Variation in Biofilm Formation of Bacteria Isolated from Fish Catch and Surfaces of a Fishing Vessel

This pioneering study investigates bacteria isolated from marine pelagic fish, fishing vessels, and gear surfaces, focusing on the variability in biofilm formation across different substrates, media, and cultivation conditions. Bacteria from fish intestines, skin, and gills, including spoilage organisms and potential fish and human pathogens, can contaminate vessel surfaces, gear, and containers and may act as microbial reservoirs and transmission vectors. In this study, biofilm formation was evaluated at air–liquid interfaces and on submerged plastic, metal, and glass surfaces under various incubation temperatures and media. Vibrio spp. were isolated both from fishing nets and fish gills, particularly Vibrio alginolyticus, V. gigantis, and V. pelagius. Although V. harveyi was examined as a representative vibrio, it did not form a biofilm on polypropylene. Photobacterium damselae subsp. damselae, Pseudomonas fragi, P. gessardii, Psychrobacter spp., and Rothia endophytica showed a strong affinity for stainless steel. Overall adhesion regardless of media type was highest for P. gessardii, followed by P. damselae and Aeromonas veronii, which adhered strongly to steel, glass, and polypropylene; however, only P. gessardii also adhered well to polystyrene, an important finding because these are known fish and human pathogens. These results highlight species-dependent biofilm triggers and their substantial variability and provide guidance for standardized marine biofilm protocols.