Strategy for Testing the Efficacy of Ballast Water Treatment Technologies

摘要

One of the principal vectors of aquatic invasive species introductions is the transport of organisms in ballast water. The primary management practice to reduce such introductions during routine ballasting operations is mid-ocean ballast water exchange (BWE). Due to BWE limitations (e.g., safety, route, efficiency), ballast water treatment (BWT) technologies to remove or inactivate entrained organisms are being developed. BWT technology is in the very early stages of development as are the testing approaches to gauge BWT efficacy. During reviews of various BWT systems for the U. S. Coast Guard, it became clear that while the testing methodologies may be technically sophisticated, the test programs generally employ inappropriate measures of system effectiveness and frequently lack adequate experimental design. BWT effectiveness must be based upon either species-specific physical removal or organism viability/propagation. This report provides an overview of concepts needed for effective testing of BWT technology efficacy. The focus is to relate both theoretical and design issues to BWT test program development and conduct. Examples from experiences with Coast Guard's scientific audits, workshops, and available literature illustrate key principles and methodological problems encountered. Also discussed is the need for research into new methods for ascertaining viability, and investigations to discover surrogate species whose inactivation represents the response of a broad spectrum of taxa identified in ballast water.