Eco-Morphological Patterns and Diversity of Some Fishes from the Ogu River in Rivers State, Niger Delta, Nigeria

Abstract

Aim: Eco-morphological studies show that morphological traits are adaptive, which means that traits evolve and change as a result of the activities going on in the environment such as predation, competition, and other biotic associations. This study was taken to determine the eco-morphological patterns of some fishes from the Ogu River in Ogu/Bolo Local Government Area of Rivers State, Niger Delta, Nigeria. Study Design: Field work and random sampling. Place and Duration: Three stations were sampled along the Ogu river and the duration of the study was four months (January- April 2018). Methodology: A total of 193 individual fishes were caught, comprising of 5 families and 11 species. Fish samples were obtained with the aid of a seine net; identified, weighed and morphometric measurements were made, to provide the eco-morphological attributes. Fishes were dissected to measure intestinal length. Statistical analysis includes Principal Component Analysis (PCA) of morphometric ratios and intestinal length - total length ratios of fish. Results: The fish species found were Tilapia guineensis, Tilapia zilli, Mugil bananensis, Mugil curema, Liza falcipinnis, Liza dumerili, Liza grandisquamis, Pomadasys rogerii, Pomadasys jubelini, Lutjanus endecacanthus and Eucinostomus melanopterus. Tilapia guineensis was the most abundant species, Shannon Weiner diversity index (H) ranged from 1.83 - 1.96, Simpson’s dominance index ranged from 0.79 - 0.85. The PCA analysis using different morphological attributes revealed 4 groups in feeding regime (omnivorous - Mugilids; herbivorous - Cichlids; larger carnivores - Lutjanids and smaller carnivores - Pomadasyids), and 3 groups in the fishes habitat preference in water as (1: Cichlids, 2: Mugilids and 3: Pomadasyids, Lutjanids and Gerreids). Conclusion: This study revealed morphometric attributes of some fishes of the Ogu river in Rivers State Nigeria and their relation with feeding, microhabitat and environmental parameters.