Update regarding the status of adult pallid sturgeon upstream of Intake dam
The female and two males that were in the Powder River for several days exited the Powder River simultaneously at 3:30am Wednesday June 18th. Crews relocated the female on the 18th approximately three river miles downstream of the Powder and attempted to recapture her but were unsuccessful until Friday June 20th. A quick abdominal exam revealed the absence of eggs and the loss of four pounds demonstrates that spawning occurred with someone (pallid or shovelnose). Crews accessed the female on June 7, while the fish was still in the Powder River, and confirmed that spawning had not occurred. See the attached picture showing the release of code 36 following a quick exam.
We assume spawning occurred in the Powder River. This assumption is based on the duration of time spent in the Powder River, females evaluation of eggs before and after exiting the tributary, quick exit of all three fish despite little change in river conditions, the apparent downstream dispersal of the two males, and slow downstream migration of the female. Crews have switched efforts from locating fish to daily larval sampling in the lower Powder River to evaluate spawning and larval hatching success. Larval sampling will be the focus for several more days. Larvae collected will be sent to a lab for identification and genetic analysis. Adult pallid monitoring and locations will resume following larval sampling.
The attachment has three pages showing the status of these pallids on June 6, 16, and 20th.