TEMPORAL DISTRIBUTION AND ABUNDANCE OF SHRIMP POSTLARVAE AND JUVENILES IN THE MANGROVES OF MUTHUPET, TAMILNADU, INDIA

The temporal distribution patterns of the predominantly occurring post larvae and juvenile shrimps in the mangrove and associated habitats of Muthupet, India were investigated for two years from February 1984 to January 1986. Among the eight commercially important species recorded , Penaeus indicus H. Milne Edwards, P. merguiensis De Man, P. monodon Fabricus and Metapenaeus dobsoni (Miers) were predominant. The postlar val recruitment size varied with species: P. indicus and P. merguiensi s recruited at the size of 9-11 mm total length (TL), P. monodon at 12 -14 mm TL and M. dobsoni at 4-6 mm TL. The species P. indicus, P. merg uiensis and M. dobsoni were observed continuously throughout the study period with maximum abundance occurring from July to September in 198 4-85 and from August through October in 1985-86. P. monodon occurred s easonally from November to January in both years. Postlarvae and juven ile catches were low during low salinity and high salinity periods and a higher density was observed in the months of moderate water salinit y. Large numbers of P. indicus, P. merguiensis and M. dobsoni clearly showed the preference to the detritus rich muddy substrate, whereas P. monodon did not show any preference and was equally abundant over dif ferent substrate types.