Abstract

Fish farming, especially the African catfish (Clarias gariepinus) farming plays a vital role in addressing protein demands in Nigeria. However, disease outbreaks linked to bacterial fish pathogens pose significant challenges to aquaculture productivity and public health. Therefore, this study isolated and characterized the bacteria associated with the gills of C. gariepinus sourced from three farms in Rumuolumeni, Port Harcourt, Rivers State, Nigeria. Nine live fish samples were collected, and the gills were aseptically processed for the isolation of bacteria associated with the gills using standard plate count on nutrient agar. Isolates were identified using morphological, biochemical, and molecular (16S rRNA) methods. Results obtained showed that, the total heterotrophic bacterial count ranged from 1.5± 1.1 to 3.3± 0.02 ×10⁵ CFU/g. Molecular identification revealed the presence of seven bacterial species: Vibrio cholerae, Enterobacter aerogenes, Salmonella paratyphi, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Staphylococcus aureus. Staphylococcus aureus was the most prevalent (26.9%), followed by S. epidermidis (19.2%) and Salmonella paratyphi (15.4%). All the bacterial isolated are potential pathogens and therefore are of potential health risks to consumers of catfish. There is therefore the need by relevant authorities to have policies in place for improved aquaculture management practices to ensure fish safety and public health