Effect of starvation on the DNA content of sole larvae (Solea solea L.).

Much work has been devoted to the study of the role played by starvation in the natural field mortality of the early larval stages of marine fishes. The RNA/DNA ratio seems to show a variability which adversely affects its application in situ. Conceptual considerations have led to a proposal of a new biochemical index, the DNA amount in the larva (DNA/DW). Several rearing experiments were carried out with fed and starved Dover sole (Solea solea ) larvae under 2 temperature conditions. It is confirmed that the RNA/DNA ratio during ontogenetic development of fed individuals exhibits a strong variability. The effect of starvation is very sharp in the early stages, characterized by a rapid increase beyond the significant threshold of 30; for metamorphosing larvae, this effect appears to be less important and the threshold falls to 15. These results are discussed and compared with previous works, especially those based on the RNA/DNA ratio.