|Scientific Name:||Scyliorhinus stellaris (Linnaeus, 1758)|
Squalus stellaris Linnaeus, 1758
|Taxonomic Notes:||Possibly sometimes confused with the smaller Scyliorhinus canicula.|
|Red List Category & Criteria:||Near Threatened (Regional assessment) ver 3.1|
|Assessor(s):||Ellis, J., Serena, F., Mancusi, C., Haka, F., Morey, G., Guallart, J. & Schembri, T.|
|Facilitator/Compiler(s):||Lawson, J., Walls, R. & Dulvy, N.|
European regional assessment: Near Threatened (NT)
Nursehound (Scyliorhinus stellaris) is a large-bodied catshark that occurs in coastal and inshore waters of the eastern Atlantic, between southern Scandinavia and Senegal, and is also present throughout the Mediterranean Sea. It is found at depths of less than five metres to at least 125 m, but is most common at depths of 20–63 m. It is locally abundant in certain areas of the Northeast Atlantic and may therefore be sensitive to localised exploitation. It is taken as bycatch in bottom trawl, gill net, and longline gears, and targeted by recreational fisheries. Trawl surveys do not sample the main habitats for this species, but catch rates are low and there is no evidence of decline or range contraction. In the Mediterranean Sea, limited data on the exploitation and trends in abundance indicate that this population is declining, particularly around the Balearic Islands and in the northwest Mediterranean Sea. The capacity for recovery is affected by potentially low levels of connectivity between discrete populations around islands far from the continental coast. This is a large bodied species that may therefore be more sensitive to exploitation than Small Spotted Catshark (Scyliorhinus canicula), which also occurs in the region. Given its large size, patchy range, and evidence for declines in areas of the Mediterranean Sea such as the Gulf of Lions, the species is estimated to have undergone a decline of nearly 30% over the three generation period (45-60 years). It is therefore assessed as Near Threatened as it is close to qualify for a threatened category under Criterion A2.
In the eastern Atlantic this species occurs in coastal and shallow shelf seas from the Shetland Isles and southern Norway in the north, to northwest Africa in the south. Around the British Isles, it is uncommon throughout the North Sea but locally abundant in areas of the southern and western coasts. In particular, it seems most abundant in parts of the English Channel, Bristol Channel, Cardigan Bay and around the Lleyn Peninsula and Anglesey (Ellis et al. 2005). In the Mediterranean Sea it appears to be more abundant in the Adriatic and Ionian Seas and along the Albanian coast, compared to the western Mediterranean Sea (Baino et al. 2001). It was absent from trawl surveys conducted off the coasts of Morocco, Spain and France, and does not occur in the Black Sea (Compagno et al. 2005). Its depth limits are one to 409 m.
Native:Albania; Algeria; Belgium; Bosnia and Herzegovina; Croatia; Cyprus; Denmark; Egypt (Egypt (African part), Sinai); France (Corsica, France (mainland)); Germany; Greece (East Aegean Is., Greece (mainland), Kriti); Ireland; Isle of Man; Israel; Italy (Italy (mainland), Sardegna, Sicilia); Lebanon; Libya; Montenegro; Morocco; Netherlands; Norway; Palestinian Territory, Occupied; Portugal (Portugal (mainland)); Slovenia; Spain (Canary Is., Spain (mainland)); Sweden; Syrian Arab Republic; Tunisia; Turkey (Turkey-in-Asia, Turkey-in-Europe); United Kingdom (Great Britain, Northern Ireland)
|FAO Marine Fishing Areas:|
Atlantic – eastern central; Atlantic – northeast; Mediterranean and Black Sea
No data on population size or structure are available for the Northeast Atlantic or the Mediterranean Sea. In the Mediterranean Sea, demersal trawl effort has increased both numerically and technologically in the shelf and slope areas. From 1974 to 1987 effort in trawl fisheries in the Gulf of Lions increased from a small, low powered fleet with a total of 2,700 hp (horse power) to a total of 19,940 hp. This increase in effort corresponded to a decrease in abundance of this species in a long-term groundfish diversity study, where abundance declined steadily from 1970 to the 1980s, and it became entirely absent from Gulf of Lions catches after 1988 (Aldebert 1997). In the Balearic Islands, 131 survey hauls were made between 40 and 1,800 m depth from 1996–2001, and while two other catshark species had the highest reported abundances of all elasmobranch species, this catshark was entirely absent (Massutí and Moranta 2003). More recently, 12 trammel net surveys carried out in the Balearic Islands between 2000 and 2003 also captured no specimens around the Balearic Islands (Morey et al. 2006). In the western half of the Adriatic Sea this species was considered rare as far back as 1987 (Jardas 1984), although it was recorded in trawl surveys carried out in 1948 and 1998, suggesting that it may still have been present in low numbers (Jukic-Peladic et al. 2001). Given the absence of this catshark in numerous trawl surveys, and reported abundance declines corresponding with increased fishing effort, it is estimated to be decreasing in the Mediterranean Sea.
In the absence of species-specific data in the Northeast Atlantic, the population trend is unknown, but it is suspected that with similar fishing pressure the species is likely to be declining in these waters as well. Considering the abundance trends from Aldebert (1997), a decline of 94-98% of baseline levels is estimated for the three generation period (1957-2001, 1957-2016, 45-60 years) for the Gulf of Lions. However, according to Baino et al. (2001), this species is more rare in the western Mediterranean and more abundant in other regions in the Mediterranean Sea, and therefore the Gulf of Lions may not be representative of this species abundance in the Mediterranean, nor the Northeastern Atlantic (where no data are available). It is thus estimated that the species has declined by almost 30% in European waters for the three generation period (45-60 years).
|Current Population Trend:||Decreasing|
|Habitat and Ecology:|
This catshark is found from the shallow subtidal to the continental platform, most commonly at depths of 20–63 m (Compagno et al. 2005), but with a maximum depth down to 400 m (Bauchot 1987, Serena 2005). Within the northern Tyrrhenian and southern Ligurian Seas, this species is distributed from 55-409 m depth (Baino and Serena 2000). It often occurs on rough or rocky inshore bottoms, or surfaces with algal cover. In the Mediterranean Sea it occurs on coralline algal substrates (Compagno et al. 2005), and reportedly has active breeding areas in the Ligurian Sea and in the waters surrounding the Tuscan archipelago (De Sabata and Clò 2013).
This egg laying species deposits large, 10–13 cm long thick-walled egg cases on algae in the subtidal or lower intertidal zone during spring and summer (Ellis et al. 2005). Egg case deposits have been found on rocky reefs in the Mediterranean Sea, mostly between 30 and 50 m depth (De Sabata and Clò 2013). Once the eggs are deposited they take up to nine months to hatch with size at birth reportedly 10–16 cm total length (TL; Tortonese 1956, Bauchot 1987). Males mature at 77 cm TL and females at 79 cm TL (Bauchot 1987). The maximum reported length for this catshark in the Mediterranean Sea is 150 cm TL, and with a common average size of 40–55 cm TL (Bauchot 1987). The generation length of this species is estimated to be 15.02-20 years, based on estimates of three Scyliorhinidae species (Galeus sauteri, Haploblepharus pictus, Poroderma pantherinum).
|Generation Length (years):||15.02-20|
|Use and Trade:||This species is a moderately important commercial species in European waters, particularly around the British Isles.|
Overfishing appears to be the major cause driving the decline of this catshark in the Mediterranean region, and low connectivity may be limiting population recovery. It is taken as bycatch in several semi-industrial fisheries in Spain, the Adriatic Sea, Sicily and Cyprus. Artisanal fisheries catch this species elsewhere, as it is regularly present in fish markets in Malta, Tunisia, Greece, Cyprus and Turkey. Little information on landings and catches exists for this species, partly due to the lack of species-specific data. In many areas, for example the Balearic Islands fishery and in Italian waters, reported landings and catch data group this species with the more common Small Spotted Catshark (Scyliorhinus canicula) or even more generally with all other elasmobranch species.
This species is protected in six marine reserves around the Balearic Islands, but no other species-specific conservation measures are in place throughout its range. Further monitoring and protection measures are therefore encouraged.
|Citation:||Ellis, J., Serena, F., Mancusi, C., Haka, F., Morey, G., Guallart, J. & Schembri, T. 2015. Scyliorhinus stellaris. The IUCN Red List of Threatened Species 2015: e.T161484A48923567.Downloaded on 25 November 2017.|
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