Kantoussan J. auteur aut IRD Ecoutin Jean-Marc auteur aut IRD Laë Raymond auteur aut IRD Thiaw O. T. auteur aut IRD Tito de Morais Luis auteur aut IRD text journalArticle eng text/pdf born digital access This study examines the effects of increasing salinity on fish assemblage structure in the Casamance Estuary, Senegal. using a series of indices. The study data were derived from commercial fishery surveys conducted between April and July 2005. Analysis of within-trophic-group diversity in the Casamance Estuary shows a significant drop in the diversity of apex predators in the upper. more saline reaches of the estuary. By contrast. primary consumers adapted well to salinity changes and exhibited higher taxonomic diversity in the upper reaches of the estuary than in the lower reaches. The findings also indicate decreases in average sizes of the landed species and the trophic levels among fish catches in the direction of the upper reaches. However, the catch per unit effort (CPUE) was globally higher in the upstream area of the estuary as compared with the downstream area. This increasing CPUE trend from the lower towards the upper reaches is attributed to (i) the high primary productivity in the upper Casamance Estuary; (ii) the increasing abundance of euryhaline fish species in an upstream direction: and (iii) 'telescoping' of the food chain through the presence of mostly herbivorous fishes in the upper reaches. Such a situation likely facilitated high fish production in the upstream area of the estuary, though multimetric indices indicated unfavourable living conditions for many fish taxa in this area. specialized biological indicators Casamance Estuary ecosystem monitoring fishery statistics inverse hypersaline estuary Senegal taxonomic diversity SENEGAL AFRIQUE DE L'OUEST ZONE TROPICALE 040 036 40 2 175-185 2018 1814-232X https://www.documentation.ird.fr/hor/fdi:010073214 10.2989/1814232x.2018.1474802 1814-232X [F B010073214] https://www.documentation.ird.fr/hor/fdi:010073214 https://www.documentation.ird.fr/intranet/publi/2018/07/010073214.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2018-09-03 2023-07-11 fdi:010073214 fre