Physical characteristics and simulated transport of pallid sturgeon and shovelnose sturgeon eggs

Journal of Freshwater Ecology
By: , and 

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Abstract

The imperiled pallid sturgeon (Scaphirhynchus albus) and closely related, but more common, shovelnose sturgeon (S. platorynchus) are believed to broadcast adhesive, demersal eggs in the current and over coarse substrate in turbid rivers of the North American midcontinent. It has been hypothesized that eggs settle immediately following fertilization, but field conditions preclude direct observation. We conducted laboratory studies to characterize the diameter, shape, settling velocity, and specific gravity of pallid sturgeon and shovelnose sturgeon eggs. Based on these laboratory measurements, we then modeled the potential fate of pallid sturgeon eggs by considering these physical properties in the context of two field sites where spawning has occurred. Although eggs of pallid sturgeon and shovelnose sturgeon were of a similar size and shape, shovelnose sturgeon eggs had slightly higher specific gravity and settling velocity. For representative hydraulic conditions at documented spawning sites in the mainstem Missouri and Lower Yellowstone Rivers, eggs of both species will likely be concentrated near the bed although some eggs may be distributed throughout the water column. Simulations of egg transport indicate that eggs may be transported up to several hundred meters downstream from spawning locations in the approximate length of time required for eggs to become adhesive. Estimates of egg transport presented here rely on simplifying assumptions about river hydraulics and limited understanding of how eggs interact with the complex substrates and flow near the bed; results highlight the need for additional studies to evaluate the fate of eggs and fertilized embryos of both species.

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Publication type Article
Publication Subtype Journal Article
Title Physical characteristics and simulated transport of pallid sturgeon and shovelnose sturgeon eggs
Series title Journal of Freshwater Ecology
DOI 10.1080/02705060.2020.1736191
Volume 35
Issue 1
Year Published 2020
Language English
Publisher Taylor and Francis
Contributing office(s) Columbia Environmental Research Center
Description 22 p.
First page 73
Last page 94
Country United States
Other Geospatial Missouri River basin
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