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 were studied. Larvae and postlarvae of commercially
important species viz. Metapenaeus dobsoni (Miers),M.affinis (H.Milne Edwards). M. monoceros
(Fabricius), Penaeus merguiensis de Man 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 penaeid prawn larvae
for aquaculture is indicated