International conference ICAWA 2017 and 2018 : extended book of abstract : the AWA project : ecosystem approach to the management of fisheries and the marine environment in West African waters

Sardinella aurita is an overexploited small pelagic fish and a key species in Senegal at socioeconomics level, nevertheless the growth parameters which is a good indicator of fish stressors, have not been updated since 30 years. In this work, we analysed S. aurita (n = 32 300) age and growth in Senegal taking into account the tropical seasonality. Growth parameters are then compared with those previously obtained in the literature on the same geographical area (since 60 to 34 years) and more widely in different locations in tropical North Atlantic and Mediterranean Sea. The results show a significant difference of growth parameters in Senegal since thirty years, indeed growth of S. aurita became slower and its maximum size has significantly decreased. The comparison of S. aurita variability in growth performance reported in Mauritania-Senegal coast, as well as in Mediterranean Sea and Eastern/Western Atlantic Ocean reveals a significant influence of environmental parameters and/or the level of exploitation. In one hand in tropical Atlantic, S. aurita growth in Eastern Central is similar to the one reported in Western Central, while S. aurita growth is rather slow in Mediterranean Sea where, vs tropical Atlantic, Sea temperature and prey availability are lower. On the other hand, in the Atlantic Western Central, where the fishing pressure on the stock is lower over the last decade vs Atlantic Eastern Central, an increase in asymptotic length is observed, while in the Mediterranean Sea and Atlantic Eastern Central, where the fishing pressure is higher, the asymptotic length has drastically decreased. We assume that the fishing pressure and the climate change, or a combination of both, have an effect on the biological parameters of S. aurita.