|Scientific Name:||Etmopterus spinax (Linnaeus, 1758)|
Squalus spinax Linnaeus, 1758
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Coelho, R. Blasdale, T., Mancusi, C., Serena, F., Guallart, J., Ungaro, N., Litvinov, F., Crozier, P. & Stenberg, C.|
|Reviewer(s):||Cavanagh, R.D., Valenti, S.V., Stevens, J.D. & Fowler, S.L. (Shark Red List Authority)|
A common lantern shark occurring in the Eastern Atlantic and Mediterranean Sea on outer continental shelves and upper slopes at depths of 70–2,000 m, and most abundant at 200–500 m. A non-commercial species, all specimens captured as bycatch by commercial fishing vessels are discarded thus limiting the data available. Data from the Mediterranean Sea, Eastern Central and South Atlantic indicate that the species is still relatively commonly caught in scientific trawl surveys and there is no evidence that the population has declined there. A recently introduced ban on bottom trawling below 1,000 m depth in the Mediterranean Sea will afford it protection there. Deepwater fisheries also operate off the coast of western Africa, but these are relatively limited at this time. However, deepwater fisheries are intense in the Northeast Atlantic and scientific trawl surveys indicate that catch rates of this species declined by approaching 20% between the 1970s and 1998–2004. This species shows size structure segregation with depth. The deeper-occurring larger mature female sharks are probably more affected by the commercial deepwater fisheries operating in the Northeast Atlantic than the immature stages that are found in shallower waters. An assessment of Near Threatened is warranted in the Northeast Atlantic, given the apparent decline and continued, intense deepwater fishing pressure. Elsewhere and globally, the species is assessed as Least Concern because there is no evidence for population decline throughout the rest of its range and there are areas of refuge from fishing pressure. Continued monitoring is required to ensure that this species is not detrimentally affected by expanding deepwater fisheries in the future, particularly in the Eastern Central and Southeast Atlantic.
|Range Description:||Mediterranean Sea: found in the Western Mediterranean (Spain, France, Italy, Albania, Malta, Libya, Tunisia, Algeria, Morocco). |
Northeast, eastern central and southeast Atlantic: Iceland and Norway south to Senegal, Sierra Leone, Côte d'Ivoire to Nigeria, Cameroon to Gabon, Azores and Cape Verde Islands (Compagno in prep.).
Native:Algeria; Cameroon; Cape Verde; Côte d'Ivoire; France; Gabon; Iceland; Italy; Libya; Malta; Morocco; Nigeria; Norway; Portugal (Azores, Madeira, Portugal (mainland)); Senegal; Sierra Leone; Spain; Tunisia; United Kingdom
|FAO Marine Fishing Areas:|
Atlantic – northeast; Atlantic – southeast; Atlantic – eastern central; Mediterranean and Black Sea
|Range Map:||Click here to open the map viewer and explore range.|
Data collected from 1985–2002 by the Italian national GRUND project (Gruppo Nazionale Risorse Demersali) and from 1994–2002 by the MEDITS project (Mediterranean International Trawl Survey) (Relini 1998, Bertrand et al. 2000) provided information on the abundance and bathymetric distribution of Etmopterus spinax. Analysis of trends in Biomass Index (BI kg per km²) of E. spinax from 1985–2002 indicated stable populations in the northern Tyrrhenian Sea (Relini et al. 2000, Cecchi et al. 2004). Etmopterus spinax was present at both high frequency (19% of the hauls) and high abundance (between 1 and 10 kg per km²) in the Mediterranean, with a standing stock biomass of 4% (2,248 t). The species was found to have an especially high presence in the western-central part of the Mediterranean basin (Morocco, Spain, France, Tyrrhenian, Corsica, Sardinia and Sicily coasts) (Baino et al. 2001). Data collected in the Gulf of Valencia (Spain) during 1988–1989 from a bottom trawl fishery for Red Shrimp Aristeus antennatus revealed the presence of E. spinax in 87.5% of trawls carried out between 450 and 675 m depth, with a mean abundance of 1.04 specimens per hour trawl (Guallart 1990). All sizes were represented in the captures (from juveniles to adults of both sexes) and observations made in later years did not reveal any significant change in the abundance of E. spinax in this area (J. Guallart pers. comm. 2006).
Catch rates in Scottish surveys from 1998–2004 were 81% of those in Ministry of Agriculture, Fisheries and Food (MAFF) surveys in the 1970s (T. Blasdale pers. comm. 2006). These surveys cannot be directly compared as they used different gear and vessels and fished different depth ranges, but they do appear to indicate that population levels have declined slightly from pre-fishery levels (Jones et al. 2005).
In southern Portugal Catch Per Unit Effort (CPUE) data for captures with deepwater longlines set from 450–780 m depth are 1.71/1,000 hooks (s.d.= 1.83) (R. Coelho unpubl. data). Deep water trawlers in the Algarve capture this species from 200–700 m depth and CPUEs are highest at 500 m depth with a capture rate of 15.74 specimens per hour (Coelho et al. 2005b). CPUE (kg per hour fished) from French deepwater trawl vessels in ICES Division VIa (West of Scotland) showed discard rates of this species to peak at 18.3 kg/hr at 500 m and then decline to 1.3 kg/hr at 700 m (ICES WD, Crozier 2003).
Eastern Central and Southeast Atlantic
This species was common off the coast of Northwestern Africa in the 1980s and was still very common in more recent surveys (Gulyugin et al. 2006).
|Current Population Trend:||Unknown|
|Habitat and Ecology:||Etmopterus spinax is found on the outer continental shelves and upper slopes at depths of 70–2,000 m, mostly between 200 and 500 m (Compagno in prep.). In the Mediterranean E. spinax has been recorded from 300–2,000 m depth (F. Serena pers. obs. 2007). In the Adriatic Sea it is reported down to 1,200 m depth (Ungaro et al. 2001). In the Thyrrenian Sea, Italy, Cecchi et al. (2004) found the typical depth distribution to be 322–633 m. In the Gulf of Valencia, Spain it is commonly caught by commercial bottom trawls between 300 and 675 m, and is slightly more abundant below 550 m (Guallart 1990). In the northeast Atlantic E. spinax has been caught at depths of 400–1,000 m (Merrett et al. 1991a,b; Bridger 1978). In general, smaller (<30 cm) individuals tended to occur at depths of less than 500 m whilst mature individuals were found at mid-depths (500 to 600 m) (P. Crozier pers. comm.). In Sierra Leone E. spinax is found as shallow as 200 m but is a dominant species at depths greater than 400 m (Litvinov 1993). In Morocco E. spinax is captured at depths of 400–800 m, is a resident species at 400–500 m and is dominant at 600 m and sub-dominant at 600–900 m (Litvinov 1993).|
Estimated age at maturity is five to six years (Cecchi et al. 2004), although longevity is unknown for the species. Size at maturity has various estimates: females mature between >30–46 cm total length (TL); 33–36 cm (Compagno in prep); 38–40 cm (Capapè et al. 2001, Cecchi et al. 2004); 46 cm (n=76) in the northeast Atlantic (Crozier unpub. data); 31 cm in South Portugal (Coelho and Erzini 2005); and >30 cm in the Adriatic (Ungaro pers. comm.). Males mature between 25–38 cm: 33–36 cm TL (Compagno in prep.); 35 cm (Capapè et al. 2001); 38 cm (n=105) in the northeast Atlantic (Crozier unpub. data); 25 cm in South Portugal (Coelho and Erzini 2005); and 28–30 cm in the Adriatic (N. Ungaro pers. comm.). The maximum size recorded for E. spinax was a female of 60 cm TL but specimens are rarely larger than 45 cm (Compagno in prep.).
The velvet belly is ovoviviparous producing 6–20 pups per litter (Compagno in prep, Fischer et al. 1987), with a mean ovarian fecundity of 18 eggs (n=14) and a mean embryonic fecundity of 10 pups (n=15) (Crozier unpub. data). In the Thyrrenian Sea mature females were observed at 40 cm TL carrying six embryos of 6.5 cm TL in the uterus (Cecchi et al. 2004). Females produce a litter once a year (Bini 1967, Tortonese 1956) and pups are between 8 and 14 cm TL at birth (12 to 14 cm (Compagno in prep.); 10–11 cm (Fischer et al. 1987); 11 cm (n=15) (Crozier unpub. data)). Smaller pups of 8–10 cm TL have been reported for the Adriatic (Marano et al. 2000).
This species feeds on small fishes, squids, and crustaceans (Compagno in prep.). The diet of E. spinax has been analysed as follows: crustaceans 74.8%, fishes 16.9%, cephalopods 6.9%, polychaetes 0.9% others 0.5% (Bello 1998, Cecchi et al. 2004). In the Rockall Trough in the Northeast Atlantic the diet of E. spinax was reported to consist mainly of benthopelagic organisms, with fish and crustaceans of secondary importance (Mauchline and Gordon 1983). Smaller specimens (<39 cm) of this species feed on mid-water fish that were completely absent from the stomachs of larger individuals. The differences in diet were thought to be partly due to prey selection and also because larger fish live at greater depths. In South Portugal a significant ontogenic variation in feeding ecology was observed, with specimens smaller than 17 cm TL feeding mainly on euphausiids, specimens from 17–27 cm TL feeding mainly on euphausiids and natant decapods and specimens larger than 27 cm TL feeding also on teleosts and cephalopods (Neiva et al. submitted). In Angolan waters, off the west African coast, the diet of this species has been described as follows: cephalopods (63%), crustaceans (33%) and teleosts (4%) (Zaera 2005).
This species is caught as a bycatch of bottom trawl fisheries and is known to be discarded by Italian (Abella and Serena 2002) and Spanish (Guallart 1990) fleets. Most specimens discarded are either dead or in very poor condition (J. Guallart pers. comm.). This species occurs at depths of 70–2,000 m, but mostly between 200–500 m in the Mediterranean. The main depth range of this species is within the range of Mediterranean fisheries. However, the ban on bottom trawling below depths of 1,000 m in the Mediterranean, adopted by all members of The General Fisheries Commission for the Mediterranean (GFCM), will afford protection in the deeper part of its bathymetric range. This measure came into force in September 2005.
Etmopterus spinax is most abundant in the northeast Atlantic between 400 and 800 m and large mature female E. spinax are found in waters around 600 m. This may suggest that these mature sharks are being affected more by the commercial deep-water fisheries than other life stages of E. spinax that are found in shallower waters. Therefore it is suggested that this species may also be susceptible to heavy commercial fishing in the northeast Atlantic (Coelho 2007).
It is caught as bycatch in bottomtrawls fishing for Nephrops norvegicus and Pandalus borealis in the Skagerrak and Kattegat by Swedish fishermen. It has never been recorded in logbooks and most is probably discarded at sea. Off the south coast of Portugal (Algarve), this species is captured in high quantities as bycatch of the deep water fisheries that operate at these depths, namely the bottom trawl fishery that targets Norway Lobster (Nephrops norvegicus), Red Shrimp (Aristeus antennatus) and Deepwater Pink Shrimp (Parapenaeus longirostris), and the near bottom longline fishery that targets European Hake (Merluccius merluccius), Conger Eels (Conger conger) and Wreck Fish (Polyprion americanus). In both fisheries, all captured specimens are discarded (Coelho et al. 2005a), and even though most are still alive when returned to sea, they usually have severe injuries (due to the long trawling periods or as a result of the hooks) that are likely to impair their survival.
Eastern Central and Southeast Atlantic
In general, very little is known of the threats that affect this species off the African coast. Off the Angolan coast, E. spinax is an uncommon species, captured rarely by bottom trawlers and always discarded. Where this species is common off Morocco (western Sahara), Mauritania, and Sierra Leone it is taken in trawls. However, catches are not recorded because of species identification problems and because this bycatch is discarded.
There are no species specific management measures. The General Fisheries Commission for the Mediterranean (GFCM) banned bottom trawling below depths of 1,000 m in the Mediterranean in February 2005 and this came into force in September 2005.
In Swedish waters (e.g., Skagerrak and Kattegat) bottom-trawls are required to have a selective grid that should help to reduce bycatch of E. spinax.
|Citation:||Coelho, R. Blasdale, T., Mancusi, C., Serena, F., Guallart, J., Ungaro, N., Litvinov, F., Crozier, P. & Stenberg, C. 2009. Etmopterus spinax. The IUCN Red List of Threatened Species 2009: e.T161388A5412576.Downloaded on 24 October 2017.|