Grass carp threaten Great Lakes

Grass carp could invade Great Lakes, inflict damage

March 11, 2014

A newly released scientific paper raises fresh concerns about the potential for grass carp to invade the Great Lakes and do significant damage.

The study was published in the Canadian Journal of Fisheries and Aquatic Sciences.

Plant-gorging grass carp probably could survive in all of the Great Lakes, scientists said, adding that if the fish get established, they might significantly damage the environment.

As many as 45 grass carp were caught in the Great lakes between 2007 and 2012, according to the study.

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

Researchers documented for the first time last year that grass carp had spawned successfully in the Great Lakes, based on an analysis of four fish captured in Ohio’s Sandusky River, a tributary of Lake Erie.

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, crass 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.

A hurdle to keeping the carp out of the Great lakes is the patchwork quilt of policies and regulations, according to lead study author Marion Wittmann. Unlike bighead and silver carp, they are not illegal to possess under federal law. The fish is banned in Michigan and Minnesota; in Wisconsin, they can be used only for research. But the five other Great lakes states- Illinois, Indiana, Ohio, Pennsylvania and New York- allow their use with special permits.

“We’d like to see the Great Lakes states harmonize their policies,” said Tammy Newcomb, senior water policy advisor with the Michigan Department of Natural Resources.

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