Bacteria: Five bacterial strains, representing three classes [two Bacillus sp. (Bacilli), one Labrenzia sp. (Alphaproteobacteria), and two Isoptericola sp. (Actinobacteria)], were isolated from moon snail egg collars at the same time as P. piscicida and produced biofilms in the laboratory. These strains were used to evaluate pseudochelin A's potential to inhibit biofilm formation in environmental isolates. The biofilm inhibition assay was performed as described above except for the following variations. The environmental isolates were diluted to a starting OD600 of 0.01 in M63 liquid broth prepared with artificial seawater (see Table ) and 98 μL was transferred to each well, including the vehicle control. Inoculated plates were incubated in a static incubator for 40 to 48 h at 30 °C and residual biofilms were quantified following the same methods described above.