Diversity of muddy-bottom benthos in a tropical estuarine ecosystem: Cross River estuary, off the Gulf of Guinea, southeastern Nigeria. – I. Ewa-Oboho, S. W. Petters, N. Essien and E. Antai
The community structure of soft-bottom fauna is described for the Cross River estuary, Gulf of Guinea, with special reference to relationship between diversity and tropical estuary. Of the 105 species of invertebrates collected in June 2004, polychaetes comprised 80% by number of species and 68.5% by number of individuals. Density ranged from zero to 4374m-2 with a mean of 634m-2 per station and biomass ranged from zero to 10.96gm-2 with a mean of 2.0gm-2. Numerical analysis indicated considerable faunal homogeneity characterized by polychaetes. From measures of diversity it is concluded that the soft-bottom community of the Cross River estuary is not rich for a tropical estuary. Physical processes (riverine run-off and frontal systems) mainly influenced community structure and function in the lower estuary whereas biological processes (predation) seemed to prevail in the middle reaches.