Greenland Institute of Natural Resources assesses demersal redfish in NAFO Subarea 1; biomass remains far below historic levels.
Assessment of Demersal Redfish in NAFO Subarea 1
Northwest Atlantic Fisheries Organization
Serial No. N7742
NAFO SCR Doc. 26/022
SCIENTIFIC COUNCIL MEETING –JUNE 2026
Assessment of Demersal Redfish in NAFO Subarea 1
by
Rasmus Nygaard Greenland Institute of Natural Resources rany@natur.gl
NYGAARD, R. 2026. Assessment of Demersal Redfish in NAFO Subarea 1. NAFO Scientific Council Research Document, SCR Doc. 26/022: 1-10.
Abstract
Two species of redfish are common in West Greenland, golden redfish (Sebastes norvegicus) and deep-sea redfish (Sebastes mentella). Golden redfish has a shallower depth distribution than deep-sea redfish. Redfish stock structure is complicated and connectivity to other nearby stocks is unknown.
The fishery targeting demersal redfish in subarea 1 increased during the 1950 from a level of more than 10.000 tons and peaked in 1962 at more than 60.000 tons. Catches then decreased to around 3000 tons in the beginning of the 1970’s but increased again to around 10.000 tons by 1975. By 1986 catches had decreased to around 5000 tons and thereafter remained below 1000 tons per year with few exceptions.
The differentiation between stocks in official statistics is however not straight forward. Historic catch is also uncertain, particularly in the years 1977 to 1979 where in numerous cases cod was in many cases reported as redfish in logbooks. Prior to the implementation of sorting grids the shrimp fishery have been shown to have unregistered bycatches (particularly during the 1980’s and 1990) far greater than official landings.
There are several surveys of relevance to the assessment of redfish at west Greenland but only the Greenland shrimp and fish survey covers the distribution other surveys of relevance is the EU-Germany survey, and the Greenland Deep survey. Few other surveys also contain relevant information, like the historic Greenland- Japan survey and the inshore surveys in divisions 1D, and 1A.
Survey results indicate decreasing biomass of Golden redfish from the 1980’s to very low levels for two decades but slow recovery since then. However, the recovery been stagnant during the most recent two decades and remain far below the historic levels. Dep-sea redfish biomass was also at low levels from 1987 in the surveys but show signs of recovery after from 2008, but without no clear evidence of further recovery during the recent decade.
Recruitment indices indicate numerous of recruits from 1986 to 2000, but far lower numbers of rectuits during the the 2000’s and an almost complete lack of recruits from 2010 to 2018. However, the Greenland Shrimp and Fish survey indicates several new year classes since 2020, at levels like the 1990’s.
Northwest Atlantic Fisheries Organization
www.nafo.int 2 Biology
Two species of redfish are common inshore and offshore in West Greenland, golden redfish (Sebastes norvegicus) and deep-sea redfish (Sebastes mentella). Golden redfish has a shallower is connected to the shelf and fjord areas on shallower water, whereas the stock structure of deep-sea redfish is more complicated and can be divided into demersal stocks, and pelagic stocks. Deep-sea redfish can be found in the same areas as golden redfish including shallow waters and inside the fjords, and is the dominating species at greater depths offshore (>400m). Relationship to other redfish stocks off East Greenland, Irminger Sea and Iceland is unclear. Stock identities in terms of reproduction were investigated by a joint ICES/ICNAF Study Group (Anon., 1983). The study group concluded that The concept of self-sustaining units or stocks in NAFO Subarea 1 remained unproved for both species due to a general lack of records of maturing or spawning (bearing) specimens. The working group suggested strong relations to the two golden and deep-sea redfish stock complexes off East Greenland, Iceland and Faroes (ICES Subareas V and XIV). However, spawning individuals with live larvae are yearly observed in the inshore trawl survey in Nuuk in April-may.
Length distributions from commercial landings 1962 to 1991 reveals fish in the catches greater than deep-sea Lmax. Therefore historic catches are likely a mixture of both species. During the years, annual growth increments of 4 cm were indicated by repeatedly pronounced peaks in length compositions at 7-8 cm and 12 cm probably corresponding to age 1 and 2 (Nederaas, 1990).
Description of the Fisheries
The fishery targeting redfish in subarea 1 increased during the 1950 from a level of more than 10.000 tons and peaked in 1962 at more than 60.000 tons (Table 1 and figure 1). Catches then decreased to around 3000 tons in the beginning of the 1970’s but increased again to around 10.000 tons by 1975. By 1986 catches had decreased to around 5000 tons and since then has been below 1000 tons per year with few exceptions. However, there is high uncertainty about the total landings of redfish in subarea 1. In the 1977, non- Greenland vessels were excluded access to the valuable cod fishery in subarea 1, which led to massive miss- reporting, where catches of cod were reported as other species such as American plaice, redfish, wolffish, finfish not specified and in these years total catches of redfish are overestimated (Horsted S.A. 1980).
With the decreasing cod stock and the increasing shrimp fishery during the 1980’s and 1990, significant amounts of redfish may have been taken and discarded in the trawl fishery targeting shrimp. At least in the early part of the shrimp fishery some trawlers would to stop hauling close to the surface and leave the trawl hanging vertically in water so that the floating redfish would surface and be sorted from the shrimp catch, before finally retrieving the trawl. It seems unlikely that this practice would have been reported, since the redfish catch never reached the deck and the by-catch of redfish in the early part of the shrimp fishery may have been significantly underestimated. Riget et al, 1988, estimated a by-catch of redfish in 1988 to be 111 million and 15.584 tons out of a total shrimp catch of 49.089 tons. And based on the by-catch pr. kg shrimp from the Greenland shrimp and fish survey (SFW) and the total shrimp catch, Engelstoft J.J. (1996) estimated the total by-catch of redfish in the 1994 shrimp fishery to 4234 tons and 180 million individuals. A higher mean length of the redfish stock in the 1988 study accounted for the weight difference between the two studies (Engelstoft J.J. 1996). To minimize by-catch in the shrimp fishery, offshore operating shrimp trawlers have been equipped with grid separators since 2002 (G.H. 2001) and the grid separators have also been mandatory for inshore operating vessels since 2011(G.S. 2011). The implementation of sorting grids in the shrimp fishery has led to a high protection of redfish larger than 14 cm and in 2007 the by-catch of redfish in the shrimp fishery was estimated to 0.5% of the shrimp catch equivalent to about 700 tons in 2007 (Sünksen 2007). In 2025, 2011 tonnes of redfish were reported. logbook reported bycatch of redfish was 133 tonnes (RED) mainly from the shrimp fishery. Inshore reported factory landings of commercially sized redfish amounted to 40 tonnes and another 40 tonnes were reported in logbooks mainly from offshore trawlers targeting Greenland. (Table 1 and figure 1). Besides the demersal redfish, Statlant 21A data further contain catches from a pelagic fishery beaked redfish (Sebastes mentella) that occurred for from 2000-2008 that was conducted close to the edge of the Greenland EEZ and far off the shelf of division 1F. Indeed, the differentiation between stocks in official statistics is however not straight forward and the two redfish
Northwest Atlantic Fisheries Organization
www.nafo.int 3 species, golden redfish are combined in the catch statistics (table 1). The Greenland authority operates the quota uptake by categorising the catches in three types of redfish. Redfish caught by bottom trawl and longlines on the bottom are called Sebastes norvegicus (REG). Redfish caught pelagic are called Sebastes mentella ( and 3) fish caught as by-catch in the shrimp fishery are named Sebastes sp.
Commercial fishery data
Information on historical length composition was derived from sampling of EU-German commercial catches of golden redfish during 1962-90 covering fresh fish landings as well as catches taken by freezer trawlers (figure 2). Samples were quarterly aggregated and mean length was calculated. These, data revealed gradual mean size reductions from 45 to 35 cm, with the most significant reductions occurring during the 70s. The length frequency further indicates that Golden redfish constituted atleast part of the historic catches.
Survey data
The EU-Germany survey, the Greenland deep-water survey and the Greenland Shrimp and Fish survey are the most important.
The Greenland Shrimp and Fish survey has the largest geographical coverage and good overlap with both species (0-600m, NAFO 1A-F since 1988 and ICES XIV since 2008). The Greenland Shrimp and fish survey also uses a shrimp trawl and catch redfish from age 1 (SCR 26-01). The Greenland shrimp and fish survey timeseries was recalculated in 2026 for the entire timeseries using the same area file programming and coding.
The EU-Germany survey has the longest history but a shallower (0-400m, ICES XIV, NAFO 1C-F since 1982) and is based on a fast moving codtrawl and may be better at catching large redfish than the slow moving shrimp trawl used in the Greenland shrimp and fish survey. The EU-Germany survey is most important for Golden redfish as it does not fully cover the depth distribution of deep-sea redfish.
The Greenland deep-water survey covers a smaller geographical and is to deep to fully cover the distribution of Golden redfish (400-1500m, NAFO 1C-D since 1998).
Besides the recent surveys, a joint Greenland-Japan existed from 1987 to 1995 somewhat overlapping the areas and depths as the present Greenland deep-water survey. The surveys were however conducted with different vessels and gears and the results are not directly comparable. Results from division 1C and 1D indicated a decreasing biomass of deep-sea redfish from 1987 to 1995.
Golden redfish
The EU-Germany and Greenland Shrimp and fish survey have revealed a slightly increasing biomass of golden redfish from 2005 to 2015 (figure 3.). The indices in the survey has not been updated in west Greenland since 2016, and the 2020 indices were based on just a few stations. The Greenland shrimp and fish survey was also at a low level from 1992 to 2005 but slowly increased until 2012. A few large hauls in the survey causes the higher biomass estimates in 2016 and 2019. The indices for golden redfish have been stable in the most recent 4 years. The EU-Germany and the Greenland Shrimp and fish survey show good agreement in the biomass indices for Golden redfish. The biomass indices therefore remain far below the level in the early 1980’s and the early indices were obtained after the large fishery in the 1960’s.
Deep-sea redfish
The EU-Germany survey results for deep-sea redfish remains at a low level throughout the timeseries from 1982, likely related to poor depth overlap with deep-sea redfish and is not included in the Biomass indices for deep-sea redfish. The Greenland-Japan survey indicate that the biomass decreased from 1987 to 1995 (figure 4).
Northwest Atlantic Fisheries Organization
www.nafo.int 4 The Greenland deep survey and the Greenland Shrimp and fish survey both indicated that the biomass remained low until 2007 (figure 4). Both the Greenland deep-sea survey and the Greenland shrimp and fish survey agree that the biomass of deep-sea re