Chapt 5 Ballast Water Exchange Experiments, page 5- 1 Chapter 5. Ballast Water Exchange Experiments on Tankers

The primary objective of this research component is to measure the efficacy of ballast water exchange in removing various types of taxa from ballast tanks of oil tankers. There are very few quantitative studies that have measured the effects of exchange, and these are restricted to just a few vessel types and measure the effect on a small subset of entrained taxa. It is likely, however, that the efficacy of exchange varies by vessel type, tank design, and organism type. To date, there have been no measures of ballast water exchange for oil tankers. Ballast water exchange is the most widely used national and international management strategy to limit new invasions associated with ships ’ ballast water (Hallegraeff 1998, Zhang & Dickman 1999, Dickman and Zhang 1999,. Moreover, exchange is currently the only treatment method available for commercial ships to reduce the quantities of non-indigenous coastal plankton in ballast water (National Research Council 1996). This practice is recommended by the International Maritime Organization (IMO) to reduce the risk of invasion by shipping. Furthermore, the U.S. Congress passed the National Invasive Species Act of 1996 (NISA) to encourage ballast water exchange. Specifically, NISA requests that vessels arriving from outside of the Exclusive Economic Zone (EEZ) voluntarily conduct open-ocean exchange of ballast tank