TRAVERSE CITY, Mich. -- Invasive grass carp have reached three of the Great Lakes and pose a significant environmental risk there, but time remains to prevent them from getting out of hand, according to a scientific analysis released Friday.
The grass carp is among four Asian carp species threatening to reach the world's largest surface freshwater system.
Grass carp have been found in Lakes Erie, Michigan and Ontario, although it's uncertain how many there are or how widely they have spread, U.S. and Canadian researchers said. At least some are reproducing.
Grass carp were introduced to the U.S. in the early 1960s to control weed growth in waterways. Like other Asian carp, some escaped into the Mississippi River and have migrated northward toward the Great Lakes.
The carp have turned up more often in recent years and the threat of a full-fledged invasion appears to be rising, especially because some of those caught have been fertile, said Marc Gaden, spokesman for the Great Lakes Fishery Commission. Grass carp reared in hatcheries, which some states allow, are supposed to be sterilized before being released into the wild.
"Our assessment is saying that yes, they were showing up before, but now they're starting the invasion process," said Becky Cudmore, Asian carp program manager for Canada's fisheries and oceans agency and the report's primary author. "They have arrived. Now is the time to act."
A Section on 01/29/2017