Juvenile fish assemblages in the creeks of the Gambia Estuary

Abstract

A fyke net survey of the juvenile and small fish assemblage of the Gambia estuary was conducted on three sampling occasions during the maximum recruitment season, from May to November 2002. This is the first detailed description of that particular component of the fish community in the Gambia estuary. The overall fyke net fish assemblage comprised 51 species, with a majority of young individuals of large and medium size species and the adults of small species. This assemblage is defined as the "small fish component of the mangrove channels". The assemblage is dominated by true estuarine and certain marine species, all able to complete their life cycle within the estuary. The sea spawning species whose juveniles use the estuary mainly as a nursery ground, are not very diverse or abundant during the recruitment season. They are limited to the lowest part of the estuary due to the low salinity prevailing in the middle and upper reaches during the rainy season. This suggests that extreme seasonal variability (river flooding) in certain West African tropical estuaries at the time of maximum recruitment by certain marine species may reduce the nursery ground value for these taxa.

Seasonal changes in water quality and fisheries of Tanbi Wetland National Park

“…The total number of fish species (43) caught during this research resemble findings of Vidy et al, (2004) who reported a total of 47 fish species from 26 families within the creeks of the River Gambia estuary, similar to the 43 species and 25 families caught during this research in TWNP. This is considerable, given the small size of the current study site and its location within a highly populated area.…”

“…Being a nursery ground closest to the Atlantic coast of The Gambia, it is noteworthy that the current fish assemblage of this area is less than in past predictions for the River Gambia estuary both in abundance and biomass (see Albaret et al, 2004;Vidy et al, 2004;Simier et al, 2006;White et al, 2012). The implications of these changes on the daily catches/CPUE of the local fisherman are important, since they are used to fishing for estuarine species.…”

“…The decline in rainfall following the Sahelian drought in the 1970s, combined with increasing demand for economic goods and services have led to major ecological changes in West African mangrove estuaries (Vidy et al 2004), which have not been well documented yet. Hence, there is a great need to fill this information gap for countries such as The Gambia, where mangrove estuaries support the three major economic sectors (Fisheries, Agriculture and Tourism) (National Environment Agency, 2010).…”

“…African mangrove estuaries such as the inverse estuary of Sine Saloum in Senegal (Albaret et al, 2004), (Panfili et al, 2004), (Vidy et al, 2004) and the highly polluted estuary of Bietri in Ivory Coast (Hayé Claire et al, 2009). was argued to be its low salinity gradient (from freshwater conditions upstream to marine conditions, 39ppt) downstream (Simier et al, 2006).…”

Seasonal composition, abundance and biomass of the subestuarine fish assemblage in Solís Chico (Río de la Plata estuary, Uruguay)

“…Finally, the little abundant G. barbus, M. americanus and P. cromis are species widely cited in the Río de la Plata estuary, where they develop their life cycles. Estuaries are essential areas for reproduction and nursery of larvae and juvenile fishes (Whitfield, 1999;Beck et al, 2001;Vidy et al, 2004). Regarding the length structure of the collected fish assemblage, a large representation by juvenile stages was observed, mainly captured by the beach seine net.…”