REPRODUCTIVE DYNAMICS OF BANANA PRAWN, PENAEUS MERGUIENSIS DE MAN FROM MAHARASHTRA COAST.

Reproductive dynamics of commercially important penaeid prawn Penaeus merguiensis was investigated in the coastal waters of Maharashtra during 2002-2003 by collecting data from inshore nearshore and offshore, waters. The size at maturity was 123 mm for males and 133 mm for females. The species spawned throughout the year with two spawning peaks, major one during March-May and minor during October-December and spawning area of the species is offshore waters >40 m depth. Ova diameter study showed tendency to shed all their eggs at one instance, but the progression of modal sizes of mature females demonstrated that females with spawning periodicity of 26±5.5 days could spawn about 12 times during their life span. The sex ratio showed that mainly large sized mature females migrate towards offshore deeper waters. Fecundity was exponentially related to length by F= 0.000000528*TL^5.2086. The population fecundity index in nearshore and offshore areas indicated two peaks with major spawning activity during March-April and minor during August-September. The egg production by the surviving population in the sea, gave major peak during April-May and a minor during November. The occurrence of juveniles in the catch was bimodal and their mean size declined twice in inshore, nearshore and offshore waters which pointed to two recruitment pulses in March and November in inshore waters and in March and December in nearshore and offshore waters. The percentage of juveniles was the highest in March which suggested that post-monsoon spawning in November was the most effective. The ratio of juveniles and the egg production gave annual survival rate of 0.03%. The monthly survival showed bimodal trend with peak in April (0.07%) and November (0.03%), which suggested that spawning during November-December and May-June was responsible for the two cohorts, the post-monsoon and pre-monsoon, among which the former was more successful. [ABSTRACT FROM AUTHOR]