Category : Featured Elasmobranch
Sicklefin devil ray
Identification: Head extends anteriorly past the disc, and with short horn-like projections; mouth located on ventral surface of head and contains pitted, tessellated teeth; branchial filter plates are fused. Pectoral fins large and triangular, anterior margin straight, posterior margin falcate. A thin tail that is shorter than the disc width and with no spine. Dorsal surface covered with denticles. Coloration is greenish brown dorsally; ventral surface is smooth, white anteriorly white, posteriorly grey.
Size: This mobulid reaches a length of up to 370 cm disc width (DW). Male sexual maturity is 240-250 cm DW, and female sexual maturity is 270-280 cm DW. Size at birth is greater than 150 cm.
Distribution: Known only from scattered locations throughout the Atlantic, Pacific, and Indian Oceans, but mostly in tropical and temperate waters.
Habitat: This species is found mostly oceanic waters deeper than 200 m, but may also inhabit coastal waters.
Biology: Reproduction is yolk-sac viviparity, with one pup per litter. Age at maturity, longevity, gestation time, and reproductive periodicity are unknown. Mature females have been found in the southern Gulf of California during the summer and fall months. This species is often solitary but has been known to form small groups. The diet of this species ranges from small fishes to planktonic fish eggs and copepods, which potentially could be accidently ingested while swimming.
General Interest: Mobula tarapacana is considered data deficient on the IUCN Red List, however, its low fecundity may make it a vulnerable species. Though M. tarapacana has a limited threat from coastal fisheries, it is vulnerable to pelagic forms of fishing, such as gill nets and longlines. Longlines in particular may be a threat to this species because of the species’ propensity for fishes as prey. In Indonesia, mobulid catches are increasing because of the high value of gill rakers in the medical market in Asian countries. Additionally, in the off-season of shark fishing, mobulids are being targeted for human consumption and as bait for other fishing methods. Catch rates are low in the Gulf of California and in the Philippines, where a ban on fishing for manta rays is in place.
By: Melissa Nehmens