|Scientific Name:||Mobula mobular|
|Species Authority:||(Bonnaterre 1788)|
Raia mobular Bonnaterre, 1788
|Taxonomic Notes:||Since expert examination is needed to distinguish M. mobular from M. japanica (the spinetail devilray), a circumtropical species also known from the tropical Atlantic (Notarbartolo di Sciara 1987), past reports of giant devilrays from the Atlantic may have been due to incorrect identification of spinetail devilrays.|
|Red List Category & Criteria:||Endangered A4d ver 3.1|
|Assessor(s):||Notarbartolo di Sciara, G., Serena, F. & Mancusi, C.|
|Reviewer(s):||Fowler, S.L., Valenti, S.V. & participants of the Shark Specialist Group Northeast Atlantic workshop|
This huge plankton-feeding ray is the largest of the genus Mobula. It has a very low reproductive capacity (giving birth to a single huge pup at unknown intervals) and its geographic range is probably limited to offshore deepwaters of the Mediterranean (and possibly adjoining North Atlantic waters). It is taken as bycatch on longlines, in swordfish pelagic driftnets, purse seines, trawls and in fixed tuna traps, to unsustainable levels. Given high bycatch mortality, its limited reproductive capacity and range Mobula mobular is listed as Endangered A4d. More research is needed on its exploitation, distribution, biology and ecology. In particular, catch data are required, and stock assessments should be undertaken where the species is fished.
|Range Description:||The Giant Devilray occurs in offshore, deep waters and, occasionally, in shallow waters (Bradai and Capapé 2001) throughout the Mediterranean Sea, in waters ranging in depth from few tens of metres to several thousands (with the exception of the northern Adriatic) and possibly in the nearby North Atlantic. Outside the Mediterranean it occurs along the coast of Africa from Morocco to Senegal, the Canary Islands, Madeira, the Azores, Portugal, and as a vagrant, off southern Ireland (Notarbartolo di Sciara 1987). However, since expert examination is needed to distinguish M. mobular from M. japanica, a species known from the tropical Atlantic (Notarbartolo di Sciara 1987), past reports of Giant Devilrays from the Atlantic may have been due to incorrect identification of Spinetail Devilrays.|
Native:Algeria; Croatia; France; Greece; Israel; Italy; Malta; Spain; Tunisia
|FAO Marine Fishing Areas:||
Present - origin uncertain:
Atlantic – eastern central; Atlantic – northeast; Mediterranean and Black Sea
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There are no population estimates for the Giant Devilray. The species appears to live in very low densities throughout its range.|
|Habitat and Ecology:||Like all mobulids, the Giant Devilray is an epipelagic batoid feeding on planktonic crustaceans and small schooling fishes, which are trapped on its specialised branchial filter plates. In the Mediterranean a likely important prey item for the Giant Devilray is the euphasiid shrimp Meganyctiphanes norveggica. Mobulids are aplacental viviparous matrotroph rays, in that the pups receive their nourishment from uterine milk secretion (Wourms 1977). They give birth to a single huge pup. A term embryo of M. mobular born from a specimen, caught in the northern Tyrrhenian Sea in late spring 1986 (Notarbartolo di Sciara and Serena, 1988), with a disc 1659 mm wide and a weight of 35 kg is the largest Mobula embryo on record (Notarbartolo di Sciara, 1987). It is not apparent from the literature whether M. mobular has a restricted reproductive season in the Mediterranean. Tortonese (1957) described a rather undeveloped embryo from a female caught in Palermo in September. The observations of Notarbartolo di Sciara and Serena (1988) suggest that in the northern Mediterranean the species gives birth in summer and that the pup could be up to 1,660 mm disc width at birth; the gestation period is still largely conjectural, but could be one of the longest known in Chondrichthyans (Serena 2000).|
Although there is no direct fishery for Giant Devilrays, high mortality rates are reported for this species from accidental takes in swordfish pelagic driftnets in the Mediterranean (Muñoz-Chàpuli et al. 1994), to unsustainable levels. Giant Devilrays are also accidentally captured in longlines, purse seines, trawls (Bauchot 1987), and fixed traditional tuna traps 'tonnare'. They are also occasionally caught as bycatch in the western central Ligurian Sea, where long line catches have been monitored since 1999, especially from the harbours of Imperia and Sanremo. Devilray bycatch in the Ligurian Sea is always discarded (Orsi Relini et al. 1999).
The extent of influence of Mediterranean habitat degradation on Giant Devilrays is unknown. Given their low position in the trophic web, high levels of contamination from organochlorine compounds or trace elements are unlikely. However, their epipelagic habits make devilrays particularly vulnerable to oil spills and to disturbance from high levels of maritime traffic.
The Giant Devilray is included in the Annex II 'List of endangered or threatened species' to the Protocol concerning Special Protected Areas and Biological Diversity in the Mediterranean of the Barcelona Convention, which came into force in 2001. Recent regional legislation (e.g., GFCM, ICCAT) has introduced new basin-wide banning of pelagic driftnets; if implemented, this would eliminate one of the most severe threats to the species.
Conservation actions recommended for the future are the incorporation of Mobula mobular into the nat. I legislation of the Contracting parties to the SPA Protocol to the Barcelona Convention and the implementation of this policy. The Ligurian Sea Cetacean Sanctuary could be an effective for this species against driftnets. Raising awareness with fishermen to maximise the live release of bycatch, after disentanglement, is also important.
|Citation:||Notarbartolo di Sciara, G., Serena, F. & Mancusi, C. 2006. Mobula mobular. The IUCN Red List of Threatened Species. Version 2014.2. <www.iucnredlist.org>. Downloaded on 02 October 2014.|