Pallid Sturgeon Use of the Missouri River Downstream of Fort Peck Dam in 2011

The hydrologic regime in the Missouri River below Fort Peck Dam during 2011 was very unique due to spillway releases, increased discharge from the Fort Peck powerhouses and elevated discharge during spring from the Milk River.  This water year represented the first deviation from baseline conditions since monitoring programs have been in place.  Thirty-one telemetered wild adult pallid sturgeon (Scaphirhynchus albus) (2 gravid females, 4 non-gravid females, 25 males) were tracked in the Missouri, Milk and Yellowstone rivers.  Over 40% of these fish, including a gravid female, migrated at least 200 km up the Missouri River during the spawning season as opposed to 0-5% during the prior nine years.  Larval fish sampling resulted in a total of 53 paddlefish (Polyodon spathula) from the Milk River and 39 paddlefish, 24 shovelnose sturgeon (S. platyorhynchus) and 1 genetically confirmed pallid sturgeon from the Missouri River.  This is the first documentation of pallid sturgeon spawning in the Missouri River below Fort Peck Dam and the first genetically confirmed wild pallid sturgeon larvae in the Missouri River basin.   The documentation of use, spawning and reproduction shows that the Missouri River below Fort Peck Dam is used by pallid sturgeon if flow regimes are suitable.