In summary, this study begins to establish the microbiota of marine egg masses, specifically those from moon snail egg collars, as a source of metabolites with antibiofilm properties. We have identified the active metabolite, pseudochelin A, as the responsible agent for biofilm-formation inhibition in S. aureus and its presence in twenty-four of the thirty-eight active fractions. Pseudochelin A, a known siderophore, has biofilm-disruption properties that appear to be associated with its iron-sequestration properties. In addition, 6 was detected directly within egg collar extracts by MS, and a key biosynthetic gene was amplified from DNA extractions of 30% of the collected egg collars (Fig. ). Thus, indicating that pseudochelin A may have an ecological role in protecting the egg collars from biofouling. Work is ongoing to identify the metabolites responsible for eradicating pre-formed biofilms and those that inhibit P. aeruginosa biofilms.