Longnosed skate
Dipturus oxyrinchus
What to check for
Location
Northeast Atlantic
Technical location
Atlantic, Northeast, Azores Grounds, Barents Sea, Bay of Biscay, Iceland and Faeroes Grounds, Irish Sea, Porcupine Bank, English Channel, Bristol Channel, Celtic Seas, West and Southwest of Ireland, North Sea, Norwegian Sea, Spitzbergen, and Bear Island, Portuguese Waters, Rockall, West of Scotland, Skagerrak, Kattegat, Transition Area, Baltic Sea
Caught by
Bottom trawl (beam)
Rating summary
Longnosed skate has low resilience to fishing, there are no reference points are defined for this stock and it is severely data limited. There is no specific management plan in place and greater protection is needed. Skate species are often bycatch in other fisheries. Some longnosed skate is caught by beam trawls, which have significant impact on the seabed, including damage to benthic communities and vulnerable marine habitats. Bycatch can be high and may include vulnerable species.Rating last updated October 2023.
Technical consultation summary
Longnosed skate has low resilience to fishing, there are no reference points are defined for this stock and it is severely data limited. There is no specific management plan in place and greater protection is needed. Skate species are often bycatch in other fisheries. Some longnosed skate is caught by beam trawls, which have significant impact on the seabed, including damage to benthic communities and vulnerable marine habitats. Bycatch can be high and may include vulnerable species.
How we worked out this Rating
Longnosed skate has low resilience to fishing, there are no reference points defined for this stock and it is severely data limited.Route 2 (data limited) scoring has been applied to this rating owing to the lack of reference points for biomass and fishing pressure. Longnosed skate is considered to have low resilience to fishing.No information about longnosed skate stock status is available for this area due to a lack of reliable survey and catch data. Longnosed skate are only included in reports that cover several species of rays and skates with no detailed information about the individual species. Nothing is known about the current population trends in the Northeast Atlantic region. Therefore, there is concern for biomass.Landings data for skate species in the area are not reliable as landings are often reported as generic skates and are considered to be confounded with landings of Norwegian, flapper and blue skate. There are concerns that landings of prohibited and endangered skate species are misreported as longnosed skate because this species is not included in fishery regulations. Therefore, there is concern for fishing pressure.In 2015 IUCN reported that the population was Near Threatened with declining populations in Europe. Longnosed skate is thought to have declined by 30% from 1984 - 2014. A separate assessment in the Irish Sea identified the species as locally Vulnerable.Large specimens are sometimes retained and used for human consumption; smaller specimens are often discarded. ICES cannot quantify the corresponding catches or discard survival. The species occurs across a wide depth range and is therefore vulnerable as by-catch in almost all mixed demersal fisheries.
There is no direct management plan for skates and rays in these waters. They are usually caught as bycatch.There are a lack of reference points for the stock, which prevents the development of management plans. ICES advises that the collection of species-specific landings data should be introduced for more species of rays and skates to help inform on the status of these stocks. However, species-specific quotas may increase misreporting or discarding.Identification of skate and ray species at the point of sale is difficult as they are commercially valued for their wings and so the bodies are often discarded and the wings skinned. However, DNA analysis of skate wings on sale in the UK suggests that longnosed skate do not often reach the market.There is no direct management plan for longnosed skate in these waters. They are usually targeted and caught as bycatch in otter, tangle and gillnet and beam trawl fisheries. There are gear restrictions in place in Northern waters for vessels although it is not clear how these support skate management. Some protected areas have been designated in these waters but offshore areas are not managed.In North Sea waters, vessels larger than 15m, are only permitted to land a maximum of 25% of the catch (whole weight) as skates and rays.Skates and rays caught in the Northwest waters (ICES subareas 6 and 7) and North Sea waters (ICES subareas 2a, 3a and 4) 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.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
Beam trawls have significant impact on the seabed, including damage to benthic communities and vulnerable marine habitats. Bycatch can be high and may include vulnerable species.Longnosed skate are usually targeted and caught as bycatch in otter, gillnet and beam trawl fisheries which have impacts on the wider environment and species. Data for targeted and bycatch landings and discards are limited.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.Beam trawling is one of the least selective and high impact methods of fishing. Bream trawling, especially using chain-mat gear, is damaging to the seabed and is known to have a significant impact on benthic communities, although less so on soft substrates. Heavy gear tends to have a higher seabed impact than otter trawling. Seabed penetration depends on the sediment, and varies between 1cm and 8cm.Beam trawling has the potential to catch a wide variety of non-target species. Common bycatch 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 protection 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 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.
References
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., Abella, A., Serena, F., Stehmann, M.F.W. and Walls, R., 2015. Dipturus oxyrinchus. The IUCN Red List of Threatened Species 2015: e.T63100A48908629. Available from: https://dx.doi.org/10.2305/IUCN.UK.2015-1.RLTS.T63100A48908629.en. [Accessed on 10.10.2023].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].Froese R. and Pauly D. (Editors), 2021. Longnosed skate, Dipturus oxyrinchus - Fishbase. Available at https://www.fishbase.se/summary/Dipturus-oxyrinchus [Accessed on 10.10.2023].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. 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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].Sguotti, C., Lynam, C. P., Garcia-Carreras, B., Ellis, J. R. and Engelhard, G. H. 2016. Distribution of skates and sharks in the North Sea: 112 years of change. Glob Change Biol, 22: 2729-2743. doi:10.1111/gcb.13316. Available at https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.13316 [Accessed 04.10.2023].van Denderen, P. Bolam, S., Hiddink, J.G., Jennings, S., Kenny, A., Rijnsdorp, A., and van Kooten, T., 2015. 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