Assessment of the impact of Abiotic factors on the fish assemblages in a tropical estuary creek

Fish assemblage structures of Badagry creek, Nigeria in relation to abiotic (physical and chemical) variables were studied for 2 years period (November, 2011 – September, 2013). Environmental parameters were monitored in sampling stations randomly selected in each of the threezones established in the creek (3 stations per zone). Fishermen catcheswere monitored in three major landing sites around the creek (one siteper zone). The physico-chemical parameters investigated were withinthe tolerance limits for aquatic life. Conductance, Salinity and Water depth data showed significant differences (p < 0.05) across zones whereas with an exception of pH and Phosphate, there were no significant variations (p > 0.05) in physicochemical parameters measured seasonally. The survey of fish in the Badagry creek recorded more estuarine and near-shore marine species with a total of 4,045 fish individuals comprising 36 species from 22 families. Dominant fishes included Tilapia zillii (15.2%), Chrysichthys nigrodigitatus (11.3%) and Ethmalosa fimbriata (11.2%). Fish diversity indices in dry season were higher than wet season. Water depth was found to be the most important abiotic factor determining the abundance of species ecological categories. The other abiotic factors tested also showed some influence on the species (ecological categories) abundance, suggesting the importance of environmental parameters in determining fish distribution and abundance.

Keywords:

Fish abundance , Abiotic factors , Diversity , Badagry creek ,