O.K. Kareem, A.N. Olanrewaju, F.V. Oluwale

1Department of Aquaculture and Fisheries Management, University of Ibadan, Ibadan, Nigeria
2Department of Fisheries Technology, Federal College of Freshwater Fisheries Technology, P.M.B 1060, Maiduguri, Nigeria
3Department of Zoology, University of Ibadan, Ibadan, Nigeria

(Manuscript received 20 May 2024; accepted for publication 12 February 2025)

Abstract. Declining status and the reported endangerment of some of the native species is an indication that the structure of the existing stock would not be consistent with the erstwhile. Identity would have been influenced by plasticity of the fish species, while some of the species populations would have reflected changes because of adaptation to the prevailing environmental factors which vary by geographic locations. Hence, this study determined seasonal changes in morphological attributes among sexes of H. odoe population in Eleyele Lake, Southwestern Nigeria. Specimens collected were weighed (g) and 24 morphometric and seven meristic characters were evaluated to test the hypothesis differentiation. Landmark-based geometric morphometric information was obtained using 11 landmark features to extract the body shape data according to established protocols. Data generated were subjected to descriptive analysis, Hotelling T-test, and discriminant function analysis (DFA) at α0.05. The t-tests analysis showed significant variation (P<0.05) in some morphometric characters across sex and seasons. However, base of pectoral length (0.85±0.13 cm), base of pelvic length (0.79±0.12 cm) and post-orbital length (3.29±0.46 cm) were marginally higher in wet season samples than those of dry season, while slightly higher dorsal fin length (4.22±0.57 cm) were observed in female. The meristic characteristics differ only between season groups. Dorsal fin rays (9.00±0.00) and pectoral fin rays (12.75±0.43) were higher in wet season samples (P<0.05). The DFA analysis revealed that all morphometric characters were not significantly different across sex and season groups. These results confirm that the level of variation between season groups is more significant than sex groups.