Effects of various locally isolated microphytoplankton diets on the growth and survival of larvae of sea scallop, Placopecten magellanicus

Two diatoms and one flagellate, indigenous to coastal waters of Nova Scotia were identified, isolated and cultured. Feeding experiments were done to evaluate whether they can be potentially used for sea scallop larval diets. Their effectiveness on growth and survival of the larvae were compared to a reference diet of flagellates and diatom diets widely used in bivalve aquaculture. The microphytoplankton used include indigenous species such as Navicula, Chaetoceros, Prymnesium and reference species such as Tahitian Isochrysis, Monochrysis and Chaetoceros calcitrans. Also it included an unfed treatment. The reference species and isolated species were maintained at 20 and 14°C respectively. The larvae were fed with 25,000 cells/ml from Day 3 to Day 9 and 35,000 cells/ml from Day 10 to Day 35. Growth and survival rates were determined by subsampling the larvae at an interval of 4–5 days. Starvation and dietary effects on larval survival and growth are discussed. The effectiveness was compared to the reference flagellates and diatoms diets. (Abstract shortened by UMI.)...