The Great Lakes Erie, Michigan, and Ontario have been invaded by an Asian carp species, the grass carp. The carp is proving to be an environmental risk for the Great Lakes region, but researchers feel that there is still time to prevent the spread. The grass, bighead and silver carp are some of the Asian carp species that threatens freshwater systems around the world.
Carp are a species of oil freshwater fish native to Europe and Asia. The grass carp is voracious and feed on aquatic vegetation that is needed for habitat and spawning grounds of other native fish. Bighead and silver carp are the most feared and compete with other native fish that feed on microscopic plants and animals. Some of these carp, scientists say, are reproducing. Grass carp were first brought to the U.S. to control weeds in waterways in the early 1960s. Some escaped, migrating into the Mississippi River and swam upstream towards the Great Lakes.
Marc Gaden, a spokesman for the Great Lakes Fishery Commission, said that the consensus on the risk to the Great Lakes region is “pretty substantial” from the Asian carp. While it was know that a limited number of grass carp were in U.S. lakes, some have spread into Lake Michigan through a waterway in Chicago while other carp may have been released “intentionally or by accident,” the Columbia Daily Tribune reported.
The carp have been showing up recently to the point of an invasion, Gaden continued. Some captured carp have even been fertile. Grass carp are allowed to be raised in hatcheries by some states but are mandated to first be sterile prior to being released into wild waters.
Since 2012, 23 grass carp were captured in Canada including five in Toronto from the waters of Lake Ontario, stated Becky Cudmore, the Asian carp program manager for Canada’s fisheries and oceans agency and the lead author of the study. According to the study, grass carp will soon become established in Lakes Huron, Erie, Ontario, and Michigan within a decade unless steps are taken to effective stop them, stated the Columbia Daily Tribune. Lake Superior, which is colder and offers less food, has a lower risk for the invasive carp.
Scientists are researching how to prevent established populations from reproducing over multiple generations. Tougher laws against the introduction of carp into the region and stopping fertile fish from being released from hatcheries are two of the strategies in preventing the invasive carp species. Another possibility would be to use nets that block the carps’ path to spawning areas during their reproductive season. Cudmore speaking to the Chicago Tribune said that their assessment says yes, the carp were showing up before, however, now they are starting their natural process of invading the area they are in. “They have arrived. Now is the time to act.”
By Cheryl Werber