Biology

This is an Arctic species which feeds in mid-water. Unlike most other flatfish, its ‘blind side’ is dark grey rather than white. Greenland halibut spawns in summer (April to June). It is a relatively slow-growing and long-lived species. Males become sexually mature when 7-8 years old and 55-65 cm long and females when 9-11 years old and 65-80 cm. They move into deeper water as they grow and can reach lengths of 120cm. Maximum reported age 30 years.

Stock information

Criterion score: 0.5 info

Greenland halibut is a long-lived, low productivity species with low resilience to fishing pressure. The stock is currently in a relatively stable state and is not overfished. There are no reference points to indicate whether the stock is being subjected to overfishing, but it is thought that the it can withstand the current level of fishing pressure.

The fishable biomass (fish 45cm or longer - the minimum legal size) increased from 591,555 tonnes in 2007 to 783,560t in 2014, and has since declined to 715,671t in 2019. MSY-based reference points have not been defined, but the stock remains above Bpa (500,000 tonnes) and so is considered to be at full reproductive capacity. The harvest rate has been increasing since 2008 and is at the highest in the time-series, at 0.039 in 2018. Recruitment is sporadic and the last strong year class was in 2013.

ICES advises that when the precautionary considerations are applied, catches in 2020 should be no more than 23,000 tonnes - the same as previous advice for 2018 and 2019. This is expected to lead to a 20% decrease in biomass, taking it to 574,000t - remaining above Bpa. Even with 0 fishing pressure, the biomass is predicted to decrease by 6% over 5 years owing to poor recruitment.

In 2019 there was an update assessment, which increased estimates of biomass by 15% but did not change the perception of the overall trend. There is a lack of age data, making estimates of biomass, recruitment and harvest rates uncertain. While recruitment to the stock happens at age 1, recruitment to the fishery happens at size 45cm, and it is not known what age this is. ICES normally provides advice for a two-year period for this stock, but in 2019 the advice was for only one year. ICES states that the advice next year should be based on MSY or precautionary fishing mortality reference points: these still need to be defined.

Management

Criterion score: 0.75 info

The primary management measure for this stock is a Total Allowable Catch, but this is set higher than the scientific advice and is regularly exceeded. There are no management plan, harvest control rule or reference points against which stock size and fishing pressure can be assessed. Scientific advice for managing this stock is therefore based on precautionary considerations.<br
This fishery has a history of quotas being set above scientific advice and catches being above the quota. This stock is accessed primarily by Norway and Russia, and a Total Allowable Catch is set by the Joint Norwegian-Russian Fisheries Commission (JRNFC). From 1992-2009 the fishery was regulated by only allowing longline and gillnet vessels smaller than 28m to carry out targeted fishing for Greenland halibut. Targeted trawl fishing was prohibited. The 38th JRNFC session in 2009 cancelled the ban on targeted Greenland halibut fishing and established a TAC of 15,000t, which has gradually increased since.

On average over the past five years, JRNFC TACs have been set 20% higher than the advice: while the advice has averaged 18,500t, TACs have averaged 22,000t. The EU also sets a combined TAC for its waters, covering part of this stock and part of the stock in subareas 5, 6, 12, and 14 (Iceland and Faroes grounds, West of Scotland, North of Azores, East of Greenland) of around 1,000t. There are also catches in the Jan Mayen EEZ, which are not regulated by TAC, and which in 2018 were 210t. Recent total catches of this stock have averaged 25,500t, and were 65% above the advice in 2015, declining to 24% above the advice in 2018.

As well as TACs, there is a minimum size regulation for Greenland halibut (45 cm), and since 2012 it has been mandatory to use sorting grids. Bycatch of undersized Greenland halibut must not exceed 15% by number in each haul. When fishing for other species, bycatch of Greenland halibut of up to 7% of the total landings by weight (at the end of fishing operations) is permitted. Norway sets quotas for trawlers and vessels above 28m. Vessels smaller than this can have quota if using longline and gillnet, but can only fish at certain times of the year.

Discards are considered to be negligible.

Capture Information

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In 2018, around 61% of the catch was by trawling, 26% by longlining and 11% by gillnetting. The vast majority of catches were by Russia and Norway.

There are designated MPAs in Norwegian and Russian waters, within which all fishing is prohibited. It is an offence for any fishing vessel to fish on or in close proximity to known areas of coral reef or coral garden. Norwegian vessels report the presence of cold-water corals or sponges in a catch and then move 2-5 miles away to continue fishing - this is monitored through Vessel Monitoring Systems. Gillnets are generally size selective, either not retaining fish small enough to pass through the meshes or not admitting fish that are too large. Interactions with seabirds and marine mammals are estimated to be low. Gillnets don’t tend to have significant habitat impacts, with the main interaction being from anchors to keep the nets in place.

Alternatives

Based on method of production, fish type, and consumer rating: only fish rated 2 and below are included as an alternative in the list below. Click on a name to show the sustainable options available.