Toxic effects of Gymnodinium cf. mikimotoi unsaturated fatty acids to gametes and embryos of the sea urchin Paracentrotus lividus

The toxicity of the main Gymnodinium cf. mikimotoi polyunsaturated fatty acid, has been investigated using the sea urchin gamete and embryo bioassays. The 18:5n3 fatty acid delays or inhibits first cleavage of Paracentrotus lividus eggs and provokes abnormalities in the embryonic development. These effects were compared with those of other polyunsaturated fatty acids, 18:4n3, 20:5n3 and 22:6n3, which are also present in this alga. A classification of the different fatty acids, based on their effects on sea urchin egg cleavage and the determination of the half inhibiting concentrations (IC50) is proposed.