Distribution and invasion ecology of Marenzelleria viridis in the Estonian Coastal Waters

The habitat selection and invasion of a new polychaete Marenzelleria viridis is described. Up to now the species has Iow biomass and abundance values in Estonian coastal waters. M. viridis prefers gravel substrate. The increase in the abundance of M. viridis coincides with the decline of that of another polychaete, Nereis diversicolor, in uniform habitats but not in the patchy environment. lt is likely that M. viridis may become a numerically dominant species in the zoobenthos of the region in the following years