Use of L-DOPA and soluble bacterial products to improve set of Crassostreavirginica (Gmelin, 1791) and C. gigas (Thunberg, 1793)

Solutions of L-dihydroxyphenylalanine (L-DOPA) and culture supernatants of the marine bacterium Shewanella colwelliana were used to treat competent Cr assostrea larvae before transferring them to setting tanks. Setting trials were done in laboratory containers and on a larger scale in a Chesapeake Ba y hatchery. Hatchery results showed a consistent and repeatable improvement in set of C. virginica after treatment with either L-DOPA or bacterial sup ernatants. Laboratory results were more variable, and differences between t reatments were less pronounced. Pretreatment of larvae with theophylline le d to a more rapid onset of settlement behavior in L-DOPA treatments but not in supernatant treatments, and had no clear effect on over-all set on cult ch.