Effect of environment with low dinoflagellate concentration on the toxicity to mice of alcoholic extracts from the sponge Tedania ignis.

We have examined the toxicity of samples of sponges from mangrove lagoons in Venezuela, rich in dinoflagellates [1972 (1710, 4642) dinoflagellates/liter (median and 90% confidence interval of 4 samples, spanned over an 8 month period)]. After transferring them for 135 days to a coral reef poor in dinoflagellates [35 (18, 87) dinoflagellates/liter (4 samples)] there was an 85% decrease in lethal potency to mice.