PRELIMINARY SURVEY OF ICTHYOFAUNAL DIVERSITY OF IKOT OKUBARA RIVER, AKWA IBOM STATE, NIGERIA

This study investigated the composition, abundance, and ecological dynamics of fish species in the Ikot Okubara River, focusing on seasonal variations and growth patterns. A total of 19 fish species were identified, categorized by taxonomic order, family, genus, and species, with data collected over seven months from May to November, 2024. The dominant species, Oreochromis niloticus, accounted for 45.4 % of all recorded occurrences, highlighting its ecological significance of p > 0.005 and adaptability to varying environmental conditions. The study revealed a significant difference in fish abundance between wet (199 individuals) and dry (70 individuals) seasons, indicating a 71 % reduction in fish populations during the dry season. Notably, O. niloticus remained prevalent throughout both seasons, demonstrating resilience, while other species exhibited more restricted seasonal distributions. The Index of Preponderance (% IP) indicated that O. niloticus was the most dominant species, with an overall % IP of 77.75. The size structure analysis showed considerable variation in total length and weight among species, with Parachanna obscura ranging from 8.2 cm to 32.0 cm and O. niloticus spanning from 8.5 cm to 24.5 cm. Length-weight relationships indicated positive allometric growth for most species, with O. niloticus exhibiting a slope (b) of 2.6403 and a strong correlation coefficient (r = 0.8803). This research contributes valuable data to the understanding of fish diversity and dynamics in southern Nigeria, providing a baseline for future ecological assessments and informing conservation efforts aimed at protecting aquatic biodiversity in the region.