Biologists Catch Enormous ‘Real Life River Monster’ in Michigan

The seven-foot-long female lake sturgeon was microchipped and released promptly back into the water

A photo of an enormous brownish grey fish laying on the deck of a boat. Next to the fish is a reseacher dressed in winter gear and a mask. The fish is larger in length than the reseacher.
Lake sturgeons have a striking appearance with their shark-like tails, five rows of bony plates lining their brownish grey bodies called "scutes", and their whisker-like barbels below their rounded snout. Jason Fischer/USFWS

On April 22, during an annual survey of the lake sturgeon population in a river in Michigan, biologists reeled in a colossal catch. Weighing in at 240 pounds and measuring nearly seven feet long with a girth of about four feet, the female fish is estimated to be at least 100 years old, reports Annamarie Sysling for NPR. Officials suspect it may also be one of the largest lake sturgeons ever recorded in the United States.

The sizeable sturgeon was caught using a frozen round goby as bait, attached to a line that reached deep into the Detroit river, reports Mike Jordan for the Guardian. After the scientists felt a bite on their line, it took the crew of three scientists several minutes to haul the "real life river monster" into their boat using a net, according to a Facebook post from the Alpena Fish and Wildlife Conservation Office.

"All of the sudden, this gray and white shadow came to the surface, and for about 5 to 8 minutes, we struggled to try to get the fish into the net," said biologist Paige Wigren to NPR.

Lake sturgeons have a striking appearance, with shark-like tails, five rows of bony plates called scutes lining their brownish gray bodies, and whisker-like barbels below a rounded snout. The fish's natural habitat spans freshwaters in North America, including the Great Lakes basin, the Hudson Bay and Mississippi River drainages, where they feed along the bottom of lakes and riverbeds for small invertebrates, reports Amy Woodyatt for CNN. As the largest freshwater fish within the Great Lakes, lake sturgeon can grow up to nine feet long and weigh more than 300 pounds per the U.S. Fish & Wildlife Service. Female sturgeon can live up to 150 years while males only live between 50 and 60 years.

Currently, lake sturgeon are considered a threatened species in Michigan and 18 other states because of overfishing and habitat loss, the Guardian reports. It is estimated that during the 19th century, there were more than half a million sturgeon lurking in the Detroit River, NPR reports. Now, scientists suspect there are fewer than 7,000 left in the river.

After the female sturgeon was caught, researchers recorded its length and weight, microchipped the fish, and released it back into the water.

"The fact that the sturgeon has survived for so long and probably has seen way more than any of us could imagine is kind of phenomenal, and just, I think everybody loves a good ... fish story," says biologist Jennifer Johnson, the researcher lying next to the fish in the viral image, to NPR.