MESA: Northern Rockfish
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Adult northern rockfish as seen from Delta submersible. |
The northern rockfish, Sebastes polyspinis, has one of the most northerly distributions among the 60+ species of Sebastes in the North Pacific Ocean. It ranges from extreme northern British Columbia around the northern Pacific Rim to eastern Kamchatka and the northern Kurile Islands and also north into the eastern Bering Sea. Gulf of Alaska northern rockfish grow significantly faster and reach a larger maximum length than Aleutian Islands northern rockfish.
Little is known about the life history of northern rockfish. Like other species of Sebastes they have internal fertilization of eggs and bear live young. Parturition (larval release) occurs in the spring and is completed by summer. They attain a maximum age of about 70 years. The preferred habitat of adult northern rockfish in the Gulf of Alaska is relatively shallow rises or banks on the outer continental shelf at depths of ~75-150 m. The highest concentrations of northern rockfish appear to be associated with relatively rough (variously defined as hard, steep, rocky, or uneven) bottom on these banks. Older juveniles (>20 cm) are found on the continental shelf, generally at locations inshore of the adult habitat. Northern rockfish are generally planktivorous and eat mainly euphausiids and calanoid copepods. Predators of northern rockfish are not well documented, but likely include larger fish, such as Pacific halibut, that are known to prey on other rockfish species. Northern rockfish are important to the commercial fishery in the Gulf of Alaska where about 4,000 tons are caught by trawlers each year.
Contact:
Jon Heifetz
Auke Bay Laboratories
Alaska Fisheries Science Center, NOAA Fisheries
Ted Stevens Marine Research Institute
17109 Pt Lena Loop Rd
Juneau AK 99801
Jon.Heifetz@noaa.gov
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