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This review examines the nutritional factors that influence the growth and survival of larval bivalves. Factors considered include feed form (live phytoplankton, preserved phytoplankton and artificial feeds) and feed biochemical composition (protein, lipid, carbohydrate and essential fatty acids). These factors, as they relate to larval production, are discussed in terms of growth and survival rates. To facilitate comparisons among larval studies, growth rates and feeding rates are standardized to common units. In addition, the standardized results for larvae of the Pacific oyster (Crassostrea gigas Thunberg) are analysed using linear regression techniques to determine the strength of the correlations between daily doses of biochemical feed components and daily growth rates. Piecewise linear spline modelling is used to determine maximum effective dose response, the point where feeding additional biochemical components to the larvae yields no significant improvements in growth. Derived from these analyses are suggested daily rations of lipid, protein, carbohydrate, eicosapentanoic acid, docosahexanoic acid and energy for larvae of C. gigas.

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The coralline red algae, Lithothamnion glaciale, Phymatolithon laevigatum, P. rugulosum, and Corallina officinalis, induced >85% of laboratory-reared larvae of Strongylocentrotus droebachiensis to metamorphose. Larvae must contact live L. glaciale or its spores for metamorphosis to occur; the inducer is not sensed in the water column. However, aqueous extracts of L. glaciale can induce metamorphosis, suggesting that the inducing factor is chemical. Neither ashed nor boiled L. glaciale induces metamorphosis, indicating that the factor is heat-labile and that thigmotaxis, per se, is not important in the response. The amino-acid, γ-aminobutyric acid (GABA), which induces settlement of other marine invertebrate larvae, also induces significant rates of metamorphosis of S. droebachiensis at concentrations ≥ 10-4 M. A reduction (with antibiotics) in the number of live bacteria on the surface of L. glaciale does not affect the rate of metamorphosis of larvae.

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