|Scientific Name:||Rhinobatos rhinobatos (Linnaeus, 1758)|
Raja rhinobatos Linnaeus, 1758
|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 A2b (Regional assessment) ver 3.1|
|Assessor(s):||Bradai, M.N. & Soldo, A.|
|Reviewer(s):||Dulvy, N.K. & Allen, D.J.|
|Contributor(s):||Walls, R.H.L., Notarbartolo di Sciara, G., Morey, G, Marshall, A., Hicham, M., Compagno, L.J.V., Mouni, A., Bucal, D., Dulvy, N.K., Heenan, A. & Coelho, R.P.|
|Facilitator/Compiler(s):||Walls, R.H.L. & Dulvy, N.K.|
Mediterranean regional assessment: Endangered (EN)
The Common Guitarfish (Rhinobatos rhinobatos) is a large-bodied (up to 162 cm total length) benthic species that occurs at depths of zero to 180 m. It is widespread in the Mediterranean Sea, but subjected to fishing pressure throughout most of its range. This batoid is targeted in east African coastal waters, where its meat is exported within the region and its fins are exported to the Asian fin trade market. It is targeted in inshore coastal habitats by subsistence fisheries, and is also taken as bycatch in shrimp trawl fisheries, bottom trawl cephalopod fisheries, and artisanal gillnet fisheries. These types of fishery as well as commercial trawl fisheries are suspected to have interacted with the species similarly in the Mediterranean Sea. In the northern Mediterranean Sea, guitarfishes were historically quite common, but the Common Guitarfish's absence during research trawl surveys conducted in 1994–98 from the Alboran to Aegean Sea and absence from landings reported in Mazara del Vallo (Italy) suggest that it is now locally extinct. In areas of the southern Mediterranean Sea (e.g., Gulf of Gabès, and perhaps elsewhere along the still relatively lightly fished Mediterranean-African coast) guitarfishes are still present in catches, but with a large fraction of immature individuals.
The rarity and low rate of encounter of this species makes it impossible to assess changes in abundance over time. However, given i) evidence for local extinctions in more than one area of the Mediterranean Sea; ii) intense, continued fishing pressure throughout the region; and iii) no enforced species-specific protection in these waters, the Common Guitarfish is suspected to have declined by at least 50% over three generations (40.5 years) thereby meeting the threshold for a listing of Endangered in the Mediterranean Sea. If more accurate species-specific data were available in future, it is quite possible this species might require uplisting to a higher threat category as this is a conservative suspicion based on lacking information.
|Range Description:||The Common Guitarfish historically occurred throughout the Mediterranean Sea, appearing more prevalent in the southern and eastern regions (Capapé 1989, Whitehead et al. 1984), particularly in the Gulf of Gabès (Quignard and Capapé 1971, Enajjar et al. 2008). It is suspected to be locally extinct in the northern region of the Mediterranean Sea based on a lack of sightings or landings in more recent decades. This guitarfish has a depth range of zero to 180 m.|
Native:Algeria; Cyprus; Egypt (Egypt (African part), Sinai); France (France (mainland) - Possibly Extinct); Greece (Greece (mainland)); Israel; Italy (Italy (mainland) - Possibly Extinct); Lebanon; Libya; Montenegro; Morocco; Palestinian Territory, Occupied; Spain (Baleares - Possibly Extinct, Spain (mainland) - Possibly Extinct, Spanish North African Territories); Syrian Arab Republic; Tunisia; Turkey (Turkey-in-Asia, Turkey-in-Europe)
Possibly extinct:Albania; Bosnia and Herzegovina; Croatia; Monaco; Slovenia
|FAO Marine Fishing Areas:|
Mediterranean and Black Sea
Little is known about the Common Guitarfish's population size, but fishermen's knowledge and trawl survey data suggest a marked declines driven by unregulated fishing throughout its range. Anecdotal evidence suggests that this species was historically common throughout the northern Mediterranean Sea. In the late 19th century, Doderlain (1884) commented on the daily presence of this species in the Palermo fish market. In the early 20th century, it was considered a typical resident over sandy substrates around the Balearic Islands (De Buen 1935). The International Trawl Survey in the Mediterranean (MEDITS) conducted surveys from the Alboran to the Aegean Sea between 1994 and 1999, failing to catch this species at all (Baino et al. 2001), which suggests a marked decline in abundance. The absence from these relatively rigorous, annual trawl surveys that indeed cover the majority of the Common Guitarfish's depth range led Relini and Piccinetti (1991) to report this species as locally extinct in the northern regions of the Mediterranean Sea.
Observations from the 1970s and 1980s indicate that this species used to be prevalent in the southern and eastern Mediterranean basins (Quignard and Capapé 1971; Whitehead et al. 1984; Echwikhi et al. 2012, 2013). It is still caught in the Gulf of Gabès and potentially elsewhere along the southern coast of the Mediterranean Sea where fishing pressure has typically been less intensive until more recently. All sizes and sexes of this species are landed in the Gulf of Gabès and the proportion of mature and immature individuals varies with season and capture area (Enajjar 2009). Recent reports reveal that the Common Guitarfish is still common in Turkish waters, particularly in the Iskenderun Bay area (Soldo et al. 2014) where it is landed as bycatch (Başusta et al. 2008).
The demersal nature of this guitarfish and the localized decline within the northern Mediterranean Sea indicate that there are low levels of connectivity between geographic subpopulations. Given evidence for local extinction in parts of the Mediterranean Sea and intense and continued fishing pressure in the region in the absence of any effective, enforced fisheries management that might protect the species or its habitat, the Common Guitarfish is suspected to have declined in the Mediterranean Sea by at least 50% over three generations (40.5 years).
|Current Population Trend:||Decreasing|
|Habitat and Ecology:|
This bottom-dwelling batoid can be found over sandy, muddy, shell, and occasionally macroalgal-covered substrates (De Buen 1935, Whitehead et al. 1984). It inhabits shallow areas of in the intertidal zone and waters <180 m deep.
This is an aplacental live bearing species that gives birth in late summer to early autumn following a gestation period of 10−12 months. Mating and ovulation take place after parturition. The average uterine fecundity is 5.34 young per year with each pup measuring ~30 cm total length (TL) at birth. The size at maturity for females and males is 79 and 70 cm TL, respectively, and the smallest gravid female observed is 75 cm TL (Enajjar et al. 2008). The largest male recorded is ~140 cm TL and the largest female 162 cm TL, both caught in the Gulf of Gabès (Capapé et al. 1996). Age at maturity is two to three years (Ismen et al. 2007), and maximum age is at least 24 years (Başusta et al. 2008); generation length is therefore ~13.5 years.
|Generation Length (years):||13.5|
|Movement patterns:||Not a Migrant|
|Use and Trade:||The Common Guitarfish is likely discarded as bycatch but may also be retained for its meat and fins in the Mediterranean region, particularly in the African Mediterranean as it is known to be consumed locally in West Africa from fisheries operating in the Eastern Central Atlantic.|
|Major Threat(s):||The biology and inshore habitat preferences of this guitarfish make it highly susceptible to population depletion from overexploitation. Although wide-ranging, the Common Guitarfish exists within a depth range (zero to 180 m) that is highly likely to be exposed to fishing pressure throughout most of its geographic range. Its coastal habitat makes it an easy target for artisanal fisheries and it is likely to be caught incidentally in many commercial fisheries operating along the majority of the Mediterranean coastline, including the Egyptian commercial trawl fishery off the coast of Alexandria. Nursery grounds are also likely to be affected by human activities and disturbance in many areas of the heavily human-populated Mediterranean coastline.|
In 2012, this species was added to Annex II of the Barcelona Convention. Parties to the Convention agreed that elasmobranch species listed in Annex II of the Protocol concerning Specially Protected Areas and Biological Diversity in the Mediterranean, which includes Recommendation GFCM/36/2012/1, cannot be retained on board, transhipped, landed, transferred, stored, sold or displayed or offered for sale, and must be released unharmed and alive, to the extent possible. This convention, however, is not currently enforced.
In 2013, the EU banned the removal of shark fins on board vessels (CEC 2013), in line with advice from the International Union for the Conservation of Nature’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.
|Citation:||Bradai, M.N. & Soldo, A. 2016. Rhinobatos rhinobatos. The IUCN Red List of Threatened Species 2016: e.T63131A16527789.Downloaded on 17 August 2018.|
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