Assessing Demersal Fish Stocks: A Length-Based Bayesian Biomass Estimation Approach on the North-West Coast of India

The north-west coast of India along the north-eastern Arabian Sea is the most productive zone along the Indian coastline owing to its wide continental shelf area and perennial productivity. The region is known for its rich multi-species demersal resources and dominance of trawl-based marine capture fisheries. Length-based Bayesian Biomass estimation (LBB) approach provides a potent tool for assessment of data deficient tropical multi-species fisheries where the time series catch and effort data are either not reliable or poorly resolved up to species level. The present study assesses the stock status of five commercially important demersal fish stocks, having varying population and life history traits to give insights in to the well-being of the demersal fishery of the region. The results obtained from the LBB analysis showed B/B₀ value in the range of 0.23 to 0.42, whereas B/B_MSY ranged between 0.62 and 1.10. Though four of the stocks were found to be overfished, the population trend for these four stocks showed an increasing trend, which is supported by the recent diversion of bottom trawl effort towards pelagic trawling. These stocks are expected to perform better in coming years if the present diversion of trawl efforts towards upper water column persists.