Virtual population analysis and estimates of maximum sustainable yield of some commercially important fish species in the coastal waters of Ghana and management implications
Samuel KK Amponsah, Patrick K Ofori-Danson, Francis KE Nunoo, Godfred Ameyaw
Virtual Population Analysis (VPA) was carried out to evaluate maximum sustainable yield (MSY) and the recruitment status for three commercially important fish species, particularly, Brachydeuterus auritus,Scomber japonicus, and Engraulis encrasicolus in response to the alarming rate of decline in annual catches. For this purpose, length frequency data was obtained from fish landing sampling sites along the eastern coast of Ghana from June 2014 to January 2015. Obtained data was measured for standard length and subjected to analysis using FISAT II. The outcome of VPA was applied in the estimation of maximum sustainable yield (MSY) for the three targeted fish species. VPA outcome revealed the strong existence of recruitment within the population of the assessed fish stocks. Further, small-sized fishes experienced higher harvesting rate, a proxy for growth overfishing. Estimated MSY for Brachydeuterus auritus, Scomber japonicus, and Engraulis encrasicolus were 4946.84 tons, 3085.35 tons and 4803.91 tons respectively. The estimated MSY values were lower than annual fish landings for 2014. Results indicated that the assessed fish species were not only plagued with unsustainable fishing pressure and growth overfishing, but vulnerable to recruitment overfishing in the future. In the absence of urgent management measures, the perceived collapse of targeted fish species will worsen food insecurity in vulnerable fishing households in Ghana. To sustainably maintain the fisheries of the assessed fish stocks, mesh sizes should be increased, implemented and enforced.
Samuel KK Amponsah, Patrick K Ofori-Danson, Francis KE Nunoo, Godfred Ameyaw. Virtual population analysis and estimates of maximum sustainable yield of some commercially important fish species in the coastal waters of Ghana and management implications. International Journal of Fisheries and Aquatic Research, Volume 2, Issue 3, 2017, Pages 01-07