Thornback ray

There is no concern for biomass for thornback ray in the West of Scotland, however, there is concern for fishing pressure.This stock is data limited. There are only proxy reference points available for this thornback ray stock. The stock size indicator has declined, however, it remains above the MSY Btrigger proxy (Itrigger) and therefore, there is no concern for the biomass.Although landings have declined in recent years, fishing pressure remains high and is above the FMSY proxy. Therefore, there is concern for fishing pressure. Thornback ray has a low resilience to fishing pressure.ICES advises that when the MSY approach is applied, landings should be no more than 96 tonnes in each of the years 2023 and 2024. This is lower than the advice for 2021 and 2022 (137 tonnes) due to a decrease in the biomass indicator.

Thornback ray in the West of Scotland are poorly managed and the joint TAC in place is not a suitable management method.There is no management plan in place for thornback ray in this area. Demersal elasmobranchs are usually caught as bycatch in the mixed demersal fisheries for roundfish and flatfish. Misidentification between skate and ray species may occur but is unlikely to happen for thornback ray which is well-known and commercially important.In 1999, a common Total Allowable Catch (TAC) for 'skates and rays' was first introduced. Five regional quotas are in place for the group of skates and rays, rather than for the individual species. This method of management has been deemed as unsuitable for protecting individual species, but species-specific quotas may also lead to discarding. In 2023, the TAC for skates and rays were set as follows:1,764 tonnes for ICES areas 2.a and 4 (68% UK)48 tonnes for ICES area 3.a9,797 tonnes for ICES areas 6.a, 6.b, 7a-c, and 7e-k (30% UK)1,537 tonnes for ICES area 7.d (16% UK)5,519 tonnes for ICES areas 8 and 9 (0.2% UK)Skates and rays caught in the Northwest waters (ICES subareas 6 and 7) with all fishing gears, are exempt from the landing obligation, based on their high survivability rates. Any skates and rays that are discarded are required to be released immediately and below the sea surface.There is no official minimum conservation reference size (MCRS) in place but some of the UK's Inshore Fisheries and Conservation Authorities (IFCAs) have an MCRS of 40cm disc width for skates and rays.Any vessels fishing using bottom trawls or seines, with catches comprising more than 10% of haddock, cod and skates and rays combined, are required to use either a) a 120 mm cod-end, or b) an eliminator trawl with 600 mm large mesh panels and a 100 mm cod-end. For vessels fishing using bottom trawls or seines with catches comprising less than 10% of haddock, cod and skates and rays combined, vessels are required to use a cod-end mesh size of 100 mm with a 100 mm square mesh panel, except for vessels with catches comprising over 30% of Norway lobster.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.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) but there are no details yet on how and when these will be developed. FMPs 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 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 metTimeframes for stock recoveryTechnologies such as Remote Electronic Monitoring (REM) to support data collection and improve transparency and accountabilityConsideration of wider environmental impacts of the fishery

Otter trawling is likely to cause some damage to the seabed. Bycatch is moderate and may include vulnerable species.Thornback rays are a coastal and shelf species. In this area they are caught as bycatch by bottom trawls and gillnet fisheries. However, it is also targeted in some local, seasonal fisheries with trawls and static nets.Demersal trawls have contact with the seabed, resulting in penetration and abrasion of habitat features. The impact of trawling on the seabed depends on where trawling happens, and on what scale. For example, habitats that are used to natural disturbance through tides and waves are less sensitive to impacts. Areas not used to mobile towed gears are typically more sensitive.Demersal otter trawls have the potential to take relatively high quantities of bycatch (> 40% of catch weight).There is a lack of information on what bycatch species are commonly found in this area but common bycatch in bottom trawls includes mixed crabs, urchins, lesser spotted dogfish, nursehound, dragonet, starry ray, and smelt. Endangered, threatened and protected (ETP) species including angel shark, blue skate and flapper skate have been depleted through fishing in this area.It's difficult to avoid catching skates and rays in nets and because of their peculiar shape and size, it's also difficult for them to escape the net once captured. Therefore, selectivity programmes are in place to reduce skate and ray catches and their survival rates. Discard rates of skates and rays can vary dramatically (30 - 70%), depending on the marketability and management measures in place. Nearly all skates below 30cm total length are discarded by English vessels.Bycatch can include juvenile skate as they can hatch from their egg cases between 10-20 cm total length and therefore, may be able to escape through the nets. The survival rate of juveniles upon discarding is extremely variable and depends 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 impacted by water pressure changes. They can also have thick and abrasive skins and thorns for protection, and some have spiracles and a buccal-pump respiratory which excretes a mucus, allowing 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.Habitat regulation measures across European waters include Marine Protected Areas (MPAs). If those MPAs were found to be subjected to bottom trawling, MCS would assign a default red rating unless there is evidence (e.g. through environmental impact assessment) indicating that the activity does not damage the integrity of the site. EU regulations prohibit bottom trawling below 800m and restrict activities between 400-800m. Spatial management is continually being developed, which will restrict the footprint of this gear on the seabed. However, there remains some uncertainty about the location of some sensitive seabed habitats so these remain at risk.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.

Dedman, S., Officer, R. Brophy, D., Clarke, M. Reid, D. G. 2017. Towards a flexible Decision Support Tool for MSY-based Marine Protected Area design for skates and rays, ICES, 74 (2) pp. 576-587. Available at https://academic.oup.com/icesjms/article/74/2/576/2669563 [Accessed on 04.10.2023].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., Sköld, 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 04.10.2023].Ellis, J. R., Burt, G.J., Grilli, G., McCully Phillips, S.R., Catchpole, T.L., Maxwell, D.L. 2018. At-vessel mortality of skates (Rajidae) taken in coastal fisheries and evidence of longer-term survival. Journal of Fish Biology. 92, 1702-1719. Available at https://pubmed.ncbi.nlm.nih.gov/29675895/ [Accessed on 04.10.2023].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. Available at https://doi.org/10.1073/pnas.1618858114 [Accessed on 04.10.2023].ICES. 2022. Thornback ray (Raja clavata) in Subarea 6 (West of Scotland). In Report of the ICES Advisory Committee, 2022. ICES Advice 2022, rjc.27.6. Available at https://doi.org/10.17895/ices.advice.19754422 [Accessed on 04.10.2023].ICES.2022. Working Group on Elasmobranch Fishes(WGEF).ICES Scientific Reports. 4:74. 848pp. Available at http://doi.org/10.17895/ices.pub.21089833 [Accessed on 04.10.2023].Kennelly, S. J. & Broadhurst, M. K., 2021. A review of bycatch reduction in demersal fish trawls. Rev Fish Biol Fisheries 31, 289–318. Available at https://doi.org/10.1007/s11160-021-09644-0. [Accessed on 04.10.2023].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. Available at https://academic.oup.com/icesjms/article/72/6/1861/921176 [Accessed on 04.10.2023].Mangi, S., Kupschus, S., Mackinson, S., Rodmell, D., Lee, A., Bourke, E., Rossiter, T., Masters, J., Hetherington, S., Catchpole, T. and Righton, D. 2018. Progress in designing and delivering effective fishing industry science data collection in the UK. Fish 00:1-21. Available at https://onlinelibrary.wiley.com/doi/10.1111/faf.12279 [Accessed on 04.10.2023].Shephard, S. Reid, D.G.,Gerritsen, H.D, Farnsworth, K.D. Estimating biomass, fishing mortality, and total allowable discards for surveyed non-target fish, ICES Journal of Marine Science, Volume 72, Issue 2, 1 January 2015, Pages 458-466. Available at https://academic.oup.com/icesjms/article/72/2/458/2801434 [Accessed on 04.10.2023].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. Available at https://www.nwwac.org/_fileupload/Papers%20and%20Presentations/2016/06%20FG%20Skates%20and%20Rays/Silva,%20Ellis%20&%20Catchpole_2012_Skate%20catches.pdf [Accessed on 04.10.2023].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. Available at https://backend.orbit.dtu.dk/ws/portalfiles/portal/119579329/Post_print.pdf [Accessed on 04.10.2023].