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Graduate Research Fellowship
The Influence of Habitat Degradation on Nektonic Abundance and Production in Unvegetated Estuarine Shallows
David Gillett
Graduate Research Fellow 2007-2008
Chesapeake Bay Virginia NERR, VA
Virginia Institute of Marine Science

One of the pressing problems currently facing estuarine ecologists and managers is determining the relationships between habitat quality and nekton production in shallow water habitats. The macrobenthos of estuarine shallows serve as an abundant, energy rich food source to estuarine nekton, particularly demersal and benthivoric species, and the species composition and production of those organisms is related to the environmental health and quality of a given area. As these food sources change with habitat degradation, the usefulness of these systems to the nekton likely changes as well. Between April and September 2006 the composition and production of the macrobenthic communities at a series of sites that comprise a gradient of habitat degradation, from the relatively pristine Catlett Islands to the excessively toxic and eutrophied parts of the Elizabeth River were characterized from. I am now proposing to assess how the organic matter in these different macrobenthic communities is used by commercially and ecologically important finfish and crustaceans by empirically estimating nekton abundance, biomass, natural abundance, 15N and 13C content, and consumption of macrobenthos by those nekton along the aforementioned gradient of environmental degradation. Nekton production will be estimated and combined with previously collected macrobenthic production estimates to model trophic transfer efficiency from the macrobenthos to the nekton. The results of this research will provide a direct estimate of how habitat alteration or protection may alter the estuarine food web, both within the National Estuarine Research Reserve System and temperate estuaries around the country. Locally, this study will provide a detailed description of the -nektonic community and food web of the Chesapeake Bay Virginia NERRS site.

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