Watch: Nearly 7-foot, 240-pound lake sturgeon caught in Detroit River believed to be 100+ years old
Biologists have discovered an extremely rare "river monster" in the Detroit River that they believe has been lurking in the water since 1920.
A three-person crew from the Fish and Wildlife Conservation Office in Alpena, Michigan, made the unexpected catch on April 22 while they were conducting their annual study of the river's sturgeon fish population, according to an agency statement obtained by PEOPLE.
"It was the biggest fish our team has ever seen," Jason Fischer, one of the fish biologists that caught the sturgeon, said in the statement. "This fish took all three of us to get it onto our boat."
The massive 6-foot, 10-inch lake sturgeon, who weighed in at an impressive 240 lbs., is believed to be one of the largest sturgeon ever recorded in the United States. Biologists estimated the sturgeon to be a female, hatched around 1920. After being measured, weighed, and marked with a unique tag, the fish was released back into the river so biologists can identify her if she's ever caught again.
According to the U.S. Fish and Wildlife Service, the typical lifespan of lake sturgeon is 55 years for males and 80-150 years for females.
Fischer reeled in the monster with fellow biologists Paige Wigren and Jennifer Johnson.
"She was tired out and didn't fight us very much," Wigren told the Associated Press. "Imagine everything that fish has lived through and seen."
Wigren added that, during the catch, she thought to herself, "Yep, this is going to be a real good fish story."
Lake sturgeon are considered to be a threatened species in Michigan. The fish population's deterioration has been fueled by over-harvesting, habitat loss, damming of tributaries, and pollution, among other factors, according to the U.S. Fish and Wildlife Service.
Fischer noted in the statement that more than 28,000 lake sturgeon use the St. Clair-Detroit River System, and of those fish, about 5,5000 come from the Detroit River. Though the population has significantly declined, it is still one of the largest in the Great Lakes, the statement said.
"The U.S. Fish and Wildlife Service partners with a number of other agencies and universities, including the Michigan Department of Natural Resources, U.S. Geological Survey, Department of Fisheries and Oceans Canada, and Michigan Sea Grant," Fischer added. "Together we monitor lake sturgeon populations in the St. Clair-Detroit River System and help populations recover through habitat restoration projects such as constructing rocky spawning reefs."
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