§ Mr. DafisTo ask the Secretary of State for the Environment what research has been conducted by his Department on the effect of tributyl tin used as an anti-fouling marine biocide on ship hulls upon the marine environment with particular reference to the shellfish population.
§ Mr. YeoMy Department funded research into the impact of tributyl tin—TBT—on dog whelks,Nucella lapillus, which exhibit effects at very low concentrations. This led to such effects being used as a biological indicator for a survey of TBT in the North sea reported upon in 1992. Current research is using the biological indicator to monitor recovery of the marine environment since the 1987 ban on TBT use on vessels of less than 25 m long and in assessing the implications of TBT use on vessels over 25 m.