On October 4, 2011, the National Wildlife Federation ("NWF")released a report titled Feast and Famine in the Great Lakes: How Nutrients and Invasive Species Interact to Overwhelm the Coasts and Starve Offshore Waters, claiming that a combination of excessive nutrients and invasive zebra and quagga mussels are causing ecosystem breakdowns in the Great Lakes. According to NWF, excessive nutrients are threatening local species by causing large-scale algal blooms in near-shore waters and invasive mussels are reducing fish populations by depleating nutrients, including plankton, that would support shrimp-like crustaceans, a critical link in the food chain.
Julie Mida Hinderer, the reports co-author, said excessive discharges of phosphorous, which was a problem in the 1950's and 1960's, are reoccurring and are likely due to changes in farming practices. Hinderer went on to explain that the problem is worsened because zebra and quagga mussels consume the beneficial algae in the lakes while leaving the toxic algae behind. Hinderer noted that current estimates state that there are 400 trillion mussels in Lake Michigan alone. The worst algal bloom occurred in Lake Erie in the summer of 2011, was up to two feet thick in some places, and extended across almost the entire western basin and into the central basin.
Andy Buchsbaum, the regional executive director of NWF's Great Lakes Regional Center, noted that the prey fish population in Lake Huron has reduced by 95% over the past fifteen years and that their population in Lake michigan has seen the same reduction over the past 10 years. Typically, when prey fish populations reduce so do predator fish populations--Great Lakes predator fish include lake whitefish and Chinook salmon.
The report recommends the following solutions to the nutriend and mussel problems: negotiating a stronger Great Lakes Water Quality Agreement to better address nutrients entering the lakes, enacting a federal farm bill that includes programs to reduce agricultural runoff, and using the Clean Water Act to uphold water quality standards. Other potential solutions include using fish management or introducing a microbe into the lakes to reduce mussel numbers.
