DETROIT, Mich. (WLNS) — An Alpena Fish and Wildlife Conservation Office crew made a spectacular catch in the Detroit River last week, hauling in what it called a “real life river monster.”

It was a massive sturgeon, 6 feet, 10 inches long and weighing in at 240 pounds. The AFWCO estimated the fish, believed to be female, has probably been in the waters for 100 years.

The Associated Press reports it was caught April 22 near Grosse Ile, south of Detroit, by a team working on an annual sturgeon study.

“We have a big net. This fish was all muscle,” U.S. Fish and Wildlife Service biologist James Boase told the AP. “There was a lot of adrenalin flowing. I couldn’t be more proud of them.”

The fish is one of the largest lake sturgeons ever recorded in the U.S., according to AFWCO. It tagged a Friday Facebook post showing off the sturgeon “#dinosaurfish” and “#isthatadolphin,” among other things.

The fish was released back into the river, as is policy for members of the threatened species found in the Detroit River.

—The Associated Press contributed to this report.