While at NOAA I ran a series of evaluations on the efficacy of proposed ballast tank treatment methods to prevent invasive species invasions. In the Great Lakes and ports worldwide, commercial cargo ships are a vector for invasive species introductions. Water is taken into the ballast tanks of these ships to balance the cargo and trim the ship. Invasive species including zooplankton can hitch a ride in the tanks, and then be deposited in a new place. If ballast tanks can be treated in some way, then the risk of introductions can be mitigated. I evaluated physical and chemical treatment methods targeting zooplankton resting eggs using toxicological bioassays. I also sampled inside the ballast tanks of giant cargo ships, and it was like spelunking in a steel cave.The photo shows a UV-light collimator, hand-made by Dr. Ernest Blatchely. Products include: Raikow et al. 2007a, Raikow et al. 2007b, and Raikow et al. 2006.