Ray, Blonde

Raja brachyura

Method of production — Caught at sea
Capture method — Demersal otter trawl
Capture area — North East Atlantic (FAO 27)
Stock area — Bristol Channel
Stock detail

7f,g


Picture of Ray, Blonde

Sustainability rating four info

Sustainability overview

The stock status is unknown. Blonde ray is relatively vulnerable to fishing because it matures at a large size and produces relatively few young. As a result, young blonde rays can be overfished before they have had a chance to reproduce.

There is no specific management plan for skates and rays but the North Devon Fishermen’s Association (NDFA) have implemented better management for example closed areas and a minimum landing size (so that skates and rays get a chance to reproduce before being caught).

There is a lack of data which precludes effective management.

Both demersal otter trawls and beam trawls are associated with the occasional capture of endangered species and beam trawls can pose significant risks to the habitat. However, management can mitigate these risks. Management is generally better in inshore waters.

Biology

Blonde ray are an inshore species belonging to the Rajidae family of skates and rays. Maximum length is 110 cm. Length at maturity is 81-83 cm at ages 4-5 years. Found predominantly on sand and steep sandbanks and commonly occurs at depths from 14-146 m. Relatively few eggs are produced, meaning that few juveniles will be produced each year. In the English Channel, females with well-developed eggs occur from February to August. Eggs are laid in cases known as “mermaids purses”. Blonde ray breed in the Bristol Channel in April and May. Although it has a relatively broad geographical range, this species is most abundant from the British Isles to Portugal. Blonde ray is relatively common in inshore and shelf waters (down to about 150 m) in the English Channel and Irish Sea, Bristol Channel and St George’s Channel. Blonde rays are particularly vulnerable to depletion due to their late age at maturity, slow growth and they produce few young. Little is known about connectivity of blonde ray stocks, yet, connectivity is crucial for managing skates and rays and provides a long-term perspective of their population trends.

Stock information

Criterion score: 0.75 info

Stock Area

Bristol Channel

Stock information

The state of the stock in the Irish and Celtic Seas is unknown.

There is conflicting advice on population trends: survey catch rates of juveniles are increasing but medium-sized skates (including blonde ray), have shown long-term population declines between 1901-1907 and 1989-1997. Blonde ray is assessed as Near Threatened by IUCN.

Scientists recommend that under a precautionary approach, no more than 895 tonnes are caught in each of 2017 and 2018. However, recent years landings have stabilized around 1170 tonnes per year.

In the Irish and Celtic Sea, the Blonde Ray has a patchy distribution but can be locally abundant on particular grounds. The patchy distribution of this species makes it difficult for scientists to interpret survey data, and its tendency to form aggregations makes it vulnerable to localized depletion. The quality of landings data has too poor to create stock assessments. This has improved in recent years but more information is required on discards and their survival rates to determine the true level of mortality caused by fishing.

Over the past 7 years or more, the North Devon Fishermen’s Association (NDFA) have collected species-specific landings data for Blonde and other ray species in the Bristol Channel. These data show that landings are increasing despite reduced effort in the fishery suggesting the Blonde ray population in the fished area is stable and the fishery sustainable.

Management

Criterion score: 0.5 info

There are no management plans for this species and no specific management objectives are known to ICES.

Skates and rays are managed under five regional quotas (called TACs) which are applied to a group of species, rather than quotas for each species. This has been deemed as an unsuitable method for protecting individual species, but species-specific quotas may not be suitable because it may increase unnecessary discarding of skates and rays.

Other management methods are currently being considered at an EU level. Methods to avoid catching rays include modifying fishing gear to observe their escape behaviour and design fishing gear accordingly. However, it is difficult to avoid catching rays in fishing gear (because of their peculiar shape) so fishing gear modifications have been suggested to improve the potential survival of rays so that they can be quickly and safely discarded. These methods require improved (and expensive) scientific studies and education and compliance of implemented measures during fishing. Other potential conservation measures include closed seasons or areas to protect skates and rays at more vulnerable times e.g. when they are spawning. The landings landing obligation will be applied from 1 January 2019 and this is likely to impact skate and ray management.

There is no official minimum landing size for many skates and rays outside the 6 nautical mile limit in European waters. However, some IFCAs mandate a minimum landing size (40-45 cm disc width) in inshore waters in England and Wales. There is direct management of fishing effort for vessels since 2003 which allocates effort in kW-days to different groups of vessels, depending on gear, mesh size and area. However, this only applies to vessels of >15 m and therefore, the inshore (smaller) fleets are generally not effort managed to the same extent. Under EU law, where skates are rays are targeted with gillnets, a minimum mesh size of 22 cm is required in the Celtic Sea.

There is an important deficit of information about the catches, discard and survival of skates and rays. The only current long-term monitoring is the recording of catches that are brought back to port (landings data). However, this information doesn’t tell scientists much about the health of the stock and therefore more studies are needed to monitor the stock effectively.

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.

The North Devon Fishermen’s Association (NDFA) are a founder member of the Seafish skates and rays group. By adopting initiatives to restrict landing sizes, identify conservation zones and improve catch reporting the NDFA has contributed to improved management of the ray fisheries in the Bristol Channel (such as through a closed area, a minimum size of 45cm. However some species are not mature at this size e.g. 45cm disc width for blonde ray correspond to 63.6 cm long, yet around 50% of blonde rays only mature at 78.2 cm and 85.6 cm for males and females respectively. All rays below the minimum size are handled with care and returned immediately to the sea in order to increase its chance of survival. There is good enforcement e.g. VMS in trawl fleets (>12m), although there is limited management for vessels <10m. The Fisheries Science Partnership project involves fishermen and scientists working together to fill in important knowledge gaps e.g. on discard survival rates. Additionally, The Skate and Ray Producers Association, the Shark Trust and Seafish have improved species identification and reporting of catches.

Capture Information

Criterion score: 0.5 info

Blonde rays in this area are caught predominantly by bottom trawls. Blonde ray is usually caught as bycatch but may be targeted on a seasonal basis.

Bycatch
Otter trawls are not a very selective gear. The catch 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 in offshore otter trawl fisheries but it is illegal to land these species.

Discards
Because skate and rays are a peculiar shape and size, it is difficult for them to escape from fishing gear once caught. Therefore, other methods must be used to increase their likelihood for survival: skates and rays are generally a hardly species but their survival rate after discarding is extremely variable depending on fishing and handling methods: discard survival varied between 25%-100% in beam trawl surveys. In this specific area, discarding rates and survival is unknown.

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. Discards rates vary dramatically (30 - 70%).

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 accustomed the seabed is to natural disturbance. Fishing occurs over a mixture of seafloor types e.g. sandy, muds, gravel. IFCAs ensure bottom trawling occurs in areas where there will be minimal damage to habitats such as mobile sands.

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 Advice 2016 Book 5. Blonde ray (Raja brachyura) in divisions 7.a and 7.f-g (Irish Sea, Bristol Channel, Celtic Sea North). Available at: http://ices.dk/sites/pub/Publication%20Reports/Advice/2016/2016/rjh-7afg.pdf

Responsible Fishing From The North Devon Fishermen's Assoc. NFDA 2006

Silva, J. F., Ellis, J. R. and Catchpole, T. L. (2012), Species composition of skates (Rajidae) in commercial fisheries around the British Isles and their discarding patterns. Journal of Fish Biology, 80: 1678-1703. doi:10.1111/j.1095-8649.2012.03247.

ABPmer, 2013. Understanding the market and supply chain for fish caught and landed in Northern Devon.

McCully, S. R., Scott, F., and Ellis, J. R. 2012. Lengths at maturity and conversion factors for skates (Rajidae) around the British Isles, with an analysis of data in the literature. -ICES Journal of Marine Science, 69: 1812-1822.



Marandel, F., Lorance, P., Andrello, M., Charrier, G., Le Cam, S., Lehuta, S. Trenkel, V.M. 2017. Insights from genetic and demographic connectivity for the management of rays and skates. Canadian Journal of Fisheries and Aquatic Sciences IN PRESS.

Scientific, Technical and Economic Committee for Fisheries (STECF) - 56th Plenary Meeting Report (PLEN-17-03); Publications Office of the European Union, Luxembourg.