Occurrences of Intersexual Hound Sharks, Iago cf. omanensis (Triakidae: Carcharhiniformes) from North-western Bay of Bengal

Abstract

Intersexual hound sharks, Iago cf. omanensis (Triakidae) were found in unusually large numbers from India coast, north-western Bay of Bengal. A total of 154 specimens were collected during August 2018 to July 2019 from Digha Mohana Fish Landing Centre (West Bengal, India) whose size ranged from 21.5 to 59.7 cm total length (TL) with a mean length of 40.06 ± 0.57 cm (Mean ± SE, n = 154). Out of these 154 samples, most of the specimens (94.77%, n = 145) exhibited uncalcified claspers, except a few which were having long, calcified claspers (5.22%, n = 8). Most of the sharks appeared to be male juveniles from external observations, but upon dissection it was noticed that all specimens except one were fully functional females with clearly visible ovaries, oviducal glands, oviducts, uteri and a few with pups. Only one specimen had male primary and secondary reproductive structures. The present study reports instance of hermaphroditism in large numbers in any shark population which is quite rare and unusual and therefore, necessitates a comprehensive and focused study to understand the reproductive strategy of the species.