Biological invasions by organisms transported in ship ballast water are an increasing cause of environmental degradation and a significant source of economic costs to society. In preliminary research, the P.I. have adapted probabilistic models to estimate invasion risk from propagule pressures, and enumerated adult organisms from samples of Great Lakes ship ballast water. Though invasion risk from resting stages of invertebrates is generally believed to be considerable, it has not yet been quantified due to the technical difficulty of identifying resting eggs from morphological characters. Thus, the goals of this research are to identify and enumerate resting eggs in samples through a combination of molecular and statistical techniques. Pilot studies to assess the feasibility of this approach indicated that high-quality quantitative estimates of propagule pressure can be obtained through a four step process: (1) extraction of nuclear and mitochondrial DNA; (2) separation of gene sequences using denaturing gradient gel electrophoresis; (3) identification of taxonomic groupings based on gene sequences; and (4) estimation of species relative abundance with statistical models. The proposed research will use this method to provide estimates of propagules pressure from 20 ships and to conduct risk assessments of invasion.
