Survival, growth and biochemical composition of larvae of the the lion's paw scallop, Nodipecten subnodosus, in batch- and flow-through culture

Abstract

Interest in mariculture of the lion's paw scallop, Nodipecten subnodosus, is increasing due to the overexploitation of wild populations in Mexico and the species' high market demand. Four larval and three postlarval trials of N. subnodosus were carried out using batch- or flow-through culture in 500-L tanks in the laboratory to test the variability of the culture methodology in terms of percent survival (S) and growth. Temporal changes in weight and energy substrates (proteins, lipids and carbohydrates) were also assessed during larval development. The larval period of N. subnodosus fed with a binary algal diet lasted 12 to 15 days at 26 °C. Maximal S to metamorphosis was 19 to 22%. Higher larval growth rate was observed in trials where larvae were fed higher amounts of microalgae in both batch (10.1 μm d−1) and flow-through (9.7 μm d) systems. Postlarvae exhibited up to an order of magnitude higher shell gross growth rate (GGR) than larvae, and differences in total yield appeared to be related to the amount of food. Total dry weight, ash-free dry weight, proteins, and lipids decreased significantly in D-stage larvae and increased thereafter, reaching new maximal values in pediveligers. Combined results suggest that N. subnodosus larvae stocked at high densities (10 to 20 larvae mL−1) in batch and flow-through culture can reach high growth rates when fed sufficient amounts of high-quality algae. The latter method also allowed to substantially increase the stocking larval/postlarval density without compromising larval growth or postlarval yield. Larval biochemical patterns indicated that D-stage larvae growth and survival were heavily dependent on protein/lipid egg reserves. Accumulation patterns in umboned-pediveliger stages also suggest that metamorphosis relied on protein-lipid metabolism.