Thornback ray
Raja clavata
What to check for
Location
Irish Sea, Bristol Channel, Celtic Sea North
Technical location
Atlantic, Northeast, Bristol Channel, Celtic Sea (North), Irish Sea
Caught by
Bottom trawl (beam)
Rating summary
Thornback ray in the Irish Sea, Bristol Channel, and Celtic Sea North is not overfished, or subject to overfishing. There is no management plan for skates and rays and the joint TAC has been deemed an unsuitable method for protecting individual species. Beam trawls have significant impacts on the seabed, including damage to benthic communities and vulnerable marine habitats. They can also have high bycatch, potentially of vulnerable species.Rating last updated January 2023.
Technical consultation summary
Thornback ray in the Irish Sea, Bristol Channel, and Celtic Sea North is not overfished, or subject to overfishing. The stock size indicator has been increasing and is now at the highest point in the time series, and above the MSY Btrigger proxy (Itrigger). Landings have remained constant over the last decade, and have remained below the advice given by ICES. Fishing pressure is below the FMSY proxy. There is no management plan for skates and rays and the joint TAC has been deemed an unsuitable method for protecting individual species. Beam trawls have significant impacts on the seabed, including damage to benthic communities and vulnerable marine habitats. They can also have high bycatch, potentially of vulnerable species.
How we worked out this Rating
Thornback ray in the Irish Sea, Bristol Channel, and Celtic Sea North is not overfished, or subject to overfishing.Thornback ray stock size has been increasing and it is now at the highest point in the time series, and above the MSY Btrigger proxy (Itrigger).Landings have remained constant over the last decade, and have remained below the advice given by ICES. Fishing pressure is below the FMSY proxy.ICES advises that when the MSY approach is applied, landings should be no more than 1833 tonnes in each of the years 2023 and 2024. This is higher than the advised landings for 2021 and 2022 (1596 tonnes) due to an increase in the biomass index.
There is no management plan for skates and rays and the joint TAC has been deemed an unsuitable method for protecting individual species.There is no direct management plan for skates and rays in these waters. They are usually caught as bycatch in otter and beam trawl fisheries, which target finfish (including flatfish and gadoids).Skates and rays are managed under five regional quotas (called TACs) which are applied to a group of species, rather than individual skate and ray species. This includes cuckoo ray, thornback ray, blonde ray, spotted ray, and small-eyed ray (undulate ray has a separate TAC). This has been deemed as an unsuitable method for protecting individual species, but species-specific quotas may increase discarding. Alternatives to the current TAC system are being explored, which may include the possible introduction of individual TACs for key stocks.A high-survivability exemption to the Landings Obligation was provided for skates and rays in the Celtic Seas ecoregion. Any skates and rays that are discarded are required to be released immediately and below the sea surface.Other management methods being considered are fishing gear modifications, education, conservation measures (such as closed seasons during spawning times). Some protected areas have been designated in these waters but offshore areas are not sufficiently managed. There are no official minimum landing sizes except for some IFCAs, which, mandate a minimum landing size (40-45 cm disc width) in inshore waters in England and Wales.Fishermen off North Devon have a voluntary seasonal closed area over what they consider to be a nursery ground.Both the EU and UK have fishery management measures in place, which can include catch limits, targets for population sizes and fishing mortality, and controls on what fishing gear can be used and where. In the EU, compliance with regulations has been variable, and there are ongoing challenges with implementing some of them. There was a target for fishing to be at Maximum Sustainable Yield by 2020, but this was not achieved. The Landing Obligation (LO), an EU law that the UK has kept after Brexit, requires all quota fish to be landed, even if they are unwanted (over-quota or below minimum size). It aims to promote more selective fishing methods, reduce bycatch, and improve recording of everything that is caught, not just what is wanted. Compliance with the LO is generally poor and actual levels of discards are difficult to quantify using the current fisheries observer programme. UK administrations are in the process of replacing the landing obligation with country-specific Catching Policies.In the UK, it is too early to tell how effective management is, as the Fisheries Act only came into force in January 2021. The Act requires the development of Fisheries Management Plans (FMPs) (replacing EU Multi-Annual Plans). FMPs are currently in development, but the scope of them remains unclear. They have the potential to be very important tools for managing UK fisheries, although data limitations may delay them for some stocks. MCS is keen to see publicly available FMPs for all commercially exploited stocks, especially where stocks are depleted, that include:Targets for fishing pressure and biomass, and additional management when those targets are not being met, based on the best available scientific evidenceTimeframes for stock recoveryImproved data collection, transparency and accountability, supported by technologies such as Remote Electronic Monitoring (REM)Consideration of wider environmental impacts of the fishery
Beam trawls have significant impacts on the seabed, including damage to benthic communities and vulnerable marine habitats. They can also have high bycatch, potentially of vulnerable species.Thornback ray is a coastal and shelf species. It is one of the most commercially important skate species and is usually caught in the eastern Irish Sea by, the Bristol Channel or southern Irish coasts. It can be targeted seasonally or as bycatch in trawl and gillnet fisheries.Discard rates of skates and rays vary dramatically (30 - 70%), depending on the marketability and management measures in place. For example, nearly all skates below 30 cm LT are discarded by English vessels. Bycatch can include juvenile skate as they can hatch from their egg cases at sizes of 10-20 cm LT and therefore, may be able to escape through the nets. Their survival rates upon discarding is extremely variable, depending on the fishing and handling methods used to capture them. Elasmobranchs have the potential for relatively high survival rates because they do not have swim bladders (and thereby are not as impacted by pressure changes), they can have thick and abrasive skins and thorns (which protect them) and some have spiracles and a buccal-pump respiratory which excrete a mucus, which allows the skate or ray to ventilate and acquire oxygen when out of the water. Inshore and coastal fisheries using trawls, longlines, gillnets and tangle nets generally show low at-vessel mortality. There are a lack of studies available on long-term skate and ray survival when they are released into the wild.Demersal trawls have contact with the seabed resulting in penetration and abrasion of habitat features. The impact of trawling on the seabed depends on the location and scale in which trawling occurs. For example, areas that are used to natural disturbance through tides and waves, are less sensitive to habitat impacts. Areas not used to mobile towed gears are typically more sensitive to trawling.Beam trawling, especially using chain-mat gear, is a high impact method of fishing and can have a significant impact on benthic communities. Heavy gear tends to have a higher seabed impact than otter trawling and seabed penetration can vary between 1cm and 8cm, depending on the sediment.There are Marine Protected Areas (MPAs) in this area, some of which are designated to protect seabed features from damaging activities. This fishery overlaps with parts of these MPAs, but the proportion of the catch coming from these areas is expected to be relatively low in relation to the unit of assessment (i.e. less than 20% of the catch or effort), and so these impacts have not been assessed within the scale of this rating. Given the important role that MPAs have in recovering the health and function of our seas, MCS encourages the supply chain to identify if their specific sources are being caught from within MPAs. If sources are suspected of coming from within designated and managed MPAs, MCS advises businesses to establish if the fishing activity is operating legally inside a designated and managed MPA, and request evidence from the fishery or managing authority to demonstrate that the activity is not damaging to protected features or a threat to the conservation objectives of the site(s).To improve monitoring and reporting of fishing activity, MCS would like to see remote electronic monitoring (REM) with cameras implemented, used and enforced. To reduce the impacts of fishing on the marine environment we would like to see a just transition to the complete removal of bottom towed gear from offshore Marine Protected Areas designated to protect the seabed. We also want to see reduction and mitigation of environmental impacts including emissions and blue carbon habitat damage.
References
Cook, R., Gaudian, G., des Clers, S. and Seip- Markensteijn, C.M., 2022. Marine Stewardship Council (MSC) Public Certification Report: Scottish Fisheries Sustainable Accreditation Group (SFSAG) Northern Demersal Stocks. Prepared by Control Union (UK) Limited on behalf of Scottish Fisheries Sustainable Accreditation Group (SFSAG). May 2022. Available at https://cert.msc.org/FileLoader/FileLinkDownload.asmx/GetFile?encryptedKey=BdxOJoY7Sf4DmNJEB/m47M6xx0rRfgP/niGx3vj5Ud8hadYI3XCNrnlSFL/jlTgK [Accessed on 13.07.2022].Eigaard, O.R., Bastardie, F., Breen, M., Dinesen, G.E., Hintzen, N.T., Laffargue, P., Mortensen, L.O., Nielsen, J.R., Nilsson, H.C., O'Neill, F.G., Polet, H., Reid, D.G., Sala, A., SkOld, M., Smith, C., Sorensen, T.K., Tully, O., Zengin, M., Rijnsdorp, A.D., 2016. Estimating seabed pressure from demersal trawls, seines, and dredges based on gear design and dimensions. ICES Journal of Marine Science, Volume 73, Issue suppl 1. Pages i27-i43. Available at https://academic.oup.com/icesjms/article/73/suppl_1/i27/2573989 [Accessed on 12.07.2022].Froese, R. and D. Pauly. Editors. 2022. FishBase. Thornback ray. Available at https://www.fishbase.se/summary/SpeciesSummary.php?ID=2059&AT=thornback+ray [Accessed on 16.01.2023].Hiddink, J., Jennings, S., Sciberras, M., Szostek, C.L., Hughes, K.M., Ellis, N., Rijnsdorp, A.D., McConnaughey, R.A., Mazor, T., Hilborn, R., Collie, J.S., Pitcher, C.R., Amoroso, R.O., Parma, A.M., Suuronen, P. and Kaiser, M.J. 2017. Global analysis of depletion and recovery of seabed biota after bottom trawling disturbance. PNAS. 114:31, pp. 8301-8306. https://doi.org/10.1073/pnas.1618858114.ICES. 2022. Thornback ray (Raja clavata) in divisions 7.a and 7.f–g (Irish Sea, Bristol Channel, Celtic Sea North). In Report of the ICES Advisory Committee, 2022. ICES Advice 2022, rjc.27.7afg. Available at https://doi.org/10.17895/ices.advice.19754425 [Accessed on 10.01.2023].ICES. 2022. Working Group on Elasmobranch Fishes (WGEF). ICES Scientific Reports, 4:74. Available at http://doi.org/10.17895/ices.pub.21089833 [Accessed on 10.01.2023].Kennelly, S. J. & Broadhurst, M. K., 2021. A review of bycatch reduction in demersal fish trawls. Rev Fish Biol Fisheries 31, 289–318. https://doi.org/10.1007/s11160-021-09644-0.Kynoch, R., Fryer, R. & Neat, F., 2015. A simple technical measure to reduce bycatch and discard of skates and sharks in mixed-species bottom-trawl fisheries. ICES J Mar Sci,72(6):1861.Shark Trust. 2020. Thornback Ray ID Guide. Available at https://www.sharktrust.org/faqs/thornback-ray-id-guide [Accessed on 10.01.2023].Silva, F., Ellis, J. & Catchpole, T., 2012. Species composition of skates (Rajidae) in commercial fisheries around the British Isles and their discarding patterns. J Fish Biol., 80:1678–1703.van Denderen, P. Bolam, S., Hiddink, J.G., Jennings, S., Kenny, A., Rijnsdorp, A., and van Kooten, T., 2015. Similar effects of bottom trawling and natural disturbance on composition and function of benthic communities across habitats. Mar Ecol Prog Ser. 2015;541:31–43.
Sustainable swaps
Learn more about how we calculate our sustainability ratings.
How our ratings work