Due to declining natural fisheries resources globally, significant percentage now come from aquaculture. However, for sustainable demand and supply, safety and quality status must be paramount. This study investigated the pathogenic bacteria diversities in African catfish, (Clarias gariepinus), their seasonal variations and public health significance. One hundred and thirty-five samples were collected from skin, gill and guts of forty-five adult catfish (C. gariepinus) from Royal Fish Farm at Ewupe; Farm 360 at Alagbon; and Oluwadare Farm at Arobieye within Ado-Odo/Ota Local Government Area, Ogun State, Nigeria. Sampling and experiment were carried out during rainy, harmattan and dry seasons; between April 2019 and February 2020. Qualitative and quantitative microbiological analysis were carried out on fish samples to determine the bacteria load, and to identify the varieties of bacteria pathogens that were present in the fish and water samples. Data collected were subjected to statistical analysis using Analysis of Variance and Mean were separated using Duncan Multiple Range Test. High diversity of bacteria species was observed, such as Escherichia coli, Staphylococcus aureus, Salmonella typhimurium, Salmonella typhi, Shigella sp, Enterobacter aerogenes, Pseudomonas aeruginosa, Streptococcus faecalis, Klebsiella sp, Serratia sp, Proteus mirabilis, Micrococcus sp, Vibrio cholera, Aeromonas sp, Citrobacter sp, and Bacillus subtilis across the three seasons in each study areas. Bacteria load in gut to gill and skin are in the order: gut ? gill ?skin. During the rainy season, the total aerobic count of the gut at Royal Fish Farm (1.24x107±0.06c) was significantly higher (P?0.05) than that from the gill (7.88x106±1.22b), while at the gill it was also higher than found from the skin (6.08x105±0.18a). The same trend was observed in the harmattan season (1.93x107± 0.28c, 1.45x106 ±0.06b, 8.44x105 ± 0.92a) and dry season (2.14x108 ± 0.03c, 1.56x107 ± 0.07b, 1.45x106 ± 0.03a). The total aerobic counts from Farm 360 and Oluwadare Farm also depicted similar trends observed in Royal Fish Farm. However, the bacteria load during the dry season shows a high significant difference (P?0.05) when compared with rainy and harmattan seasons. In view of high contamination of bacteria pathogens recorded in this study, which exceeded the recommended limit by the international Commission for Microbiological Specification for Foods (ICMSF), it therefore shows, that these fish can pose a high risk to human health if consumed.

Keywords: : Aquaculture, Bacteria load, Microbiological analysis, High diversity, Public health significance