A Simple Device for Measuring the Minimum Current Velocity to Maintain Semi-Buoyant Fish Eggs in Suspension

Authors

Julias S. Mueller, Texas Tech University
Brandon D. Cheek, Texas Tech University
Qingman Chen, Texas Tech University
Jillian Groeschel, Texas Tech University
Shannok K. Brewer, Oklahoma State University
Timothy B. Grabowski, University of Iceland; United States Geological Survey; Texas Tech UniversityFollow

Date of this Version

12-2013

Document Type

Article

Citation

The Prairie Naturalist 45: 84–89. December 2013

Comments

Published by the Great Plains Natural Science Society, 2013. United States government work. Public domain material.

Abstract

Pelagic broadcast spawning cyprinids are common to Great Plains rivers and streams. This reproductive guild produces non-adhesive semi-buoyant eggs that require sufficient current velocity to remain in suspension during development. Although studies have shown that there may be a minimum velocity needed to keep the eggs in suspension, this velocity has not been estimated directly nor has the influence of physicochemical factors on egg buoyancy been determined. We developed a simple, inexpensive flow chamber that allowed for evaluation of minimum current velocity needed to keep semi-buoyant eggs in suspension at any time frame during egg development. The device described here has the capability of testing the minimum current velocity needed to keep semi-buoyant eggs in suspension at a wide range of physicochemical conditions. We used gellan beads soaked in freshwater for 0, 24, and 48 hrs as egg surrogates and evaluated minimum current velocities necessary to keep them in suspension at different combinations of temperature (20.0 ± 1.0 °C, 25.0 ± 1.0 °C, and 28.0 ± 1.0 °C) and total dissolved solids (TDS; 1,000 mg L^-1, 3,000 mg L^-1, and 6,000 mg L^-1). We found that our methodology generated consistent, repeatable results within treatment groups. Current velocities ranging from 0.001–0.026 needed to keep the gellan beads in suspension were negatively correlated to soak times and TDS and positively correlated with temperature. The flow chamber is a viable approach for evaluating minimum current velocities needed to keep the eggs of pelagic broadcast spawning cyprinids in suspension during development.