Pallid Sturgeon Habitat Dynamics

Science Center Objects

CERC scientists apply advanced measurement and modeling approaches to quantifying habitats in large rivers. Our research has been applied to improving the understanding of the reproductive ecology of the endangered pallid sturgeon (Scaphirhynchus albus) in the Missouri River.

The Issue:  The hypothesis spawning habitat quality may be limiting to pallid sturgeon populations emerged through 1) observations of fish spawning on revetted, outside bends on the channelized Lower Missouri River, and 2) very low rates of wild recruitment. CERC scientists have evaluated the documented spawning habitats on the Lower Missouri River and on the near-natural Yellowstone River.

 

R/V Whiskey One equipped with acoustic Doppler current profiler

R/V Whiskey One is shown equipped with an acoustic Doppler current profiler (ADCP) and precision GPS for surveying the Missouri and Yellowstone Rivers in Montana and North Dakota.

(Public domain.)

Addressing the Issue: Spawning habitat characterization starts with knowing locations of reproductive adult pallid sturgeon, provided through coordinated telemetry of tagged adult fish. Selected patches are thoroughly characterized using hydroacoustic techniques including multibeam echo sounding, acoustic Doppler current profiling, high-resolution sidescan sonar, and acoustic video (adaptive resolution imaging sonar [ARIS] and dual-frequency identification sonar [DIDSON]). Substrate at spawning sites is also characterized with conventional sampling using ponar or dredge samplers and benthic imaging.

If spawning is successful (that is, adult males and females aggregate, eggs are released, fertilized, and incubated, and eggs hatch to allow free embryos to enter into their drifting phase), the next hypothesized population limitations are for survival of the free embryos and later stages during their first year. Free embyros drift for 9-11 days and then transition to first feeding. A dominant working hypothesis is that the free embryos are unable to exit the highly hydraulically efficient navigation channel when it is time to transition to feeding and they therefore starve.

 

 

Lisbon-Jameson chute particle model

Particle dispersion model for the Lisbon-Jameson chute on the Missouri River at a water discharge of 247,000 cubic feet per second. 

(Public domain.)

For the drift stage, CERC scientists have focused on calibrating and validating 1-dimensional hydraulic advection/dispersion models in coordination with US Army Corps of Engineers partners. This effort involves using rhodamine-WT dye trace experiments to evaluate the critical parameter values in these models related to dispersion processes.

Next Steps: The selected habitats of the Missouri and Yellowstone Rivers are very different and the hydraulic characteristics of the Yellowstone habitat is being used to help design spawning habitat improvements on the Lower Missouri River. Understanding gained from functional habitats on the Yellowstone River will inform design of rehabilitated habitats on the Lower Missouri River, and lessons learned from branch habitat assessments will be used in developing habitat assessment protocols for experimental implementations.

 

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