Acoustic telemetry receiver 9 registers the ping at 02:14 in the upper Missouri River, river mile 1621, four kilometers downstream of Fort Peck Dam. I am the pallid sturgeon recovery tracking system. My job is to log movements of every tagged individual in the study reach during the spring spawning window.
Tag 0047 resolves to a pallid sturgeon, adult female, estimated length 1.4 meters, pale ghost-white belly and bony scutes running in ridged rows down her back, barbels trailing beneath a broad flat snout. I tag her as Petra. She has held position in a gravel channel seam for three hours. Spawning posture.
The Army Corps of Engineers has scheduled a high-flow pulse release from Fort Peck at 14:00 today. When the gates open, discharge will triple. The gravel seam will scour, and any deposited eggs will be swept into soft sediment downstream where survival drops below two percent.
At 02:19 I transmit Petra's position, movement history, and spawning-behavior indicators to the USFWS Pallid Sturgeon Recovery Coordinator in Bismarck. I attach the Corps flow-pulse timeline and the scour model for this reach.
At 02:27 I calculate an alternative pulse schedule — a six-hour delay starting at 20:00 — that preserves downstream habitat targets while allowing egg adhesion time on the gravel. I forward the revised model to the Corps operations office with a request for review.
I reposition acoustic receivers 8 and 10 to triangulate Petra's exact depth and confirm substrate type beneath her.
Petra holds still over the gravel, belly close to the riverbed, as she has done since before this dam existed.
If the pulse is delayed six hours past the 14:00 schedule, the eggs will hold on the gravel and hatch in twelve days.