Reproductive strategy of six species of gammarid amphipods namely Maera othonides, Photis digitata, Corophium triaenonyx, Orchestia platensis, Quadrevisio bengalensis and Gandidierella gilesi covering aspects like sex ratio, fecundity, reproductive cycle and brood mortality were studied during October 1997 to September 1998. There was a preponderance of females over males all through the year and the sex ratio in all the species deviated significantly from the expected 1:l ratio. Breeding activity was continuous in M. othonides and P. digitata. While C. triaenonyx was found to breed twice in an year, 0. platensis, Q. bengalensis and G. gilesi were found to breed only once in a year. Brood mortality was found to be high during the monsoon months. The study pertained to the amphipods from Vellar Estuary and Killai Backwaters. 

Reproductive strategy, amphipods