Overlapping and unique toxic effects of three alternative antifouling biocides (Diuron, Irgarol 1051®, Sea-Nine 211®) on non-target marine fish

The use of alternative biocides has increased due to their economic and ecological relevance. Although data regarding the toxicity of commercial alternative biocides in marine organisms are accumulating, little is known about their toxic pathways or mechanisms. To compare the toxic effects of commercial alternative biocides on non-target pelagic fish (flounder) embryos, we investigated the adverse effects of developmental malformation and transcriptional changes. Three biocides including Diuron, Irgarol 1051® and Sea-Nine 211® produced a largely overlapping suite of developmental malformations, including tail-fin fold defects and dorsal body axis curvature. In our test, the potencies of these biocides were ranked in the following order with respect to malformation and mortalities: Sea-Nine 211® > Irgarol 1051® > Diuron. Consistent with the toxicity rankings, the expression of genes related to heart formation was greater in embryonic flounder exposed to Sea-Nine 211® than in those exposed to Irgarol 1051® or Diuron, while expression of genes related to fin malformation was greater in the Irgarol 1051® exposure group. In analyses of differential gene expression (DEG) profiles (fold change of genes with a cutoff P