Preliminary Yield Assessment for Yellowfin and Skipjack Tuna Stocks Exploited by Sri Lanka's Coastal and Offishore Fleets

Abstract

This preliminary assessment utilised monthly catch and fishing effort data available for 1994. Estimates were made for the biomass recruiting to the fishery in each month. These were in turn used within a Thompson and Bell type fishery model, to obtain predictions of the catches likely to result from increased fishing effort. The findings suggest that considerable scope exists to increase the catches of both yellowfin and skipjak. It was necessary to make assumptions concerning the number of zero age recruits, and the proportion ofthese subsequently entering the Sri Lankan fishery. The associated sensitivity analyses showed that the findings are only marginally affected by deviations from the assumptions.