Pallid Sturgeon MIA

When reproductive pallid sturgeon go missing during spring spawning season CSRP biologists become quickly concerned as every day at large means a decrease in the probability of relocation prior to spawning.  Because reproductive pallid sturgeon have been observed to move great distances (>10 miles per day), especially during spring spawning migrations, increased effort is required to search longer river segments when they go missing.  Pallid sturgeon may go undetected for a number of reasons but is typically one of the following three.  Pallid sturgeon may simply migrate outside of the estimated search radius, in which case subsequent searches covering more river miles may locate them.  Another possibility is that pallid sturgeon may move into habitats from which their acoustic signal does not resonate well or are not easily accessed by boat and therefore are not searched regularly.  In this case the pallid sturgeon might go undetected until it moves out of such habitats. Lastly, pallid sturgeon may migrate into relatively large tributaries that are not regularly searched.  Biologists believe that tributary confluences and the lower portions of tributaries may provide refuge, feeding opportunities, or reproductive requirements of the species in the highly modified Lower Missouri River.  This is exactly what biologists suspected when multiple days of searching the mainstem Missouri River failed to locate PLS11-004, a reproductive female previously found approximately 5 miles downstream of the Kansas River confluence in Kansas City, KS.  So up the Kansas River CSRP biologists went in search of PLS11-004, to river mile 15 to the Johnson County water intake weir.  Originally built in 1964, it has since seen its share of modifications and currently supplies roughly 10 billion gallons of water per year to Water District 1, or WaterOne, of Kansas.  CSRP biologists believed that if PLS11-004 had chosen the Kansas River, current river levels would not permit her to swim past the weir and she would certainly be in the lower 15 miles.  When it was all said and done PLS11-004 was located by another CSRP crew in the mainstem of the Missouri River approximately 15 miles upstream of the Kansas River, leaving biologist to wonder where she’d been and what she’d been up too.  In any case, her unpredictable behavior treated one CSRP crew to the sights and sounds of the Kansas River which they seldom frequent.

Johnson County water intake weir on the Kansas River.

By Jake Faulkner

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