Numbers of larvae and primary plantigrades of the mussel Mytilus edulis in the western Dutch Wadden Sea

Abundance of larvae and primary plantigrades in the blue mussel Mytilus edulis L. was studied quantitatively in the western part of the Dutch Wadden Sea. Observations were made in seven years between 1981 and 1996. In general, a first large peak of larvae appeared in May, followed by one or more much smaller peaks until September. For pelagic larvae an approximate life time of four to six weeks was calculated (on average about five weeks). Pelagic larvae appeared to have a relatively higher survival chance at low larval concentrations than at high concentrations. No relation could be demonstrated between time of larval peaks and spring tides. Year-to-year differences in abundance of plantigrades did not predict mussel recruitment success on nearby tidal flats.