Nutritional value of Pavlova spp. (Prymnesiophyceae) for spat of the Cortez oyster Crassostrea corteziensis during late-nursery culturing at the hatchery

Abstract

Three Pavlova species were evaluated for their nutritional value as diets for growth and survival of the Cortez oyster Crassostrea corteziensis spat during late-nursery cultivation at a hatchery. Microalgae were provided as monospeci¢c diets (Pavlova salina, P .s p. C50 andP. sp. C53) and in binary combinations of diets112,1 1 3a nd 213 at 80^90 10 3 cells mL 1 for 21 days. Juveniles experienced high survival rates and grew well with all dietary treatments, but binary diets yielded greater survival and growth of spat. From the three binary treatments, Diet 6 (P .s p. C50 andP. sp. C53) promoted signi¢cantly (Po0.001) fastest growth of juveniles in shell height (0.19 mm day 1 ), shell length (0.14 mm day 1 ), total wet weight (0.04 g day 1 ) and dry weight of meat biomass (0.024 g day 1 ). For all shell dimensions, the lowest growth rates occurred with Diets 2 (P .s p. C56 alone) and 3 (P. sp. C50 alone). These results highlight the importance of testing microalgal diets for bivalve spat rather than just relying on published nutritional values.