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Fish and macroinvertebrate community structure

and habitat use patterns in salt marsh creeks of southern

New Jersey, with a discussion of marsh carbon exportation

By Rodney Alan Rountree, Ph.D.

Dissertation director: Professor Kenneth W. Able


Faunal composition, abundance, biomass and size structure of fishes and macroinvertebrates were described from polyhaline intertidal and subtidal marsh creek habitats in a southern New Jersey estuary. New Jersey marsh creeks support a rich fauna, including 64 species of fishes, 13 invertebrates and the diamondback terrapin. Although estuarine species numerically dominant the fauna, a more diverse assemblage of species utilize the creeks primarily as a nursery for young-of-the-year (YOY). Abundance, biomass and faunal composition were strongly seasonal with peaks in May and August. Variation in community structure was found among creeks of different size and within creeks along a mouth-to-headwater gradient. Many species which utilize marsh creeks appear to undergo passive or active tidal movements. Creek morphology is hypothesized to influence community structure directly through the mediation of tidal dynamics, and indirectly through the mediation of tidal and diel changes in physical conditions along the creek gradient. Fish and decapad species assemblages, and abundances, were strongly influenced by diel period suggesting diel movements. Summer flounder, Paralichthys dentatus, growth, foraging habits and temporal patterns of habitat use were assessed. Summer flounder grew rapidly and appear to undergo tidal foraging movements into the creeks. Patterns in growth and seasonal emigration of fifteen fishes were examined in detail. Most species grew very rapidly and exhibited well defined pulses of emigration from the creeks. Major emigration pulses of YOY from the creeks occurred from July through September. Two types of emigration patterns were evident: 1) emigration at a specific size (size dependent emigration), and 2) seasonal emigration independent of size. Patterns in abundance and growth of YOY fishes in New Jersey marsh creeks strongly suggest that seasonal migration of fishes constitutes a major pathway of energy export from the marsh into coastal waters. Recent research on patterns of marsh creek community structure and mechanisms of energy exchange between the marsh and marine waters are reviewed. Ontogenetic migrations and cyclic foraging movements are the two major types of animal movements which result in energy exchange between the marsh and adjacent habitats.


This page was last modified on July 20, 2001

Copyright © 1999 by Rodney Rountree. All rights reserved

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