|Scientific Name:||Glaucostegus cemiculus (Geoffroy Saint-Hilaire, 1817)|
Rhina cemiculus Geoffroy St. Hilaire, 1827
Rhinobatos cemiculus Geoffroy Saint-Hilaire, 1817
|Taxonomic Source(s):||Eschmeyer, W.N., Fricke, R. and Van der Laan, R. (eds). 2016. Catalog of Fishes: genera, species, references. Updated 29 September 2016. Available at: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. (Accessed: 29 September 2016).|
|Red List Category & Criteria:||Endangered A3bd (Regional assessment) ver 3.1|
|Assessor(s):||Soldo, A. & Bradai, M.N.|
|Reviewer(s):||Dulvy, N.K., Walls, R.H.L., Kemp, J.R. & Allen, D.J.|
|Contributor(s):||Notarbartolo di Sciara, G., Morey, G, Brahim, K., Camara, L., Litvinov, F., Dulvy, N., Doumbouya, F., Ducrocq, M., Heenan, A., Sidi, N. & Fordham, S.|
|Facilitator/Compiler(s):||Walls, R.H.L. & Dulvy, N.|
Mediterranean regional assessment: Endangered (EN)
The Blackchin Guitarfish (Glaucostegus cemiculus) is a demersal, shallow water species. It is large with low fecundity and therefore likely to have a slow, sensitive life history. Most information comes from West Africa, but similar patterns of exploitation and retention are expected in the Mediterranean Sea, so a regional status can be inferred from this information. The Blackchin Guitarfish is taken as bycatch by international trawling fleets, artisanal gillnet fisheries, and bottom trawl cephalopod fisheries operating within its range. A decrease in overall landings and reduction in the size of specimens landed have been observed since the 1990s. A projected decline of ≥50% within three generations (15−30 years) is suspected based on i) the disappearance of the Blackchin Guitarfish from localized regions of the Mediterranean Sea; ii) severe declines in other guitarfishes (family Rhinobatidae) and wedgefishes (family Rhyncobatidae); iii) the continuation of fishing pressure in shallow coastal habitats; and iv) the potential for fishing effort to further target guitarfishes for their highly valued fins, particularly in the absence of other overfished shark species. The Blackchin Guitarfish is therefore assessed as Endangered in the Mediterranean Sea under Criteria A3bd.
|Range Description:||The Blackchin Guitarfish appears more prevalent in the southern and eastern regions of the Mediterranean Sea (Capapé 1989). The species is thought to have disappeared from the northern coastal waters, from the Alboran to Aegean Sea, including the Adriatic Sea (Relini and Piccinetti 1991, Ferretti et al. 2013).|
Native:Algeria; Cyprus; Egypt (Egypt (African part), Sinai); Greece (East Aegean Is., Greece (mainland), Kriti); Israel; Lebanon; Libya; Malta; Morocco; Palestinian Territory, Occupied; Syrian Arab Republic; Tunisia; Turkey (Turkey-in-Asia, Turkey-in-Europe)
Possibly extinct:Albania; Bosnia and Herzegovina; Croatia; France (Corsica, France (mainland)); Italy (Italy (mainland), Sardegna - Native, Sicilia - Native); Monaco; Montenegro; Slovenia; Spain (Baleares, Spain (mainland))
|FAO Marine Fishing Areas:|
Mediterranean and Black Sea
|Population:||Based on anecdotal evidence, this species was historically common throughout the northern Mediterranean Sea. In the late 19th century, Doderlein (1884) commented on the daily presence of this species on the Palermo fish market. In the early 20th century, it was considered a typical inhabitant of sandy habitats around the Balearic Islands (De Buen 1935). It has disappeared from bottom trawl surveys conducted from the Alboran Sea to Aegean Sea by the Mediterranean International Trawl Survey programme, which suggests it may have been driven to local extinction in this area (Relini and Piccinetti 1991). Trawl surveys in the Adriatic Sea similarly did not detect this species between 1948 and 2005, indicating further local extinction (Ferretti et al. 2013). The Blackchin Guitarfish appears to be present only in parts of the southern Mediterranean basin (e.g., Gulf of Gabès and perhaps elsewhere along the more lightly-fished African Mediterranean coast) where it is still caught as bycatch, but with a large proportion of immature individuals (Enajjar et al. 2008, Bradaï and El Ouaer 2012, Echwikhi et al. 2014). This guitarfish was once considered common in the southern Mediterranean Sea (Whitehead et al. 1984), particularly around the Gulf of Gabès (Bradaï et al. 2006) and east coast of Tunisia (Quignard and Capapé 1971). Recent reports show that it is still a common species off Turkey, particularly in the Iskenderun Bay area (Soldo et al. 2014). Based on disappearance from trawl surveys encompassing the entire northern coast of the Mediterranean Sea, perceived rarity from limited catches elsewhere in the region, and a lack of reduction in fishing effort or implementation of management, this species is projected to decline by at least 50% over the next three-generation period.|
|Current Population Trend:||Decreasing|
|Habitat and Ecology:|
The Blackchin Guitarfish occurs in marine and brackish waters in subtropical areas. It is a demersal species, living over sandy or muddy substrates, with a depth range that spans from shallow water to ~100 m. The presence of all size classes in the southeast region of the Gulf of Gabès (Zarzis, Djerba) suggests that conditions for reproduction and development are favourable in this area and may be used as nursery habitat (Bradaï et al. 2006).
This species is live bearing with yolk-only nutrition. The gestation period takes eight to ten months, and it reproduces once per year (Enajjar 2009); each female carries four to 12 embryos. Size at birth is ~36.5−38 cm total length (TL). Recent reports show that specimens fished from Tunisian waters do not exceed 202 cm TL and the development of the ovaries and uterus indicate that females begin to mature at 131 cm TL, while males reach sexual maturity at 118 cm TL (Enajjar et al. 2012). Whitehead et al. (1984) reported the maximum TL as 180 cm, however within the Gulf of Gabès in the southern Mediterranean Sea the maximum reported TL is 192 cm for males and 230 cm for females. The size at maturity is 110 and 100 cm TL for females and males, respectively. The generation length of the Blackchin Guitarfish is inferred to be between five and ten years, based on the life histories of similar, better studied species.
|Generation Length (years):||5-10|
|Use and Trade:||There is limited available information on the use or trade of the Blackchin Guitarfish in the Mediterranean region, although it may be a valued bycatch for its fins, and is found in artisanal fisheries in parts of its range in the Mediterranean.|
|Major Threat(s):||This species is taken as bycatch by international trawling fleets, artisanal gillnet fisheries, and bottom trawl cephalopod fisheries operating within its range. Generally, it is threatened by capture in inshore trawls and static nets. In the Gulf of Gabès, it supports targeted demersal artisanal fishing with gillnets from April to August (Bradaï et al. 2006); neonates and females with encapsulated eggs are also caught in shallow water fisheries in these waters, and bottom trawlers catch juveniles throughout the year (Bradaï et al. 2006).|
In 2013, the European Union (EU) banned the removal of shark fins on board vessels (CEC 2013), in line with advice from the International Union for Conservation of Nature Species Survival Commission’s Shark Specialist Group and other shark fishery experts, in order to enhance enforcement of the 2003 EU ban on shark finning (CEC 2003) and facilitate improved shark fishery data collection.
In 2011, the European Union (EU) put in place a regulation (CEC 2011) prohibiting EU vessels from fishing for guitarfishes in EU waters of the International Council for the Exploration of the Sea (ICES) sub-areas I (Barents Sea), II (Norwegian Sea, Spitsbergen and Bear Island), III (Skagerrak, Kattegat, Sound, Belt Sea, and Baltic Sea), IV (North Sea), V (Iceland and Faroe Islands), VI (Rockall, northwest coast of Scotland and North Ireland), VII (Irish Sea, West of Ireland, Porcupine Bank, English Channel, Bristol Channel, Celtic Sea, and Southwest of Ireland), VIII (Bay of Biscay), IX (Portuguese waters), X (Azores grounds) and XII (north of the Azores), but not in the Mediterranean Sea.
In 2012, parties to the Barcelona Convention agreed that this species (as listed in Annex II of the Specially Protected Areas and Biological Diversity Protocol for the Mediterranean) cannot be retained on board, transshipped, landed, transferred, stored, sold, displayed or offered for sale, and must be released unharmed and alive, to the extent possible, pursuant to Recommendation GFCM/36/2012/1 (FAO 2012).
The bycatch and harvest trends of the Blackchin Guitarfish should be monitored, and research undertake to confirm current distributions and population trends.
|Citation:||Soldo, A. & Bradai, M.N. 2016. Glaucostegus cemiculus. The IUCN Red List of Threatened Species 2016: e.T63132A81165103.Downloaded on 14 August 2018.|
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