Effects of chlorine treatment in reducing viable zooplankton populations in ballast water tanks

HERNANDEZ M. C..; ESTEBAN M. PAOLUCCI; POTAPOV A.; HUGH MACISAAC

Kananaskis, Alberta, Canada

Encuentro; CAISN's Annual General Meeting; 2013

CAISN

Currently, international ships arriving to the Great Lakes are required to exchange/flush mid-ocean water to reduce the possibility of freshwater species invasions. On a normally-operating bulk carrier traveling between Canada and Brazil, we conducted experiments on fully-ballasted tanks using four treatments: mid-ocean ballast water exchange (BWE), chlorination (Cl), both (BWE + Cl) and neither (controls) to determine their effects on abundance of viable zooplankton. Preliminary results suggest that the combined treatment had lower viable zooplankton counts and thus provided better protection than either treatment by itself.