Long-term changes in imposex frequency in file dogwinkles, Nucella lima G., and tributyltin concentrations in bay mussels, Mytilus trossulus G.

We quantified imposex in file dogwinkles (Nucella lima) and tributyltin (TBT) contamination in bay mussels (Mytilus trossulus) from a number of sites in Auke Bay, Alaska, previously studied in the late 1980s. Imposex occurrence and TBT contamination have generally declined in spatial extent and severity over time. However, high levels of TBT contamination (0.069 microg TBT/g wet tissue wt.) and imposex (100% of females affected) are still present near a large boat docking facility in the bay and deserve continued attention because of the importance of this bay to the local economy and fisheries.