Three tiny fish larvae that were captured by U.S. Geological Survey scientists in May 2014 have just been confirmed to be pallid sturgeon. These new genetic identifications add to mounting evidence that critically endangered pallid sturgeon spawned successfully in the Lower Missouri River downstream of Gavins Point Dam, South Dakota.
Although successful spawning by the endangered fish was detected in the Lower Missouri River in 2014, it does not necessarily mean that the species is on its way to recovery.
Newly hatched pallid sturgeon free embryo. On average, pallid sturgeon hatch between 7 to 9 millimeters (about 0.25 to 0.35 inch).
“Collection of these recently-hatched pallid sturgeon, still in their early developmental stages, verifies that suitable conditions and functional spawning habitats for pallid sturgeon do at times exist in the Lower Missouri River downstream of Gavins Point Dam,” said USGS scientist Aaron DeLonay. “However, the pallid sturgeon population is still small and reproduction sufficient to increase the population has not been documented.”
The three new larvae were 1-3 days old and collected on May 30, 2014 from the main channel of the Missouri River, just above its confluence with the Platte River near Bellevue, Nebraska. The presence of such young larvae may be used to infer where the parents spawned between the Platte and Gavins Point Dam. The three fish were among hundreds of larval shovelnose sturgeon and paddlefish captured in the 2014 study. Previously reported pallid sturgeon larvae captures in 2014 were of older fish and considerably further downstream.
The pallid sturgeon were positively identified using genetic analyses developed by Jennifer Eichelberger and Dr. Edward Heist at Southern Illinois University Carbondale. Recent developments by Dr. Heist have resulted in genetic tests that inexpensively screen specimens of sturgeon and paddlefish to identify possible pallid sturgeon. Other genetic analyses are then used to confirm identification and determine whether sturgeon larvae collected in samples may be closely related, or possibly siblings from a single spawning event. Preliminary analyses indicate that these three specimens are not siblings from a single spawning female.
These findings build on previous efforts under the Comprehensive Sturgeon Research Project, a research collaboration among the USGS, U.S. Army Corps of Engineers Missouri River Integrated Science Program, Nebraska Game and Parks Commission, and Montana Fish Wildlife and Parks. More photos and trip reports are available on the Comprehensive Sturgeon Research Blog.
Pallid sturgeon free embryo at 2 days post hatch. At two days after hatching the free embryos are generally 9 to 11 millimeters (0.35 to 0.45 inch).
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