How effective is Open Ocean Ballast Exchange?
The efficacy of open-ocean exchange with respect to minimizing species introductions is arguable. So far only a few studies have examined the effectiveness of open-ocean ballast exchange, the only ballast water management practice approved by the United States to date. Existing studies have been restricted to just a few vessel types and assessed the effect of exchange for only a few organisms. Our lack of knowledge and detailed assessments concerning the mechanics and effectiveness of ballast water exchange represents a fundamental gap in determining the value of exchange compared to alternative strategies, as a barrier to future invasions. This is a national issue of importance to all coastal regions and a program could be implemented at the national level. However, within such a national implementation, the special needs related to the Great Lakes must be acknowledged. For the Great Lakes, the protective effects of exchange may be greater than for other coastal regions. For ships bou
