Bentfin devil ray


The bentfin devil ray, also known as the lesser devil ray, smoothtail devil ray, smoothtail mobula or Thurston's devil ray, is a species of ray in the family Mobulidae. It is found worldwide in tropical, subtropical and warm temperate oceans, with records from Australia, Brazil, Chile, Costa Rica, Ecuador, Egypt, El Salvador, Eritrea, Guatemala, Honduras, India, Indonesia, Ivory Coast, Japan, Malaysia, Maldives, Mexico, Myanmar, Nicaragua, Oman, Pakistan, Peru, the Philippines, Saudi Arabia, Senegal, South Africa, Sri Lanka, Thailand, United Arab Emirates, United States, Uruguay and Vanuatu. It likely occurs in many other locations in tropical, subtropical and warm temperate oceans. It is found both offshore and near the coast.

Description

The bentfin devil ray can reach a disc width of and weigh about. The length of the disc is about 1.95 times its width. The front edge of the disc is nearly straight near the snout, but curves sinuously as it approaches the broad, triangular pectoral fins. The back edge is concave, becoming straight as it approaches the tail. On either side of the snout are cephalic flaps, and the mouth is on the underside of the head. The dorsal fin is about 80% as high as it is long. The length of the tail is between half the disc width and the whole disc width, and the tail does not bear a spine. The upper surface of this ray varies from dark grey to olive-grey, and the under surface is white. The rear of the tip of the pectoral fins is black and the front edge of these fins is white, as is the tip of the dorsal fin.

Distribution and habitat

This species is probably circumglobal, and has been recorded from tropical and sub-tropical waters in the Atlantic Ocean, the Indian Ocean and the Pacific Ocean. In inshore waters it is mainly pelagic, seldom going as deep as.

Ecology

Like other closely related species, the bentfin devil ray feeds on plankton. Water is funnelled into its mouth as it swims and planktonic particles are filtered out as the water leaves through the gill rakers. In the Gulf of California, the commonest item in the diet is Nyctiphanes simplex, a species of krill, but this fish also feeds seasonally on opossum shrimps.

Status

M. thurstoni is a large fish with a high age at maturity and a low fecundity rate, producing as it does a single pup at a time. Although it has a wide range, it is targeted by fisheries in some regions and is caught as bycatch in gill nets and by trawling in others. There are reports of landings in Indonesia, the Philippines, Mexico and Brazil, and it is likely that it is landed in other places as well; it is probably caught in West Africa and also in eastern Asia, where the gill rakers are valued as well as the flesh. The population trend is unknown but the fish is reported as being uncommon. For these reasons, the International Union for Conservation of Nature has rated its conservation status as being "endangered".