Date Awarded

2006

Document Type

Thesis

Degree Name

Master of Science (M.Sc.)

Department

Virginia Institute of Marine Science

Abstract

The Chesapeake Bay spawning stock of striped bass, Morone saxatilis, is considered one of the largest sources of juvenile production along the Atlantic coast and exhibits a high degree of interannual recruitment variability. Year class strength is judged by near-shore seine surveys that cover major tributaries of Chesapeake Bay and survey results are incorporated into annual stock assessments. In these surveys, the contribution of the Rappahannock River (Virginia) to total production is significant. In this system, abundance of juveniles is highest at a single seine site, suggesting that juvenile production may be related to habitat heterogeneity and food availability. To evaluate this possibility, we describe daily variability in prey consumption, prey composition, and prey selection of juvenile striped bass at the productive site (RK 89) and habitat-specific patterns in feeding along an estuarine gradient that included the productive site. I examined diets of juvenile striped bass collected in five 24-h seine surveys at RK 89 in 1983 and conducted seine hauls at four stations (RK 89, RK 81, RK 71 and RK 60) in 2004. During 24-hr sampling, more fish were caught at 1800 hours and 2100 hours than at other times. In 2004, significantly more fish were caught at RK 89 than at RK 60. Fish were significantly less full at 0300, 0600 and 0000 hours than at all other times. Prey with the highest Index of Relative Importance values were dipteran larvae, calanoid copepods and polychaetes, ranking 1-3 respectively in both years. Peak mean density of Bosmina, other cladocerans, calanoid copepods, and dipteran larvae occurred at RK 89. However, fish were fuller at RK 60 than at RK 89. YOY striped bass showed some indications of selective feeding. As young striped bass grow in the Rappahannock River, they gradually disperse from natal areas into heterogeneous nursery habitats downriver. This ontogeny is reflected in diets as smaller fishes upriver fed on many individuals of smaller plankton prey (especially calanoid copepods) and were less full than cohorts downriver that consumed fewer individuals of larger benthic prey (especially polychaetes).

DOI

https://dx.doi.org/doi:10.25773/v5-b15q-kz11

Rights

© The Author

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