In order to study possible effects of fishery on whelks ( (Buccinum undatum) in the Wadden Sea, shell damage and shell repair were measured in a sample of 80 whelks in the collections of the National Museum for Natural History, Leiden, collected in de former Zuyderzee near Wieringen in 1926 i.e. before the closure of the Zuyderzee in 1932. Formerly this was one of the fishing areas for whelks; whelks have now disappeared from the Wadden Sea. All shells showed damage of the outer lip, and those > 3 cm showed repairs of older damages of the outer lip as well, moreover, 7 had a hole in the last whorl. Because whelk fishery apparently causes so much shell damage, these repaired damages are thought to be due to whelk fishery. Unsuccessful attacks of lip-peeling crabs can also produce repair scars on gastropod shells, but in temperate areas their frequency should be much lower than c.100 % and the damage produced more specific. Fishery and the damage it caused to the shells of whelks are argued to be responsible for the gradual decline in whelk landings from the Wadden Sea since the peak in landings in 1925/26 (fig. 1), but not for its extinction in the Wadden Sea. The final blow, by which the whelk became extinct in the Wadden Sea in the 1980s, was the introduction of tributyltin (TBT) antifouling paint for ships, which causes imposex and reproduction failure. As modern beamtrawl fishery proves very harmful for benthic organisms, protected areas are necessary in the North Sea. Only the indication of such protected, fishery free areas in the North Sea, and a total ban on the use of TBT antifouling paint will prevent extinction of the whelk in the North Sea.