Estimation of Striped Bass Egg Drift Patterns in the Lower Savannah River using Gellan Gum Balls

Bill Davin
Dept. of Biology, Berry College, 490430 Berry College, Mount Berry, GA 30149, Phone: (706) 290-2663, Fax: (706) 238-7855, e-mail: bdavin@berry.edu

Since the 1970s, alterations of water flow patterns in the Lower Savannah River near Savannah, GA, have impacted the native striped bass population. Research has indicated a decrease in the number and a change in the distribution of striped bass eggs within the Little Back River (LBR), a historic spawning site. The goal of this project was to determine the movement pattern of simulated striped bass eggs in the LBR using Gellan Gum Balls, which have a mean density and diameter similar to striped bass eggs. Over the course of eight sampling days, approximately 2.5 million balls were released into the LBR and recoveries were made at four sites. In addition, a number of physical parameters were measured. Results show the drift rate was 67 % of the prevailing current and approximately 27 % of the balls left the LBR through Rifle Cut. Results also indicate that eggs settle to the river's bottom during slack tide and are then picked back up on a tidal flow. There also is evidence that striped bass eggs could be exposed to soft sediments and increased salinity if the adults are attempting to use historic spawning sites.