Habitat ecology of intertidal nekton in southern New Jersey salt marshes:

Intertidal creeks are of particular importance to the nekton community as they represent a critical corridor linking marsh surface and subtidal habitats during periods of tidal inundation. Nekton use of intertidal creeks is controlled by marsh hydroperiod and varies temporally and spatially according to multiple physical and biological factors. Many oligohaline and mesohaline southern New Jersey salt marshes have been altered through anthropogenic disturbance, in the form of salt hay farming, or the invasion and subsequent dominance of Phragmites australis. Intertidal creeks are especially vulnerable to marsh habitat alteration, which may affect creek structure and function, but may be mitigated (or reversed) through habitat restoration efforts. Intertidal creek nekton were sampled in multiple marsh types (i.e., natural, invasive-dominated, and marshes treated either to remove Phragmites or to restore tidal flow to former salt hay farms) using three different sampling gears (i.e., weirs, seines, and underwater video) to compare nekton utilization between marsh types, determine general nekton tidal use patterns, and evaluate overall restoration success. Intertidal creek nekton collections in all marsh types consisted primarily of resident nekton and were dominated by a relatively low number of ubiquitous intertidal species, especially Fundulus heteroclitus. Low tide stages were characterized by resident nekton (dominated by F. heteroclitus), while high tide stages were characterized by a variable mix of transient (dominated by Anchoa mitchilli, Menidia menidia, and Callinectes sapidus) and resident nekton. Examination of intertidal creek nekton at multiple spatial and temporal scales within the tidal cycle (using seines and underwater video) generally found that the tidal use patterns of the most abundant nekton were similar in all marsh types. Most studies found that treated marsh creeks provided enhanced conditions for intertidal nekton, as evidenced by species abundances in treated marshes as compared to natural or invasive-dominated marshes. However, the short and long-term response of intertidal creek nekton suggests that the stage of the restoration may influence the results of comparisons between marsh types and should be considered when evaluating marsh restorations.