Incidence of pregnant endangered devil rays (Elasmobranchii: Mobulidae) from the Gulf of Mannar and Palk Bay, southeast coast of India

Out of the nine valid extant mobulid species confirmed globally, seven have been reported in India.All mobulids are vulnerable due to anthropogenic pressure, i.e. commercial fisheries, for their gill plates, which are traded on the international market.Information on their reproductive biology including, the seasons of mating, pupping, and nursery grounds are still largely unknown from Indian waters.The present study reports the occurrence of pregnant endangered devil rays, longhorned pygmy devil ray Mobula eregoodoo, oceanic manta ray Mobula birostris and Bentfin devil ray Mobula thurstoni in Indian waters, off the southeast coast.All three species were observed to have a single pup each.Our observations of mobulid catch from 2020 to 2022 indicates a predictable occurrence of pregnant devil rays either for feeding or for pupping (July to November), with a peak during November in the Gulf of Mannar and Palk Bay.The size-atbirth was in the order of 33.3 cm disc width (DW), 125.8 cm DW and 40.5-60.5 cm DW for M. eregoodoo, M. birostris and M. thurstoni respectively.Mobula thurstoni chiefly consumed needle squid and Acetes spp., while the gut contents of the other two species were completely digested.The observations on M. thurstoni suggests a pupping/nursery/feeding ground off the Gulf of Mannar, probably assist to develop area-based management interventions.