed fisheries in Central Region and in Southeast Alaska are small and conservatively managed using guideline harvest limits by area. The fisheries in the Westward Region (Kodiak area) have been managed conservatively using historic catch data, trip limits, and daily bag limits in the past. A stock assessment program is being developed in Westward Region using acoustics as an index of abundance with a goal to incorporate this data into an age-structured model in the future.
In Southeast Alaska, tagging studies have been performed on black rockfish. A total of 4,590 black rockfish were tagged and released with dart tags from 1996–2002. The majority of these fish were released around the north side of Kruzof Island. A total of 47 fish were recovered with an average distance of 4 km between release and recovery locations. Fish were recovered at distances of less than 1 km to 15 km from their release locations.
The Alaska Department of Fish & Game sport fish division is conducting research on recompression of rockfish caught by anglers. Rockfish that are brought up from depth are often at risk to death or injury due to changes in water pressure due to expanding gas in their swim bladder. Research conducted by both the Alaska Department of Fish and Game and Oregon State University show promise in increased short term survival after recompression. By releasing the rockfish at depth, the expanded gas may contract and external signs of barotrauma may disappear. More research is being conducted to determine the effects of recompression on long term survival.