Polydactylus sextarius

Polydactylus sextarius is a small- to medium-sized threadfin which attains a maximum total length of but is more common. ==Distribution==

Polydactylus sextarius is found in the Eastern Indian Ocean and Western Pacific. Its range extends from southwestern India to Papua New Guinea, north to Japan. It is rare in the Philippines, eastern Indonesia, and Papua New Guinea. ==Habitat and biology==

Polydactylus sextarius is found where there are sandy and muddy bottoms on the continental shelf and it appears to favour depths of . This carnivorous species has its diet dominated by shrimps of less than length and amphipods but it has also been recorded feeding on crabs, mysids, fishes and polychaetes. Sampling of the population in the Bay of Bengal off India found that a large proportion of the fish are hermaphrodites and that these fell within the range of standard length of , with a smaller proportion of females with standard lengths of between . The hermaphrodites with comparatively large testes were counted as mature males and these measured standard length) while the fish with granulated ova of diameter were considered to be mature females and these fell within the standard length range of . The species undergoes a protandrous sex change starting as juveniles, becoming hermaphrodites and ending as females progression. They first reach sexual maturity as hermaphrodites which function as males and there is no evidence which suggests that females develop directly from juveniles. ==Fisheries==

Polydactyus sextarius is an important species for commercial fisheries in the Bay of Bengal and off Thailand where it is caught using trawls. ==Species description==

Polydactylus sextarius was first formally described as Polynemus sextarius in 1801 by Marcus Elieser Bloch and John Gottlob Schneider with the type locality given as Tranquebar in India. ==References==