Invertebrates – animals without backbones – include molluscs (snails, mussels, oysters and their relatives), crustaceans (such as crabs, lobsters, prawns) and insects. The vast majority of species on the planet are invertebrates, and they perform many essential functions. For example, they pollinate crops and form the base of many food chains providing an important source of food for bigger animals. However, some are a nuisance and attack crops, so pesticides are designed to kill them – but as well as the target species, pesticides can also kill other insects such as honeybees. Currently, there is widespread concern about the demise of bee populations in some areas, with some pesticides being under suspicion as potentially playing a role.
Tributyltin (TBT) is a biocide used as an anti-fouling agent on ships’ hulls, and as an antifungal on textiles. However, it has also been found to affect several non-target species, and it particularly disrupts reproduction in aquatic molluscs, and causes a condition called imposex where the female grows a penis. At least 150 species are affected by TBT, including common British species such as dog-whelks, periwinkles, mussels, and European and Pacific oysters. TBT has also been found at relatively high concentrations in top predators such as dolphins, tuna and sharks. Following pressure from environmentalists, the International Maritime Organisation (the governing body responsible for international shipping) banned TBT from ship’s hulls in 2008.
It seems that mollusc species may be especially vulnerable to the effects of several hormone disrupting chemicals. This is an issue which needs to be addressed to ensure that they are adequately protected.
CHEM Trust’s report Effects of Pollutants on the Reproductive Health of Male Vertebrate Wildlife - Males Under Threat by Gwynne Lyons.
This report shows that male fish, amphibians, reptiles, birds and mammals have been harmed by chemicals in the environment. Widespread feminisation of male vertebrate wildlife is highlighted. These findings add to mounting worries about the role of hormone-disrupting or so-called ‘gender-bending' chemicals in the environment, and the implications for human health.