The Coast Guard has issued final ballast water standards applicable to ships on the Great Lakes. Currently, "salties" (ships that enter the Great Lakes system from the ocean) must discharge their ballast tanks before entering the Great Lakes through the St. Lawrence Seaway. The Coast Guard has acknowledged, however, that some organisms could survive in remaining puddles of water and mud. The new standards will require onboard treatment of ballast water to kill as many fish, mussels, and even microbes as possible. 

The new standard limits numbers of living organisms in particular volumes of water. Ships will have to install equipment meeting the standards developed by the International Maritime Organization. "Once fully implemented, this ballast water discharge standard will significantly reduce the risk of an introduction of aquatic nuisance species in the Great Lakes," said Rear Adm. Michael Parks, commander of the Coast Guard's Cleveland district. However, in a written statement, the Coast Guard said that it "fully intends to issue a later rule that will establish a more stringent phase-two discharge standard."