Aquatic Sciences Meeting, Albuquerque 2001

SS35 Biological and Ecological Responses to Low Oxygen in Constant and Fluctuating Environments (Spatial and Temporal Connections)

Date: Thursday, February 15, 2001, Time: 3:45:00 PM

Location: La Cienega

Eby, L, A, Duke Marine Lab, Beaufort, USA, lae5@duke.edu

Crowder, L, B, Duke Marine Lab, Beaufort, USA, lcrowder@duke.edu

ECOLOGICAL EFFECTS OF HYPOXIA ON THE FISH COMMUNITY IN THE NEUSE RIVER ESTUARY, N.C.

Landscape modification to coastal watersheds and nutrient loading into coastal rivers often lead to water quality degradation and associated habitat loss for fishes. We examined the ecological effects of intermittent seasonal hypoxia on the demersal fish community in the Neuse River estuary, North Carolina. We hypothesized that intermittent hypoxia would alter spatial distributions and decrease habitat quality for juvenile fish. Synoptic water quality and bottom trawl sampling (May through October, 1997-1999) indicated that catch rates and species diversity decreased in hypoxic areas. Most species were excluded from areas with dissolved oxygen concentrations less than 2.0 mg/L. When large hypoxic zones were present, high densities of fish were found in shallow, oxygenated areas. In situ cage experiments (June and August 1999) demonstrated decreased in fish growth rates, associated with both density dependent and density independent mechanisms. Our data suggest that intermittent hypoxia decreases habitat quality sufficiently to decrease growth in juvenile fish and potentially the production potential of coastal estuaries.

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Aquatic Sciences Meeting, Albuquerque 2001

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