Deepsea and oceanic redfish

Scientific: Sebastes mentella. English: Deepwater redfish, deepsea rosefish, beaked redfish, oceanic redfish. Icelandic: djúpkarfi, úthafskarfi. For more languages see the Marine Animal Dictionary.

Biology and distribution

The deepsea redfish is in many regards similar to the golden redfish. It just lives deeper. The fishing areas around Iceland and global distribution are very comparable (except for the depth of course). Size in catches is similar, but the deepsea redfish matures larger, or at the size of 37 to 42 cm long. It is very difficult to age determine the deepsea redfish. Spawning time is similar as with golden redfish but the deepsea redfish has more larvae, or from 40,000 to 400,000. The main food is also zooplankton, mostly krill. It is benthopelagic as the golden redfish but differs as there seem to be two stock components; one is along the continental shelf break but the other below 500 m depth in the open ocean, living apparently a pure pelagic lifestyle.

To confuse matters, this pelagic deepsea redfish is not the same as the oceanic redfish. The oceanic redfish is a distinctly separate stock, living in the open ocean above 500 m depth over the Reykjanes ridge southwest of Iceland. Very little is known about the biology of this stock.

For information on factors that are shared by all the redfish species and also on comparison between the species, see the main category on redfishes.

Catch and fishing gear

The catch composition of the redfishes is quite complex, as species have sometimes not been separated in catches (it is obligatory now) and they can be difficult for inexperienced people to identify. A method used here to separate the catches of demersal species from logbooks is to assign redfish catches from below 500 m to deepsea redfish and catches above that to golden redfish. Before 1980 most of the catches were in shallow waters and therefore probably golden redfish. Trawlers began to fish more in deeper waters after that and catches of deepsea redfish increased to around 40,000 tonnes annually. Lately the catches have declined to about 20,000 tonnes annually. A combined TAC is given for golden redfish and demersal deepsea redfish. Both stocks are almost exclusively fished with bottom trawls.

Catches of oceanic redfish were started in 1982 by the Soviet Union. Iceland joined the oceanic redfish fishery in 1989. The stock is fished with pelagic trawls by several nations in the North Atlantic. Most of them are party to an international agreement on total allowable catch and the share of individual countries. The total catch has varied from 27,000 tonnes to 180,000 tonnes since 1990. Recently, catches have been around 80,000 tonnes annually. The majority of these catches are, however, conducted outside the Icelandic EEZ and the foreign fleets have never fished for this stock in Icelandic waters.

The Icelandic catch has in this period varied from 14,000 tonnes to 63,000 tonnes, inclusive of a figure of 10% for estimated discards of blemished and infected fish. Oceanic redfish is mainly caught in the summer months at depths of 200 - 500 m in the Irminger Sea, within the EEZ of Iceland and Greenland and in international waters.

There is increasing scientific evidence for concluding that the catch of oceanic redfish near the Reykjanes ridge and in the Irminger Sea is in fact not limited to this stock component, and that pelagic deep-sea redfish has increasingly been caught in this fishery, as the use of large pelagic trawls has increased and ships have to a large extent fished at depths of over 600 m. In recent years, most of the Icelandic catch has been fished below that depth. The question then arises whether the deep-sea redfish stock component may belong to the deep-sea redfish stock in Icelandic waters which is already fished intensively and subject to careful monitoring. Research on the genetic make-up of these components is presently being carried out and is likely to answer these basic questions.

Stock status (from the Marine Research institute)

At the beginning of 2009, ICES concluded that there are three biological stocks and hence three management units of deep sea redfish (Sebastes mentella) in the Irminger Sea and adjacent waters: a ‘Deep Pelagic’ stock below 500 m, a ‘Shallow Pelagic’ stock above 500 m, and an ‘Icelandic Slope’ stock on the continental shelf of Iceland. The East Greenland Shelf is most likely a common nursery area for the three stocks.

In 2010, 17 700 t of Icelandic slope redfish were landed, or about 2 000 t less than in 2009. The state of the stock is considered stable at a low level. ICES and MRI recommend that effort should be kept low and that the TAC in Icelandic waters should not exceed 10 000 t for the quota year 2011/2012.

In 2010, an estimated 2 400 t of shallow pelagic redfish were caught, which is similar to 2008 and 2009. Little fishing was conducted on the main fishing grounds south and southeast of Greenland. Some of the catches were taken in the same area as the deep pelagic redfish. Annual landings were highest at about 100 000 t in 1993–1995. The Icelandic fleet has fished very little from this stock in recent years. Given the very low state of the stock, ICES advises no directed fishery.

In 2010, the estimated landings of deep pelagic redfish were about 62 000 t, compared to 52 000 t in 2009. Annual landings were between 80 000 and 140 000 t in 1995–2004. The Icelandic fleet caught about 14 500 t in 2010, which is similar as in 2009.

ICES will not give advice on the pelagic redfish stocks for 2012 until the autumn 2011, and will base the advice on the results from the international acoustic/trawl redfish survey conducted in the Irminger Sea and adjacent waters in June–July 2011.

Processing and markets

Most of the deepsea redfish catch and all of the oceanic redfish catch is processed and frozen at sea. The markets are much the same as for golden redfish.

References and further information

References: (Jónsson & Pálsson, 2006).

For full citation and further information on fishes in general see this page.

Hreiðar Þór Valtýsson, University of Akureyri