Cholera kills approximately one hundred thousand people every year with the global price tag of combatting the spread of this devastating disease exceeding hundreds of millions of US dollars. The pathogenic phase of Vibrio cholerae, the causative agent of cholera is well documented but its environmental lifecycle is poorly understood. V. cholerae is a natural inhabitant of marine and estuarine waters and it is here that it is subjected to an arsenal of selection pressures such as predation by eukaryotic protist grazers, osmotic stress from changing levels of salinity and temperature differentials. One means of resisting predation is to attach to and form biofilms on copepods and other chitinaceous organisms. Pathogenic and toxigenic V. cholerae strain, A1552 is naturally resistant to protist grazing and has an increased aptitude to bind to the surface of chitinaceous organisms. The genes involved in these survival mechanisms quite often overlap with the genes involved in pathogenesis of humans. Here, we have created a library of 10,000 V. cholerae A1552 transposon mutants. This library will be screened for survival and for other phenotypes such as increased biofilm formation and extracellular toxin secretion. These phenotypes have been observed when V. cholerae is exposed to the surface feeder Acanthamoeba castellani, the flagellate Cafeteria roenbergensis and the planktonic feeder Tetrahymena pyriformis. Mutants with a supressed or increased ability to survive or with an altered phenotype in the presence of these feeders compared to the wild type will be sequenced to identify the genes involved in survival and interaction with grazers.