Tiny invaders in Lake Erie; 4 new species discovered in 3 years

August 18, 2018

Tiny invaders in Lake Erie; 4 new species discovered in 3 years

CLEVELAND, Ohio – The most recent non-native creatures to invade Lake Erie are a pair of microscopic zooplankton that researchers fear could impact the delicate balance of an already tenuous ecosystem.

The discovery of the latest exotics to enter the lake comes two years after two other non-native zooplankton were found in Lake Erie’s western basin, joining an estimated 185 invasive species already present in the lake.

Although researchers are uncertain what specific risks the tiny creatures may pose, they said the discovery causes them concern, nevertheless.

“The fact that these are the third and fourth non-native zooplankton found in Lake Erie in the past three years is an alarming trend,” said Molly Flanagan of the Alliance for the Great Lakes. “A new non-native species in one Great Lake poses a potential risk for the entire region.”

The new species are Diaphanosoma fluviatile, which is from Central and South America and the Caribbean, and Mesocyclops pehpeiensis, a native of Asia. Lake Erie is the farthest north either species has been found in the Western Hemisphere. They were both discovered by researchers from the Cornell University Biological Field Station working with the U.S. EPA in the western basin over the past three years.

These zooplankton are about the size of a grain of rice and appear similar to the most abundant native zooplankton present in the lake, Mesocyclops edax, which are the primary food sources for fish. Lake Erie contains more fish than all the other Great Lakes combined.

Justin Chaffin, a senior researcher with Ohio State University’s Stone Lab, said scientists must first determine if the two non-native species will replace the native species or have any impact on the food web.

“There are other invasive zooplankton of similar size as the two new ones, and they have had little to no impact on food webs or socio-economic impacts,” Chaffin said.

Other invasive species such as the spiny water flea and fishhook water flea “have caused some havoc on the Great Lakes food webs and make it difficult for fishermen to reel in their fishing lines,” Chaffin said.

Marc Smith of the National Wildlife Federation said the two newest non-native zooplankton likely entered Lake Erie from the ballast water of trans-oceanic ships. He said they provide evidence that it would be a devastating mistake for Congress to weaken ballast water legislation by removing the US EPA from its monitoring role, as is being considered.

“With four new non-native species of zooplankton in the Great Lakes in the past three years, it shows that whatever we’re doing to keep them out is not working,” Smith said.

“Invasive species have had tons of economic and environmental impact on the Great Lakes. It’s much easier to prevent them from coming in than to spend millions of dollars trying to remove them from the Great Lakes.”

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