Ray, Cuckoo

Leucoraja naevus

Method of production — Caught at sea
Capture method — Demersal otter trawl
Capture area — North East Atlantic (FAO 27)
Stock area — North Sea and Skagerrak and Kattegat
Stock detail

4 and 3a


Picture of Ray, Cuckoo

Sustainability rating five info

Sustainability overview

The stock status of cuckoo rays is unknown although their abundance has been generally increasing with fluctations.

There is no specific management plan for skates and rays in these waters but there is some improved management in inshore waters. They are managed under a quota for many skates and rays but greater protection is needed. Fishing occurs over a mixture of sandy and gravel substrates. 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.

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

Cuckoo rays belong to the Rajidae family which includes skates and rays. Cuckoo rays are a small to medium sized inshore and coastal shelf species attaining a maximum length of about 70cm. Males and females mature at between 54 and 59cm in length when approximately 4 years old. Maximum age 12 years.

Stock information

Criterion score: 0.75 info

Stock Area

North Sea and Skagerrak and Kattegat

Stock information

The state of the stock in these areas is unknown. Cuckoo ray abundance has been generally increasing with fluctuations in the population size. Populations are above the long-term average in the last seven years, though the stock size has recently decreased. It is unknown if the level of fishing is sustainable or not. Since their populations are still above the long-term average, there is no concern for biomass.

Scientists believe that landings should be no more than 116 tonnes in each of the years 2018 and 2019 but recorded landings were 170 tonnes in 2016. Therefore, there is concern for fishing mortality. 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 new North Sea Multi-Annual Plan (NSMAP), which came into effect July 2018, requires that several whitefish stocks (Cod, Haddock, Plaice, Saithe, Sole, Whiting, Anglerfish (Lophius piscatorius), Northern Prawn and Norway lobster)) are fished at MSY by 2020. However, there is a requirement to take into effect “the difficulty of fishing all stocks at MSY at the same time”. Precautionary management should be applied to stocks where no adequate scientific information is available (which includes some skate and ray species). The precautionary approach should ensure that exploitation is appropriate to restore and maintain the harvested species populations above levels, which can produce MSY. The NSMAP also requires that discards should be avoided and reduced where possible and that a good environmental status should be achieved by 2020. The effectiveness of the NSMAP is to be re-evaluated in 2023 and every five years thereafter (European Commission 2018c).

The European Commission have considered that skates and rays caught in the North Sea (including in ICES divisions 2a and 3a, and ICES subarea) 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 (European Commission 2018a). Though cuckoo rays are shown to have lower survival rates than other skate species, they will still be except from the landing obligation. This is to allow continued fishing and accurate data collection. However, the exemption will only be granted until the 31 December 2019 (European Commission 2018a).

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.

Capture Information

Criterion score: 0.5 info

Cuckoo rays in this area are almost exclusively caught by bottom trawls. Cuckoo ray is an offshore species and forms an important component of mixed demersal fisheries, taken as bycatch in beam and otter trawls. Also targeted by sea anglers.

Bycatch
Bycatch in beam trawls from this area include mixed crabs, urchins, lesser spotted dogfish, nursehound, Dragonet, starry ray, smelt. Angelshark 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. Cuckoo ray are generally found on sand and gravel habitats. 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 the Ross worm (or sabellaria). Cuckoo rays frequent sandy seafloors in depths of 70-100 m (Dedman et al. 2017).

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. 2017. Cuckoo ray (Leucoraja naevus) in Subarea 4 and Division 3.a (North Sea, Skagerrak, and Kattegat). Published 6 October 2017. rjn.27.3a4 DOI: 10.17895/ices.pub.3183.

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

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

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, https://doi.org/10.1093/icesjms/fsu146