As of July 1, ships planning to enter U.S. waters will have to show they are doing their part to stem the tide of invasive species. The Coast Guard is implementing new regulations that will require big ocean vessels to empty their ballast tanks at sea before entering U.S. waters, in theory washing out foreign plants, animals, and bacteria that otherwise could invade U.S. waters. U.S. officials and scientists are becoming increasingly alarmed at bioinvasions.