Imposex in gastropods from Venezuela

Abstract

The imposex phenomenon is a superimposition of male characters on gastropod females due to exposure to tributyltin (TBT). There have been no previous reports of this phenomenon in the southern Caribbean, which is inhabited by some edible and commercially exploited gastropod populations. To determine whether imposex is affecting some of these local gastropod populations, surveys were conducted at several sites with different levels of boating activity around Margarita Island and on the continental coast of Venezuela. The species affected were Chicoreus brevifrons, Chicoreus (Phylonotus) margaritensis and Leucozonia nasa; however, no females with obstructed vagina were observed. Imposex was observed in a coastal lagoon and on the coast at sites characterized by medium to high boat concentrations, but was not detected in open waters with low marine traffic. A survey of local boat operators indicated that the use of TBT had stopped 2–3 years prior to this study and had been replaced by regular application of other antifouling paints. This is the first report of imposex in Venezuela, but further studies incorporating the bioindicators identified here are needed in order to determine the full extent of TBT contamination and the biological implications in zones with marine traffic. Key words: edible gastropods, TBT, marine pollution, imposex, southern Caribbean.