Species Compositon of Freshwater Prawns in Ase Creek, Southern Nigeria

Abstract

Eight hundred species of freshwater prawns were sampled from fishers catch in Ase Creek between June and September 2010. Sampling was conducted forthrightly from two stations with the help of the fishers who used different types of fishing gears. Samples collected were sorted and identified in the laboratory. Data collected were analyzed using descriptive statistics, percentages and Ponderal Index. Result of the study showed that three prawn species (Macrobranchium felicinum 460, M. vollenhovenii 314 and Atya gabonensis 26) were sampled in the creek, with M. felicinum and A. gabonensis being dominant and least species respectively. The M.felicinum had a Ponderal Index (PI) of 57.50% and M.vollenhovenii 39.25%, while A. gabonensis accounted for 3.25% of the population sampled. Female prawns accounted for 63.88 % of the population sampled. Gravid individuals of M. felicinum and M. vollenhovenii encountered were 4.50 and 1.63 % respectively, of the population sampled and were encountered only at the beginning of sampling and none at the end, indicating that the prawns spawn at the onset of the rains when the flood level begins to rise. The results of the physico-chemical properties were, mean temperature 25.5±2.3°C, mean pH 6.7 0.7,mean dissolved oxygen 6.5± 1.1mg^-1 and mean conductivity 226± 68μmhos. The dominance of M. vollenhoveni is an indication of better adaptability to the Ase River ecosystem than other species of prawns.