Decreasing the impact of TBT containing antifouling paints - Imposex in dog whelks and other sea snails

The dog whelk is a carnivorous sea snail of up to 4 cm that is found on most rocky shores in the OSPAR area.

The dog whelk and related snail species are extremely sensitive to the harmful effects of tributyltin (TBT) and are therefore used as indicator species to demonstrate effects of TBT on the marine ecosystem. TBT has been extensively used as an antifouling in ship paints. Depending on the concentration of TBT in the seawater, female dog whelks develop non-functional male characteristics (such as a penis) in a syndrome called imposex. International measures have been taken to prohibit the use of TBT. This should phase out TBT from the marine environment and improve the water quality.