Diet and feeding regimens for larval doughboy scallops, Mimachlamys asperrima

Nine microalgal species commonly cultured as food in mariculture were assessed as food for larvae of Mimachlamys asperrima. Larvae were cultured for seven to nine days in a shaker incubator cabinet and fed a range of monospecific, binary and ternary algal diets. When fed a single algal species, the greatest increases in shell length occurred with Pavlova lutheri. When fed the remaining eight algal species in combination with P. lutheri, Chaetoceros calcitrans and Tahitian Isochrysis aff. galbana produced the greatest shell length increases. In both these experiments, increases in larval shell length were correlated with larval survival. The greatest larval growth recorded in these trials was with a diet combining the three previously listed algae. To optimise the use of this ternary diet, the maximum proportion of C. calcitrans in the diet before significant reductions in growth occurred was estimated at 44%. However, synergistic improvements in growth of larvae fed ternary diets were achieved with the inclusion of as little as 10% C. calcitrans. Larval growth decreased when the frequency with which larvae were fed each of the three algal species in the ternary diet was reduced from daily, to diets in which six days passed before larvae received each species. The concentration and storage (2-7 days) of the ternary diet before feeding did not affect larval growth or survival, nor did the change from discontinuous (twice daily) to continuous feeding regimens.