Effects of various algal diets and starvation on larval growth and survival of Meretrix meretrix

Effects of food availability on larval growth and survival of Meretrix meretrix were studied in two experiments by feeding the larvae with different algae diets and by starving the larvae for different periods of time. Newly hatched larvae of M. meretrix were fed with five different marine microalgae species, singly and in various mixtures. Best growth was with Isochrysis galbana as a single species diet. Nutritional value of the other single species diets was in the order of Dunaliella sp. > Phaeodactylum tricornutum > Platymonas subcordiformis > Pavlova viridis. Of the mixtures tested, 50% I. galbana / 50% Dunaliella sp., 50% I. galbana / 50% P. tricornutum, and 50% I. galbana / 50% P. subcordiformis, supported growth and metamorphosis equivalent to those of the I. galbana control. At 25 °C, larvae of M. meretrix were deprived of food for various days to study the growth compensation from the outset of development. The results showed that M. meretrix larvae could survive long feeding delays, and even reach metamorphosis without food added, although starvation had significant effects on growth. These results suggested that M. meretrix larvae had the capacity to survive ‘starvation’ using alternative sources of energy. It also showed that growth, survival and metamorphosis of M. meretrix were affected by many factors besides food quality and quantity.