THE ROUGH TINGLE OCENEBRA-ERINACEA (NEOGASTROPODA, MURICIDAE) - AN EXHIBITOR OF IMPOSEX IN COMPARISON TO NUCELLA-LAPILLUS

The muricid gastropod Ocenebra erinacea exhibits imposex (occurrence of male parts in addition to the female genital duct), a phenomenon which is caused by tributyltin (TBT)-compounds leached from ships' antifouling paints. Five stages of imposex development (1-5) with two different types at stage 1 can be distinguished and are documented with SEM-photographs for the first time. Four additional alterations of the genital tract are shown. Close to harbours and marinas, O. erinacea females exhibit malformations of the pallial oviduct, which seem to inhibit copulation and capsule formation resulting in sterilization. The TBT accumulation in the whole body and the accumulation pattern in single tissues are described; contrary to other prosobranchs no sex-related differences were found. The VDS, uncubed RPS and average female penis length of a population were analysed regarding their quality as parameters for TBT biomonitoring. On the background of the ecology of this species the VDS is chosen as the best index. Only in highly polluted areas should the uncubed RPS be used as a secondary parameter. A statistical study, based on the analysis of natural populations of Nucella lapillus and O. erinacea, allows a comparison of the specific TBT sensitivity of the two bioindicators. Dogwhelks exhibit a greater TBT sensitivity, namely at slightly polluted sites, nevertheless even here rough tingles develop obvious imposex characteristics.