Salinity is an important determinant of estuarine faunal composition; previous studies, however, have indicated conflicting accounts of continuous vs. relatively rapid change in community structure at certain salinities from geographically distinct estuaries. This study uses a large fisheries monitoring database (n>5,000 samples) to explore evidence for estuarine salinity zonation by nekton in the lower St. Johns River estuary (LSJR). There was little evidence to support the presence of estuarine salinity zones except at the extremes of the salinity gradient (i.e., 0.1–1.0 and 34–39). The LSJR estuarine nekton community exhibits progressively slow ecological change throughout most of the salinity gradient with rapid change at the interfaces with fresh and marine waters—an ecoline bounded by ecotones. This study affirms the rapid change that occurs at the extremes of the salinity spectrum in certain estuaries and is relevant to efforts to manage surface water resources and estuarine ecosystems. Given the disparity in the results of the studies examining biological salinity zones in estuaries, it would be wise to have, at minimum, a regional understanding of how communities are structured along the gradient from freshwater to marine.
Estuaries & Coasts is the journal of the Coastal and Estuarine Research Federation. Begun in 1977 as Chesapeake Science, the journal has gradually expanded its scope and circulation. Today, the journal publishes manuscripts covering aspects of research on physical, chemical, geological or biological systems, as well as management of those systems, at the interface between the land and the sea. The interface is broadly defined to include areas within estuaries, lagoons, wetlands, tidal rivers, watersheds that include estuaries, and near-shore coastal waters. The journal publishes original research findings, reviews, techniques, and comments.
The Coastal and Estuarine Research Federation is a private, nonprofit non partisan organization. The Federation was created in 1971, when the members of two older, regionally-based estuarine research societies (AERS and NEERS) decided that a national organization was needed to address estuarine and coastal issues more broadly. The regionally based Affiliate Societies now number seven and encompass all of the coastal regions that border the United States, Canada and Mexico.