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Leucoraja naevus

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA CHONDRICHTHYES RAJIFORMES RAJIDAE

Scientific Name: Leucoraja naevus
Species Authority: (Müller & Henle, 1841)
Common Name(s):
English Cuckoo Ray
Synonym(s):
Raja naevus Müller & Henle, 1841
Taxonomic Notes: Was previously referred to as Raja naevus. Early papers often confused Cuckoo Ray with Sandy Ray (Lecoraja (Raja) circularis).

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2009
Date Assessed: 2008-12-01
Assessor(s): Ellis, J., Ungaro, N., Serena, F., Dulvy, N.K., Tinti, F., Bertozzi, M., Pasolini, P., Mancusi, C. & Notarbartolo di Sciara, G.
Reviewer(s): Cavanagh, R.D., Kulka, D.W. & Valenti, S.V. (Shark Red List Authority)
Justification:
This small-bodied skate is relatively widespread in the Northeast Atlantic, from southern Norway to northern Morocco, including the Mediterranean Sea. It is also reported from Senegal. It occurs at depths of 20-500 m, and is more common at ~200 m in the Mediterranean Sea. This species is taken as bycatch in mixed demersal fisheries through much of its range and utilized in some areas. Leucoraja naevus is apparently rare in the Mediterranean Sea and was caught rarely but consistently (only 42 out of 6,336 survey tows) during Mediterranean-wide trawl surveys from 1994-1999. It is now not found in the Gulf of Lions in the northwestern Mediterranean, the species was reported in comparable surveys from 1957-60 to 1980-84 but was not captured in later surveys from 1992-95. It is, however, still recorded in areas that have been less intensively trawled, such as the Balearic Islands. This relatively small skate may have some capacity to withstand moderate fishing pressure, compared to larger skates that are highly vulnerable to rapid depletion as a result of their limiting life-history characteristics. Given observed declines in heavily trawled areas of the Mediterranean, combined with areas of its range that are less heavily fished, it is currently assessed as Near Threatened in this region. Abundance trends, as indicated by surveys, are not consistent in the Northeast Atlantic. The Celtic Sea stock was assessed under the DELASS project, indicating a decrease with subsequent increase. Survey data for the North Sea have indicated a decline, following an earlier increase. In western areas, survey catch rates have increased in the Irish Sea and declined in the Celtic Sea. It should be noted that survey catch rates are based on all individuals, and no analyses of the relative abundance of mature fish have been made. Observed increases and declines tend to be of a low magnitude, and overall the population may be stable. At present this species is assessed as Least Concern, globally, as the total population is not considered to have declined significantly. However, more information on stock identity is required, and the status of stocks in those areas where it is exploited most in the Northeast Atlantic (e.g., Celtic Sea and Bay of Biscay) need to be better assessed.

Geographic Range [top]

Range Description: Northeast and eastern central Atlantic: occurs off coasts northward from the Shetland Isles and southern Norway in the north, to Morocco in the south, and also reported from Senegal (Stehmann and Bürkel 1989).

Mediterranean Sea: northern, western and central-eastern waters, excluding the Adriatic Sea. Countries of occurrence include: Algeria, France, Greece, Italy, Malta, Morocco, Spain and Tunisia. (Baino et al. 2001, Stehmann and Bürkel 1989, Bertrand et al. 2000, Jukic-Peladic et al. 2001, Relini et al. 2000, Stehmann and Bauchot 1987, Tinti et al. 2003).
Countries:
Native:
Algeria; France; Greece; Italy; Libya; Malta; Morocco; Norway; Portugal; Senegal; Spain; Tunisia; United Kingdom
FAO Marine Fishing Areas:
Native:
Atlantic – northeast; Mediterranean and Black Sea; Pacific – eastern central
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Northeast and Eastern Central Atlantic
This species is abundant in the northern North Sea, off northwest Scotland, Irish Sea, Celtic Sea and is also one of the dominant rays around the Iberian Peninsula (ICES 2006). It is only rarely observed in the inner parts of the Bristol Channel and in the eastern English Channel and southern North Sea. Preliminary stock assessments were made for the Celtic Sea stock during the DELASS project (Heessen 2003), though the results were inconclusive. Catch rates in trawl surveys in the Irish Sea appear to be increasing slightly, with a decrease in the Celtic Sea (Ellis et al. 2005b), whereas IBTS data indicate a steady increase followed by a decline in the North Sea (ICES 2006). However, these catch rates refer to all individuals and not just mature fish. Observed increases/declines tend to be of a low magnitude, and overall the population may be stable. Cuckoo ray is a relatively small-bodied species that is most abundant on offshore grounds. It forms a relatively high proportion of skate and ray landings in those areas where it is abundant. More information on stock status is required, and the status of stocks in those areas where it is exploited most (e.g., Celtic Sea) need to be better assessed.

Mediterranean Sea
The Cuckoo Ray (L. naevus), is relatively rare in the Mediterranean however, it does not appear to have been previously common in the area. This species was rarely caught in the MEDITS trawl survey from 1994-1999. The MEDITS survey covers the north Mediterranean coast almost continuously from west Morocco and Spain in the west Mediterranean to the Aegean Sea in the eastern Mediterranean (Baino et al. 2001). Six trawl surveys are carried out each year in the coastal areas of four arbitrary geographically defined areas: western (Morocco, Spain, France), western central (Tyrrhenian, Corsican, Sardinia and Sicily coasts), eastern central (Adriatic, Ionian and Albanian coasts) and the eastern (Aegean Sea). A total of 6,336 tows have been performed between 1994 and 1999 in depths ranging from 10-800 m. This species was recorded in only 42 of 6,336 tows during this survey (frequency of occurrence of 1%) and was more frequently captured in the eastern Mediterranean (Baino et al. 2001). Leucoraja naevus is now not found in the Gulf of Lions. A time series of comparative trawl surveys in the Gulf of Lions between indicate that L. naevus was historically present in both shelf and slope trawl surveys in 1957-1960 and in 1980-1984 (150-800 m), but was not present on the shelf or slope in comparable surveys in 1992-1995 (Aldebert 1997).

This species does not appear to have been captured in historical and recent trawl surveys of the Adriatic Sea (Jukic-Peladic 1999). It is still caught off the Balearic Islands, where Massuti and Moranta (2003) reported it in relatively recent trawl surveys.

Little is known of this species' current distribution and abundance along northwest African coastlines, however, it now appears to be uncommon along the Tunisian coastline.
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: Found on the continental shelf and slope at depths of 20-500 m, and is more common at ~200 m in the Mediterranean Sea. It is typically an offshore species, occurring further offshore than, for example, Spotted Ray and Thornback Ray. It is abundant on coarse sand/gravel substrates in the Irish Sea and western English Channel. The size at maturity is estimated at 55 cm for both males and females (Walker 1999) with a maximum size of about 72 cm (Stehmann and Burkel 1984, Ellis et al. 2005b). L. naevus is benthic, occurring in waters of 12-290 m around the British Isles (Ellis et al. 2005a), though it is occasionally recorded in deeper waters (to 500 m) west of the British Isles and in the Mediterranean. Age at maturity for females and males is estimated at 7.4 years and 6.8 years, respectively, in the North Sea (Walker 1999). Longevity is reported at 12 years (Du Buit 1976b). Females produce about 90-102 eggs per year after an eight month gestation period (Du Buit 1976a, Bauchot 1987, Clark 1922). Juveniles feed on small crustaceans with larger individuals becoming increasingly piscivorous (Ellis et al. 1996).
Systems: Marine

Threats [top]

Major Threat(s): Taken as bycatch in mixed demersal fisheries through much of its range. Due to it occurring further offshore than other rays (e.g. blonde and thornback rays), it is of less importance to recreational fisheries.

Northeast and Eastern Central Atlantic
Rajids are an important component of demersal fisheries in the northeast Atlantic and Leucoraja naevus is landed and sold (Holden 1977, ICES 2006). It may be an important component in mixed demersal fisheries where abundant, and is landed as a bycatch in trawl fisheries throughout its Atlantic range, though smaller individuals tend to be discarded. This species is one of the more frequent species landed by the commercial fisheries operating in the Celtic Sea and Iberian waters.

Mediterranean Sea
Presumably captured as bycatch of multispecies fisheries. Rajids are an important component of the demersal fisheries of northwest Europe and L. naevus is landed and sold (Dulvy et al. 2000, Holden 1977). The situation may be similar in the Mediterranean, where the cuckoo ray may be captured as part of the bycatch of multispecies trawl fisheries typical in the shelf seas of the Mediterranean. Benthic trawl effort has increased both numerically and in technological terms in the shelf and slope areas of the Mediterranean over the last 50 years. For example, the Gulf of Lions area was initially exploited by small-scale benthic trawl fisheries comprising 27 small low powered boats (total nominal horse power of 2,700 hp), more recently effort has increased to a total nominal horse power of 19,940 hp (1974 to 1987). Since then half of the fishing effort in this area has been displaced to targeting small pelagic fish (Aldebert 1997). The continental shelf and upper slope of the Mediterranean Sea are highly exploited, with intensive commercial trawling occurring at depths ranging from 50 to 700 to 800 m (Colloca et al. 2003, Massuti and Moranta 2003).

Moreover, although only adult individuals may be landed for consumption, most size classes are likely to be taken in fishing nets as the legal mesh size used in much of the Mediterranean is approximately 20 mm.

The relatively small size of this ray species suggests that its life history and demography may allow some capacity to withstand moderate fishing pressure (Dulvy et al. 2000, Stevens et al. 2000).

Conservation Actions [top]

Conservation Actions: Though there are no species-specific management measures for this species, there is a TAC for skates and rays in the North Sea and adjacent waters, and they may benefit from more generic management measures for demersal fisheries (e.g. mesh size regulations, effort reduction).

Recommended measures: Monitoring of bycatch levels and population trends.

Citation: Ellis, J., Ungaro, N., Serena, F., Dulvy, N.K., Tinti, F., Bertozzi, M., Pasolini, P., Mancusi, C. & Notarbartolo di Sciara, G. 2009. Leucoraja naevus. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 29 August 2014.
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