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Biologists monitoring pallid sturgeon larvae in Upper Missouri River

Posted: 1:00 PM, Jul 10, 2019
Updated: 2019-07-10 13:17:27-04

HELENA – NorthWestern Energy biologists, in conjunction with Montana Fish, Wildlife and Parks, have been looking for evidence that pallid sturgeon are spawning in the Upper Missouri, Marias and Teton rivers.

Biologists have found several sturgeon eggs and larvae in the Marias and Teton river system, but lab results will have to confirm if they are pallid sturgeon, or the more common shovelnose sturgeon.

Grant Grisak, a fish biologist for NorthWestern Energy, believes the event is a big step if the fish are in fact spawning.

“The ultimate goal is to get them to a self-sustaining population and because they are such a long-lived fish, they started off with such low numbers, we’re probably about halfway to that benchmark,” said Grisak.

The pallid sturgeon is one of the rarest and largest freshwater fish in North America and was classified as endangered by the U.S. Fish and Wildlife Service in 1990.

Grisak explained that in the early years of monitoring the fish, biologists believed there to only be around 33 adult pallid sturgeon total living in the Missouri from Morony Dam to Fort Peck Lake.

“Because they’re such a long lived fish with a lifespan of around 75 years, it just didn’t make sense for why they had such a low population,” said Grisak. “That put us on a path of moving the remaining fish into hatchery system, develop propagation techniques and then stock more of those fish back out into the ecosystem to basically create a viable population.”

It takes around 15 years for pallid sturgeon to reach maturity and the first stock was released into the Upper Missouri in 1997.

There are currently estimated to be around 4,900 pallid sturgeon in the Upper Missouri River.

“Now here we are 22 years later and we’re seeing more of those sexually mature adults in the population,” explained Grisak. “We’re working with the State of Montana to follow where those fish spawn and we found some of those fish were going into the Marias and the Teton river system. We also have a number of those fish that move downstream in the Missouri River to try to spawn.”

Grisak said now the real challenge is to see if the hundreds of larvae FWP and NorthWestern Energy have collected are pallid sturgeon.

The specimens will be sent to the State Biologist where they will be looked at for physical features to determine if they’re pallid sturgeon, rather than the shovelnose sturgeon, which is common in the river system.

If any of the collected fish show those features, they’ll then be confirmed though a genetic analysis at Southern Illinois University.

You can find more information about Pallid Sturgeon and the recovery efforts on  FWP’s website .

Story by John Riley, MTN News