Shared from the 3/18/2019 Sandusky Register eEdition


Grass carp larvae found in Maumee River


Larvae from grass carp, a variety of Asian carp, have been found for the first time in the Lake Erie watershed.

An Erie County fish scientist who works in a government office at NASA Plum Brook Station helped confirm the discovery of the newly hatched grass carp in the Maumee River.

But grass carp in other stages of life — fertilized eggs, juveniles and adults — have been found in Lake Erie tributaries and in the lake itself, including in the Sandusky River.

In theory, at least, the grass carp could be a major threat to the lake, said Patrick Kocovsky, a scientist at the U.S. Geological Survey office at Plum Brook.

“If grass carp become abundant in Lake Erie, they could consume large amounts of aquatic vegetation, ultimately reducing habitat for native fish and other aquatic animals, and diminishing food resources for waterbirds,” Kocovsky said. “The Lake Erie ecosystem is a major contributor to the Great Lakes’ multibillion-dollar fishery.”

But Kocovsky told the Register he is encouraged by the fact that only a few grass carp have been found since 2014, when efforts to catch them in Lake Erie and in the lake’s tributaries were stepped up.

The University of Toledo said in a news release that last June a sampling crew from the school working with the U.S. Geological Survey found suspected grass carp in the Maumee near the Interstate 280 bridge and near the mouth of the river next to Brenner’s Marina.

Six suspected grass carp larvae were identified from the sample in January 2019.

Nicole King, a research technician at the University of Toledo, identified the larvae. She was part of the crew that took the larvae from the Maumee.

Kocovsky said King contacted him about the larvae.

Kocovsky, an Asian carp specialist, observed photographs of the larvae taken with a microscope, looking at the length, shape, color and number of muscle segments and agreed they looked like grass carp larvae. Samples sent to a laboratory confirmed a genetic match.

Kocovsky said the different varieties of Asian carp pose different threats to Lake Erie.

Grass carp like to eat vegetation, while bighead carp and Asian carp eat plankton and algae. All Asian carp are considered invasive species and can affect the lake’s ecology. It’s almost impossible to say which fish would be worse for the lake, Kocovsky said.

While bighead carp have been found in Ohio, they were last recorded in the Lake Erie watershed in 2000, when a bighead carp was reported in Sandusky Bay, according to the U.S. Geological Survey’s Nonindigenous Aquatic Species website. Silver carp have not been recorded in Lake Erie or the Lake Erie watershed, the website says.

Grass carp have been found in Erie, Ottawa and Sandusky counties and other Ohio locations.

The U.S. Geological Survey maintains an office, the Lake Erie Biological Station, at NASA Plum Brook Station in Erie County. The office, which has 10 people when it’s fully staffed, conducts research and has a research boat, the Muskie, which uses Huron as a home port but currently is in winter storage in Port Clinton.

The staff at the Lake Erie Biological Station was furloughed during the recent partial shutdown of the federal government.

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