Algal diets for broodstock maintenance of the doughboy scallop Mimachlamys asperrima (Lamarck)

The effect of monospeci®c algal diets on ®ltration rate (algal cells h ±1 ) and fecundity of Mimachlamys asperrima was investigated.Filtration rates of seven algal species were monitored to indicate species preferences and to estimate maximum daily ®ltration rates.Cells of Chaetoceros calcitrans and Pavlova lutheri were ®ltered most rapidly; however, on a cell weight (mg h ±1 ) and cell volume (mL h ±1 ) basis, scallops ®ltered more Rhodomonas salina and Tetraselmis chui from the water column.Filtration rates when fed the diatom Chaetoceros muelleri were the lowest of the tested species, with a relatively low weight and volume of the algae ®ltered.Maximum ®ltration rates of the tested species were estimated to vary between 2.25 3 10 9 and 7.68 3 10 9 cells scallop ±1 day ±1 .Filtration of algal species by M. asperrima varied in accordance with both scallop size and water temperature.Five of the seven algal species previously tested were then selected for use as monoalgal diets for female M. asperrima and fed for 4 weeks.Fecundity of scallops after this treatment did not necessarily re¯ect ®ltration rates, being greatest for scallops fed C. muelleri, which was signi®cantly greater than that of the scallops fed C. calcitrans.Percentage development of eggs to D-veliger larvae did not differ in accordance with the maternal diet.A combined diet of C. muelleri, P. lutheri and Tahitian Isochrysis aff.galbana averaging » 2.5 3 10 9 cells scallop ±1 day ±1 was found to be suitable for the maintenance and conditioning of M. asperrima broodstock in recirculating systems.