Gender disruptors

Citation

(1999), "Gender disruptors", Nutrition & Food Science, Vol. 99 No. 2. https://doi.org/10.1108/nfs.1999.01799bab.007

Gender disruptors

Gender disruptors

Detailed research by scientists from MAFF's Centre for Environment, Fisheries and Aquaculture Science have shown that a number of flounders in some heavily polluted estuaries are being "feminised" through contact with pollution. The effects of the substances, oestrogenic hormones and their mimics, include egg cell growth in the testes of male fish and egg yolk production in male and juvenile female fish. Flounders were chosen for use in this study because these fish spend parts of their life cycle in estuaries where contaminants were expected to be highest and any biological effects might be more pronounced. Fish from estuaries of the Tamar, Alde and Dee were entirely normal. In the estuaries of the Tees, Mersey, Tyne, Wear, Humber, Clyde, Southampton Water, Thames and Crouch at least some of the male and juvenile female flounders were found to have enlarged livers and to be producing yolk protein, an abnormal condition diagnostic of oestrogen exposure. In the estuaries of the Tyne, Wear, Mersy and Tees male fish were producing as much yolk as normal females. In the Mersey and Tyne between seven and 17 of the male fish also contained developing egg cells in their testes but there was not an excess of females in these populations. In other words, the feminised males do not seem to be completely changing sex. It is not known whether these severely affected flounder are unable to breed when they migrate to sea in the spring. Circumstantial evidence suggests that chemicals of industrial origin may play a bigger role in estuaries than upstream in rivers. The report recommends that further research is required to identify the substances responsible for feminisation of the flounder and to discover whether they are a threat to the long term stability of marine fish populations.