Principal Investigators: Thomas H. Johengen (CILER) and David Reid (NOAA/GLERL)

A "Code of Best Practices for Ballast Water Management" was developed by the Shipping Federation of Canada and the (U.S.) Lake Carrier's Association in 2000. In 2002 the St. Lawrence Seaway corporations adopted rules making compliance with the Code mandatory for entry into the Seaway. The Code promotes the maintenance of relatively clean ballast tanks through a program of regular inspection and cleaning, combined with a precautionary approach to ballasting with the objective of limiting or avoiding the uptake of ballast under specified conditions. To our knowledge, however, there has never been an assessment of the extent to which commercially operating ships can realistically apply these practices or the effectiveness of the stated practices for reducing the risk of new species introductions. We therefore conducted this scientific study to 1) test and evaluate the effectiveness of the current Best Management Practices (BMPs), focusing on a subset that are specifically applicable to ballast management for reduction of invasion risk associated with empty ballast tanks on ships entering the Great Lakes with no pumpable ballast-on-board (NOBOB), and 2) test a set of enhancements to the existing BMPs, focusing on flushing of tanks with deep ocean water, either when the ship is in NOBOB condition or as an intermediate step in deep ocean exchange. In particular, we wanted to examine whether BMPs are effective at reducing the abundance and viability of live organisms and resting stages.
To complete this objective we conducted detailed biological assessments of microbial, phytoplankton, and invertebrate communities present within both sediment and water ballast residuals for two participating ships during each entry into the lakes and compared results against ballasting history and any BMPs applied. Lastly, we attempted to more thoroughly assess the extent to which salinity toxicity, whether through open-ocean ballast water exchange (BWE) or saltwater flushing, can prevent the transfer of low-salinity species to the Great Lakes.