Ichthyoplankton transport in relation to floodplain width and inundation and tributary creek discharge in the lower Savannah River of Georgia and South Carolina

We report the results of a 3-year study of ichthyoplankton in the lower Savannah River and its coastal plain tributaries. Sampling was weekly from February through July in 1983, 1984 and 1985. Ichthyoplankton transport was used as an estimate of ichthyoplankton production. Ichthyoplankton transport in the river, for both total and most common taxa, was highest in 1983 and lowest in 1985. Ichthyoplankton transport into the river from tributary streams was also highest in 1983 and lowest in 1985. Ichthyoplankton transported from these tributaries sometimes comprised a significant percent of the larval transport at the next river station downstream from the tributary mouth. The highest larval transport occurred when the spring flood pulse was most elevated for the longest time, and larval transport at particular river stations or creeks was correlated with floodplain width in 1983 and 1984, years when flood pulses were high enough so that the adjacent floodplain was inundated during or following spawning. In 1985 the flood pulse was brief, inundation levels were low, and inundation occurred in February before most fish had spawned. Except for American shad and sunfishes, larval transport for all common taxa was greatly reduced in 1985 compared to 1983.