Date Awarded

2017

Document Type

Thesis

Degree Name

Master of Science (M.Sc.)

Department

Virginia Institute of Marine Science

Advisor

Rochelle D Seitz

Committee Member

Mary C. Fabrizio

Committee Member

Robert J. Latour

Committee Member

M. Lisa Kellogg

Abstract

Oyster reef restoration may enhance the production of ecologically or economically important fish species, an ecosystem service, by providing refuge and foraging habitat. Predicting the effects of oyster habitat restoration on fisheries production in Chesapeake Bay requires a better understanding of fish habitat use, trophic dynamics, and the processes leading to production on a habitat-scale. The objective of this thesis was to evaluate the influence of restored subtidal oyster reefs on the abundance and foraging patterns of mobile estuarine fishes. Specifically, I compared the 1) abundance, 2) stomach fullness, 3) diet composition, and 4) daily consumption rate of fishes collected from restored oyster reef habitat and from unstructured (control) habitat in the Lynnhaven River System (LRS), Virginia, a tributary of Chesapeake Bay. I sampled fishes from April – October 2016 to assess seasonal abundance and diet trends using multi-panel gill nets, and conducted 24-hour sampling events in July and September 2016 to assess daily foraging patterns and estimate habitat-specific consumption rates. The most abundant non-filter feeding fishes collected all came from the Sciaenid (drum) family: spot (Leiostomus xanthurus), silver perch (Bairdiella chrysoura), and Atlantic croaker (Micropogonias undulatus). Overall catch in oyster reef habitat was reduced relative to unstructured bottom, but species-level responses to habitat type varied. Stomach fullness trends varied by species but were associated with habitat type. Benthic prey dominated the diet of all three species, and evidence of habitat-related shifts in diet composition were apparent. Reef-affiliated prey contributed most prominently to silver perch, comprising nearly 30 – 50 % by weight. The daily consumption rate and total daily caloric intake of silver perch foraging in oyster reef habitat were nearly double the estimates from control habitat. The results suggest restored oyster reefs influence habitat use and foraging behavior in species-specific manners, likely a result of differences in functional morphology and prey preference. Restored oyster reefs in the LRS likely act as valuable forage habitat for silver perch, an important trophic link in coastal and estuarine systems. Developing realistic estimates of fisheries production on a habitat-scale requires studying species-specific trophic dynamics. Empirical estimates of the processes contributing to production are necessary to better understand the functional role of restored oyster reefs in shallow estuarine and coastal systems, and the ecosystem services these reefs may provide.

DOI

http://dx.doi.org/doi:10.21220/V5544T

Rights

© The Author

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