Seasonal fish species composition, catch rate and catch value in the small scale fishery of a tropical monsoon estuary along southwest coast of India

Abstract

Aim: The assessment of tropical coastal ecosystems involving small scale fisheries is a pre-requisite for fisheries management. With a total area of 39.9 km² Zuari estuary in Goa is one of the major estuaries located along the southwest coast of India and it holds a small scale fishery for the tribal fishermen residing along the coastal stretch of the estuary. The main objective of the study wasto analyse seasonal patterns in fish species composition, catch rates and catch value inthe small scale fishery of Zuari Methodology: Insitu fishing operations were carried out on monthly basis in Zuari estuary from September, 2013 to August, 2015 and fish and shellfish fauna collected during the study were identified to the family, genus and species levels. The data collected on the species assemblages were used to study the seasonal patterns in fish assemblages, catch rates (CPUE) and catch value (VPUE) in Zuari estuary. Results: Atotal of 68, 715 organisms weighing 13980.4 kg were caught in 288 fishing operations from 2013 to 2015 in Zuari estuary. Two hundred and thirteen species from 74 families were identified and 30 species contributed about 60-70% of the catch. Escualosa thoracata, Sardinella longiceps, Mugil cephalus, Tenualosa toli, Fenneropenaues indicus, Portunus pelagicus, Thryssa malabarica, Rastrelligerkanagurta, Nematalosa nasus and Metapenaeus dobsonii were the dominant species on the basis of relative importance index (RH). There were significant seasonal variations in abundance, species composition, catch rate (CPUE) and catch value (VPUE). There was seasonality in fish species composition and maximum species diversity was observed during pre-monsoon season. The ecologically vulnerable aquatic species contributed 20-25% of the total catch and it is inferred that the estuary has a greater role in protecting these species. Interpretation: Small scale gillnet fishery of the estuary is analysed and documented in this study. The seasonal patterns in fish species composition catch rate and catch value are essential requirements for designing fisheries management. The present study gives insights formulate fisheries management actions to monitor and protect the fisheries resources of the estuary to ensure sustainable fisheries.