|Scientific Name:||Mustelus asterias Cloquet, 1819|
|Taxonomic Source(s):||Eschmeyer, W.N. (ed.). 2015. Catalog of Fishes. Updated 6 April 2015. Available at: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. (Accessed: 6 April 2015).|
|Red List Category & Criteria:||Near Threatened (Regional assessment) ver 3.1|
|Assessor(s):||Farrell, E., McCully, S., Dulvy, N., Mancusi, C. & Ellis, J.|
|Reviewer(s):||Serena, F. & Abella, A.|
|Facilitator/Compiler(s):||Walls, R., Lawson, J. & Dulvy, N.|
European regional assessment: Near Threatened (NT)
Starry Smoothhound (Mustelus asterias) is widespread on the continental shelf to a depth of 200 m, ranging from northern Europe to northwest Africa, including the Mediterranean Sea. The species is vulnerable to capture in trawl, gillnet, trammel net and line gear. In the Mediterranean Sea, smoothhounds (Mustelus spp.) are valued for human consumption and are often retained and marketed, whereas in the northern parts of the Northeast Atlantic they have little market value and are often discarded. No reliable species-specific fisheries catch data are available because landings data often refer to all smoothhounds combined, or even smoothhounds combined with Tope (Galeorhinus galeus) or spurdogs (Squalus spp.). The Northeast Atlantic and Mediterranean Sea are considered different subpopulations, based on differences in reproductive biology.
Abundance trends in fishery independent survey data from northwestern European waters suggest that the Northeast Atlantic subpopulation is estimated to be increasing. However, there has been a corresponding increase in reported landings from this region, and given the absence of effective species-specific management for this subpopulation, abundance trends and catch volumes must be carefully monitored.
In the Mediterranean Sea, abundance trends in fishery independent trawl survey data show that this subpopulation has been declining in both the Gulf of Lions and the Adriatic Sea over the past 50 years. Landings of all smoothhounds in the Mediterranean Sea declined by about 85% between 1994 and 2006. No information is currently available on subpopulation trends in the southern Mediterranean Sea and northwestern coasts of Africa, although this species is also caught and landed there in relatively intensive coastal fisheries. It is suspected to have undergone a decline of around 30% through the three-generation period (53 years).
Considering the decline of the species in the Mediterranean Sea and its increasing trend in the Northeast Atlantic, this species is assessed as Near Threatened as it is close to meet the threshold for a threatened category under criterion A2. It should however be noted that the situation in the Mediterranean Sea may be worse than estimated given the grouping of smoothhounds in landings data and consequent masking of species-specific population trajectories. This European status must therefore not undermine the situation in these waters that needs to be addressed.
This species’ northernmost range in the Northeast Atlantic extends to Scottish and southern Norwegian waters. The range extends southwards into the waters of Sweden, Denmark, Germany, The Netherlands, Belgium, France, the United Kingdom, Ireland, Spain and Portugal (Compagno et al. 2005). The range extends beyond the Northeast Atlantic into northwestern Africa in the Eastern Central Atlantic. The International Council for the Exploration of the Sea (ICES) Working Group on Elasmobranch Fishes (WGEF) considers there to be one management unit of this species in the continental shelf waters of the Northeast Atlantic (ICES 2012). This unit spans the North Sea, English Channel, waters west of Scotland, the Celtic Seas, the Bay of Biscay and Iberian waters. It is unknown if this stock management unit corresponds to a single biological population; tagging studies are ongoing. This smoothhound is found throughout the entire Mediterranean Sea, including the Black Sea (Eryılmaz et al. 2011). Its depth limit is one to 200 m.
Native:Albania; Algeria; Belgium; Bosnia and Herzegovina; Bulgaria; Croatia; Cyprus; Denmark; Egypt (Egypt (African part), Sinai); France (Corsica, France (mainland)); Georgia (Abkhaziya, Adzhariya, Gruziya); 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)); Romania; Russian Federation (European Russia, Krasnodar); Slovenia; Spain (Baleares, Canary Is., Spain (mainland), Spanish North African Territories); Sweden; Syrian Arab Republic; Tunisia; Turkey (Turkey-in-Asia, Turkey-in-Europe); Ukraine (Krym, Ukraine (main part)); United Kingdom (Great Britain, Northern Ireland); Western Sahara
|FAO Marine Fishing Areas:|
Atlantic – northeast; Atlantic – eastern central; Mediterranean and Black Sea
Within the coastal waters of the United Kingdom, this species can be found in the Outer Thames, Solent, Bristol Channel and Cardigan Bay (Ellis et al. 2005a). In Irish waters, it is most abundant in the western Irish Sea and the coastal waters of southeast Ireland (Farrell 2010). Martin et al. (2010) found that the mean density of this smoothhound more than doubled between 1988 and 2008 throughout the English Channel. Similar trends were reported from various trawl surveys in the Northeast Atlantic between 1992 and 2012, where the highest increase in abundance was observed in French surveys (Dureuil 2013).
Although species-specific data are limited, data for all smoothhounds (Mustelus spp.) provides a good proxy for trends in landings and relative abundance. This is especially true for Starry Smoothhound (M. asterias), which is the most frequently encountered smoothhound species in the Northeast Atlantic (ICES 2013). In the Bay of Biscay landings have increased strongly from 151–499 tonnes (t) from 1996–2004, and have remained stable in Portuguese waters since an initial peak in 1999 (ICES 2007). Fishery independent surveys of the Celtic Seas, southern North Sea, English Channel and Irish Sea all suggest increasing trends in nominal catch per unit effort (CPUE; ICES 2010, 2013). For example, a fishery independent survey in the eastern English Channel and southern North Sea also found an increase in CPUE from about 0.1–0.3 individuals per hour in the early to mid-1990s to around 1.0–1.3 in 2009–2011.
A relative abundance survey conducted by the Centre for Environment, Fisheries and Aquaculture Science (Cefas) in the Celtic Sea recorded a peak in 2000 and again in 2004 over a 17-year time series, although the year 2000 peak was not found in a concurrent French survey (ICES 2007). Nonetheless, a United Kingdom beam trawl survey also found an increase in smoothhound relative abundance and frequency of occurrence (ICES 2011). The trend of the population in the Northeast Atlantic is therefore of an increase.
This species is less common than Common Smoothhound (Mustelus mustelus) in the Mediterranean Sea, although the potential for misidentification should be noted. In the northern Mediterranean Sea, the International Bottom Trawl Survey in the Mediterranean (MEDITS) found that the frequency of occurrence was very low, with this smoothhound recorded in only five of 6,336 hauls conducted from 1994–1999 at 10–800 m depth (Baino et al. 2001). The occurrence of this species also decreased in trawl surveys conducted in 1948 and 1998 in the Adriatic Sea (Jukic-Peladic et al. 2001). Aldebert (1997) reports a clear decrease in abundance of smoothhounds in comparable surveys in the Gulf of Lions, southern France, from 1970–1995. In Hvar trawl surveys conducted in 1948 in the Adriatic Sea, occurrence of this smoothhound was about 1.0 (frequency log-transformed), compared to about 0.1 in comparable MEDITS surveys conducted in the same area in 1998, which shows a decline of 90% from 1948 to 1998. A decline of 91% is inferred for the three generation period of 53 years (1948-2001). Most recently, between 2006 and 2008, Fortuna et al. (2011) examined trawl fisheries in the Adriatic Sea, and found that this species was rarely caught as bycatch, with a catch rate of 0.0048 individuals per haul. In 2009 two specimens were caught in the southwestern Black Sea (Eryılmaz et al. 2011).
Catch data should be examined with caution as the catches reported as smoothhounds often consist of an aggregation of small-sized demersal sharks. Data reported to the Food and Agriculture Organisation of the United Nations show that smoothhound landings steadily increased between 1950 and 1978 to 14,000 t, after which they fluctuated between about 6,500 and 14,000 t from 1978–1994 (FAO 2008). After 1994, landings dropped significantly to 2,980 t in 1997 and did not exceed 2,200 t from 2001–2006 (FAO 2008). It is likely that this species has never been very abundant in the Mediterranean Sea. However, the available information on landings (although not species-specific) combined with the more detailed information derived from fishery-independent trawl surveys, suggest that this particular species has declined in abundance in the Mediterranean Sea. In some cases, as in the northern Tyrrhenian Sea, this species can be considered locally extinct due to overfishing (Ferretti et al. 2005, 2008).
Considering the outlined declines through the Mediterranean Sea, the species is inferred to have undergone a decline of at least 30% over three generations (around 53 years) throughout its Mediterranean range. While in the Northeast Atlantic the population trend is of an increase and in the Mediterranean Sea the species seems to be decreasing, the overall trend is considered to be stable.
|Current Population Trend:||Stable|
|Habitat and Ecology:|
This demersal smoothhound species is found at a maximum depth of about 200 m, on sandy and gravelly bottoms (Compagno 1984, Ellis et al. 2005a). In waters surrounding the United Kingdom, it seems to be most abundant in large bays, outer parts of large estuaries and in coastal areas (Ellis et al. 2005a). In Irish waters, this species is most abundant in the western Irish Sea particularly off the shallow sandy beaches (Farrell 2010). Recent tagging data suggest that it is seasonally migratory across its Northeast Atlantic range (Farrell et al. 2010b, Winter and van Oversee 2013).
In the Northeast Atlantic, females give birth between April and July. No published information exists on the location of parturition and nursery areas, though neonates and juveniles are periodically abundant in shallow areas of the English Channel, southern North Sea/Thames Estuary and Bristol Channel (Ellis et al. 2005a,b; Dureuil 2013) and in shallow waters off sandy beaches on the southeast coast of Ireland (Farrell 2010). In the Irish Sea, large pregnant females are seasonally abundant in May off Holyhead, Wales (Farrell 2010). Mating may occur in the southern Celtic Sea in October (Dureuil 2013). The natural mortality rate of this species in the Northeast Atlantic was estimated at 0.219 per year and the intrinsic rate of population increase at 0.079 per year (Dureuil 2013).
The reproductive biology of this live bearing with yolk sac species is variable between the Northeast Atlantic (Farrell et al. 2010b) and the Mediterranean Sea (Capapé, 1983). In the Northeast Atlantic, ovarian fecundity ranged from one to 28 oocytes and uterine fecundity from five to 20 embryos (ICES 2014). Average total length (TL) at birth is 30 cm (Compagno et al. 2005), though other estimates have ranged from 34.9–38.1 cm TL (Farrell et al. 2010a). Gestation period was about 12 months, followed by a resting period of about 12 months, resulting in a biennial reproductive cycle. Length and age at 50% maturity estimates for males and females were 78 cm TL and four to five years and 87 cm TL and six years, respectively (Ferrell et al. 2010b). Using sectioned vertebrate, asymptotic length and longevity estimates were 103.7 cm TL and 20.2 years in females and 123.5 cm TL and 11.8 years in males (Farrell et al. 2010a).
In the Mediterranean Sea there are no published age or growth studies for this species, however there is some information on reproductive traits. Ovarian fecundity ranged from 10–45 oocytes and uterine fecundity from 10–35 embryos. Unlike the Northeast Atlantic subpopulation, females reportedly have an annual reproductive cycle in the Mediterranean Sea, and sexual maturity is attained at about 75 cm in males and about 96 cm TL in females (Capapé 1983). The species is inferred to have a generation length of 17.8 years, based on data from the closely related species Mustelus mustelus.
|Generation Length (years):||17.8|
|Use and Trade:||
The species is commercially valuable in the Mediterranean Sea, where it is utilized fresh, frozen, or salted and dried for human consumption. It is regularly present on the Adriatic, Tyrrhenian, Tunisian and Turkish markets; and sold fresh, frozen, refrigerated or salted-dried (Fisher et al. 1987). Often discarded by commercial fisheries in the Northeast Atlantic, but the species is important for recreational fisheries in some areas of this region.
This smoothhound is caught seasonally as bycatch in trawl, gillnet and longline fisheries, some of which discard or land the species, depending on market demands (ICES 2012). There are areas of local abundance throughout its range. Preliminary analyses of bycatch data indicate that juveniles are typically discarded, but no evaluation of discard survival rate has been undertaken (ICES 2012). Fishing mortality was estimated from the catch ratio from surveys of the Northeast Atlantic across the sub-adult and adult age classes (5–13 years). Since 1992 the fishing mortality has been variable, but overall has declined from 0.25 to 0.15. Nonetheless, the current level may still be slightly above the fishing mortality that produces maximum sustainable yield (FMSY = 0.11; Dureuil 2013).
In addition to being discarded as bycatch, this species may be landed for human consumption, and is used as bait for the inshore whelk fishery in England and Ireland. ICES landing statistics combine dogfish and smoothhounds together so there are little accurate data on Northeast Atlantic landings, and levels of bycatch are largely unknown. They are also an important sport angling fish in some areas, where most fish are returned to the sea, and often tagged. These areas include the Bristol and English Channels, the United Kingdom, the eastern and western Irish Sea, and off the coast of the Netherlands (ICES 2012).
Mediterranean SeaThere is a high level of exploitation on the continental shelf and upper slope to about 800 m depth in the Mediterranean Sea (Massuti and Moranta 2003, Ferretti et al. 2005). Smoothhounds are captured by demersal trawls, trammel nets, gillnets and longlines in this region (Bauchot 1987). Semi-industrial fisheries in the Adriatic Sea, off Sicily, Spain and Cyprus are known to take these species, and also artisanal fisheries elsewhere. Smoothhounds are retained and used in the Mediterranean Sea, where they are regularly sold for human consumption in many areas (Fischer et al. 1987).
There is currently no restriction on catch. Based on its approach to data-limited stocks, ICES advised in 2012 that 2013–2014 catches should be reduced by 4%. Despite this advice and commitments to manage commercial fisheries, there are currently no European Union limits on landings or proposals for management.
The European Community Council Regulations 850/98 for the ‘conservation of fishery resources through technical measures for the protection of juveniles of marine organisms’ details the minimum mesh sizes that can be used to target fish. Smoothhounds would be classed under ‘all other marine organisms’ and so can only be targeted in fixed nets of more than 220 millimeters (ICES 2012).
There is currently no restriction on catch. Species-specific management measures are necessary to prevent further declines in this region, including improved data collection to species level for commercial landings. This species (M. asterias) is listed in Appendix III of the Barcelona Convention, which suggests it should be afforded regulations regarding exploitation in the Mediterranean Sea (Recommendation GFCM/36/2012/1). The listing directs the recording and reporting to national authorities of all encounters with the species (including catch, bycatch, discard) and encourages improved data collection and scientific monitoring. However, compliance with this directive has been poor, and thus Mediterranean data on this species remains seriously lacking. The Balearic Island Marine Reserves offer minimal protection to smoothhounds, as they are protected within the waters of the reserve.
Further research should be conducted on the population size and trend of the species.
|Citation:||Farrell, E., McCully, S., Dulvy, N., Mancusi, C. & Ellis, J. 2015. Mustelus asterias. The IUCN Red List of Threatened Species 2015: e.T39357A48940630.Downloaded on 19 August 2018.|
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