A recent study by the University of Wisconsin–Superior‘s Lake Superior Research Institute (LSRI) shows that Lakers are transporting non-native species from the lower great lakes to western Lake Superior. Ballast water is held in the bottom of ships to improve vessel stability. The water is taken up as cargo is loaded or unloaded. The LSRI studied ballast water discharges at the Port of Duluth from 10 U.S. and Canadian lakers last year from late summer to early winter; 13 of the 15 discharges sampled contained invasive zooplankton.
The study does not cover whether these species were alive upon discharge or what their chances are for survival in Lake Superior. Nonetheless, the results are being considered as evidence towards the necessity for practical ballast water management solutions. The Chamber of Marine Commerce members and the Lake Carriers’ Association provided support for this research.