Abundance and distribution of striped bass eggs and larvae in the Savannah
River Estuary--Implications for channel dredging window
Principal Investigator: Cecil A. Jennings
Funding: U.S. Army Corps of Engineers, Savannah District
Research Coordinator: Thomas R. Reinert
Objectives: To determine the abundance of striped bass eggs spawned in the estuary and to define the temporal and spatial
extent of spawning activities; to evaluate the potential exposure of eggs and larvae to dredging activities associated with
harbor deepening and maintenance.
Research in this area began in the late 1970's with the construction of a tide-gate and diversion canal aimed at diverting
flood-tide waters from the Back River into the Front River. The goal was to reduce the amount of maintenance dredging in
the shipping channel. Pursuant to this purpose, the tide gate was a success; however, these modifications precipitated a
crash in the striped bass population due to increases in salinity on the spawning grounds and accelerated seaward transport
of eggs to areas of toxic salinity.
The Georgia Unit began work in this area beginning in 1983 and the current U.S. Army Corps of Engineers funded project
began in 1994 with additional funds obligated to continue research through 1998. Hopefully, findings from this research
will allow management decisions regarding maintenance of the Savannah Harbor (e.g., deepening, dredging) to be made in
cooperation with striped bass population restoration efforts.
Project Status: Completed, December 1998
CONCLUSIONS
?Egg density remains critically low
?Historic Back River spawning grounds produced 0.2% of the eggs
produced
of the late 1970’s
?Most spawning is occurring in the Front River, upstream of the industrialized harbor
?Salinities in historic spawning locations appear suitable for spawning
?15 adults were sampled to assess maturational stage—all showed signs of maturity but also showed
evidence of reproductive distress. Low sample size prevents further conclusions
?Spatially, the dredging window may be moved from Front River mile 5.0 to river mile 12.0.
?Salinities below this point are lethal most of the time during spawning season.
?Continued monitoring is required