The Relationship Between Imposex and Tributyltin (TBT) Concentration in Strombus Gigas from the British Virgin Islands

Abstract

The queen conch, Strombus gigas (Linnaeus, 1758), was collected from sites with substantial boating activity and adjacent reference sites from the British Virgin islands in 2008-2009 to determine the incidence and severity of imposex. Comparisons were made to a previous study by phillip (2000) in the same area to determine if there were any changes in imposex over the last decade. imposex was present in S. gigas at all sites with boating activity, but not found in individuals collected at reference sites. Tributyltin (TBT) and its degradative product, dibutyltin (DBT), were found in S. gigas, turtle grass, Thalassia testidium (Banks ex Konig), and marine algae from sites with known point sources of TBT. we established a relationship between the highest incidence and severity of imposex and TBT concentrations in the tissues of S. gigas from sites with elevated boating activity (Road Harbour > Nanny Cay > Trellis Bay), suggesting that TBT, a known inducer of imposex in female prosobranch gastropods, is the causative agent. Strombus gigas is the second most important commercial fishery species in the Caribbean and any factors that could affect reproduction and population ecology are important in maintaining a viable population and managing a sustainable fishery. we suggest using S. gigas as a sentinel of TBT pollution despite not meeting all of the recommended criterion, such as lack of non-dispersive larvae.