Ray, Blonde

Raja brachyura

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

7f,g


Picture of Ray, Blonde

Sustainability rating five info

Sustainability overview

The stock status is unknown as there are lack of data to determine trends. 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). However, there are a lack of data, which precludes effective management and whilst the area have implemented a voluntary minimum landing size for the species, it is set at too small a level to sufficiently protect the species.

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 excempt 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.

Beam trawling is also associated with discarding of unwanted fish and sometimes catch Endangered, Threatened and Protected species but capture rates can be reduced with appropriate gear modifications. This fishing method can pose significant damage to the seafloor.

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: 1 info

Stock Area

Bristol Channel

Stock information

Prolonged high fishing effort has led to the reduced size, range, and diversity of Irish Sea rays (Dedman et al. 2017).

The state of the stock in the Irish and Celtic Seas is unknown and there are no reference points for the stock.

A survey has shown that catch rates for blonde ray have increased, however, this survey is not considered appropriate enough to determine a stock size indicator. 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. There is concern for biomass as there is no suitable stock size indicator available to determine abundance trends.

The quality of landings data has too poor to create stock assessments. The quality has improved in recent years but blonde ray landings are still confused with spotted rays, and there is a substantial lack of discard and survival rates, to accurately determine if fishing mortality is at a healthy level. Additionally, landings have been greater than those advised by ICES: estimated landings in 2017 were 1019 tonnes, whilst ICES advised that landings should be no larger than 895 tonnes for the same year. Therefore, there is concern for fishing mortality.

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.

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.

Bristol Channel: The North Devon Fishermen’s Association (NDFA) are a founder member of the Seafish skates and rays group. The NDFA have adopted initiatives to restrict landing sizes (a minimum size of 45cm), identify conservation zones (and closed areas) and improved catch reporting. Hence, the NDFA has contributed to improved management of the ray fisheries in the Bristol Channel. Whilst some of these measures may be effective at protecting the species, minimum size restrictions may be limited in their efficacy as some skate and ray species are not mature at this size e.g. a 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.

Capture Information

Criterion score: 0.75 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
Bycatch in beam trawls from this area include mixed crabs, urchins, lesser spotted dogfish, nursehound, Dragonet, starry ray, smelt. Angel shark and common skate (critically endangered, IUCN) were depleted through incidental capture in trawls in this area. Invertebrates such as crabs and urchins are vulnerable to damage.

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. 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).

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. In beam trawls, VMS shows the location of trawling. IFCAs ensure bottom trawling occurs in areas where there will be minimal damage to habitats e.g. by requesting that otter trawls avoid vulnerable features such as ross worm (or sabellaria).

Blonde rays inhabit offshore sandbanks and coastal shallows (Dedman et al. 2017). They occur over sandy, mud and gravel substrates.

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



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

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.