Abstract
Fishes and invertebrate macrofauna (nekton) inhabiting three low salinity, intertidal rivulets were sampled biweekly from July 1981 through June 1982. Twenty-nine species of fishes (24,335 individuals, 9.671 kg wet weight) representing 19 families and four species of invertebrates (6,812 individuals, 4.708 kg wet weight) were collected. The most abundant species were spot (Leiostomus xanthurus), grass shrimp (Palaemonetes pugio), bay anchovy (Anchoa mitchilli) and Atlantic menhaden (Brevoortia tyrannus). Only a few large predacious fish (e.g., largemouth bass,Micropterus salmoides) were collected in the rivulets although largemouth bass and longnose gar (Lepisosteus osseus) were abundant in a nearby permanently flooded area. The number of species was greatest during the warmer months and lowest, during the winter. There were three seasonal peaks of numerical abundance: spring peak attributed to the influx of junvenile spot Atlantic menhaden, Atlantic croaker (Micropogonias undulatus), and southern, flounder (Paralichthys lethostigma); summer peak due to grass shrimp; and fall peak to bay anchovy and grass shrimp. The occurence of these species was not correlated with salinity in the study area. Average densities of spot and Atlantic menhaden in the oligohaline rivulets at the peak of juvenile recruitment were similar to the average densities of these species reported for salt marshes. The results suggest that oligohaline estuarine areas contain important nursery habitat for some euryhaline species.
Published Version
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