Cultivation of the diatom algae Chaetoceros calcitrans f. pumilus (Paulsen) Takano, 1968 as food for giant oyster larvae Crassostrea gigas (Thunberg)

An impact of modified nutrient media F/2 and Conway on the growth and biomass accumulation of the diatom algae Chaetoceros calcitrans f. pumilus, which is a part of the food for cultivated larvae of the giant oyster Crassostrea gigas in the IMBR RAS nursery, was studied. Maximum values of cell and biomass concentrations were obtained on the modified F/2 nutrient medium (11.22 × 106 cells·ml-1 and 4.93 g·l-1, respectively), and they were much larger than those obtained on Conway medium. Growth parameters of C. calcitrans f. pumilus depended on the ratio of inorganic nitrogen and phosphorus, as well as on the silicon content in nutrient media. The ratio N : P = 12.5 and the silicon concentration of 24 mg·l-1 in the modified F/2 nutrient medium are shown to be approaching the optimal ones for increasing growth rate of diatom algae. It is found that the microalga in concentration 150 × 103 cells·ml-1, cultivated on different nutrient media and included in food composition, has impact on the growth rate of giant oyster larvae. An average daily amount of growth of larvae, whose diet included algae cultivated on modified F/2 nutrient medium, was higher than that of larvae cultivated on Conway medium.