Larval fishes of a Middle Atlantic Bight estuary: assemblage structure and temporal stability

Abstract

We collected weekly, quantitative ichthyoplankton samples over 6 years (1989-1994, 1309 samples) to identify temporal scales of variability in the abundance and occurrence of larval fish assemblages near Little Egg Inlet in southern New Jersey, U.S.A. We collected species that spawn in the estuary (30%), both the estuary and continental shelf (35%), continental shelf (25%), and the Sargasso Sea (10%). The following analyses suggest an annually repeated seasonal progression of species assemblages: (i) the rank abundance of the 20 dominant species did not change significantly from year to year, (ii) variation in the density of the dominant species was primarily explained by intraannual rather than interannual variation, and (iii) multivariate analysis of the assemblage matrix identified five seasonal assemblages that occurred during all six years. We found that the timing and duration of each of these seasonal groups were correlated with two characteristics of the annual temperature cycle, magnitude (higher or lower temperature) and trajectory (increasing vs decreasing temperature). We suggest that the repeated occurrence of larval fish assemblages in temperate estuaries along the U.S. coast may, in part, be driven by local environmental processes.

Life history and habitat use of the speckled worm eel, Myrophis punctatus, along the east coast of the United States

“…Portions of the flood tide waters from the ocean are diverted into the mouth of Little Sheepshead Creek (Charlesworth 1968;Chant et al 2000). Recent work has shown that ichthyoplankton samples collected from a bridge at this location are representative of the larger estuary (Witting et al 1999;Chant et al 2000;Neuman et al 2002).…”

“…1), leptocephali entering the estuary were collected with, three 30 min sets of a plankton net. Additional details of this sampling program are available (Witting et al 1999;Able and Fahay 2010). At Beaufort Inlet, leptocephali were collected with a plankton net which was deployed during night-time flood tides and sampled the surface (0-1 m) (Fig.…”

Near-Surface Larval and Juvenile Fish in Coastal Habitats: Comparisons Between the Inner Shelf and an Estuary in the New York Bight During Summer and Fall

“…Atlantic Ocean water flows into the estuary through Little Egg Inlet during flood tides, with portions diverted into the mouth of Little Sheepshead Creek Charlesworth 1968). Previous work has shown that ichthyoplankton samples collected from Little Sheepshead Creek are representative of the estuarine assemblage Neuman et al 2002;Witting et al 1999).…”

“…Sampling of larvae and pelagic juvenile fish in the Great Bay-Little Egg Harbor estuary has occurred on a weekly basis year-round since 1989 (Able and Fahay 2010;Witting et al 1999). A 1-m diameter, circular plankton net (1 mm mesh) fitted with a General Oceanics flowmeter is suspended from a bridge over Little Sheepsheads Creek to a depth of 1.5 m during night-time flood tides in these well-mixed waters (Table 1; Fig.…”

“…The similarity in occurrences and range of lengths of species collected on the inner shelf and in the estuary suggested that both sampling approaches were effective in collecting the pelagic stages of larval and juvenile fishes. The difference in magnitude of fish concentrations was likely due primarily to the high abundance of A. mitchilli larvae in the estuary resulting from intense spawning during summer (Able and Fahay 2010;Witting et al 1999).…”