Mustelus mustelus 

Scope: Mediterranean
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Chondrichthyes Carcharhiniformes Triakidae

Scientific Name: Mustelus mustelus (Linnaeus, 1758)
Regional Assessments:
Common Name(s):
English Common Smoothhound
Squalus mustelus Linnaeus, 1758
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).
Taxonomic Notes: Mustelus mustelus and M. asterias are morphologically similar and may be misidentified. Many early works may refer to either of the two species (Wheeler 1978). Mustelus asterias is distinguished from M. mustleus by a narrower inter-narial space and the presence of white spots on the dorsal and upper lateral sides of the former.

There is a demonstrated high level of contemporary and historical misidentification of unspotted Mustelus asterias as M. mustelus in the Northeast Atlantic Ocean region (Farrell et al. 2009, Farrell 2010). There are no reliably confirmed records of M. mustelus occurring north of Portuguese waters (Farrell 2010). Quignard and Capapé (1972) described a M. mustelus specimen from Portuguese Atlantic Ocean waters based on dermal denticle morphology and this remains the most northerly reliably identified record of this species.

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2bd (Regional assessment) ver 3.1
Year Published: 2016
Date Assessed: 2016-03-25
Assessor(s): Farrell, E.D. & Dulvy, N.K.
Reviewer(s): Walls, R.H.L. & Allen, D.J.
Facilitator/Compiler(s): Walls, R.H.L.
Mediterranean regional assessment: Vulnerable (VU)

The Common Smoothhound (Mustelus mustelus) is widespread, most commonly found in shallow waters from the surface to 50 m depth, but also as deep as 350 m. The species is susceptible to capture in trawl, gillnet, trammel net, and line gear. No species-specific fisheries catch data are available for the Common Smoothhound (Mustelus mustelus) because landings data often refer to all smoothhounds (Mustelus spp.) combined. In the Mediterranean Sea, the Common Smoothhound is valued for human consumption and often retained and marketed. Mediterranean landings of all smoothhounds, of which the Common Smoothhound is the most common, declined by approximately 85% between 1994 and 2006. Time series catch data from comparable trawl surveys and landings in the Gulf of Lions, Ligurian Sea, showed a clear decrease in the abundance of smoothhounds from 1970 onwards, although data from the Adriatic Sea suggest that the abundance of the Common Smoothhound did not change from 1948–98.

Both catch and fishery-independent scientific survey data available from the Mediterranean Sea suggest that significant declines have occurred. The species is considered to meet the criteria for Vulnerable in these waters, based on estimated and inferred continuing declines over three generations (~53 years) of at least 30%. Catches and population trends need to be carefully monitored throughout the region and management intervention is required.

Geographic Range [top]

Range Description:The Common Smoothhound is distributed throughout coastal and continential shelf waters of the Mediterranean Sea (Serena 2005).
Countries occurrence:
Albania; Algeria; Bosnia and Herzegovina; Croatia; Cyprus; Egypt (Egypt (African part), Sinai); France (Corsica, France (mainland)); Gibraltar; Greece (East Aegean Is., Greece (mainland), Kriti); Israel; Italy (Italy (mainland), Sardegna, Sicilia); Lebanon; Libya; Malta; Monaco; Montenegro; Morocco; Palestinian Territory, Occupied; Slovenia; Spain (Baleares, Spain (mainland), Spanish North African Territories); Syrian Arab Republic; Tunisia; Turkey (Turkey-in-Asia, Turkey-in-Europe)
FAO Marine Fishing Areas:
Mediterranean and Black Sea
Additional data:
Lower depth limit (metres):350
Upper depth limit (metres):5
Range Map:39358-3

Population [top]

Population:The Common Smoothhound is more common than the Starry Smoothhound (M. asterias) in the Mediterranean Sea. Surveys undertaken by the International Bottom Trawl Survey in the Mediterranean (MEDITS) in the northern Mediterranean Sea between 1994 and 1999 at 10–800 m depth recorded this species in 111 (2%) of 6,336 hauls, mostly between zero and 50 m depth (Baino et al. 2001). Aldebert (1997) reported a clear decrease in abundance of smoothhounds in comparable surveys in the Gulf of Lions, southern France, from 1970 onwards. The occurrence of the Common Smoothhound in comparable trawl surveys conducted on the shelf of the Adriatic Sea in 1948 and 1998 was relatively stable (Jukic-Peladic et al. 2001). In Hvar trawl surveys conducted in 1948 on the shelf of the Adriatic Sea, occurrence (frequency log-transformed) was about 1.0, compared to about 0.1 in comparable MEDITS surveys conducted in the same area in 1998. In “Gruppo Nazionale Risorse Demersali” (GRUND) surveys conducted in Italian seas between 1985 and 1998, the percentage presence was 21.9%. Most of the population was concentrated in the Adriatic Sea and southern waters of Sicily, and the species was absent from the Ligurian Sea and from Sardinian waters (Relini et al. 2000). Fortuna et al. (2011) observed trawl fisheries in the Adriatic Sea between 2006 and 2008 noting the rarity of this species, with a bycatch rate of 0.0256 individuals per haul within this time period. The annual bycatch estimate was 863 individuals (95% confidence intervals: 818 to 891 individuals).

A fishery-independent survey from 2007–08 in the Gulf of Gabès off Tunisia (southern Mediterranean basin) caught a mean of 2.2 individuals per km of gillnet per day (Echwikhi et al. 2013). The Common Smoothhound was more abundant in this study area compared to the northern Mediterranean coasts (Echwikhi et al. 2013).

To the east of the Mediterranean basin, Tserpes et al. (2013) analysed data from the fishery-independent MEDITS surveys in the Aegean Sea between 1998 and 2008, finding very low catch of the Common Smoothhound (zero to 14 individuals), with high variability.

Based on varying population trends throughout the region, it is inferred and suspected that the Common Smoothhound has declined in the Mediterranean Sea by at least 30% over a three generation period (~53 years).
Current Population Trend:Decreasing
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:This demersal coastal species is found on the continental shelves and uppermost slopes, from the intertidal to at least 350 m depth, but usually in shallow waters from 5–50 m over sandy and muddy substrates (Bauchot 1987, Notarbartolo di Sciara and Bianchi 1998, Compagno et al. 2005, Serena 2005).

Biological information is available from Tunisia and other areas of the Mediterranean Sea. Males mature at 70–112 cm total length (TL), and females at 107.5–124 cm TL (Da Silva 2007, Saïdi et al. 2008) or 80 cm TL reported elsewhere in the Mediterranean Sea (Whitehead et al. 1984, Bauchot 1987, Serena 2005). The length at 50% (L50) maturity for males and females was 97.1 and 117.2 cm TL, respectively (Saïdi et al. 2008). Off Senegal, L50 was reported as 82 cm TL for males, and 95 cm TL for females (Capapé et al. 2006). From this study, litters of four to 21 embryos were reported.

Reproduction is viviparous with yolk-sac placenta. It takes place annually, with parturition occurring during late April and early May and mating during May and early June off Tunisia (Saïdi et al. 2008). Costantini et al. (2000) also confirm the period of May–June for the Adriatic Sea. The gestation period is nine to 11 months (Smale and Compagno 1997, Notarbartolo and Bianchi 1998, Da Silva 2007, Saïdi et al. 2008). Females give birth to four to 18 pups per litter depending on their size (Fischer et al. 1987, Smale and Compagno 1997, Saïdi et al. 2008). Size at birth is 34–42 cm TL (Bauchot 1987, Notarbartolo and Bianchi 1998, Serena 2005, Saïdi et al. 2008). Da Silva (2007) studied the age and growth of this smoothhound off South Africa, and it can be assumed these values will be similar to those in the Mediterranean Sea. Maximum observed age was 25 years. Age at 50% maturity was determined at 10.75 years for females and 9.1 years for males. Natural mortality was estimated at 0.05 per year. Generation length is therefore estimated at 17.8 years.
Generation Length (years):17.8
Movement patterns:Unknown

Use and Trade [top]

Use and Trade: The Common Smoothhound is regularly marketed in the Mediterranean Sea (Bauchot 1987). It is valued for its white meat; the meat of other species including the Blue Shark (Prionace glauca) and the Sand Tiger Shark (Carcharias taurus) have been known to be sold as this species.

Threats [top]

Major Threat(s): There is a high level of exploitation on the continental shelf and upper slope to about 800 m depth in the Mediterranean Sea (Massutí and Moranta 2003). Smoothhounds are captured with demersal trawls, trammel nets, gillnets, and longlines in this region (Bauchot 1987). Semi-industrial fisheries in the Adriatic Sea, off Sicily, Spain, and Cyprus take these species, as well as artisanal fisheries elsewhere in the region. Smoothhounds are retained for consumption in the Mediterranean Sea (Fischer et al. 1987). Landings data reported to the Food and Agricultural Organisation of the United Nations (FAO) show that landings of smoothhounds (likely including the Common Smoothhound, Starry Smoothhound, and Blackspotted Smoothhound; M. punctulatus, of which the Common Smoothhound is the most common in this region) steadily increased between 1950 and 1978 to 14,000 tonnes (t), after which they fluctuated between ~6,500 t and 14,000 t from 1978–94 (FAO 2008). After 1994, landings dropped significantly, decreasing to 2,980 t in 1997 and did not exceed 2,200 t from 2001–06 (FAO 2008). Although these landings are not species-specific, when combined with the results of fishery-independent trawl surveys described above they suggest that this species has declined in abundance in the Mediterranean Sea.

There is taxonomic confusion between the Common Smoothhound and the Starry Smoothhound by fishermen and observers (Farrell 2010). Genetic analysis can be used to distinguish smoothhounds in landings, though this does not solve the issue of on-board misidentification in fisheries logbooks (Farrell et al. 2009, Moftah et al. 2011).

In Italian fish markets, a product labelled “palombo” is an umbrella term for numerous shark species, one of which has been identified through DNA barcoding as the Common Smoothhound (Barbuto et al. 2010). The grouping of species under one name in this manner makes it impossible to deduce landings trends, as individual species trends are masked by those they are grouped with.

Conservation Actions [top]

Conservation Actions: There are no species-specific management measures in place at present. Smoothhounds are protected within Balearic Island (Spain) marine reserves but enforcement is unclear.

Few species-specific landings data exist and improved data collection on commercial landings is needed. Current catch levels appear to be unsustainable throughout the majority of this species’ range and management intervention is required to reduce catches. Size and fishing effort control methods might be most effective for the Common Smoothhound (Da Silva et al. 2013).

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 than 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 mm (ICES 2012).

The Common Smoothhound is listed in Appendix III of the Barcelona Convention, affording it regulation of any exploitation taking place in the Mediterranean region (Recommendation GFCM/36/2012/1). All vessels encountering this species must record information on fishing activities, catch data, incidental taking, release and/or discarding events in a logbook or similar document, then all logged information must be reported to national authorities. Finally, additional measures should be taken to improve such data gathering in view of scientific monitoring of the species.

Citation: Farrell, E.D. & Dulvy, N.K. 2016. Mustelus mustelus. The IUCN Red List of Threatened Species 2016: e.T39358A16527988. . Downloaded on 18 November 2017.
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