Invasion of the Alien Creatures

Ecologists estimate that every six months a new invasive species begins carving out a spot for itself in the Great Lakes ecosystem. Many arrive as stowaways on shipping vessels that travel up the St. Lawrence Seaway, hiding out in ballast water until it’s discharged for cargo--leaving the aquatic invaders free to move about the continent. In 2006, one of the most lethal infectious diseases affecting fish populations, viral hemorrhagic septicemia, killed tens of thousands of fish in Lake Erie. Scientists believe it might have arrived in ballast water. Such losses are ruinous in a region that takes in $5.7 billion a year through the sport and commercial fishing industries. In the absence of federal rules to curtail tainted ballast discharges, in 2007 Michigan began requiring that ships treat their ballast water before releasing it in state waters. The shipping industry challenged the law in court; NRDC joined Michigan’s case, arguing that states have the right to enact their own standards. The case was dismissed in August, but NRDC is prepared to defend against the shippers’ appeals.