Dynamics and potential of commercially harvested shrimps by estuarine set bagnet in the Indus River estuary, Sindh, Pakistan

Abstract

In this study, periodic changes of population dynamics of high valued shrimp species Exopalaemon styliferus (112), Metapenaeus monoceros (265), Parapenaeopsis stylifera (688) collected from September 2017 to April 2018 by Estuarine Set Bagnet are discussed. High linearity (>0.8) among parameters was estimated by fitting a liner model and a negative allometric growth pattern in E. styliferus, P. stylifera and slight positive growth was calculated for M. monoceros. A moderate growth rate for E. styliferus whereas fast growth rate for M. monoceros and P. stylifera was calculated by applying von Bertalanffy model. Higher natural mortalities (M) for E. styliferus and M. monoceros and fishing mortalities for P. stylifera was estimated. Biological reference points or Fishing limitations (Flimitation) for three species was beyond proposed limit of exploitation rate of 0.5 indicates that resource have been reached maximum sustainable yield. A persistent recruitment pattern for three species recorded with prominent peaks (82% in June-July) for E. styliferus, (70% June-October for M. Monoceros and (47% April-May) estimated for P. stylifera. Based on the data it is recommended that use of Estuarine Set Bagnet ESBN should be banned especially in the Indus River Estuary IRE and it is hoped that data can be used for shrimp fishery management in Pakistan.