Data/hora: 09/06/2024 13:37:35

Provedor de dados: | 5
País: | France
Título: | A multimetric-index approach using fisheries data to assess fish assemblage structure in relation to salinity gradient in a tropical West African estuary
Autores: | Kantoussan, J.; Ecoutin, J. M.; Lae, R.; Thiaw, O. T.; Tito De Morais, L.
Data: | 2018
Ano: | 2018
Palavras-chave: | Biological indicators; Casamance Estuary; Ecosystem monitoring; Fishery statistics; Inverse hypersaline estuary; Senegal; Taxonomic diversity.
Resumo: | 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.
Tipo: | Text
Idioma: | Inglês

Identificador:

https://archimer.ifremer.fr/doc/00451/56222/57945.pdf

DOI:10.2989/1814232X.2018.1474802

https://archimer.ifremer.fr/doc/00451/56222/

Editor: | Natl Inquiry Services Centre Pty Ltd
Formato: | application/pdf
Fonte: | African Journal Of Marine Science (1814-232X) (Natl Inquiry Services Centre Pty Ltd), 2018 , Vol. 40 , N. 2 , P. 175-185

Fonte:

NISC (Pty) Ltd

info:eu-repo/semantics/openAccess

restricted use