Anthropogenic impacts on the stocks of the common whelk Buccinum undatum (L.)

Imposex was absent in most samples of whelks Buccinum undatum (L.) taken from the Irish Sea but was recorded in samples from the North Sea, English Channel, Clyde Sea, Svalbard and one out of two samples from the west coast of Ireland. It is evidently a relatively recent phenomenon because it was not recorded in a preserved sample taken from the North Sea in 1970. The most likely cause is tributyltin (TBT) contamination from antifoulants on boat hulls because symptoms were more severe in areas of high shipping activity than elsewhere. There appears to have been little, if any, impact on breeding performances because imposex was mostly mild. Furthermore, stocks of whelks were sufficiently large in the North Sea and other British coastal waters to support buoyant fisheries. There has been overfishing in some areas in the past, notably the Wadden Sea and (probably) off the southern part of the east coast of England, and there are fears that recent expansion of the whelk fishery, due to market opportunities in the Far East, is leading to more general over-exploitation.