Dr. Andy Casper, director of freshwater research at the Shedd Aquarium in Chicago, will speak at The University of Toledo about invasive Asian carp in rivers around the Great Lakes 4 p.m. Wednesday, April 11 in Bowman-Oddy Laboratories Room 1049.

The free, public event is titled “The contrasting ecological influence of pollution, policy and invasive species: Long-term data sets reveal complex trends in the ecology of the Illinois River.”

“The Illinois River has been impacted by two species of invasive carp, the silver and bighead, which do not have populations in the Great Lakes,” said Dr. Christine Mayer, aquatic ecologist and professor in the UT Department of Environmental Sciences. “A related species, grass carp, has recently been found spawning in Lake Erie tributaries.”

“The University of Toledo is doing important work on key issues in the ecosystem,” Casper said. “I am excited about the possibility of sharing information and potential collaborations on important Great Lakes concerns, like the influence of urban development and invasive species on our common Great Lakes resources.”

In 2015 a UT graduate student was the first researcher to discover grass carp eggs in the Sandusky River providing the first proof of spawning in a Great Lakes tributary. Grass carp are a type of invasive Asian carp. Last year, a UT researcher also found grass carp eggs in the Maumee River.

Although considered a species of Asian carp, wild adult grass carp pose significantly different risks to the Lake Erie ecosystem than bighead carp and silver carp. Both bighead carp and silver carp consume plankton, and if these species were to make their way into the Great Lakes basin, they would compete for the same source of food that ecologically and economically important native fish species need to survive. Silver carp are well known for their jumping ability and are a hazard to boaters.

Grass carp pose a risk to waterfowl habitat and wetlands, but they do not eat plankton and are unlikely to compete directly with native fish. Grass carp do not jump and are primarily herbivorous.

Later this spring, Mayer will give a seminar in Chicago at the Shedd Aquarium about the importance of healthy river habitat to Lake Erie fish and the need for tailored restoration in each river. She targets the Maumee, Sandusky and Detroit Rivers.

“The rivers and river mouths are a small area compared to the whole lake, but they hold some key habitats for fish, such as the type of environment required for reproduction,” Mayer said. “Some fish species, such as walleye, spawn both in the lake and in the rivers, but having river stocks helps increase the diversity of our ‘fish stock portfolio,’ just like your financial portfolio.”

While the river habitats are important to native fish to Lake Erie, Mayer said there also is potential for invasive species, such as grass carp, to use rivers for spawning.

“Rivers are highly affected by human alteration of habitat and inputs from the land,” Mayer said. “It is important to try to envision what kinds of conservation or restoration are best suited for the three big rivers entering western Lake Erie to contribute the most benefit to Lake Erie fisheries. Each river has unique issues.”

Water quality is a major research focus at UT. With more than $14 million in active grants underway, UT experts are studying algal blooms, invasive species and pollutants. Researchers are looking for pathways to restore our greatest natural resource for future generations to ensure our communities continue to have access to safe drinking water.