Female dog whelks grow penises
The Dog Whelk is a common mollusc and is found on most rocky shore areas and around the UK, but in busy shipping and sailing areas female Dog Whelks have been found growing unusual appendages. Scientists have discovered that marine antifouling containing TBT (tributylin) compounds is causing them to grow penises.
According to Ananova, researchers at Napier University say tiny amounts of the chemical can effect all marine life and cause sex changes among many types of mollusc, but dog whelks are the most at risk.
The change in mollusc females developing male reproductive organs is known as imposex. It's thought that the exposure to the pollutants found in antifouling products can not only bring about imposex but then can cause blockages to the females oviducts.The female stores the eggs and they are internally fertilised, but if she is unable to lay them this will then bring about her death.
A survey was carried out in 1987 around the Isle of Wight and the concentrations levels of TBT were so high that all though the Dog Whelk was still very common around the UK it had become almost extinct in some areas of the South and in particular the Solent area.
The Dog Whelks colonies around the IOW are being monitored to help establish its rate re-popularisation, but there has been calls for the use of TBT to be removed. The International Maritime Organisation plans to have a total ban on TBT use in place by 2008 but Friends of the Earth are looking for this ban to be brought forward.