Invasive grass carp in Lake Huron
It has been less than a year since grass carp were found in Lake Erie. Grass carp have been found in unknown numbers in Lake Huron. The feeding of the grass carp could rapidly wipe out all the plants in a wetland, leaving nothing and destroying areas native fish species use for spawning.
Just less than a year ago researches had evidence that the invasive grass carp were swimming and spawning near the mouth of a river in Ohio that flows into Lake Erie. More recently 10 individuals have now moved upstream to Lake Huron.
An alert was issued calling for Ohio and US Environmental Protection Agency (EPA) to begin the grass carp eradication measures immediately.
Grass carp are one of four Asian carp species threatening the Great Lakes. Originally brought to the US more than 50 years ago to control weed growth, these fish feed on aquatic plants, eating up to 90 pounds a day, damaging areas used for spawning or by migrating birds.
The voracious feeding of the grass carp could rapidly wipe out all the plants in a wetland, leaving nothing and destroying areas native fish species feel protected. The Georgian Bay Great Lakes Foundation (GBGLF) Chair Mary Muter returned from an annual conference of International Association of Great Lakes Researchers (IAGLR) with disturbing news: “These fish are very hard to catch because they elude traditional fishing nets. If 10 have been found in Lake Huron, there are likely more present.”
In further disturbing news, a 2017 bi-national risk assessment by Fisheries and Oceans Canada and the US Geological Survey determined the invasion into Lake Huron would occur within the next 10 years.
Additionally, if the arrival of the grass carp species into Lake Huron occurred sooner, the greater the risk of damage.
It has been less than a year since grass carp were found in Lake Erie and even less since the risk assessment, and already grass carp have been found in unknown numbers in Lake Huron.
According to Muter, Ohio officials have plans to continue to catch these large fish, insert tracking devices, release them live and study their movements. This plan should provide insight to devise a possible management technique to ‘control’ the population. “With both Ohio and Michigan not planning to eradicate the grass carp, this wetlands destroyer is on the verge of becoming established in the Great Lakes. To stop this invasion, it is urgent to implement every possible eradication method now,” Muter adds. As Canada spends up to $20 million to prevent grass carp from invading into Canadian Great Lake waters, it is unacceptable that agencies in the US conduct “research projects”, rather than beginning eradication methods. The future of the Canadian Great Lakes ecosystems are put at risk.
The large fish are seldom found in the deeper waters, but rather along the shorelines where there are wetlands, for them to feed off of plants. The grass carp could eventually destroy wetlands for the native fish that are being sold by commercial fishers such as walleye/ pickerel and whitefish.
“An assessment carried out in 2017 found up to 1.2 million acres of wetlands including submerged aquatic plants in the five Great Lakes,” Muter says.
“Each acre of wetland provides $1,500 annually in ecological services. If all the Great Lakes are invaded by grass carp, the cost of the loss of these ecological services could mount to $16.5 Billion per year. Can we afford to let this happen?”