The main goal of the project was to investigate the feasibility of treating ships' ballast water in existing municipal wastewater treatment plants (= publicly-owned treatment works or POTWs). The main objectives included identifying and characterizing the limiting factors that could restrict the volume of ballast water that can be treated at POTWs; and test, in a series of laboratory experiments, the effectiveness of standard municipal wastewater treatment in removing or killing ballast water organisms. We worked with staff of the City and County of San Francisco to analyse the effects of treating ballast water at San Francisco's Southeast Treatment Plant (SETP) as a model. We report here on the experimental tests and analyses of the effectiveness of treating ballast water organisms in POTWs.

The distribution of macroinvertebrates across a tidal gradient is described froma study of invertebrate distribution across tidal marsh sub-habitats, a non-quantitative survey of epifauna on intertidal rocky substrate, and a few additional observations and records from China Camp State Park, Marin County, California. In the tidal marsh study, invertebrates were sampled from distinct sub-habitat types: high-order channels, low-order channels, vegetated marsh plain, and natural levees adjacent to channels. Invertebrates were collected using a variety of trapping methods to account for capture biases associated with any one method. All common invertebrate taxa were significantly more abundant in a particular sub-habitat, and within each trapping method a few species accounted for most of the biomass. On intertidal rocks, 79% of the taxa identified to species or genus were exotic, but a few native species were common.