Enumeration fluctuated from 106 to 107, with a mean order of magnitude of 107 for both conditions. Great differences are recorder in the presence of Gram-negative and Gram-positive bacteria. Sterile conditions, which reflect the bacteria associated with Artemia cysts, show that Gram-positive, oxidase-negative organisms are the dominant population, at the instant of nonsterility commercial hatchery condition where Gramnegative, oxidase-positive bacteria constitute 100% of the isolates; those results correspond to Vibrio spp. basic taxonomy. Identification of 34 strains of VLO with the API