S. M. Nurul Amin
University Putra Malaysia, Malaysia
Title: Biological characterization of planktonic Shrimp, Acetes spp. for stock management and aquaculture
Biography
Biography: S. M. Nurul Amin
Abstract
Taxonomic characteristics, reproductive biology, food habits, population parameters like growth, mortality, exploitation status of the stock of planktonic shrimp Acetes spp, in coastal waters of Klebang Besar, Malacca, Malaysia were examined between February 2005 and March 2007. A total of three species of planktonic shrimp’s viz A. indicus, A. japonicus and A. intermedius were identified from the investigated area. It is found that sex ratio of A. indicus and A. japonicus was in favor of females. Gonadosomatic index (GSI) confirmed the continuously breeding of A. indicus and A. japonicus during the study period. Estimated mean fecundity of A. indicus was 1666.28 (±46.32) eggs. The mean monthly GSI of A. indicus proved positive significant (P<0.05) correlation with conductivity (r=0.67), salinity (r=0.65) and TSS (r=0.59)). Diverse compositions of food items in the gut contents revealed that the two shrimps were bottom feeder omnivore. Catch per unit effort (CPUE) of the estuarine push net (EPN) was found at 2.50 (±3.42) kg/fisherman/hr. Higher natural mortalities of male A. indicus and A. japonicus versus the fishing mortalities observed from the study indicated the unbalance position in the stock. Two major recruitment events per year where two cohorts were produced per year for A. indicus and A. japonicus populations. Estimated exploitation rate (E) based on the fishing mortality, indicates that the Acetes japonicus fishery is over exploited although A. indicus and A. intermedius fishery were slightly below the optimum level of exploitation. This implies that any further unrestrained increase in fishing effort might overshoot the level giving maximum sustainable yield, thus driving the stock down and leading to economic losses. Nowadays, Acetes wet tissue suspensions are being successfully used as food for all stages in the hatchery. It is also used as live food for brood stock management. Thus, Acetes as a food organism may play an important role in aquaculture.