ASSESSMENT OF FISH DISTRIBUTION, COMPOSITION AND ABUNDANCE IN OTAMIRI RIVER, IMO STATE, NIGREIA

摘要

Study on the fish distribution, composition and abundance in Otamiri River was carried out between January and December 2021. Three sampling points (Stations 1, 2 & 3) were selected along the stretch of the nver and used for the study. Fish populationwas assessed using different fishing gears such as hooks and lines gillnets, cast nets and traps while one-man dugout and planked canoes were the crafts used Species diversity indices were estimated using standard procedure. Results revealed a total of757 fish samples comprising of 15 species, 10 genera, 9 families and 4 orders. The family Cichlidae ranked the highest as the most abundant fish species having 363 samples, while Distichodontidae ranked the lowest with just 5 fishs Peimen- The highest species richness (15) was recorded between the months of January and March while the least value (11) was obtained between April and June. SimpSon's Index (D) value manged from 0.02 between July and September and 0.005 between the months of January and March. Results of Simpson s Reciprocal Index (1/D) showed that fish species caught between May and August were not as diverse as those obtained between September and December. This may indicate that some anthropogenic activities (agncultural/crop farms, construction sites, sewage discharges, timber harvesting, industrial discharge mining and sand dredging) observed at the study sites tended to increase during raining season which subsequently led to the decrease in fish diversity. These activities could be said to have some deleterious effects on fish distribution, composition and abundance in Otamiri River. Thus management strategies should be put in place by relevant authorities to check human activities in the area.