Morphometric and Meristic Analysis of Gymnarchus niloticus (Teleostei: Gymnarchidae) from Oyan Dam and Epe Creek in South West, Nigeria
A study of morphometric and meristic characteristics of Gymnarchus niloticus from Oyan dam in Ogun State and Epe creek, Lagos State used three meristic and ten morphometric measurements in relation to standard length and head length. The body measurements and proportions did not bring out definite demarcation in the morphology of Gymnarchus niloticus from the two locations, even though; slight differences were observed in all the parameters measured. Specimens from Oyan dam were longer (mean = 92.6 mm) than those from Epe creek (75.6 mm). Similarly meristic counts also showed slight differences in the two locations with dorsal fin ray count in Oyan dam specimens higher (165.7) than Epe Creek specimens (155). The t-Test revealed no significant differences exist in these character ratio data at 5% probability level of significance. These results have in dictated that minor difference observed in morphometric characters and meristic counts may be due to environmental influence on the species.
Key words: Gymnarchus niloticus, morphometric characters, meristic characters, Oyan dam, Epe creek