Effect of Vibrio alginolyticus on larval survival of the blue mussel Mytilus galloprovincialis

Abstract

The effect of increasing concentrations of Vibrio alginolyticus on survival of Mytilus galloprovincialis larvae was studied in a 48 h static bioassay in 1 l glass bottles. Five bacterial densities were tested ranging from 10(2) to 10(6) bacteria ml(-1). Larval survival and normality (veliger larvae with the typical D-shape) were evaluated after 48 h. An inverse relationship between bacterial concentration and larval survival and normality was observed. In spite of high larval survival (79%) under conditions of high bacterial density (10(5) bacteria ml(-1)), the percent of normal larvae was 11%. Besides an irregular shape, abnormal larvae also presented velum reduction. Results from this study suggest that concentrations of V. alginolyticus lower than 10(3) bacteria ml(-1) should be maintained during M. galloprovincialis larval culture.