|Scientific Name:||Scyliorhinus canicula|
|Species Authority:||(Linnaeus, 1758)|
Squalus canicula Linnaeus, 1758
|Taxonomic Notes:||May be some confusion with the larger and less common Scyliorhinus stellaris, which occurs within a similar range.|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Ellis, J., Mancusi, C., Serena, F., Haka, F., Guallart, J., Ungaro, N., Coelho, R., Schembri, T. & MacKenzie, K.|
|Reviewer/s:||Dudley, S., Soldo, A., Francis, M. & Valenti, S.V. (Shark Red List Authority)|
A small, common catshark, widespread in the Northeast and Eastern Central Atlantic, from Norway and the Shetland Islands to Senegal (possibly along the Ivory Coast), and found throughout the Mediterranean Sea. This is one of the most abundant elasmobranchs in the Northeast Atlantic and Mediterranean Sea. Although localized depletions appear to have occurred in some areas (e.g., in the Wadden Sea and off Malta), scientific surveys throughout the majority of its range suggest that populations are stable or even increasing in some areas. Reproduction is oviparous and the species appears to be relatively productive biologically, thus may be able to withstand higher levels of exploitation. Though commercial landings are made and large individuals are retained for human consumption, the species is often discarded and studies show that post-discard survival rates are high. The species is assessed as Least Concern because overall population trends appear to be stable and there is no evidence to indicate that the global population has declined significantly. Catches and population trends should be monitored.
|Range Description:||Widespread in the northeast and eastern central Atlantic from the Shetland Islands and Norway in the north, to western Africa (Morocco, Western Sahara and Mauritania to Senegal, possibly along the Ivory Coast) in the south, including the Mediterranean Sea (Compagno et al. 2005). It does not occur in the Black Sea, although there may be occasional records of this species as a vagrant (Compagno et al. 2005).
Though there is some spawning in shallow sublittoral habitats, where the eggs are laid on macroalgae, spawning also occurs further offshore on grounds with biogenic fauna (e.g., sponges, hydroids and bryozoans), such as the northern Bristol Channel, around the south and west coasts of Ireland and in the Irish sea loughs (Ellis and Shackley 1997, Sims 2003, Ellis et al. 2005a).
Data from the Mediterranean International Trawl Survey (MEDITS) programme indicates that this species occurs extensively throughout the northern Mediterranean Sea (Baino et al. 2001). These surveys were carried out from the Alboran (western Mediterranean) to the Aegean Sea (eastern Mediterranean), between April and June, from 1994?1999. Across the 40 different survey subsectors and depth strata, S. canicula was caught everywhere with the exception of the northern and southwestern Adriatic Sea, northwestern and northern Ionian Sea and off eastern Sicily. Concentrations of juveniles are located on the upper slopes (~200 m), in particular around northeastern Corsica and northeastern Sardinia, which may be nursery grounds. Nursery grounds may also be found off Livorno, Tuscany (Baino and Serena 2000). The highest numbers of juveniles were found on the edge of the shelf off western Morocco. Length frequency distribution (LFD) data provided by Baino et al. (2001), in combination with other studies (D?oughia et al. 1995 and Relini et al. 1999), suggest that nursery areas are located on the seabed at depths of about 200 m. The species appears to segregate with size (Baino and Serena 2000).They move into coastal waters as they mature, and mature adults then return back to the shelf edge for reproduction.
Native:Albania; Algeria; Belgium; Côte d'Ivoire; Denmark; Egypt; Estonia; Finland; France; Germany; Greece; Greenland; Iceland; Italy; Latvia; Libya; Lithuania; Macedonia, the former Yugoslav Republic of; Mauritania; Morocco; Netherlands; Norway; Poland; Portugal (Azores, Portugal (mainland)); Russian Federation; Senegal; Serbia (Serbia); Spain (Spain (mainland)); Sweden; Turkey (Turkey-in-Europe); United Kingdom (Great Britain, Northern Ireland); Western Sahara
|FAO Marine Fishing Areas:||
Atlantic – eastern central; Atlantic – northeast; Mediterranean and Black Sea
|Range Map:||Click here to open the map viewer and explore range.|
Common throughout its range. This species is one of the most abundant elasmobranchs within the Northeast Atlantic and Mediterranean Sea.
The EU-funded Development of Elasmobranch Assessments project (DELASS) concluded that S. canicula would be best assessed as forming local populations (e.g., on the level of an ICES division) because of the limited movements and migrations of the species and its oviparous nature, assuming that immigration and emigration from adjacent populations are either insignificant or on a par (Heessen 2003). Survey trends in most shelf seas (including the North Sea, northwest Scotland, Irish Sea, English Channel, Celtic Sea and Cantabrian Sea) seem stable (Heessen 2003, MacKenzie 2004, Ellis et al. 2005b, ICES 2007). There may be many separate sub-populations of this species, due to its lack of migration between different areas, e.g. Hebrides and west coast of Scotland, southern North Sea and English Channel. Stocks around northern Scotland, particularly the Shetlands and the Hebrides, may be increasing in size (MacKenzie 2004).
Data from the MEDITS trawl surveys indicates that this species is common in the Mediterranean (Baino et al. 2001). It had a high frequency of occurrence (28% of trawls) and high abundance in these trawl surveys, being particularly abundant in the Gulf of Lions and the Catalan and Aegean Seas. Maximum biomass indices were reported off northeast Corsica between 50 and 100 m depth (340 kg/km²) (Baino et al. 2001). Juveniles made up the main proportion of the population (78% of total population) sampled (Baino et al. 2001). Comparison between trawl surveys in 1948 and 1998 showed no significant differences in distribution and abundance of S. canicula in the Adriatic Sea (Juki?-Peladi? et al. 2001) although there is evidence of constant increasing of trawl fishing pressure. Fishery independent and fishery dependent data from the Tyrrhenian and Ligurian seas were compared by Abella and Serena (2002) to determine population trends. No clear trends were found and apparent discrepancies for this species were considered attributable to a shift in target species and the range of operation of the fishery.
Eastern Central Atlantic:
This species is reported as the most frequent and abundant elasmobranch recorded at 25?300 m depth, and as common down to 400 m depth off Morocco and Sierra Leone (Litvinov 1993).
|Habitat and Ecology:||
This is a small, temperate, bottom-dwelling catshark is found o from the shallow sub-littoral to the edge of the continental shelf to depths of at least 300 m in the north (Ellis et al. 2005), and occur deeper further south and in the Mediterranean Sea. Around the British Isles they are more common in waters <150 m deep. The species is widespread and abundant on a variety of substrates (sandy, coralline algal, gravelly or muddy bottoms). They are known to aggregate by sex and size, though it is unclear whether this sexual segregation is behavioural or habitat-linked. Within loughs, females exhibit strong philopatric behaviour to refuging sites, while males are wider ranging and less philopatric (Sims 2003). However, studies on the wider continental shelf are lacking.
S. canicula is an oviparous species that deposits egg-cases protected by a horny capsule with long tendrils. These egg-cases are often deposited on macroalgae (e.g., Fucus, Laminaria and Himanthalia) in shallow coastal waters (Wheeler 1978, Compagno 1984, Capapé et al. 1991). Further from shore, egg-cases are deposited on sessile erect invertebrates, including sponges, hydroids, soft corals and bryozoans (Ellis and Shackley 1997, Rodriguez-Cabello et al. 1998). Extrapolating egg-laying rates in captive specimens to a whole year provides an estimated fecundity of 29?62 eggs/year for Northeast Atlantic populations (Ellis and Shackley 1997). Capapé (1977) and Capapé et al. (1991) estimated annual fecundity at 96?115 and 45?190 respectively for Mediterranean populations. Fischer et al. (1987) estimated that females can deposit up to 100 eggs per year. Fecundity increases with maternal size (Capapé 1977, Ellis and Shackley 1997, Henderson and Casey 2001).
Spawning can take place almost all year round (Capapé 1977, Capapé et al. 1991, Ellis and Shackley 1997), although there are seasonal patterns in spawning activity. In the northeast Atlantic, S. canicula has an annual cycle with a protracted 10?11 month breeding season (Ellis and Shackley 1997) In the Mediterranean Seathey breed annually from November to July, or possibly all year round (Capapé 1977).
Gestation lasts approximately 5?11 months (usually eight to nine months), depending on ambient water temperature, and the sex ratio of recently hatched fish is about 1:1 (Ellis and Shackley 1997). In the Northeast Atlantic, the gestation period has been estimated at five to six months (Ellis and Shackley 1997). Size at birth is 7?11 cm total length (TL) (Springer 1979, Ellis and Shackley 1997).
Size at maturity is reportedly 35 to 47 cm total length (TL) for females and 30?44 cm for males (Capapé 1977, Jardas 1979, Ungaro et al. 2002, Capapé et al. 2000). In the Northeast Atlantic, females reach maturity at 52?65 cm TL, and males at 49?55 cm TL (Ellis and Shackley 1997). Maximum size is reported at 80 cm TL by Ellis et al. (2005b) and Relini (1999), and at 100 cm by Compagno et al. (2005). The species generally appears to grow to a larger size in the Atlantic than the Mediterranean (Compagno et al. 2005).
They feed on a variety of invertebrates (including polychaetes, crustaceans and molluscs) and fishes (Ellis et al. 1996).
This species is a moderately important commercial species in European waters, particularly around the British Isles. It is primarily taken by bottom trawls, but also fixed bottom nets and pelagic trawls (Compagno in prep.).
Mostly taken as a bycatch in various demersal fisheries (especially trawl and gill net). In some areas larger specimens may be landed for human consumption or they may be landed as bait for whelk fisheries. They have a high survivorship when discarded from trawl fisheries. Revill et al. (2005) reported a 98% discard survival rate from a Western English channel trawl fishery and Rogriguez-Cabello et al. (2005) found a 90% survival rate for S. canicula discarded by commercial trawlers in the southern Bay of Biscay. Another study reports an almost 100% survival rate of released individuals of this species (Sanchez et al. 2000). S. canicula is frequently recorded misleadingly as ?dogfish? in fisheries landings data.
Although S. canicula has been reported to be locally extirpated from the Wadden Sea between the Netherlands and Germany (Wolff 2000a,b), this area is at the edge of the species? distribution. Therefore this localised depletion is not considered to have had a significant effect on the entire global population.
Portuguese official fisheries statistics for landings of Scyliorhinus spp (S. canicula and S. stellaris) in the Algarve (DGPA 1988-2001), show that average landings were 115,079 kg per year during the years 1988, 1989 and 1990, compared to averages of 154,820 kg per year during the years 1999, 2000 and 2001. These values show that there has been an increase of 34.5% in landings by the commercial fishing fleet of this genus in the Algarve during the last decade. However, this increase in landings could mean that there has been a great reduction in discards (DGPA 1988-2001). Only S. canicula were recorded during bottom longline and trammel net surveys off the Algarve (at depths of 200?550 m and 10?90 m, respectively) analysed by Erzini et al. (1998, 2001). No S. stellaris were reported in either of the surveys and therefore the huge majority of Scyliorhinus spp. landings from the Algarve are considered to be S. canicula.
Captured as bycatch in various demersal fisheries and retained for human consumption in some areas. For example, they are a commercially valuable species in Italy and only individuals <36 cm TL are discarded (Abella and Serena 2005). A semi-industrial fishery for this species operates in Spain, the Adriatic Sea, Sicily and Cyprus. Regularly found in fish markets in countries around the Adriatic Sea, Greece and Malta, where it is sold under the generic name of ?Mazzola?. Although demersal fishing pressure is intense in many parts of the species range in the Mediterranean, this species has a high post-discard survival rate. Local depletions may have occurred in some areas. Landings data from Malta indicate that catches fell from 1985?1995, but these may not be directly indicative of population trends.
Eastern Central Atlantic
Also taken as bycatch of demersal fisheries operating off the coast of western Africa, although little specific information is available from this area.
|Conservation Actions:||None in place.|
|Citation:||Ellis, J., Mancusi, C., Serena, F., Haka, F., Guallart, J., Ungaro, N., Coelho, R., Schembri, T. & MacKenzie, K. 2009. Scyliorhinus canicula. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 26 May 2013.|
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