There is a narrow mixing corridor of the two, and the salinity front (located in a band across the ecoregion's meeting the open ocean) shifts with the winds and seasons.

Black drum (Pogonias cromis), Whitemouth croaker (es:Micropogonias furnieri), and King Weakfish (Macrodon ancylodon) spawn in the bottom salinity front.

[5] Fish that take refuge in the mixed fresh and salt waters also include the Banded croaker (Paralonchurus brasiliensis) and various species of Flounder (genus Paralichthys).

The surface salinity front supports large numbers of Argentine anchovy (Engraulis anchoita) and Chub mackerel (Scomber japonicus).

But the species that do exist in the turbidity front are found in large numbers, notably zooplankton, Whitemouth croaker, and Menhaden (Brevoortia aurea).