Ray, Shagreen

Leucoraja fullonica

Method of production — Caught at sea
Capture method — demersal otter trawl
Capture area — North East Atlantic (FAO 27)
Stock area — Celtic Sea and West of Scotland
Stock detail — 6 and 7
Picture of Ray, Shagreen

Sustainability rating five info

Sustainability overview

The shagreen ray in this area is data-limited and their stock status is unknown. The preliminary analysis of data from the French onboard observation programme shows that Shagreen ray populations in the Celtic Sea may have been stable between 2007 and 2015. However, it is unknown if the species are undergoing overfishing in this area.

The landing obligation will be fully in place in 2019, which requires that all species with catch limits should be retained. However, skate and rays are exempt from the landing obligation due to their assumed high discard survival rates. There is no specific management plan for skates and rays in these waters. They are managed under a total allowable catch (TAC) for many skates and rays but greater protection is needed. Further management of the species is advised e.g. through fishery closures to allow them to reproduce.

Both demersal otter trawls and beam trawls are associated with captures of Endangered, Threatened and Protected species and beam trawls can pose significant risks to the habitat. However, management can mitigate these risks e.g. with area closures. Management is generally better in inshore waters.

Biology

Shagreen rays belong to the Rajidae family which includes skates and rays. The shagreen ray is a medium sized species growing to a maximum length of 120 cm. Males and females mature from 56 to 85 cm in length. Age at maturity and maximum age is unknown.

Stock information

Criterion score: 0.75 info

Stock Area

Celtic Sea and West of Scotland

Stock information

The shagreen ray in this area is data-limited. It is unknown if small eyed rays in this area are overfished and there are no indicators to determine any trends in biomass. However, the preliminary analysis of data from the French onboard observation programme showed that the proportion of hauls which included the Shagreen ray in the Celtic Sea, was stable between 2007 and 2015, and was at its highest level in 2015. However, only one survey has been used to determine any trends and there are a lack of data for the other areas within the fishery area. Therefore, there is concern for biomass.

It is unknown if the species are undergoing overfishing in this area, however, in 2017, ICES species-specific landings minimum estimate based on reported landings was 219 tonnes whilst the landings corresponding to advice 210 tonnes. Therefore, there is no concern for fishing mortality as landings are around those provided in scientific advice.

FishBase deems Shagreen rays to have a low resilience.

Management

Criterion score: 0.75 info

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 has been deemed as an unsuitable method for protecting individual species, but species-specific quotas may increase discarding.

The European Commission have considered that skates and rays caught in the Northwest waters (ICES subareas 6 and 7) with all fishing gears, should be exempt from the landing obligation, based on their assumed high survivability rates. However, Member States harvesting the stocks should supply data to STECF to review the effectiveness of the exception and, by the 31 May each year produce a roadmap to increase survivability, fill in the data gaps identified by STECF and produce annual reports on the progress on survivability programmes. Any skates and rays that are discarded are required to be released immediately and below the sea surface. 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 squared mesh panel, except for vessels with catches comprising over 30% of Norway lobster. (European Commission 2018b).

Other management methods are currently being considered at an EU level, 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.

Monitoring
ICES conduct assessments for most skate and ray species on a biennial basis. There are a lack of reference points for the stock, which prevents the development of management plans (Mangi et al. 2018). Data-limited approaches have been used (using some survey and landings data) but there are important information gaps. Projects including the Fisheries Science Partnership, Sustainable Management of rays and Skates (SUMARiS), National Evaluation of Populations of Threatened and Uncertain Elasmobranch Stocks (NEPTUNE) have been collecting data to close these data gaps. There are limited fishery-independent data available for the species. This is partly due to the poor overlap of surveys and this stock’s distribution. Fishery-dependent data are collected for the species and the quality of landings data has improved in recent years, however, there is some misidentification of the species level.

Enforcement
Surveillance legislation is underpinned by EU Law, which require that all vessels above 12m in length use vessel monitoring systems (VMS), and mandate at-sea and aerial surveillance and inspections of vessels, logbooks and sales documents. There is direct management of fishing effort for vessels since 2003, which allocates effort in kW-days to vessels of >15 m. However, the inshore (smaller) fleets are generally not managed by effort to the same extent.

Capture Information

Criterion score: 0.5 info

Shagreen ray are an outer shelf species. They represent a small amount of bycatch and are usually caught in trawl and gillnet fisheries and mixed demersal fisheries which target hake, anglerfish, and megrim. They are not normally targeted, though it can be an important non-target retained species in the southwestern Celtic Sea or in some deep-water fisheries on the continental slopes and offshore banks.

Bycatch may include a large variety of species such as various soles, plaice, monkfish, haddock, cod, John Dory, red gurnard, horse mackerel, boar fish and grey gurnard, skates, rays and starry smooth-hound. ETP species can occasionally be caught such as Common Skate and Spurdog in offshore otter trawl fisheries but it is illegal to land these species.

Discards
The landing obligation will be fully implemented into our seas from 2019. Skates and rays will be exempt from the landing obligation, due to their higher likelihood of survival when discarded. Member states will be required to report on skate and ray catches and discards, and any improvements in selectivity programmes. 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 reduce skate and rays catches and their survival rates. 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 (Silva et al., 2012). 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 (Ellis et al. 2018). 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 (Ellis et al. 2018). Inshore and coastal fisheries using trawls, longlines, gillnets and tangle nets generally show low at-vessel mortality. Tag-recapture studies suggest show that thornback rays were found to be in a significantly better condition when caught using longlines and tangle nets, compared to when they were captured using otter trawl or drift trammel net. There are a lack of studies available on long-term skate and ray survival when they are released into the wild (Ellis et al. 2018).

As part of the cod-recovery plan trawlers have Square Mesh Panels (SMPs) which allows bycatch species to escape the nets including dogfish. Dogfish have really rough skin which harms other species in the net. By allowing them to escape, it means that skates and rays are more likely to be discarded alive. Discards of other species may include undersized or unmarketable fish or because they are choke species.

Habitat
Bottom trawling has the potential to cause significant impact to habitat, such as removing or destroying physical features and reducing biota and habitat complexity. Therefore, the recovery time of the seabed after trawling varies greatly, and depends on the fishing gear, the substrate, intensity of the trawl and how accustomed the seabed is to natural disturbance.

Shagreen ray generally prefer sandy and rocky habitats.

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.

Dab
Halibut, Atlantic (Farmed)
Halibut, Pacific
Megrim
Plaice
Sole, Dover sole, Common sole
Sole, Lemon
Turbot (Caught at sea)
Turbot (Farmed)

References

ICES. 2018. Shagreen ray (Leucoraja fullonica) in subareas 6-7 (West of Scotland, southern Celtic Seas, English Channel). Available at: http://ices.dk/sites/pub/Publication%20Reports/Advice/2018/2018/rjf.27.67.pdf. Published 5 October 2018.

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. doi:10.1111/jfb.13597

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. https://doi.org/10.1111/faf.12279