Composition, Diversity and Food Habits of the Fish Community of a Coastal Wetland in Ghana

摘要

This study aims at stimulating the scientific community towards a better understanding of fish community ecology in relation to physico-chemical determinants in unmanaged coastal wetlands relevant for informed decision-making on ecosystem functioning and management in the tropical context. We investigated the diversity, size distribution and food habits of the fish community and the abiotic environmental conditions of the Kakum Estuary wetland in Ghana (5o 6' N; 1o 18'W) from July 2009 to February 2010. Eighteen species belonging to 18 genera and 12 families of marine, brackishwater and freshwater fishes were sampled. The poecilid Aplocheilichthys spilauchen (43.31%), the cichlid Sarotherodon melanotheron (18.12%) and the freshwater shrimp Macrobrachium macrobrachion (12.37%) were dominant. Fish communities in pools in the wetland were quite close in diversity (H' ranged from 2.2 to 2.7) and highly similar (Cs & 0.6) possibly as a result of the prevailing similar environmental conditions. Smaller individuals of the cichlids Tilapia zillii, Hemichromis fasciatus and S. melanotheron measuring 2.0-3.9 cm TL, and marine species such as Elops lacerta and Liza falcipinnis measuring 6.0-7.9 cm TL constituted between 60% and 80% of the populations, suggesting the wetland as nursery and feeding grounds for the fishes. Examination of stomach contents showed that the communities included detritivorous, planktivorous, insectivorous, omnivorous and piscivorous species. It is strongly recommended to restrict fishing in the wetland during the wet season to avoid exploitation of juvenile fishes which use the wetland as nursery and feeding grounds during that period.