Seasonal variability in penaeid prawn larval abundance in the Mandovi and Zuari estuaries, Goa

Abstract

Seasonal variations in the occurrence and abundance of penaeid prawn larvae in the Mandovi and Zuari estuaries of Goa, India were studied. Larvae and postlarvae of commercially important species viz. Metapenaeus dobsoni (Miers), M. affinis (H. Milne Edwards). M. monoceros (Fabricius), Penaeus merguiensis de Mana and Parapenaeopsis stylifera (H. Milne Edwards) were recorded in that order of abundance. Protozoea and mysis stages were dominant in surface zooplankton collections while the postlarvae were more in the bottom samples. Based on larval density, M. dobsoni appeared to be a continuous breeder. The active spawning periods in other species were during the late postmonsoon and premonsoon seasons varying with the species. Peak recruitment of postlarvae in the estuaries was observed mostly during southwest monsoon months (June to September). Penaeid prawn larval ingression was more in the Zuari Estuary compared to the Mandovi Estuary. Their numerical abundance gradually decreased towards the upstream areas. The feasibility of large scale collection of peanaeid prawn larvae for aquaculture is indicated.