Imposex in two sublittoral neogastropods from the Kattegat and Skagerrak: the common whelk Buccinum undatum and the red whelk Neptunea antiqua

Abstract

Imposex development in female whelks (Prosobranchia: Neogastropoda) has been sug- gested as a bioindicator of tributyltin (TBT) pollution in the marine environment. The occurrence of imposex in the common whelk Buccinum undatum and the red whelk Neptunea antiqua in sublittoral areas of Danish waters was related to organotin levels. In contrast, imposex was absent in reference material of N. antiqua collected in the area before 1938. The concentrations of TBT in whole body tissue of B. undatum ranged from <0.2 to 3.1 ng Sn g -1 and total butyltin (∑ BT = TBT + DBT + MBT) ranged from 1.2 to 32.9 ng Sn g -1 wet weight. The intensity (i.e. frequency and severity) of imposex was generally higher in N. antiqua than in B. undatum. At 14 stations in the Kattegat and Skagerrak, imposex was present in 9 to 89% of B. undatum and 67 to 100% of N. antiqua. N. antiqua seems to be more sensitive to TBT and would thus be the better bioindicator.