SAGINAW, MI — While ice fishing for walleye in the Saginaw River earlier this month, Dave Tanney didn't expect to pull a 61-inch prehistoric-looking fish from the depths of the river.

But he did.

Tanney of Belding is the second angler this winter to report catching a live sturgeon on the Saginaw River or Bay. The large, bottom-feeding fish are a slow-evolving species still similar to their 120 million-year-old ancestors.

Pete Studders, a manager at Scientific Anglers in Midland, was ice fishing off the shores of Linwood in Bay County when his fiancée Denise Shelagowski told him she saw something unusual on her underwater camera.

“I proceeded to go back in the shanty and looked at the camera and recognized that it was a sturgeon,” Studders said. “I dropped my lure down and watched the sturgeon inhale it.”

The story has a twist. Based on a photo of the fish the couple took before releasing it, state officials believe the sturgeon isn't a native lake sturgeon but could be one from Russia that someone released into the bay after keeping as a pet.

Although he has used his lure since, U.S. Fish and Wildlife Service biologists asked him to send the lure to Central Michigan University to see if DNA left on the lure can conclusively determine the sturgeon’s species.

Regardless of where the fish originated, seeing a sturgeon in Saginaw Bay waters is rare today, according to Adam Kowalski, a fisheries biologist for the U.S. Fish and Wildlife Service in Alpena.

Though the fish considered a "living fossil" was once abundant in the Great Lakes, overfishing and habitat loss led to their decline.

Kowalski said recent attempts to find and research sturgeons in the Saginaw-area were unsuccessful, due to the low population of lake sturgeon in the area.

Since 1994, commercial fishermen on Saginaw Bay have voluntarily helped government agencies tag and release sturgeons that get caught in their nets, according to Justin Chiotti, a Fish and Wildlife Service fisheries biologist. To date, 358 sturgeons have been tagged as a part of this program.

Jim Baker, management supervisor for the Michigan Department of Natural Resources for southern Lake Huron, said the sturgeon population is about 1 percent of what it was at its height in the mid-1800s. The creation of dams destroyed their habitat in addition to overfishing, he said.

He said that what remains now can be considered a remnant population.

Sturgeons are signs of 'ecosystem health'

When anglers land sturgeons on the Saginaw River and Saginaw Bay, it makes for more than a good fishing tale. It's also an indicator water quality, biologists say.

“They’re interesting fish,” Kowalski said. “Having been here since the time of the dinosaurs, they’re one of the oldest fish in the Great Lakes. And it’s always good to bring them back, (as an indicator of) environmental health. I wouldn’t call them the canary in the underground mine, but they could be.”

Chiotti said sturgeons are used as barometers of health in the St. Clair-Detroit River system.

“The lake sturgeon is considered an indicator of ecosystem health because it is sensitive to pollution and human disturbances," he said. "They have no natural predators since they attain such large sizes, we have methods to assess the population and they utilize a variety of habitats throughout their lifecycle."

Chiotte said some sturgeons tagged in Port Huron have been recaptured in the Saginaw Bay. He said several agencies, including the DNR and the Ontario Ministry of Natural Resources are studying sturgeon movement in Lake Huron.

"That will provide us with higher resolution movement data between lake sturgeon captured in southern Lake Huron and Saginaw Bay,” Chiotte said. “To date, 161 lake sturgeons have received (GPS) transmitters as part of this project and we plan to continue this work in 2014."

Why all the attention?

Commercial fishermen in the Saginaw area voluntarily tag and release sturgeon caught in their nets.

Lake sturgeon are listed as a threatened species in Michigan and either threatened or endangered by 19 of the 20 states within its original range in the United States, according the Michigan DNR.

They only spawn once every five years, so their recovery has been slow. Males don’t reach sexual maturity until they are about 20 years old and females reach maturity at about 25 years old.

Fishermen who catch a sturgeon on Saginaw Bay or connecting waters must release them.

“They are a protected species here, and fishing for them is catching and release only,” Baker said.

The DNR does allow a limited season for sturgeon on Black Lake. In 2013, anglers there caught six fish.

Shiawassee River seeing return of walleyes

Sturgeons aren't the only fish turning up in unusual places these days.

Walleyes are benefiting from work on a dam on the Shiawassee River in Chesaning as well. Their population in the Shiawassee River declined in the last few decades after construction of the Chesaning Dam. The fish were unable to get past the dam to spawn in the river.

But Baker said the population has increased in recent years.

“We have a very good run of fish in the Shiawassee up to the dam at Chesaning,” Baker said. “The old dam there was replaced with a rock ramp structure and allows the walleye to jump. Any additional access walleyes have to spawning habitat in our rivers is a good thing.”

Devin Grace Gill, Friends of the Shiawassee director, said that walleyes are important to the river for a variety of reasons.

“One is the recreational fishery on the Saginaw river system,” Gill said. “(Also), right now, most of the data that the DNR has tells us that the significant spawning that goes on occurs in the Tittabawassee River. If something catastrophic happens in the Tittabawassee, fish spawning areas are destroyed. It’s better to have multiple rivers for spawning than just one.”