Diversity of Bacteria and Fungi Associated with Freshwater Fishes from Mijawal River, Nasarawa, Nigeria

Abstract

Understudying the presence of bacteria and fungi population on freshwater fishes, provides the knowledge and understanding of their diversity and potential roles they may play in the health of the aquatic and terrestrial ecosystems. The present study was conducted to evaluate the diversity of bacteria and fungi species of identified fish samples from River Mijawal, Nasarawa State. The fishes were sampled from the only landing for three months (October to December, 2019) for this study. During the sampling periods, thirteen (13) different fish species were identified; they were  swabbed with sterilized swab stick from the skin surface for bacteria and fungi identification. The Dominant fish species were Tilapia zillii, Labeo senegalensis, Mormyrus rume and Mormyrus tapines. The total number of thirteen (13) bacterial and five (5) fungi species were isolated and  identified. Eight (8) of the bacteria isolates, were gram negative bacteria (Pseudomonas sp, Aeromonas sp, Serratia mercescenes, Proteus sp, Salmonella spp, Escherichia coli, Klebsiella sp, and Enterobacter sp.); whilst the other five (5) were gram positive bacteria (Bacillus sp, Micrococcus sp, Staphylococcus sp, Enterococcus sp and Listeria monocytogenes).The five isolated fungi species were Aspergillus niger, Rhizopus sp, Penicillium  sp, Trichoderma viridae and Geotrichum candidum. The frequency of occurrence of the isolated bacteria indicated that Staphylococcus sp had the highest frequency of occurrence (16.67%) while Serratia mercescens had the least occurrence (2.78%). The highest number of occurrence of the isolated fungi species was observed in Rhizopus sp while the least was recorded in Geotricum candidum. It was observed that Tilapia zillii and  Mormyrus rume had the most frequent bacteria and fungi isolates. It can therefore be deduced from the results that fish samples identified from River Mijawal has high bacteria and fungi diversity that may be pathogenic to man. The occurrence of these microbes may be attributed of human  and animal faeces in the River 

Keywords: Freshwater fishes, Microbes, River Mijawal, Nasarawa