Pêches scientifiques. Peuplements de poissons des écosystèmes estuariens, lagunaires et continentaux d'Afrique de l'Ouest. v1.7. IRD - Institute of Research for Development. Occurrence Dataset

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A multimetric-index approach using fisheries data to assess fish assemblage structure in relation to salinity gradient in a tropical West African estuary

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

Impact d'une aire marine protégée sur les activités de pêche : l'exemple de l'AMP de Bamboung (Sénégal)

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The Bamboung Marine Protected Area(Sine Saloum, Senegal) Laboratory for field ecological studies in a tropical estuary

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The Bamboung Marine Protected Area(Sine Saloum, Senegal) Laboratory for field ecological studies in a tropical estuary

International audienceno abstrac

AMPHORE. Les Aires Marines Protégées, outil de conservation et de gestion des ressources halieutiques

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Étude du régime alimentaire de deux espèces de Cichlidae en situation contrastée dans un estuaire tropical inverse d'Afrique de l'Ouest (Casamance, Sénégal) Title: Study of the diet of two species of Cichlidae in contrasting situation in a West African (Casamance, Senegal) inverse tropical estuary

National audienceThe dam anti-salt of Maka was set up as 1998 on the river Casamance (Senegal) to restore the fresh water conditions for the benefit of the rice production activity of the local populations. It separates two environments of salinity contrasted: a downstream salted part under influence of the inverse estuary and an upstream part of fresh water. The comparative study of the diets of two Cichlidae Sarotherodon melanotheron heudelotii and Tilapia guineensis living on both sides on the anti-salt dam of Maka was made on the basis of samplings over three different periods in 2006 and 2007: a warm wet season (in October), a cold dry season (in February) and a warm dry season (in May). The diets of both species are approached by a classic method of analysis of the stomach contents by noting the occurrences of preys. Compared with the Ndour et al. (2011) J. Sci. Halieut. Aquat., 4: 120-133 121 populations of S. m. heudelotii and of T. guineensis who live upstream to the dam, those living downstream to the dam present more important occurrences of preys. S. m. heudelotii tends to ingest of advantage of plant fragments to the detriment of the mud when the salinity becomes high. On the other hand, T. guineensis who has a wider trophic spectrum, tends to consume more vase (bivalves) than of plant fragments, when the salinity increases. The comparison of the diets of this two Cichlidae on both sides of the dam, shows an evolution of their diets according to the environmental conditions