A genetic analysis conducted by the U.S. Geological Survey recently confirmed that larval, or newly hatched, fish collected from the Maumee River during the summer of 2018 are grass carp, one species of invasive Asian carps that threaten the Great Lakes.
A genetic analysis conducted by the U.S. Geological Survey recently confirmed that larval, or newly hatched, fish collected from the Maumee River during the summer of 2018 are grass carp, one species of invasive Asian carps that threaten the Great Lakes. The Maumee River is a tributary to Lake Erie.
These young fish are the first grass carp collected in their larval stage from within the Great Lakes watershed. Other life stages, including fertilized eggs, juveniles and adults, have been previously documented in tributaries and shoreline areas of Lake Erie. Identifying locations with larval grass carp in the Maumee River will help inform management decisions and allow natural resource agencies to better focus limited resources on grass carp removal efforts.
“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,” said USGS scientist Patrick Kočovský. “The Lake Erie ecosystem is a major contributor to the Great Lakes’ multi-billion dollar per year fishery.”
On June 13 and 26, 2018, a sampling crew from The University of Toledo collaborating with the USGS sampled the Maumee River in Toledo, Ohio, for early life stages of grass carp. The larval grass carp were collected near the I-280 bridge in the city of Toledo and near the river mouth adjacent to Brenner’s Marina during high water flow events typical of spawning conditions for grass carp. While the samples were being processed in January 2019, six larval fish resembling grass carp were identified.
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Image via USGS.
