Rapana venosa (rapa whelk) is a large, long lived, predatory gastropod that is native to the Sea of Japan. It was discovered in Hampton Roads, VA in 1998, arriving via ballast water in coal ships from the Black Sea and eastern Mediterranean. The Molluscan Ecology Program at VIMS enacted a bounty program in collaboration with local watermen to collect rapa whelks. Between 1998 and 2009, over 22,000 whelks were removed from the lower Chesapeake Bay and its sub-estuaries . Rapa whelks have a complex life history that exploits several niches in the Bay, they are voracious predators on local shellfish resources, and there is a lack of a local predator to control them for most of their lives. O n prolonged exposure to tributyl tin (TBT), an active component in anti-fouling paints for ships as used in the shipbuilding and repair industry in Hampton Roads for over 40 years, female rapa whelks exhibit development of an accessory male penis, a state called imposex with accompanying impaired sexual function. Strangely, the presence of toxic TBT offered hope for control of an invader. A 2019-2020 survey by the Unger laboratory at VIMS (Figure 1) revisit ed select sites in Hampton Roads to sample for TBT.
Herein we describe a follow up 2021 survey of imposex in a now endemic Rapana population, again implemented as a collaboration with local watermen, in the Elizabeth River region. A total of 174 Rapana were collected (SL range 54-145mm, 53 female + 31 imposex female + 90 male). These data are compared with records from the 2000-2007 period in terms of size, sex ratio, incidence of imposex within the population and TBT concentrations in the foot tissue. The presence of all size ranges in the 2021 collections is indicative of continued reproduction and recruitment into the extant population .