The occurrence of Sagartia elegans (Dalyell, 1848) (Anthozoa: Actiniaria) in the Netherlands

The occurrence of the sea anemone Sagartia elegans var. miniata, var. nivea and var. venusta in considerable numbers at three localities in the Netherlands is reported upon. Previous records of the species in Dutch coastal waters are reviewed. Most of these are considered as doubtful. Characters to distinguish S. elegans from S. troglodytes are discussed. Attempts are made to relate local occurrence of S. elegans with temperature data. Sagartia elegans is an autochthonous species in the Netherlands but its numbers vary considerably, and populations probably have no permanent character. In the past, populations presumably have been reduced and sometimes wiped out during relatively severe winters. Reinforcement of rest populations or recolonization is likely to happen through planktonic larvae from the Channel area and from off-shore populations. Recovery of populations in Dutch coastal waters apparently takes place after consecutive mild winters.