How two large-scale “experiments” illustrate the Importance of enrichment and fishery for the functioning of the Wadden Sea ecosystem

Abstract

In the recent past, two far-reaching changes have taken place in the Dutch part of the Wadden Sea: (1) a drastic increase in the late 1970s of the annual rates of primary production and of chlorophyll concentrations (restricted to the western part of the Dutch Wadden Sea and probably induced by eutrophicated fresh water sluiced from Lake IJssel), and (2) a sudden removal in 1990 of nearly all mussel and cockle beds by commercial fishery all over the Dutch part of the Wadden Sea.