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Fish diversity and distribution in the Gambia Estuary, West Africa, in relation to environmental variables

Published online by Cambridge University Press:  15 March 2004

Jean-Jacques Albaret*
Affiliation:
IRD, BP 1386, Dakar, Senegal
Monique Simier
Affiliation:
IRD, Centre de Recherche Halieutique Méditerranéenne et Tropicale, avenue Jean Monnet, BP 171, 34203 Sète Cedex, France
Famara Sambou Darboe
Affiliation:
Department of Fisheries, 6, Col. Muammar Ghaddafi Avenue, Banjul, The Gambia
Jean-Marc Ecoutin
Affiliation:
IRD, BP 1386, Dakar, Senegal
Jean Raffray
Affiliation:
IRD, BP 1386, Dakar, Senegal
Luis Tito de Morais
Affiliation:
IRD, BP 1386, Dakar, Senegal
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Abstract

The Gambia Estuary, a “normal” estuary with a decreasing salinity gradient from the mouth towards the head, is moderately exploited by small-scale fisheries and does not receive any severe pollution from either agriculture or industrial activities. Neither the Gambia River nor its estuary are artificially impounded. As the last large West African estuary free of major human disturbance, it is of considerable interest for comparative studies on the effect of major environmental perturbations in West African estuarine ecosystems. The aquatic environment and fish communities of the Gambia Estuary (about 250 km long) were studied by purse seine sampling at different periods in the river cycle, covering all hydro-climatic seasons that are characteristic of West African estuaries. Emphasis was placed on the diversity, composition, structure and distribution of fish assemblages in relation to fluctuations in physico-chemical factors such as water temperature, salinity and turbidity. Results on the aquatic environment, mainly the salinity range (from freshwater to 39) and dissolved oxygen (never a limiting factor for fish in the estuary) and on the main characteristics of the fish fauna (high diversity of life cycles, all the ecological categories represented) indicated that the Gambia Estuary was free of major climatic perturbation and reinforced the choice of this system as a reference for the study of the effects of major perturbations on estuarine tropical fish communities.

Type
Research Article
Copyright
© EDP Sciences, IFREMER, IRD, 2004

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References

Albaret, J.J., 1987, Les peuplements de poissons de la Casamance (Sénégal) en période de sécheresse. Rev. Hydrobiol. Trop. 20, 291-310.
Albaret J.J., 1994, Les poissons : biologie et peuplements. In: Durand J.R., Dufour P., Guiral D., Zabi S.G. (Eds.), Environnement et ressources aquatiques de Côte d'Ivoire. Tome 2. Les milieux lagunaires. ORSTOM, Paris, pp. 239-279.
Albaret J.J., 1999, Les peuplements des estuaires et des lagunes. In: Lévêque C., Paugy D. (Eds.), Les poissons des eaux continentales africaines : diversité, biologie, écologie et utilisation par l'homme. Éditions de l'IRD, Paris, pp. 325-349.
Albaret J.J., Diouf P.S., 1994, Diversité des poissons des lagunes et des estuaires ouest-africains. In: Teugels G.G., Guegan J.F., Albaret J.J. (Eds.), Biological Diversity in African Fresh and Brackish Water. Geographical overviews. Ann. Museum R. Afr. Centr. Zool. 165-177.
Baran E., 1995, Dynamique spatio-temporelle des peuplements de poisons estuariens en Guinée. Relations avec le milieu abiotique. Thèses et Documents microfiches No. 142, ORSTOM, Paris.
Berry T.D., Moll R.A., Krausse G.L., 1985, Physical and chemical environment of the Gambia River, West Africa, 1983-1984. Report No. 9, Great lakes and Marine waters center international programs, The University of Michigan, Ann Arbor, Michigan, p. 202.
Blaber, S.J.M., 1981, The zoological affinities of estuarine fishes in South-East Africa. S. Afr. J. Sci. 77, 305-307.
Blaber S.J.M., Albaret J.J., Chong Ving Ching, et al. 2000, Effects of fishing on the structure and functioning of estuarine and nearshore ecosystems. ICES J. Mar. Sci. 57, 590-602.
Blaber S.J.M., 2000, Tropical Estuarine Fishes. Ecology, Exploitation and Conservation. Fish and Aquatic Resources Ser. 7, Blackwell Science.
Cleveland, W.S., 1979, Robust locally weighted regression and smoothing scatterplots. J. Am. Statist. Assoc. 74, 829-836. CrossRef
Daget J., 1960, La faune ichtyologique du bassin de la Gambie. Bull. IFAN 22, No. 2, 610-619.
Diouf P.S., 1996, Les peuplements de poissons des milieux estuariens d'Afrique de l'Ouest : l'exemple de l'estuaire hyperhalin du Sine-Saloum. Thèses et Documents microfiches No. 156, ORSTOM, Paris.
Dorr J.A., Schneeberger P.J., Tin H.T., Flath L.E., 1985, Studies on adult, juvenile, and larval fish of the Gambian River, West Africa, 1983-1984. Report No. 11, Great Lakes and Marine Waters Center international programs, The University of Michigan, Ann Arbor, Michigan.
Gray J.S., 2001, Marine diversity paradigms: the patterns of species richness examined. Sci. Mar. 65 (suppl. 2), 41-56.
Guillard, J., Albaret, J.J., Sow, I., Simier, M., Raffray, J., Tito de Morais, L., 2004, Spatio-temporal variability of fish assemblages in the Gambia Estuary (West Africa) observed by two vertical hydroacoustic methods: moored and mobile sampling. Aquat. Living Resour. 17, 47-55. CrossRef
Laë, R, Ecoutin, J.M., Mendy, A., Raffray, J., Weigel, J.Y., Sadio, O., Djobe, O., 2004, Effects of a targeted shrimp (Penaeus notialis) exploitation on fish catches in the Gambia estuary. Aquat. Living Resour. 17, 75-85. CrossRef
Lamagat J.P., Albergel J., Bouchez J.M., Descroix L., 1990, Monographie hydrologique du fleuve Gambie. ORSTOM; Organisation pour la Mise en Valeur du fleuve Gambie (OMVG), Dakar, Sénégal.
Lesack, L.F.W., 1986, Estimates of catch and potential for the riverine artisanal fishery in the Gambia, West Africa. J. Fish Biol. 28, 679-700. CrossRef
Lesack, L.F.W., Hecky, R.E., Melack, J.M., 1984, Transport of carbon, nitrogen, phosphorus and major solutes in the Gambia River. West Africa. Limnol. Oceanogr. 29, 816-830. CrossRef
Michel P., 1963, Les bassins des fleuves Sénégal et Gambie. Étude géomorphologique. Paris, Mémoires ORSTOM No. 63.
Panikkar, N.K., 1960, Physiological aspects of adaptation to estuarine conditions. Australian Fisheries Council Proceedings 32, 168-175.
Por, F.D., 1972, Hydrobiological notes on the high-salinity waters of the Sinai Peninsula. Mar. Biol. 14, 111-119. CrossRef
Savenije, H.H.G., Pagès, J., 1992, Hypersalinity: adramatic change in the hydrology of Sahelian estuaries. J. Hydrol. 135, 157-174. CrossRef
Scherrer B., 1984, Biostatistique. In G. Morin (Ed.), Montréal, Paris.
Vidy G., Darboe F.S., Mbye E.M., 2004, Juveniles fish assemblages in the creeks of the Gambia Estuary. Aquat. Living Resour., 17, 56-64.
Whitfield, A.K., 1994a, Fish species diversity in Southern African estuarine systems: an evolutionary perspective. Env. Biol. Fishes 40, 37-48. CrossRef
Whitfield A.K., 1994b, A review of ichthyofaunal biodiversity in Southern African estuarine systems. In: Teugels G.G., Guégan J.F., Albaret J.J. (Eds.), Diversité biologique des poissons des eaux douces et saumâtres d'Afrique : Synthèses géographiques. Ann. Mus. R. Afr. centr., Zool., Tervuren, 275, 149-163.
Whitfield A.K., 1998, Biology and Ecology of Fishes in Southern African Estuaries. Ichthyological. Monographs of the J.L.B. Smith Institute of Ichthyology, No. 2.