BAKER, S.M.; FAJANS, J.S.; BAKER, P.K.; University of Florida, Department of Fisheries and Aquatic Sciences; University of Florida, Department of Fisheries and Aquatic Sciences; University of Florida, Department of Fisheries and Aquatic Sciences: Demographic release in the nonindigenous green mussel, Perna viridis; Physiological evidence.

Introduced populations are predicted to exhibit a demographic release in their new location and become pests. The zebra mussel is a classic example of a nonindigenous bivalve that experienced demographic release upon introduction to the United States. The green mussel, Perna viridis, was identified in Tampa Bay Florida in 1999 and now reaches densities of over 4000 m². The native range includes tropical coastal waters and estuaries from the Persian Gulf and South Africa to the South China Sea. In the early 1990’s it was introduced to the Caribbean island of Trinidad and subsequently spread to Venezuela. In this study, we 1) documented geographical invasion patterns of P. viridis, 2) performed laboratory challenges of temperature and salinity tolerance for the Tampa Bay population, and 3) compared published temperature and salinity tolerance data for the native and introduced ranges. We hypothesized that P. viridis would exhibit a demographic release in the new location. While physiological tolerances and actual ranges did not necessarily match in the native habitat, our tolerance data closely match the observed field distribution in Florida. This suggests that, upon introduction to Florida, P. viridis did experience a realized niche expansion, more closely matching the broader fundamental niche.