Increasing levels of tributyltin-induced imposer in muricid gastropods at Phuket Island, Thailand

Tributyltin (TBT)-induced imposer, or the masculinization of female gastrop ods, was used in an investigation of TBT contamination around the major har bours at Phuket Island, Thailand. From 21 stations along the south-east coa st of Phuket Island a minimum of 50 specimens of the muricid Thais distingu enda were collected and examined for the presence of imposer in February-Ap ril 1996 and in January-April 1998. The results showed clearly that both th e incidence and the distribution of imposer increased dramatically from 199 6 to 1998. In 1996, imposer was recorded at 10 stations within 3.5 km of th e nearest port, but in 1998 imposer was present at 18 stations up to 7.5 km from the nearest port. A similar tendency to increase in the incidence and distribution of imposer was found using Thais bitubercularis and Morula mu siva as indicators., Copyright (C) 1999 John Wiley & Sons, Ltd.