Report of the ad hoc working group on the coastal pelagic stocks of the western Gulf of Guinea

Report of the ad hoc working group on the coastal pelagic stocks of the western Gulf of Guinea

Descripción

The objective of the working group was to update the statistics on the stocks of small pelagic fishes in the western Gulf of Guinea (Côte d'Ivoire, Ghana, Togo, Benin), refine the data, acquire a better understanding of the biology of the species and identify methods for a better evaluation of the stocks. The four species of concern to the Working Group were: Sardinella aurita, S.maderensis, Scomber japonicus and Engraulis encrasicolus. The sensitivity of coastal pelagic species to environ mental factors was emphasized and upwellings, discharge of coastal rivers into the sea, coastal currents, winds were related to the fisheries. The fisheries were described and in addition to the analysis of catch and CPUE data, a time-space analysis of catch statistics, yield and length frequencies were carried out, particularly for S. aurita and S.maderensis. The Working Group reviewed the biological data available and the hypotheses already put forward on the nature of the stocks of the differ ent species. Stocks assessments were based on CPUE and length frequencies data. The Working Group concluded that the recent modification of the productivity of the ecosystem was favourable to the fisheries and high catch rates and CPUE of Sardinella aurita show that the related stock (or stocks) are recovering. The Working Group recommended to pursue the study of relevant physical and oceanographical factors, to strengthen statistics, biology and data processing. Multivariate analysis were al so recommended to establish for the principal species, the typology of strata defined by fishing zone-month-gear within which reliable abundance index should be calculated.