Officials with Fisheries and Oceans Canada and the Ontario of Ministry of Natural Resources confirmed the fish caught near the mouth of the river was a live grass carp, one of four species of Asian carp, CBC News reported Friday.
Asian carp are considered highly invasive and one of the biggest threats to the Great Lakes ecosystem and the region's economically important sport fishing industry.
Lab tests revealed the carp caught by a person fishing in the Grand River was sterile, scientists said.
Several U.S. states allow the stocking of grass carp to control aquatic plants but require the fish to be sterilized to prevent them from reproducing, Fisheries and Oceans Canada officials said.
The fish from the Grand River measured more than 40 inches in length and weighed nearly 40 pounds.
The other species of Asian carp are bighead, silver and black carp.
All four species are illegal to possess as live fish in Ontario and Michigan, authorities said.