|Scientific Name:||Squatina oculata Bonaparte, 1840|
|Taxonomic Source(s):||Bonaparte, C. L. 1840. Iconografia della fauna italica per le quattro classi degli animali vertebrati. Rome.|
|Taxonomic Notes:||Squatina oculata is difficult to identify to species therefore many of the records from fishermen reports are often assigned only to genus level.|
|Red List Category & Criteria:||Critically Endangered A2bcd+3cd+4bcd ver 3.1|
|Assessor(s):||Morey, G., Serena, F., Mancusi, C., Coelho, R., Seisay, M., Litvinov, F. & Dulvy, N. (IUCN SSG Mediterranean Workshop, San Marino, 2003)|
|Reviewer(s):||Cavanagh, R.D., Ducrocq, M. & Valenti, S.V. (Shark Red List Authority)|
This large stocky angel shark was formerly a common and important demersal predator over large areas of its coastal and outer continental shelf sediment habitat in the Mediterranean sea and eastern Atlantic. Most of this region is now subject to intense demersal fisheries, and the species is highly vulnerable from birth onwards to bycatch in the benthic trawls, set nets and bottom longlines operating through most of its range and habitat. As a result of its limiting life history characteristics and bycatch in fisheries with steadily increasing effort and capacity, its abundance has declined dramatically during the past 50 years to the point where it has been apparently been extirpated from large areas of the northern Mediterranean and parts of the West African coasts. It is now extremely uncommon throughout most of the remainder of its range. Along the West African coasts this species is taken as bycatch of industrial trawl and artisanal gillnet fisheries, and was reported as common in Russian surveys during the 1970s and 1980s. Portuguese landings data from the fleet operating off Morocco and Mauritania, aggregated for S. aculeata, S. oculata and S. squatina combined indicates a 95% decline in CPUE from 1990-1998, but nothing is known of the fishing effort associated with these landings. The available data from this region indicate that there are very few recent records, and none since 2002. Industrial and artisanal fishing pressure is intense and often unregulated in this region and it is suspected that this will continue at the current level or increase in the future. The species is therefore categorized as Critically Endangered on the basis of observed and suspected past declines and suspected future declines.
|Previously published Red List assessments:|
|Range Description:||Historically occurred throughout the Mediterranean, nowadays may be more frequent in the southern regions of the Mediterranean, e.g., off the coast of Tunisia (although it is considered rare in the Gulf of Gabes) (Bradaï 2000). Within the Mediterranean, Fredj and Maurin (1987) and Fischer et al. (1987) stated its occurrence both in the eastern and western basins, whereas Ondrias (1971) and Roux (1986) limited its distribution to the western basin, the Adriatic and the Greek coasts. Nevertheless, Golani (1996) confirmed the occurrence of S. oculata in the Levantine basin, as done for Turkish waters by Bilecenoglu et al. (2002, and cites therein). Lamboeuf et al. (1995) reported it from Lybia. |
In the Northeast Atlantic the species has been reported off the Iberian Peninsula western coast, and it does not occur northwards.
Eastern Atlantic: Southern Portugal and Spain to Morocco, Mauritania, Western Sahara, Senegal, Guinea, Ivory Coast, Nigeria, Sao Tome, Gabon, Congo, Republic of Congo, Angola and Namibia (Compagno in prep).
Native:Albania; Algeria; Angola (Cabinda); Bosnia and Herzegovina; Congo; Congo, The Democratic Republic of the; Croatia; France (Corsica); Gabon; Greece; Guinea; Italy (Sardegna, Sicilia); Libya; Mauritania; Montenegro; Morocco; Namibia; Nigeria; Portugal; Sao Tomé and Principe (Sâo Tomé); Senegal; Slovenia; Spain (Baleares, Canary Is.); Tunisia; Western Sahara
|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.|
|Population:||This species is known to be caught off Tunisia and is possibly a component of catches off other countries throughout the Mediterranean including those that report angel sharks to FAO: Albania, France, Malta, Turkey (Compagno in prep). |
Vacchi et al. (2002) reported the dramatic decline in the elasmobranch catch of a tuna trap operating in Baratti (Northern Tyrrhenian Sea) between 1898 and 1922. For the genus Squatina, catches decreased from an average of 134 specimens from the period 1898 to 1905, to 95 between 1906 and 1913, and down to 15 between 1914 and 1922. This early decline probably marks the beginning of trawling activity.
Off the Balearic Islands Squatina spp. were historically documented in checklists (Barceló I Combis 1868, Fage 1907). Captures of Squatina spp. were relatively frequent until the 1970s, becoming increasingly sporadic during the 1980s in coastal artisanal fisheries (trammel nets and gillnets), trawls and bottom longline fisheries. For example, records from a Balearic lobster gillnet fishery show that it was common to capture angel sharks on a daily basis until the mid 1980s (presumably of S. aculeata or S. oculata, judging by the depth and substratum where this fishery operates). But since the mid 1990s no reports of Squatina spp. have been reported in the area (G. Morey pers. comm). Recently, Massutí and Moranta (2003) reported no captures of Squatina ssp. from four bottom trawl fishing surveys (131 hauls, at a depth range of 46 to 1,800 m) carried out between 1996 and 2001 around the Balearic Islands. In addition, the likely low interaction with stocks from other areas further affects the already low recovery capacity of isolated populations such as those around the Balearics.
Relini et al. (2000) did not report captures of S. oculata in any of 9,281 hauls during 22 trawl surveys from 1985-1998 as part of the Italian National Project. During the MEDITS program (1995-1999), a broad scale survey of the north Mediterranean coastline, spanning from west Morocco to the Aegean Sea in depths of 10-800 m, S. oculata did not appear in any of a total of 9,095 tows (Baino et al. 2001). Indeed, it appears that angel sharks are now absent from most of the northern Mediterranean coastline.
The species may be more common off the North Africa coastline than in the northern Mediterranean, for example, as reported for the Tunisia (Gulf of Gabès) coast (Quignard and Ben Othaman 1978). However, more recently, Bradai (2000) considered S. oculata to be a very rare species off Tunisia.
Data from Southern Portugal also suggest the scarcity of the species in the area, where no specimen of the genus Squatina was recorded from experimental fishery surveys using semi-pelagic longlines and trammel nets (Coelho et al. 2005). Nevertheless, the genus Squatina is reported in Portuguese fishery statistics, showing a clear decline in the last 20 years (R. Coelho pers. comm).
There are little species specific data from the West African coasts, however, this species was previously reported as common in Russian surveys in this region during the 1970s and 1980s (F. Litvinov pers. comm. 2006). Artisanal Senegalese fishermen also remember this species as common and frequently caught by lines and gillnet 30 years ago; however it is appears to have been strongly depleted to the point where it has almost disappeared, now occurring very rarely (M. Ducrocq pers. comm. 2006). Catches are now very rare according to both artisanal fishermen and observers of the industrial demersal trawl fleets (M. Ducrocq pers. comm. 2006).
|Current Population Trend:||Decreasing|
|Habitat and Ecology:||A warm-temperate and tropical angelshark of the eastern Atlantic continental shelves and upper slopes from >20 to 500 m, mostly between 50 and 100 m, deeper in the tropics than in temperate seas. Surveys off the West African coast indicate that the species may form aggregations in December (Litvinov 1993). |
Age at maturity, longevity and reproductive age are all unknown. Females are reported to mature at 100 cm TL from Tunisian waters (Capapé et al. 1990) and 89 cm from Senegal (Capapé et al. 2002), males at 71 cm from Tunisia (Capapé et al. 1990) and 82 cm from Senegal (Capapé 2002). Reaches a maximum size of 160 cm (Compagno in prep.), which is slightly smaller than that reported for other species of angel shark.
Ovoviviparous, with both ovaries functional. Gives birth in February-April (after a minimum one month gestation period) to about 3 to 8 young (Capapé et al. 1990), ranging from 22.6 cm to 27 cm in length. The gestation time, reproductive periodicity, rate of population increase and natural mortality are all unknown.
Eats small fishes, including argentines (Argentina sphyraena), horse mackerel (Trachurus, Carangidae), codlets (Gadiculus spp., Gadidae), goatfishes (Mullidae), flatfish (Citharus linguatula, Citharidae), squid (Loligo vulgaris, Loliginidae), octopus (Eledone spp., Octopodidae), and crustaceans including mud shrimp and crabs (Upogebia spp., Dorippe lanata, and Liocarcinus depurator) (Compagno in prep).
Angel sharks are highly susceptible to bycatch in trawls as they lie on the bottom. Benthic trawl effort has increased in both intensity and efficiency on the shelf and slope area Mediterranean over the last 50 years. The species is also bycaught in trammel nets and bottom longlines throughout its range. Human disturbance by habitat degradation and tourism are also possible threats to its preferred sandy nearshore habitat.
There is evidence for dramatic declines from historic data from a tuna trap operating in the Northern Tyrrhenian Sea with catches of the genus Squatina reported at an average of 134 specimens from 1898 to 1905, down to 15 between 1914 and 1922 (Vacchi et al. 2002). This early decline probably marks the beginning of trawling activity in the area, to which angel sharks are highly susceptible. A low rate of exchange between Squatina populations makes them prone to local depletion and means that recolonisation will be extremely low.
Mediterranean countries that report 'angelsharks' to FAO with this species as part of the catch include Albania, Turkey, Malta and France.
Lozano Rey (1928) reported Squatina oculata as a common species in southern and eastern Iberian coasts. Since then S. oculata has virtually disappeared from most of its former range in the Mediterranean. All species of angel sharks are highly susceptible to bycatch from benthic trawling as they lay on the bottom. They are also caught as bycatch in fixed bottom nets, on line gear, and occasionally even in pelagic trawls. The habitat of the species over the outer continental shelf and uppermost slope (20-500 m depth) is subject to intense demersal fisheries, especially off the northern coasts of the Mediterranean. There is evidence for dramatic declines from historic data from a tuna trap operating in the Northern Tyrrhenian Sea with catches of the genus Squatina reported at an average of 134 specimens from 1898 to 1905, down to 15 between 1914 and 1922 (Vacchi et al. 2002). This early decline probably marks the beginning of trawling activity in the area. Declines have also been reported from studies off the Balearic Islands where this species, previously common, may now be absent. Catch data for this species in the north Mediterranean exist for the period from 1985 to 1999. Two major trawl surveys were carried out (the Mediterranean International Trawl Survey (MEDITS) and the Italian National Project (National Group for Demersal Resource Evaluation (GRUND)). Out of a combined total of 18,376 tows, S. oculata was not caught in any (Baino et al. 2001, Relini et al. 2000). Due to increasing fishing effort and capacity throughout the Mediterranean during the last few decades, the absence of the species in any recently recorded catches and its likely limiting life history characteristics, this species is considered Critically Endangered in the Mediterranean. It is possibly extinct from waters off the northern coasts where its former known habitat and area of occurrence continue to face fishing pressure, and although it may be in a less critical situation in southern Mediterranean waters the situation there needs to be established as a matter of great urgency before this species declines beyond recovery.
Despite the scarcity of historic numerical data, the species seems to have experienced a dramatic decline in most of its range of distribution, becoming extremely rare in the northern part of the Mediterranean.
Along the West African coasts, there are no directed fisheries for this species but it is taken as bycatch of major international industrial demersal trawl fisheries and inshore bottom set gillnets.
Portuguese landings data from the fleet operating off Morocco and Mauritania, aggregated for S. aculeata, S. oculata and S. squatina combined indicates a 95% decline in CPUE from 1990-1998, but nothing is known of the level of fishing effort associated with these landings. Landings increased to a peak of 35 t in 1990 and when the fishery was closed in 1998 the total landings were 1.7 t. This represents a decline of 95% in landings in eight years, however nothing is known of the pattern of effort associated with these landings.
This species was previously reported as common in Russian surveys in this region during the 1970s and 1980s (F. Litvinov pers. comm. 2006). Artisanal Senegalese fishermen also remember this species as common and frequently caught by lines and gillnet 30 years ago; however it is appears to have been strongly depleted to the point where it has almost disappeared, now occurring very rarely (M. Ducrocq pers. comm. 2006). Catches are now very rare according to both artisanal fishermen and observers of the industrial demersal trawl fleets (M. Ducrocq pers. comm. 2006).
In Sierra Leone, Squatina species were periodically caught by demersal trawlers in the 1980s, but are now caught very infrequently in Sierra Leone (M. Seisay pers comm. 2006). Only few (62) individuals have been caught in the research surveys held in FIAS database, and none have been captured since 2002. It is suspected that most of these records are of juveniles, based on the weight of the captures. Only five individuals weighing a total of 7 kg were caught in Guinea between 1986 and 2002 and none were caught in Mauritania. In Senegal at total of 51 individuals weighing 56 kg were caught from 1971 to 2000 and none have been recorded in recent surveys. In Gambia six individuals weighing 6 kg were caught from 1986 to 2000, and none have been caught since (FIAS unpub. data).
|Conservation Actions:||The genus Squatina is protected within six marine reserves of the Balearic Islands, where fishing for these species is forbidden and they must be released if they were captured. There are no known specific conservation measures for this species throughout the rest of its range.|
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Bilecenoğlu, M., Taskavak, E., Mater, S. and Kaya, M. 2002. Checklist of the marine fishes of Turkey. Zootaxa 113: 1−194
Bradai, M.N. 2000. Diversité du peuplement ichtyque et contribution à la connaissance des sparidés du golfe de Gabès. Theses de Doctorat d’etat es-sciences naturelles.
Capapé, C., Quignard, J.P. and Mellinger, J. 1990. Reproduction and development of two angel sharks, Squatina squatina and S. oculata (Pisces: Squatinidae), of Tunisian coasts: semi-delayed vitellogenesis, lack of egg capsules, and lecithotrophy. Journal of Fish Biology 37: 347–356.
Capapé, C., Seck, A.A., Gueye–Ndiaye, A., Diatta, Y. and Diop, M. 2002. Reproductive biology of the smoothback angel shark, Squatina oculata (Elasmobranchii, Squatinidae), from the coast of Senegal (eastern tropical Atlantic). Journal of the Marine Biological Association UK 82: 635?640.
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|Citation:||Morey, G., Serena, F., Mancusi, C., Coelho, R., Seisay, M., Litvinov, F. & Dulvy, N. (IUCN SSG Mediterranean Workshop, San Marino, 2003). 2007. Squatina oculata. The IUCN Red List of Threatened Species 2007: e.T61418A12477553.Downloaded on 20 November 2017.|
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