Female size at maturity is unknown.The smallest pregnant female recorded was 236 cm disc width but large eggs have been observed in females as small as 207 cm disc width.įemales give birth to a single pup. Males mature around 198-205 cm disc width (wing tip-to-wing tip). In the Gulf of California birth occurs in the spring, with mating occurring in late spring and summer on the feeding grounds. No sex segregation has been observed, however segregation by size does occur. In the southern Gulf of California males tend to dominate during spring, and females dominate over the summer. Little is known of the biology of spine-tailed devil rays in New Zealand waters. Seasonal movements in the southern Gulf of California (subtropics) appear to be related to the abundance of krill. Spine-tailed devil rays feed mainly on krill (euphausiids), but will also eat copepods, hyperiid amphipods, crustacean larvae and small fishes. Fishery data suggests this is probably the most abundant mobulid ray in the western Central Pacific and Indo-Pacific regions. There is no information on population trends in New Zealand waters. Their movements may be similar to those of skipjack tuna, with which they are often associated. It is not known where the spine-tailed devil rays observed off northern New Zealand originate from. In the Gulf of California it is regularly caught in bottom-set gill nets and has been observed feeding close to shore in water less than 1 m deep. In subtropical and tropical regions this species is usually found in shallow coastal waters. Tuna spotter plane pilots report it is one of the most abundant large pelagic species encountered offshore during summer. In New Zealand waters this species is usually encountered at or near the surface in the open ocean beyond the edge of the continental shelf (deeper than 200 m). It is reported to at least 38 oS off the east and west coasts of the North Island.ĭevil rays are pelagic, occurring in shallow water close to shore as well as in the open ocean. The spine-tailed devil ray is probably found worldwide in tropical and warm temperate waters. mobular but the spiracle is sub-circular and located below the leading edge of the disc, and the outer half of the underside of the wing is silver with a large dark blotch near the posterior margin (pure white in M. thurstoni has a white tip to the dorsal fin similar to M. kuhlii the slit-like spiracle is located beneath the leading edge of the dorsal fin compared to above it in M. tarapacana also lack a white tip to the dorsal fin. tarapacana) and the bentfin devil ray ( M. Other devil rays occurring in the Indo-Pacific region include the lesser devil ray ( Mobula kuhlii), sicklefin devil ray ( M.
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