Population dynamics and stock assessment of Ethmalosa fimbriata in Senegal call for fishing regulation measures

Small pelagic fish occupy a significant component of the food supply in West Africa and are vitally important for the nutritional needs of local people. The bonga shad (Ethmalosa fimbriata Bowdich, 1825) is the third most-exploited of the small pelagic species fished from coastal waters of Senegal (after Sardinella aurita and S. maderensis) and is routinely consumed by Senegalese people. Bonga shad fishing is practised mainly by artisanal fishermen and of great importance to the Senegalese economy and food security in the region. Our study was designed to examine population dynamics of bonga shad to support the development of fishery management options that may improve the livelihoods of artisanal fishermen. The current rate of exploitation (E=0.8) suggests that the bonga shad in Senegal is over-fished. In addition, we describe seasonal variability in recruitment and biomass of bonga shad along the Senegal coast, its downward trend in landings over a 17-y study period, and its decline (18%) in maximum size over a 63-y period. We attribute the declines to an increase in fishing pressure and/or changes in local climate. To reverse the effects of overexploitation of the bonga shad stock, it will be necessary to drastically reduce fishing effort, apply and enforce regulatory restrictions on the capture, sale and processing of juveniles, and prohibit seiners and monofilament nets in the fishery.