Water pollution is an issue of concern over the years in many countries. This study investigated the effect of human activities on the water and soil sediments of River Ogun at Ijaye, Isabo and Sokori from June to November 2017. The physico-chemical parameters of the water in all the three locations were measured and recorded twice monthly using standard methods. Determination of phosphate and nitrate in the soil was carried out. One-way analysis of variance was employed for data analyses, and means were differentiated using Duncan multiple range tests. No significant difference (p>0.05) in the mean of all the parameters tested for in all three locations. Monthly range in temperature was within 24.75 ºC-27.55 ºC. Highest mean electrical conductivity (531.00 µs/cm), dissolved oxygen (7.56 mg/l) and alkalinity (2.80 mg/l) were recorded at Location C (Oke-Sokori). High positive correlation was obtained between water phosphate and water nitrate, soil phosphate, soil nitrate and between pH and dissolve oxygen, electrical conductivity. It was concluded that the water from all three locations are still within the recommended reference for fish. There is need to constantly monitor the water at these locations as levels of some of the parameters have exceeded the permissible limit for fish.

The food and feeding habits of eight (8) fish species Elops lacerta, Chrysichthys auratus, Schilbe mys-tus, Sardinella maderensis, Synodontis schall, Hepsetus odoe, Tilapia zillii and Mugil cephalus in Ogun estuary, Ogun State, Nigeria were studied and estimated for six months, between February and July, 2014. A total of 470 fishes were randomly collected from the commercial fishermen during the study. Results from the stomach contents analysed using frequency of occurrence and numerical methods showed that S. mystus, E. lacerta, S. maderensis, H. odoe, S. schall, T. zillii, M. cephalus and C. auratus were predators, piscivores, herbivores, piscivores, omnivores, herbivores, herbivores and omnivores respectively while H. odoe and S.mystus partly fed on E. lacerta and T. zillii respec-tively. The Diet Breadth (D) ranged from 0.76 to 0.88 and the percentage Gut Repletion Index (GRI), a reflection of frequency of feeding, ranged between 60-100%.

Parasites are the second most abundant microorganisms that infect and cause disease in wild and cultured fish after bacteria. The study investigated the parasite prevalence, abundance, mean intensity and dominance in some fresh water fish from Akomoje, Ogun River, Nigeria from February to May, 2016. Eight fish species were collected and identified to the species level. Experimental fish were measured and weighed. Endo-and ectoparasites were examined for; from Skin/scale, dorsal and caudal fins, gills, intestine and stomach of fish. Water sample was collected from shore, mid and extreme of the landing site and also analysed for parasite abundance. Prevalence of parasite in all fish species varied slightly with size. Myxozoan group revealed the highest dominance of ecto-and endo-parasites in virtually all fish species while mean intensity and abundance of Myxozoan spp. was highest in Oreochromis niloticus and Hemichromis fasciatus. Highest case of a single species of ectoand endo-parasite in a fish sample was that of Nematode larva in Chrysicthys nigrodigitatus (41.43 %) and Trichocerca sp. (Rotifera) in Mormyrus rume (52.9 %).Water analysis revealed three parasite groups that were present in the sampled fish. Conclusively, Akomoje landing site of Ogun River has a rich burden of parasites.

A study was conducted on commercially important fish species of heavy metals in water bodies. The primary objectives were to find out the amount of heavy metals concentration in the fish species, sediments and water samples at the deep and shallow part of the river, to determine the toxicity and relationship between the collected samples and the rate at which it pollutes the water. Atomic absorption spectrophotometer (AAS) evaluates their wholesomeness for human consumption. Four heavy metals (lead, cadmium, copper and zinc) were analyzed and only copper and zinc were found to be present in the digested samples. The concentration of copper in the fish (flesh) was 0.09 mg/l and that of zinc was 0.25 mg/l. In the bone samples, copper was found to have 0.17 mg/l and zinc 0.22 mg/l. In the water samples analyzed, the concentration of copper is 0.035 mg/l while that of zinc is 0.047 mg/l. In the sediment sample, the amount of copper is 310.0 mg/kg while that of zinc is 2050.0 mg/kg. This however signifies that the fish species in the Ogun River as well as the water is suitable for consumption which was found to be less than the World Health Organization (WHO) maximum recommended acceptable limits in the food.

Federal University of Agriculture reservoir is one of the recently constructed in Abeokuta, Ogun state, Nigeria, therefore the need to assess the water quality, fish diversity and catch assessment of this new water body. Data on fish species were collected on a forthnight basis using multi-stage gillnet sampling techniques for four months (September- December, 2011). Three sampling stations were randomly selected from the entire reservoir. A variety of sampling methods were used at each site in order to reach every fish species. At the river channel and the floodplain sites, traps, cast nets (2.55cm mesh), seine nets (2.55 x 2 cm mesh), monofilament nylon gillnets (15.55 cm mesh), and hook and line were employed. Efforts were made in order to catch fish species in large abundance. Some sampled fish (dead) were collected and placed in cool boxes and examined within 18 hours of capture. Others were preserved in 15% formalin and stored for later examination. A total of 863 fish specimens were caught during the study period. These were identified and classified into 5 species belonging to 3 families. The percentage species composition of the harvest by numbers and weight for all fish species that contributed more than 1% in all the stations combined, were computed. Study of the physico-chemical parameter such as dissolved oxygen ranged from 5.03 to 7.19mg/l; 26 to 280C temperature; 64.8 to 148ppm alkaline; pH 6.67-6.90; 32.5 to 53.5m transparent; 8.86 to 13.72mg/l nitrate; 0.58 to 0.64mg/l phosphate; 0.024 to 0.069 o/oo saline; 103-270cm deep. pH and water temperature serve as variables since the fluctuation of one affects the values of others. The water quality parameters were favourable for fish production. The gillnet fisheries indicated that different mesh sizes of experimental gillnets were sensitive to different fish species. 67.2mm, 78.4mm and 112mm, mesh sizes were efficient in catching Clarias gariepinus, Barbus occidentalis and the Cichlids respectively. The study has shown that middle water was the most suitable habitat for fish in the reservoir. Water level and temperature were observed to guarantee high fish yield in the reservoir.