Tusk
Brosme brosme
What to check for
Location
Northeast Atlantic
Technical location
Atlantic, Northeast, Bay of Biscay, Faroes Grounds, Irish Sea, Porcupine Bank, English Channel, Bristol Channel, Celtic Seas, West and Southwest of Ireland, North Sea, Portuguese Waters, Skagerrak and Kattegat, West of Scotland, Western Hatton Bank
Caught by
Hook & line (longline)
Rating summary
There is no concern for population size or fishing pressure for tusk in the Northeast. There are a number of management measures for tusk. However, it is a data limited species, so there is no way of assessing how well it is managed across the Northeast Atlantic as a whole. Tusk caught by longlines in the Northeast Atlantic are unlikely to cause habitat impacts. Although longlines are considered to pose low risk of bycatch there are concerns regarding the lack of information about bycatch of vulnerable species, more data on bycatch species and quantities is needed.Rating last updated August 2024.
Technical consultation summary
Tusk in the Northeast Atlantic is a data limited stock, but there appears to be no concern for biomass or fishing pressure, and has a medium resilience to fishing pressure. This tusk stock covers a wide area, but management measures are only in place for some areas. In 2023, TACs added up to 4,572 tonnes. However, there is no quota for tusk in the Norwegian fishery, the additional 30,000 tonnes TAC for demersal fish in the UK zone Subarea 4 for Norwegian vessels. Scientific advice for 2023-2024 is less than 6924 tonnes. There is no minimum landing size in Norwegian waters, and the Faroese minimum size is 40cm - smaller than the estimated size at maturity of 50cm. Longliners account for 81% of the tusk catch in these areas. This method can have a bycatch of vulnerable and endangered seabird and shark species, but the impacts of this are not fully understood.
How we worked out this Rating
Tusk in the Northeast Atlantic are a data limited stock, but there appears to be no concern for population sizes or fishing pressure.Route 2 scoring has been applied to this rating owing to the lack of references points to indicate whether biomass and fishing pressure are at sustainable levels. Tusk are considered to have medium resilience to fishing pressure.Stock assessments are carried out by the International Council for the Exploration of the Sea (ICES). The most recent assessment was published in 2023 using data up to 2022. The next assessment is expected in 2025.The total biomass or weight of tusk has been steadily increasing since 2003. In 2019 these were the highest levels since recording began in 2000. This is measured by landings per unit of effort (kg caught per 1,000 hooks in the longline fishery), which has increased from an average of 127 kg/1000 hooks from 2016-2018, to 143 kg/1000 hooks from 2018-2020. However, there was a decrease to an average of 129 kg/1000 hooks from 2021-2022. This shows a stability in biomass, therefore there is no concern for biomass.The abundance of tusk landed has showing an overall decline, including in 2021 and 2022 where the landings of 3,408t and 4550t, respectively, were lower or near the average of the preceding 5 years of 4415 tonnes. Landings have been lower than the recommended limit since 2011. Therefore, there is no concern for fishing pressure.ICES advises that when the MSY approach is applied, catches should be no more than 6924 tonnes in 2024 and 2025. This is a 11.5% decrease on the previous advice, mainly due to catch advice for data limited stocks is reduced by 20% every three years as a precautionary measure.
Some but not all appropriate relevant management measures are in place, enforced but appear to be having insufficient effect. There is no joint management plan that encompasses the whole stock area.This tusk stock covers a wide area, but management measures are only in place for some areas. Most tusk are caught as bycatch in trawl, gillnet and longline fisheries. Catches are mainly by Norwegian and the Faroe Islands longliners in the northern North Sea (4a) and the Faroese waters (5b1). There is some bycatch by UK trawlers in the North Sea.Varying catch limits (Total Allowable Catches, TACs) apply to different parts of the stock area, and the combined catch limits are lower than the scientifically recommended limits. Norway and the Faroe Islands have agreed a bilateral quota. In 2023, TACs added up to 4,572 tonnes. However, there is no quota for tusk in the Norwegian fishery, the additional 30,000t TAC for demersal fish in the UK zone Subarea 4 for Norwegian vessels. This could be of concern if it was to lead to a decline in biomass, and we will continue monitoring. The recommended maximum catch was 7,821t. The stock assessment used to make these recommendations has some uncertainties, so management should be precautionary to ensure that tusk will not be overexploited. Scientific advice for 2023-2024 is less than 6,924 tonnes.In Faroese waters there are a licensing scheme and some limits on fishing effort. These days-at-sea limits were originally aimed at controlling other fisheries (saithe, cod, and haddock), but they have not been effective at keeping catches in those fisheries at sustainable levels. Additionally, because of lower quotas for cod the fishing pressure for tusk has increased. Therefore, these effort limits may not be adequate for controlling fishing pressure.There is no minimum landing size in Norwegian waters, and the Faroese minimum size is 40cm - smaller than the estimated size at maturity of 50cm. Measures do not, therefore, prevent juvenile tusk from being caught. The Norwegian and Faroese fleet are not allowed to discard tusk, and incentives for illegal discarding are believed to be low.The EU and UK both have fishery management measures, which can include catch limits, population targets, and gear restrictions. However, compliance in the EU and UK has been inconsistent, with ongoing challenges in implementing some regulations. The goal of reaching Maximum Sustainable Yield (MSY) by 2020 was missed, with less than half of UK TACs in 2024 following ICES advice. In 2024, the EU and UK reaffirmed their commitment to sustainable fisheries by aligning management with scientific advice to gradually approach MSY. However, no new target date has been set for achieving MSY across all fisheries. The Landing Obligation (LO), an EU law retained by the UK post-Brexit, requires all quota fish to be landed, even if unwanted (over-quota or below minimum size). It aims to encourage more selective fishing methods, reduce bycatch, and improve catch reporting. However, compliance is poor, and accurate discard levels are hard to quantify with current monitoring programmes. The UK is in the process of replacing the LO with country-specific Catching Policies. The Marine Conservation Society views Remote Electronic Monitoring (REM) with cameras is one of the most cost-effective tools for providing reliable fisheries data and aiding informed management decisions. Fully monitored fisheries enhance collaboration, data accuracy, stock recovery, and reduce impacts on marine wildlife and habitats. However, the full potential of REM may only be achieved when it tracks fishing location and documents catch and bycatch, particularly where vulnerable species and habitats are at risk. As of January 2024, the EU is introducing a Remote Electronic Monitoring (REM) mandate for EU vessels, including CCTV cameras on vessels 18m or more that pose a potential risk of non-compliance, within the next 4 years. Across the UK, different approaches to REM are being taken and legislation is expected to be in place across all 4 countries within the next few years.
Most tusk in the Northeast Atlantic are caught by longlining. This method can have a bycatch of vulnerable and endangered seabird and shark species, but the impacts of this are not fully understood.Tusk are taken in mixed fisheries with ling and as a bycatch species in longline, trawl and gillnet fisheries targeting a range of species, including cod. Longliners account for 81% of the catch of tusk in these areas, 98% of landings occurred in areas 4, 5.b. or 6.a. In Area 5b around 90% of catch was by longline around the Faroe Plateau and on the Faroe Bank in areas deeper than approximately 200 m.The fisheries catching tusk are not thought to fish in marine protected areas. In some areas, closures are in place to protect juvenile tusk and spawning areas.Longlining uses baited hooks set along a long fishing line to attract the target fish. This bait, and the fish that have been hooked, attract other animals such as seabirds and sharks, which are also then caught on the lines.Longlining in demersal species, such as tusk, have a lower risk of habitat impacts than towed gear such as bottom trawling. The accidental bycatch of species such as seabirds and sharks are of greater concern. In the North Atlantic monitoring of bycatch is poor and better data is needed. There is limited information about bycatches in the ling longline fishery.Longline fisheries within the Northeast Atlantic are thought to have low levels of bycatch, but there are records of bycatch of endangered, threatened and protected species. This includes the common guillemot, northern fulmer, and black-legged kittiwake. Common guillemot is at high risk of extinction as a breeding species along the Norwegian coast. While northern fulmars are abundant in some areas but endangered in others, this species is listed as endangered in Europe. Additionally, bycatch levels may have had a negative impact on the black-legged kittiwake which has experienced severe decline in areas 4 and 6 as well as in Norway. Overall, pelagically feeding seabirds breeding along the Norwegian coast have declined substantially since the start of monitoring in 1980.A better understanding is needed of the impacts of this fishery on these species. Norwegian regulations require bird scarers on longliners, which reduces interactions. However, this does not meet best practice recommendations. For example, the Agreement on the Conservation of Albatrosses and Petrels (ACAP) states that the most effective measures are line weighting to sink baited hooks and reduce their availability to seabirds, bird scaring lines, and setting longlines at night.There may also be bycatch of skates, rays, and sharks. More data is needed to understand the level of catch and impact that this is having. Where the fishery overlaps with the Northeast Atlantic Fisheries Commission management area, longlining deeper than 200m is prohibited to protect deep water sharks.Longline fisheries have a much lower impact on habitats than bottom-towed gear such as trawls. However, they can get entangled on habitat features and mooring weights/anchors can cause abrasion and penetration of the seabed. Therefore, if they dragged across the seabed during fishing and hauling they can negatively impact on vulnerable species such as corals and sponges, which can be slow to recover.Longlining uses bait to attract the target species. Bait use is well understood in the Norwegian fishery but appears to be less understood elsewhere. Monitoring of bait use is important to ensure that the fishery is not having a negative impact on bait species such as squid, herring and mackerel.
References
Agnesi, S., Annunziatellis, A., Chaniotis, P., Mo, G., Korpinen, S., Snoj, L., Tunesi, L., Reker, J., 2020, Spatial Analysis of Marine Protected Area Networks in Europe’s Seas III. ETC/ ICM Technical Report 3/2020: European Topic Centre on Inland, Coastal and Marine waters, 40 pp. Available at: https://www.eionet.europa.eu/etcs/etc-icm/products/etc-icm-report-3-2020-spatial-analysis-of-marine-protected-area-networks-in-europe2019s-seas-iii [Accessed on 06.06.2024]ACAP, 2021. ACAP Review of mitigation measures and Best Practice Advice for Reducing the Impact of Pelagic Longline Fisheries on Seabirds. Reviewed at the Twelfth Meeting of the Advisory Committee Virtual meeting, 31 August – 2 September 2021. Available at https://www.acap.aq/resources/bycatch-mitigation/mitigation-advice/3956-acap-2021-pelagic-longlines-mitigation-review-bpa/file [Accessed on 06.06.2024]. Anderson, O.R.J., Small, C.J., Croxall, J.P., Dunn, E.K., Sullivan, B.J., Yates, O. and Black, A., 2011. Global seabird bycatch in longline fisheries, Endang Species Res 14. p 91-106. Available at https://doi.org/10.3354/esr00347. [Accessed on 06.06.2024].Clark, M., Althaus, F., Schlacher, T., Williams, A., Bowden, D., Rowden, A., 2016. The impacts of deep-sea fisheries on benthic communities: a review. ICES Journal of Marine Science 73: suppl_1. P. i51–i69. Available at https://doi.org/10.1093/icesjms/fsv123. [Accessed on 06.06.2024].Gilman, E., Chaloupka, M., Benaka, L.R., Bowlby, H., Fitchett, M., Kaiser, M. and Michael Musyl, M., 2022. Phylogeny explains capture mortality of sharks and rays in pelagic longline fisheries: a global meta-analytic synthesis. Sci Rep 12: 18164. Available at https://doi.org/10.1038/s41598-022-21976-w. [Accessed on 06.06.2024].ICES. 2024. Greater North Sea ecoregion – Ecosystem overview. In Report of the ICES Advisory Committee, 2024. ICES Advice 2024, Section 7.1, Available at https://doi.org/10.17895/ices.advice.25714239. [Accessed on 06.06.2024]ICES. 2024. Celtic Seas Ecoregion – Ecosystem overview. In Report of the ICES Advisory Committee, 2024. ICES Advice 2024, Section 7.1, Available at https://doi.org/10.17895/ices.advice.25713033 [Accessed on 06.06.2024].Pham, C., Diogo, H., Menezes, G., Porteiro, F., Braga-Henriques, A., Vandeperre F. and Morato, T., 2014. Deep-water longline fishing has reduced impact on Vulnerable Marine Ecosystems. Sci Rep 4, 4837. Available at https://doi.org/10.1038/srep04837. [Accessed on 06.06.2024].
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