THE DECLINE OF THE NORTH-SEA WHELK (BUCCINUM-UNDATUM L) BETWEEN 1970 AND 1990 - A NATURAL OR A HUMAN-INDUCED EVENT

Recent surveys in the southern and central North Sea and the Dutch Wad den Sea revealed that the whelk Buccinum undatum L. can no longer be f ound in areas where whelks were abundant twenty or more years ago. The decline of whelk populations tends to coincide with areas of various, intense human activities, which may cause either pollution or physica l damage. Potential causes for the decline of whelks from the southern North Sea and coastal areas are discussed and considered in view of N orth Sea ecology and protective policies for the North Sea.