MDC and USACE coordinate efforts to create favorable conditions for endangered lake sturgeon to spawn again

News from the region
Published Date
05/13/2022
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WEST ALTON, Mo.—Many people consider seven a lucky number.  Whether or not one believes in that notion, it seems the number seven was indeed lucky for both lake sturgeon and fisheries biologists.  After seven years, the endangered prehistoric fish are making babies in the Mississippi River again. 

Much of that luck may have been brought about by the coordinated efforts of state and federal agencies.

The Missouri Department of Conservation (MDC) and the U.S. Army Corps of Engineers (USACE) confirmed lake sturgeon spawning activity on April 23 along the Mississippi River in West Alton below the Melvin Price Lock and Dam (number 26).  The event occurred at USACE’s Maple Island Access.  This is the first spawning to be confirmed since the activity was last seen in the same area in 2015.

Lake sturgeon are an ancient fish -- they have been on the Earth for more than 150 million years and were witnesses to the death of the dinosaurs.  But the species was brought nearly to extinction themselves in Missouri by the early 1900s. They were once common in our big rivers, but overharvest and river habitat degradation caused their decline. 

In 1974, MDC listed the species as a state endangered fish and banned their harvest. In 1984, MDC staff began to raise them in MDC hatcheries, with additional help from US Fish and Wildlife Service hatcheries, from brood stock provided by the State of Wisconsin.  MDC released fingerlings from eight to ten inches long into Missouri rivers.  For more than three decades, the span of time required for the fish to attain reproductive age, MDC fisheries biologists looked for signs that the fish were on their way back through natural breeding.

“Lake sturgeon typically spawn from April to May,” explained MDC Fisheries Management Biologist Travis Moore, who leads MDC’s Lake Sturgeon Recovery Team. “As spawning begins, several males join a single female near a rocky shoreline and begin thrashing in the water. This activity mixes the eggs from the female and milt from the males and the fertilized eggs then stick to rocks until they hatch within five or six days.”

After more than 30 years, the restoration efforts seemed to have paid off when anglers observed lake sturgeon spawning for the very first time below the Melvin Price Lock and Dam in April of 2015.  MDC fisheries biologists confirmed the observations and celebrated these initial signs of success.

However, In the seven years since that last event, spawning activity seemed to have been completely absent, with no further confirmations since the spring of 2015.  Biologists were left puzzled. 

MDC Fisheries Management Biologist Sarah Peper has made it a mission to monitor the giant fish, searching for clues to unlock their spawning behavior.  “We’re tracking lake sturgeon to discover what habitat they’re using pre, during, and post spawn and to try to make ideal conditions below the dam so that they can spawn again,” Peper said.

Tracking is done by first capturing lake sturgeon on trotlines, then surgically inserting acoustic transmitters the size of a tube of lipstick.  Upon release, the movements of the fish are followed either automatically by stationary receivers planted along shore, or manually by boat-driven hydrophones.

Despite intensive monitoring, there were still no new positive signs of spawning. 

“We knew the fish had spawned here in 2015 and the Corps had records of what the conditions were at that time.  We thought if we could recreate those conditions and flow pattern across the shoreline where they spawned maybe we could get them to use this area again,” said Peper.

As luck would have it, Peper was contacted in 2020 by USACE Biologist, Ryan Swearingin from the Riverlands Migratory Bird Sanctuary.  Although MDC and the USACE had already been coordinating on lake sturgeon recovery work, Swearingin asked if there were a way that the USACE could increase their assistance with the effort.

“For me and our agency, priorities are always species in decline. Lake sturgeon are declining or considered endangered in most states they occur in.  So that was certainly a species on our radar that needed help the most and that we could potentially benefit,” Swearingin said.

Peper and Swearingin posed the same question.  Was it possible the lock and dam could be used to create conditions that might encourage lake sturgeon to spawn?

Swearingin was able to secure special funds through a grant from the Sustainable Rivers Program, a partnership between the USACE and the Nature Conservancy which seeks ways to leverage navigational structures along the river for environmental benefits.  The grant money enabled the purchase of additional transmitters, receivers, and fund an intern position to assist in the effort.  It also was used to secure the aid of hydraulic modeling.

The USACE archives detailed data on water control structure activity.  “Hydraulic modelers dove into the 2015 data to look at conditions surrounding the spawning event, and looked at similar years,” Swearingin said.  “Our hydraulics folks examined models looking at different scenarios, headwater, temperature, and water and gate openings, and that was a starting point for us this year.”

Swearingin and his crew set about taking water velocity measurements along the bank from March through May during the past year.  They coordinated with water control staff and hydraulic engineer Russel Errett to fine tune the flow along the shoreline where the lake sturgeon spawned before.   A velocity radar was also mounted this year near gate 9 along the Missouri shoreline, collecting data in real time to use in calibrating the model and dial in the gate settings.  The hope was to recreate the same “magic” that occurred in 2015.

Seven years in, that luck struck a second time when lake sturgeon were seen spawning once again on April 23.  The next day, a Sunday, Peper, Moore, and Swearingin all arrived off duty to see the event for themselves.  Swearingin even brought his children along, who spent the entire day watching the spawning. 

“It’s super exciting to get to see this.  Most professionals who work with lake sturgeon never get to see it.” said Swearingin.

“It’s one of the highlights of my career so far,” echoed Peper, adding that it was the first lake sturgeon spawning she’d ever seen in person.

So, what does this mean for the future of lake sturgeon?  Evidence so far suggests favorable conditions that encourage spawning can be created using water control structures. It will take time to continue fine tuning the flow settings and confirm results, but the future does look hopeful.   

“They chose the spot, whatever is right for them,” said Swearingin.  Moving forward, he said he would like to see more adaptive management like this in other parts of the river to help create more of those “right spots”.

After seven years of work and a bit of luck, Peper’s quest to unveil the mysteries behind lake sturgeon spawning might be realized.  But for the Show-Me-State’s lake sturgeon, the implications may be even more profound.

She said that all these efforts are to ultimately achieve one specific outcome for lake sturgeon in Missouri’s rivers.

“We want to have a viable reproductive population that’s self-sustaining.  So that there’s enough out here that they can take care of themselves.”

Learn more about lake sturgeon on MDC’s website at https://mdc.mo.gov/discover-nature/field-guide/lake-sturgeon.