Fisheries and Aquaculture

Fisheries

In the North Pacific, the commercially most important Sebastes species are: the Pacific ocean perch (S. alutus), widow rockfish (S. entomelas) and yellowtail rockfish (S. flavidus). Local fisheries along the Northwest American and West Canadian coast also aims for black rockfish (S. melanops), splitnose rockfish (S. diploproa), chilipepper rockfish (S. goodei), bocaccio (S. paucispinis) and shortbelly rockfish (S. jordani) (Amidei, 1986; Hightower, 1990). In 1995, 19,530 tons of S. alutus were landed, mainly by the USA (15,613 t), Canada (3,917 t) and the Russian Federation (3,593 t) (FAO, 1997b). The fishery of S. alutus by the USA and Canada was developing in the 1950s (Alverson and Westrheim, 1961), was senescent in the 1970s and has been developing again since 1980 (FAO, 1997a).

The traditional redfish fishery of Norway, Iceland and Greenland since the beginning of the century was accompanied by the commercial trawl fishery of an international fleet including countries like Canada, Germany, the UK, Denmark (including the Faroese Islands), Korea and the former USSR in the 1950s and 1960s. Off the Greenland coast, the Icelandic landings of S. marinus and S. mentella increased from a few hundred tons in 1951 to 12,400 tons in 1953, followed by the German directed fishery in 1955 which reached its peak in 1962 with nearly 55,000 tons (Jensen, 1979). The redfish fishery in the North Atlantic was senescent in the 1970s and developed again in the 1980s (FAO, 1997a). In 1995, the total landings of 'Atlantic redfishes' (labelled by the FAO as the Sebastes spp. complex) amounted 302,042 tons (FAO, 1997b). The fishery for the oceanic S. mentella was started by several East European countries like Bulgaria in 1982, followed by the Icelandic, Norwegian and Faroese fleets in 1989 and 1990. The main fishing season is from April through to July. Annual catches varied from approximately 105,000 tons in 1986 to 25,000 tons in 1991, with an average annual catch of about 63,000 tons (Magnússon and Magnússon, 1995). The FAO (1995) described the redfish stocks in area 21 (Northwest Atlantic) as heavily exploited to overfished and in area 27 (Northeast Atlantic) as heavily exploited. In some areas, especially on the traditional fishing grounds off West Greenland, the redfish and cod fishery was stopped completely in the early 1990s as a consequence of a severe stock decline under biological acceptable limits (Rätz, 1996 and 1997). Most of the fishermen are now trawling for northern shrimp (Pandalus borealis), causing high fishing mortality of young redfish which are caught in large amounts in their small-meshed trawls as by-catch (Riget et al., 1988; Veim et al., 1994).

For many species of the genus Sebastes, the full recruitment to commercial fisheries occurs at the age of 14 to 18 years (Gunderson, 1977; Archibald et al., 1981 and 1983). Therefore, Leaman (1991) recommends a harvesting strategy which accounts for the special biological features of these animals and the long response time (10-20 years) after exploitation.

Aquaculture

The only Sebastes species in mariculture is the kurosoi (S. schlegeli) in Japan which has a high commercial value in the Hokkaido region. These fish, having a relatively high fecundity (100,000 - 184,000 larvae), are reared from extrusion to the juvenile stage (about 10 cm) and released into the open sea to increase the natural stock (Kusakari, 1991).

Processing and utilisation

The market for rockfishes and redfishes largely aims for high-quality human consumption. The majority of redfish are a filleted at sea and deep-frozen, and some fish are smoked or salted (Muus and Dahlström, 1991).

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