The Federal Maritime Commission is seeking more information as it investigates the potential impact of Canadian environmental regulations on U.S. shipping companies operating in the Great Lakes. Nearly two years ago, the Lake Carriers’ Association filed a complaint with the commission that Canadian rules for ballast water would harm their operations. The trade association wanted to slap a $300,000 fee on any Canadian vessel entering a U.S. port. Ballast water helps ships balance their loads. But it can also transfer invasive species between water bodies. The commission wants more information on how the finalized Canadian regulations might affect U.S. ships.