Overview

Comprehensive Description

Biology

Found on sand and sand-rock bottoms (Ref. 6808). Feed on all kinds of benthic animals (Ref. 3167). Oviparous. Distinct pairing with embrace. Young may tend to follow large objects, such as their mother (Ref. 205). Eggs are oblong capsules with stiff pointed horns at the corners deposited in sandy or muddy flats (Ref. 205). Egg capsules are 10.0-14.3 cm long and 5.8-9.0 cm wide (Ref. 41250). About 40-90 eggs are laid per individual every year (Ref. 41250).
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Distribution

Range Description

Northeast and eastern central Atlantic: widely-distributed in shelf waters, from Madeira and Morocco in the south to the Shetland Isles in the north, including the Irish Sea, English Channel and south-western and north-western North Sea (Stehmann and Burkel 1984, Ellis et al. 2005a, ICES 2006).

Mediterranean Sea: western Mediterranean Sea, including the waters of Spain, France, western Italy, Tunisia, Algeria and Morocco (Bauchot 1987, Bertrand et al. 2000, Baino et al. 2001, Bertozzi et al. 2003). One doubtful record from the northern Aegean Sea (Serena 2005).
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Eastern Atlantic: Shetland Islands to Morocco, Rio de Oro (Western Sahara), and Madeira.
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Eastern Atlantic (including southern North Sea, Madeira).
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Physical Description

Morphology

Dorsal spines (total): 0; Analspines: 0; Analsoft rays: 0
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Size

Maximum size: 1200 mm TL
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Max. size

120 cm TL (male/unsexed; (Ref. 41333)); 125 cm TL (female); max. published weight: 14.3 kg (Ref. 40637)
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Diagnostic Description

Upper surface wholly prickly, except in juveniles; underside only prickly along front margins of disc; orbital thorns separate; a regular median row of 40-45 thorns in juveniles and adult females, interrupted on back in males; 60-90 tooth rows; upper surface ochre, with numerous small dark spots to margins of disc, underside white (Ref. 3167).
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Ecology

Habitat

Habitat and Ecology

Habitat and Ecology
Raja brachyura is most common on sandy sediments in waters down to about 150 m deep (Ellis et al. 2005a) in the Northeast Atlantic, though may occur deeper in the southern parts of its range. In the Mediterranean Sea it is mainly found at depths of 10?150 m to about 300 m (Baino et al. 2001). It reaches a maximum size of ~120 cm (TL) (Stehmann and Burkel 1984) and commonly reaches 40?80 cm TL. Like other skates, reproduction is oviparous. They reproduce from February to August and have a gestation period of almost seven months, with females producing about 30 egg cases/year (measuring about 12 x 8 cm, excluding horns) (Stehmann and Burkel 1984). Juveniles feed on small crustaceans (amphipods, natantids), with larger individuals more piscivorous and predating on dragonet and sand eels (Ellis et al. 1996). Little is known about its reproductive biology.

Systems
  • Marine
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Environment

demersal; marine; depth range 10 - 380 m (Ref. 6808)
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Depth range based on 1131 specimens in 1 taxon.
Water temperature and chemistry ranges based on 559 samples.

Environmental ranges
  Depth range (m): -9 - 210
  Temperature range (°C): 7.335 - 12.243
  Nitrate (umol/L): 2.853 - 12.183
  Salinity (PPS): 34.243 - 35.546
  Oxygen (ml/l): 5.566 - 6.375
  Phosphate (umol/l): 0.316 - 0.803
  Silicate (umol/l): 2.118 - 5.948

Graphical representation

Depth range (m): -9 - 210

Temperature range (°C): 7.335 - 12.243

Nitrate (umol/L): 2.853 - 12.183

Salinity (PPS): 34.243 - 35.546

Oxygen (ml/l): 5.566 - 6.375

Phosphate (umol/l): 0.316 - 0.803

Silicate (umol/l): 2.118 - 5.948
 
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Depth: 10 - 380m.
From 10 to 380 meters.

Habitat: demersal.
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Life History and Behavior

Life Cycle

Oviparous, paired eggs are laid. Embryos feed solely on yolk (Ref. 50449). Spawning mainly from February to August with at least 30 egg-cases laid (Ref. 3167). Distinct pairing with embrace. Young may tend to follow large objects, such as their mother (Ref. 205).
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Life Expectancy

Lifespan, longevity, and ageing

Maximum longevity: 8 years (wild)
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Molecular Biology and Genetics

Molecular Biology

Barcode data: Raja brachyura

The following is a representative barcode sequence, the centroid of all available sequences for this species.


No available public DNA sequences.

Download FASTA File
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Statistics of barcoding coverage: Raja brachyura

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 3
Specimens with Barcodes: 31
Species With Barcodes: 1
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Conservation

Conservation Status

IUCN Red List Assessment


Red List Category
NT
Near Threatened

Red List Criteria

Version
3.1

Year Assessed
2009

Assessor/s
Ellis, J., Ungaro, N., Serena, F., Dulvy, N.K., Tinti, F., Bertozzi, M., Pasolini, P., Mancusi, C. & Noarbartolo di Sciara, G.

Reviewer/s
Cavanagh, R.D., Kulka, D.W. & Valenti, S.V. (Shark Red List Authority)

Contributor/s

Justification
The Blonde Ray (Raja brachyura) is a relatively large-bodied skate, endemic to the northeast Atlantic and western Mediterranean Sea. Occurs on soft substrates to depths of about 150 m in the northeast Atlantic and mainly from 10?300 m depth in the Mediterranean Sea. Targeted in areas where it is locally abundant and taken as bycatch in mixed demersal fisheries using trawl, gill nets and longlines elsewhere in its range. It is apparently rare in the Mediterranean Sea, captured in only 21 of 6,336 tows in Mediterranean-wide trawl surveys conducted between 1994?1999 (at depths of 10?800 m). It is not certain whether the Blonde Ray has always been rare there; no data are currently available on historical abundance or trends for this region and there is no evidence to suggest it was ever common. The lack of data on this apparently rare species prevents an assessment beyond Data Deficient in the Mediterranean Sea at present, but given that demersal fishing pressure is relatively intense throughout large areas of its range there an assessment of catches is a priority. This species is more common in the northeast Atlantic where it is taken as bycatch and also targeted where sufficiently abundant. No formal stock assessments have been undertaken for this species. Although it is locally abundant in some areas, survey data indicate that declines have occurred. Medium sized skates showed marked declines in relative abundance, especially the Blonde Ray, in comparable research trawl surveys conducted in three locations around the British Isles in 1901?1907 and 1989?1997. Furthermore, the percentage composition of the Blonde Ray decreased by close to 30% between the two survey periods. Demersal fishing pressure is still high throughout large areas of the Northeast Atlantic and declines are inferred elsewhere, where specific data are not available. This species probably has limiting life-history characteristics, like other relatively large skates, making it vulnerable to depletion. Given observed and inferred declines, continued high levels of exploitation and this species? rarity in the Mediterranean Sea, it just fails to meet the criteria for Vulnerable A2bd globally and is assessed as Near Threatened. Improved monitoring of population trends and further assessment of the Atlantic and Mediterranean populations are a priority.
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Population

Population
Northeast Atlantic
It is relatively common in the inshore and shelf waters (down to about 150 m) in the English Channel and Irish Sea, Bristol Channel and St George?s Channel (Fahy 1989, 1991; Ellis et al. 2005a). It is less abundant in the North Sea and Celtic Sea (Ellis et al. 2005a). Blonde ray is also one of the more important ray species recorded in landings around the Iberian Peninsula (ICES 2006).

No formal stock assessments have been undertaken for this species. Although it has a relatively broad geographical range, this species is most abundant from the British Isles to Portugal. There are certain areas where it is locally abundant, for example in parts of the North Sea and Irish Sea. Hence, this species seems to have a fragmented population, possibly due to the fragmented nature of its favoured habitat. This species may have declined over the course of the 20th century (Rogers and Ellis 2000). Rogers and Ellis (2000) compared standardized catch rates of demersal fish from research vessel surveys in three areas around the British Isles (northwestern Irish Sea, Devon, and southern North Sea) from 1901 to 1907 with survey catches in the same areas from 1989?1997. In this analysis, skates of intermediate body size showed marked declines in relative abundance, especially the blonde ray R. brachyura and the thornbach ray R. clavata. Furthermore, the percentage composition of the blonde ray decreased by close to 30% between the two survey periods. Catch rates in beam trawl surveys in the English Channel and Irish Sea appear steady in recent times (Ellis et al. 2005b), and there is no consistent trend in the North Sea (ICES 2006). However, these catch rates refer to all individuals and not just mature fish.

Mediterranean Sea
The blonde ray Raja brachyura, is relatively rare in the Mediterranean. It is not certain if it has always been rare there. The species is rare but consistently caught in the MEDITS trawl surveys from 1994 to 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). The blonde ray has been recorded in a total of 21 of 6,336 tows performed between 1994 and 1999 in depths ranging from 10?800 m (Baino et al. 2001). This species was caught between 0?500 m and greatest catch rates were between 100 to 500 m (Baino et al. 2001).

The blonde ray does not appear to have been captured in either historical or recent comparative trawl surveys of the Adriatic Sea or the Gulf of Lions (Aldebert 1997, Jukic-Peladic et al. 2001, Marano et al. in press).

Little is known of this species? current distribution and abundance along northwest African coastlines, however it appears to be uncommon off Tunisia (Bradai 2000). It also appears to be relatively rare in Italian Seas, with a low frequency of occurrence in GRUND (Italian), MEDITS trawl surveys and other surveys in this area (Follesa et al. 2003, Ragonese et al. 2003, Spedicato et al. 2003, Serena et al. 2005).

Population Trend
Decreasing
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Threats

Major Threats
Northeast Atlantic
Taken in targeted fisheries in areas where it is locally abundant and taken as a bycatch in mixed demersal fisheries elsewhere in its range. Also taken in recreational fisheries. Skates are an important component of demersal fisheries in the northeast Atlantic and Raja brachyura is landed and sold (Dulvy et al. 2000, Holden 1977). This species is one of the more frequent species landed by the commercial fleet on the Portuguese cost, accounting for 44% of the total individuals sampled in Peniche and 18% in Matosinhos (Machado et al. 2004).

Mediterranean Sea
The blond ray is caught as part of the bycatch of the semi industrial (Spain) and artisanal (Morocco and Greece) fisheries with bottom trawls, gill nets and long lines (Bauchot 1987). Benthic trawl effort has increased both numerically and in technological terms in the shelf and slope area of the Mediterranean over the last 50 years. For example, the Gulf of Lions area was historically exploited by small-scale benthic trawl fisheries, comprising 27 small low powered boats (total nominal horse power of 2,700 hp). Later effort increased to a total nominal horse power of 19,940 hp (1974 to 1987). 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).
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Near Threatened (NT)
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Management

Conservation Actions

Conservation Actions
There is a minimum landing size of 40 cm for skates and rays caught in the inshore waters of various parts of England and Wales, through Sea Fishery Committee bylaws. 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).

Research is required on population numbers and trends, range, biology, ecology, habitat status and threats.
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Relevance to Humans and Ecosystems

Benefits

Importance

fisheries: minor commercial; gamefish: yes; price category: medium; price reliability: questionable: based on ex-vessel price for species in this genus
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