During the summer of 2014 sixteen science teachers from all around the Great Lakes region spent a week on board the U.S. E.P.A ship R/V Lake Guardian on Lake Erie as part of the Shipboard and Shoreline Science Workshop. Sponsored by the Center for Great Lakes Literacy, Ohio Sea Grant, Pennsylvania Sea Grant, and the U. S. Environmental Protection Agency, teachers were connected with scientists in first hand explorations of the ecology, geology, and bio-geochemical processes of Lake Erie.

Although I knew the experience on the R/V Guardian was going to be amazing, I never dreamed that the workshop would have such an impact on my students. Towards the beginning of the school year my class spends a lot of time learning about the importance of qualitative and quantitative observation. This year my students were able to apply their understanding of metric measurement while learning about the Great Lakes. Students were engaged in an activity where they had to use yarn to outline, label, and organize the shorelines of the Great Lakes to scale. After graphing the shoreline metric distances, students compared the total shoreline distances of the Great Lakes to the U.S. shoreline along the Atlantic Ocean, Pacific Ocean, and the Gulf of Mexico. Students then compared and contrasted the size of the Great Lakes to the total volume of water each lake holds, the metric mass of commercial fish caught, and the human population surrounding each Great Lake. This activity enabled me to reinforce the importance of metric measurement as we used metric rulers, triple-beam balances, and graduated cylinders in class. This also set the stage for in-depth discussion of the Great Lakes and the problems they face.

problem in the Cuyahoga River watershed, invasive species are now the real concern.

Even before zebra and quagga mussels arrived in the Great Lakes in the 1980s, the future looked a little bleak for native mussels. The invaders came close to wiping them out entirely. But small populations in Lake Erie appear to not only be surviving the invasion, but thriving. 

Average density of native mussels before the arrival of zebra mussels was two per square meter in Lake St. Clair. By 1990, zebra mussel density was at 1,600 per square meter. 

“By 1992, native mussel populations are almost gone from the southeastern portion of the lake and declining rapidly in the northwestern portion of the lake,” said [Dave] Zanatta, [a biologist at Central Michigan University]. 

By 1994, there were almost no native mussels left in the lake, with zebra now at 3,000+ per square meter. 

“But there was reason for hope,” said Zanatta. “Remnant populations of native mussels were beginning to be found in coastal wetlands in western Lake Erie in the late 1990s.” 

Zanatta’s research adds further evidence that progress continues to be made on one of the impairments of the St. Clair River – the degradation of fish and wildlife habitat – that led to its classification as an environmental Area of Concern in 1985. 

His work also sheds light on the complex ecological impacts of invasive species generally. 

With some environmental observers predicting a doomsday scenario for native game fish if Asian carp are able to establish themselves in the Great Lakes, for example, Zanatta’s mussel research suggests that the outlook for native fish might be significantly more positive than forecasts suggest.

To read the full article, click on the link above. 

**Photo of zebra mussels courtesy of Michigan Sea Grant. 

When researchers and the media talk about Asian carp reaching the Great Lakes, they are typically referring to bighead and silver carp, the two voracious phytoplankton eaters that are wreaking havoc in places like the Mississippi and Illinois rivers. But the species most likely to establish in Lake Erie may actually be a third member of the Asian carp family: grass carp. 

From The Voice: 

“Grass carp are a different kind of fish and pose different kinds of risk than bighead and silver carp,” said Jeff Tyson, administrator of the Lake Erie Fisheries Program Administrator for the Ohio Department of Natural Resources. Tyson addressed a meeting of environmental writers at Ohio State University’s Stone Lab in Lake Erie on Aug. 18. “We know we have some grass carp in the system. Grass carp impact the system through their impacts on structure and vegetation. They consume huge amounts of vegetation.”

Grass carp could put Lake Erie at risk “by damaging habitats and damaging fish in communities given the documented reproduction of grass carp in large rivers,” according to the Ohio Asian Carp Tactical Plan, 2014-2020. “Grass carp can also decimate submersed aquatic vegetation that is critical to migrating waterfowl and other water birds.” Read more. 

**Photo courtesy of Eric Engbretson, US Fish and Wildlife Service, Bugwood.org. 

“Multiple water samples taken from the Muskingum River last fall carried the environmental signature of bighead carp, an invasive species threatening the ecosystem of the Great Lakes. A report released Friday by the Nature Conservancy — in conjunction with the Muskingum Watershed Conservancy District, the Ohio Department of Natural Resources, and researchers from Central Michigan University — indicated 10 of the 222 samples from the river tested positive for bighead carp eDNA.

 

Asian carp have been established in the Ohio River for more than a decade, but these eDNA results indicate the fish could be present in the Muskingum some 80 miles north of where the Muskingum joins the Ohio at Marietta.

 

The Muskingum has a series of old dams and deteriorating locks, but if the genetic evidence is accurate, those have not provided a significant impediment to the carp moving up the river system.”

“Algal blooms and dead zones in Lake Erie were severe during the 1960s, caused primarily by large releases of phosphorus from sewage and industrial plants. The 1972 federal Clean Water Act and the 1978 bi-national Great Lakes Water Quality Agreement led to dramatic reductions in phosphorus from these sources and a rapid improvement in water quality.

 

Lake Erie, however, saw a reemergence of the algal blooms and the growth of the dead zone in the mid-1990s, and the problems are worsening. In 2011, for example, Lake Erie experienced its most severe bloom of toxic algae on record. Last fall a toxic algal bloom in the lake forced officials to shut off a public water supply system in Ohio.

 

The new studies, part of the Ecological Forecasting (EcoFore) Lake Erie project led by researchers at the University of Michigan, found that the current targets to reduce phosphorus to alleviate algal blooms in Lake Erie may not be low enough to revive the dead zone. That conclusion informed the International Joint Commission’s recommendations in February for improving Lake Erie’s water quality.

 

The findings, and those of other studies from across the Great Lakes region, are delivering an ever clearer picture of the specific causes of nonpoint phosphorus runoff, algal blooms, and dead zones. The basic drivers of these problems are no longer unknown. The new research fills a critical void in information that has been often cited as a reason that strict regulations on nonpoint pollution sources, including agriculture, were not regulated under the 1972 federal Clean Water Act.”

“Grass carp, a plant-eating species of the invasive Asian carp family, have also been found spawning in Lake Erie and its many tributaries… 

 

Though fears over invading Asian carp have largely centered on bighead and silver carp — which gulp down large amounts of plankton, the all-important food-source foundation for a healthy aquatic ecosystem — the new study suggests conservationists should pay attention to grass carp too.

 

Grasses are also an important nutritional source for native fish species, and as its name suggests, grass carp could prove detrimental in that department.

 

The U.S. government has already spent upwards of $200 million trying to slow the encroachment of Asian carp into the Great Lakes. Many worry their growing presence will turn the Great Lakes into one giant carp pond — ruining ecological diversity and the multi-billion dollar fishing industry in the region. Regional authorities remain in discussion with federal agencies over further mitigation efforts.”