The DNA/RNA ratio as a useful indicator of the nutritional condition in juveniles of Ruditapes decussatus

Condition indices have been widely used to assess how healthy individuals are under certain circumstances. It has been shown that the RNA/DNA ratio is a good indicator of the nutritional condition of severa1 marine organisms. A very sensitive fluorometric method for RNA/DNA quantification (Clemmesen, 1990) was applied to fed and starved post-larvae laboratory-reared clam, Ruditapes decussatus. The presented study shows that the RNA/DNA ratio is a useful indicator of nutritional stress for bivalve spat. The decrease in RNA/DNA ratio recorded here, under starved conditions was lower than in similar experiments on fish. A lower metabolic rate in clams may result in a slower response with respect to RNA/DNA ratios than that observed in vertebrates