Overview

Comprehensive Description

Biology

Found mainly on soft bottoms (Ref. 3167). Feed mainly on crustaceans and bony fishes depending on the sex, size and also partly with the season (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). About 20-62 eggs are laid by an individual in a year (Ref. 41314).
  • McEachran, J.D. and K.A. Dunn 1998 Phylogenetic analysis of skates, a morphologically conservative clade of elasmobranchs (Chondrichthyes: Rajidae). Copeia 1998(2):271-290. (Ref. 27314)
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Distribution

Range Description

Endemic in the Mediterranean Sea (Serena 2005). Moderately common throughout the Mediterranean Sea, particularly in the western (Morocco, Spain and France) and western central areas (Tyrrhenia, Corsica, Sardinia and Sicily) (Baino et al. 2001, Ragonese et al. 2003, Florio et al. 2003, Follesa et al. 2003, Spedicato et al. 2003, Serena 2005, Mancusi et al. 2005), rare in Adriatic and Ionian Seas (Notarbartolo di Sciara and Bianchi 1998), common along northern African coasts (Stehmann and Burkel 1984) and eastern Algerian coasts (Bertozzi et al. 2003).
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Northeast Atlantic: known only from the western Mediterranean, more common along the African coasts.
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Mediterranean Sea endemic.
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Physical Description

Size

Maximum size: 600 mm TL
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Max. size

60.0 cm TL (male/unsexed; (Ref. 3167))
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Ecology

Habitat

Habitat and Ecology

Habitat and Ecology
Benthic, mainly on soft bottoms from 100-400 m (Serena 2005), but with a wide depth range from 20-633 m. Both males and females are estimated to mature at 40-53 cm TL for (Bini 1967, Notarbartolo di Sciara and Bianchi 1998, Tortonese 1956, N. Ungaro unpublished data) with a maximum recorded size of 60 cm TL (Bauchot 1987, Stehmann and Burkel 1984, Serena 2005); common at sizes of 30-40 cm TL (Bauchot 1987). Like other skates, this species is oviparous. Reproduction is in winter and 20-62 egg cases (depending on size) are laid per year (Bauchot 1987, Stehmann and Burkel 1984, Serena 2005). Egg-cases measure 46 by 35 mm excluding horns (Stehmann and Burkel 1984, Serena, 2005). R. polystigma feeds mainly on crustaceans (L. typicus, Anphipoda and Isopoda), decapods, cephalopods and bony fishes (Vannucci 2005).

Systems
  • Marine
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Environment

demersal; marine; depth range 100 - 400 m (Ref. 3167)
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Depth: 100 - 400m.
From 100 to 400 meters.

Habitat: demersal.
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Trophic Strategy

Found mainly on soft bottoms. Feeds mainly on crustaceans and bony fishes depending on the sex, size and also partly with the season.
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Life History and Behavior

Life Cycle

Oviparous, paired eggs are laid. Embryos feed solely on yolk (Ref. 50449). Ripe females occurring mostly in the winter and deposit 20 to 62 egg-cases per year depending on size (Ref. 3167). Distinct pairing with embrace. Y oung may tend to follow large objects, such as their mother (Ref. 205).
  • Breder, C.M. and D.E. Rosen 1966 Modes of reproduction in fishes. T.F.H. Publications, Neptune City, New Jersey. 941 p. (Ref. 205)
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Molecular Biology and Genetics

Molecular Biology

Statistics of barcoding coverage: Raja polystigma

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Specimens with Barcodes: 21
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
  • Needs updating

Assessor/s
Ungaro, N., Serena, F., Dulvy, N., Tinti, F., Bertozzi, M., Mancusi, C. & Notarbartolo di Sciara, G.

Reviewer/s
Cavanagh, R.D., Kyne, P.M. & RL Expert Panel (Shark Red List Authority)

Contributor/s

Justification
The Speckled Ray (Raja polystigma) is endemic to the Mediterranean Sea. This relatively small skate (60 cm TL) mainly inhabits soft bottoms on continental shelves at depths of 100-400 m. It has a wide distribution in the Mediterranean (mostly western and western central areas) where it is moderately common. In northern Mediterranean trawl surveys from 1994-1999, the Speckled Ray was captured in 171 out of 6,336 tows. The species is a bycatch in trawl nets, but is also fished with gillnets, longline and handline in artisanal fisheries and marketed along African coasts. Although nothing is known of the impact of fisheries or of temporal population trends, its entire area of occurrence lies within intensively trawled regions. Given this species' endemicity and that large areas of its range have been historically and are presently intensively fished, it is assessed as Near Threatened on the basis of suspected declines (close to meeting the criteria for Vulnerable A4d). Further information is required from the African coasts and possible misidentifications of this species with Spotted Ray (R. montagui) off Italy are currently being investigated.
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Population

Population
Raja polystigma is moderately common throughout the Mediterranean Sea, particularly in the western (Morocco, Spain and France) and western central areas (Tyrrhenia, Corsica, Sardinia and Sicily) (Baino et al. 2001 Ragonese et al. 2003, Florio et al. 2003, Follesa et al. 2003, Spedicato et al. 2003, Serena 2005, Mancusi et al. 2005), rare in Adriatic and Ionian Seas (Notarbartolo di Sciara and Bianchi 1998), common along northern African coasts (Stehmann and Burkel 1984) and eastern Algerian coasts (Bertozzi et al. 2003).

It is found predominantly on the shelf and has been captured in the Mediterranean International Trawl Surveys (MEDITS) down to depths of 500 m (Baino et al. 2001). The overall biomass index assessed with MEDITS surveys (0-800m deep) in the west, north and eastern Mediterranean was 1.1 kg/km² (Baino et al. 2001). It was captured in 171 out of 6,336 survey tows between 1994 and 1999 and its estimated standing stock biomass throughout the northern Mediterranean Sea is 568t. Following R. clavata and R. miraletus, R. polystigma is the third most abundant skate species captured in trawl surveys performed in the south Ligurian and north Tyrrhenian Sea from 1985-2004. In this area it occupies a very wide depth range (20-633 m) concentrating between 300 and 400m. Important catches of juveniles were recorded occasionally (Serena et al. 2005). Most of the collected specimens measured between 12 and 49 cm in length (Serena et al. 2005).

Population Trend
Stable
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Threats

Major Threats
Caught as bycatch in demersal trawl fisheries but is also fished with gillnets, longline and handline in artisanal fisheries (Bauchot 1987). There is a high level of exploitation over the continental shelf and upper slope, down to a depth of 800 m in the Mediterranean Sea (Massuti and Moranta 2003). 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 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 (1974-1987) (Aldebert 1997). Raja polystigma is known to be retained and marketed along the African coasts of the Mediterranean, where both trawl and artisanal fisheries operate (Bauchot 1987). This species is rarely landed in Italian Seas and it is not possible to monitor catches (C. Mancusi pers. obs.).
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Near Threatened (NT)
  • IUCN 2006 2006 IUCN red list of threatened species. www.iucnredlist.org. Downloaded July 2006.
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Management

Conservation Actions

Conservation Actions
None in place.
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