The Nekton Assemblage of Salt Marsh Pools in a Southeastern United States Estuary

Abstract

Marsh pools are present in estuaries throughout the world and provide valuable habitat for fishes and decapod crustaceans (i.e., nekton). The purpose of our study was to examine the species composition and temporal variation of the nekton assemblage within marsh pools of a southeastern US estuary. We conducted weekly sampling of five marsh pools in the North Inlet estuary, SC from May to November 2016. Temporal variation in the nekton assemblage appeared to be related to the life history of individual species, tidal connectivity of pools with adjacent habitats, and environmental conditions within pools. Most transient species, which migrate into the North Inlet estuary as larvae or juveniles, were present primarily in early summer and late fall. Many transient species were absent or occurred in low abundance during July and August when water temperature was highest, salinity most variable, and tidal connectivity with adjacent habitats was lowest. In contrast, most resident species, which can complete their entire life cycle within the North Inlet estuary, were present and relatively abundant throughout the study as juveniles and adults. Based on the limited studies available, species richness and the ratio of transient to resident species in marsh pools at low latitudes (e.g., southeastern US) are higher compared to marsh pools at high latitudes (e.g., east coast of Canada). A more comprehensive understanding of the role of marsh pools in the life history of nekton would be useful for conserving, managing, and restoring salt marshes and the species found in these environments.