| Currently, all transoceanic vessels entering the Great Lakes must perform ballast water exchange or saltwater flushing. Non-compliant vessels presently have limited and often costly and/or time consuming alternatives available. Treatment with sodium chloride (NaCl) brine as an alternative ballast water management option was examined here.;Six shipboard trials were conducted - three trials each on vessels with residual ballast water and with full ballast tanks - under operational conditions to determine the efficacy of brine ballast water treatment. Results indicate that brine is highly effective at reducing viability of zooplankton.;It took 25 and 5 hours to achieve 100% mortality in ballasted and residual ballast vessels respectively. Brine distributed well in tanks, however, vessel movement was essential to ensure thorough mixing. This method of ballast treatment appears to be cost-effective and safe and it could be implemented to reduce risk of new invasions in the Great Lakes. |
