The reproductive biology of Secutor insidiator (N=1546) was studied from samples collected along Kerala during October 1998-December 1999. A separate scale of five stages of maturity has been developed. Analysis of data on the ova of different stages of maturation in different length groups and months showed that spawning takes place in batches regularly at intervals after the juveniles undergo the process of maturation and reach ripe stage. The length at first maturity was estimated at 75 mm. This species has a protracted spawning season extending almost throughout the year.

Maturity stages, silverbellies, length at maturity, spawning, fecundity, gonadosomatic index