Great Lakes’ Asian Carp Crisis Deepens
Concerns about Asian carp invading the Great Lakes have already prompted states to sue each other before the U.S. Supreme Court and led to plans for a White House summit. But those worries were ratcheted up even higher this month with the discovery of Asian carp DNA in Lake Michigan’s Calumet Harbor. The environmental DNA (known as eDNA — more on that later) had already been found in multiple spots between Lake Michigan and the electric barrier in the Chicago Sanitary and Ship Canal designed to block the voracious invaders and keep them from ravaging the Great Lakes’ ecosystem. With the latest discovery, environmental groups have renewed their calls to sever (ecologically speaking) the Great Lakes from the Mississippi River watershed. The two systems were linked by canal more than a century ago so that Chicago could dump its sewage, diluted with Lake Michigan water, into the Mississippi River and keep the Great Lakes clean. The most effective ecological separation, at least in the short term, would involve temporarily closing the locks between the canals and Lake Michigan and erecting barriers in other waterways without locks in order to impede the carp’s progress. In December, Michigan filed a lawsuit backed by other states demanding emergency closure of the locks until a permanent means of ecological separation can be found. Officials fear for water quality and the $7 billion Great Lakes fishing industry if the invaders reach Lake Michigan. Asian carp have damaged every U.S. waterway they’ve entered, outcompeting native species as they voraciously vacuum up plankton, and injuring boaters with their propensity for powerful leaps out of the water. But on January 19, the U.S. Supreme Court rejected Michigan’s request for immediate action without explanation, leading two lawmakers from the state, Republican Congressman David Camp and Democratic Senator Debbie Stabenow, to introduce the CARP ACT, which stands for Close All Routes and Prevent Asian Carp Today. It seeks the emergency closure of the locks and additional underwater barriers. The Supreme Court could still act on a broader aspect of Michigan’s request, which demands an end to the so-called "Chicago diversion" of Lake Michigan water. That suit was filed by Great Lakes states in 1922. In its decision at the time to leave the waterway intact, the Supreme Court left open the possibility that it could change its mind if the diversion were shown to cause harm. Michigan resuscitated the suit in December, in the face of strong opposition from the state of Illinois and industry groups that claim closing the canal would hamper shipping and flood control. Skeptics question whether the DNA that’s raising alarm bells could have been transported past the barrier on boats or barges or through Chicago’s sewer system. The Army Corps of Engineers has noted that no actual Asian carp have been found past the electric barrier. But scientists with the Nature Conservancy and University of Notre Dame, who developed the eDNA test, say the discovery of DNA in multiple tests means that Asian carp have indeed breached the barrier. Fish slough off DNA in scales, feces, urine, and mucus. Since last summer, scientists have taken hundreds of 2-liter water samples from the canals, rivers, and harbors connected to Lake Michigan. They can amplify bits of DNA taken from the biological material in the water samples and compare them with Asian carp DNA. David Lodge, the director of Notre Dame’s Center for Aquatic Conservation, says scienctists don’t know how long the DNA stays in water, and the tests can’t tell them how many fish might be in a particular lake or river. "It’s a pretty blunt instrument at the moment," Lodge says. "All it tells us is there were fish here." In the case of the Great Lakes, even that small indication is enough to make officials sweat. The Asian carp crisis has now made it all the way to the Oval Office (which is currently occupied by a Chicagoan, after all). President Obama’s top environmental advisor recently proposed an "Asian carp" summit with Great Lakes governors in early February, and state attorneys general are demanding invitations. The White House has called Asian carp a serious threat — but so far has supported Illinois in the dispute. Closing all of the Chicago-area locks would entail cooperation from the federal Army Corps of Engineers, as well as state and municipal governments. NRDC Midwest program director Henry Henderson said policymakers should take this opportunity to re-engineer an outdated shipping system that is economically inefficient and environmentally dangerous. NRDC recommends replacing the canals with a new intermodal facility that would transfer cargo from barges and ships to trucks, trains and other barges. "Looking at Asian carp as the problem instead of the alarm bell unnecessarily truncates the solution," Henderson said. "It’s not like two species of Asian carp are the problem — this 19th century canal system has been revealed to be unambiguously a highway for invasive species."
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Great Lakes’ Asian Carp Crisis Deepens