Most deep-sea redfish migrate west and south-westwards towards the continental slope as they grow and become adult. South of 70ºN, only few specimens less than 28 cm are observed, and south of this latitude deep-sea redfish are only found along the slope at depths from 450 to 650 m.
The southern limit of its distribution is not well defined, but is believed to be somewhere on the slope northwest of Shetland. The main areas of larval extrusion are along the slope from north of Shetland to west of Bear Island. The peak of larval extrusion takes place during the first half of April. Genetic studies have not revealed any hybridisation with S. marinus or S. viviparus in the area.
Fishery – dominated by Norway and Russia
The only directed fisheries for deep-sea redfish are trawl fisheries. By-catches are taken in the cod fishery and as juveniles in the shrimp trawl fisheries. Traditionally, the fishery for deep-sea redfish was conducted by Russia and other East European countries from south of Bear Island to Spitsbergen. In 1976, the landings of deep-sea redfish peeked at 269 thousand tonnes. By 1987, the fishery in the Barents Sea had decreased to 10 500 tonnes. At this time, Norwegian trawlers started fishing further south, along the continental slope at approximately 500 m depth. These grounds had never been harvested before and were inhabited primarily by mature redfish. After an increase to 49 thousand tonnes in 1991 due to this new fishery, landings have been at a level of 8 thousand –15 thousand tonnes. Since 1991, the fishery has been dominated by Norway and Russia.
Stock status and setting of quotas
The stock of S. mentella has been considered depleted and ICES has since the mid-90's recommended a ban on direct fishing. After having revised and updated all information on the stock and conducted an assessment with a new analytical population model, ICES recommended that the fishery for 2013 to be kept within 47 000 tonnes.
Norway has taken the initativ for a meeting between the Cosatal Satets to discuss a management regime for deep- sea redfish, including allocation of the stock.
Regulations and by-catches
In 1997 strong regulations were enforced in the fishery. Since 2003, all directed trawl fishery for redfish is forbidden in the Norwegian economic zone north of 62ºN. Accepted as by-catch per haul and on board at any time when fishing for other species, used to be 20 percent redfish. From 2005 until 2012 this percentage has been 15 percent. For 2013 the by-catch per haul is 20 percent, and directed trawl fishery is still forbidden.