Chesapeake Bay Ecological Foundation, Inc.

DIETARY HABITS OF AN HISTORICAL STRIPED BASS (MARONE SAXATILIS) POPULATION IN THE CHESAPEAKE BAY

By
Jennifer Caroline Griffin

Thesis submitted to the faculty of the Graduate School Of the University of Maryland Eastern Shore in partial Fulfillment of the requirement for the degree of Master Science 2001

Advisory Committee:

Professor F. Joseph Margraf, Chairman/ Co-Advisor
Associate Professor Douglas Ruby, Co-Advisor
Professor Ed Houde
Professor Reggie Harrell

ABSTRACT

Title of Thesis: Dietary habits of an historical striped bass(Morone saxatilis) Population in Chesapeake Bay

Name of degree candidate: Jennifer Caroline Griffin

Degree and Year: Master of Science, 2001

Thesis directed by: F. Joseph Margraf, Leader and Professor, Maryland Cooperative Fish and Wildlife Research Unit
Douglas E. Ruby, Associate Professor, Department of Natural Sciences

Several studies have been undertaken to determine the predatory demand the restored Population of striped bass exacts on its prey in the Chesapeake Bay. However, baseline measurements to gauge predatory demand were lacking. This study describes the diet and predatory demand of an historical striped bass population in Chesapeake Bay. Unpublished stomach content data from 932 striped bass collected between 1955 and 1959 were provided by the Maryland Department of Natural Resources. I quantified the diet using two methods, bioenergetics modeling and an index of relative importance(IRI). Bioenergetics modeling of striped bass age-1 through age-6 showed annual cumulative consumption of Atlantic menhaden to be 74% of all prey consumed by all age groups, followed by spot (6%) and clupeids (6%). The highest annual cumulative consumption of bay anchovy was by age-1 fish (43%). Predatory demand was only slightly below prey supply throughout the modeled year for all ages, and weight at the length for this sample was generally similar to a population sampled in the early 1990s. Atlantic menhaden (66%) and bay anchovy (19%) had the highest %IRI value overall, with a group of unidentified fish (11%) and clupeids (2%) following. My results show that Atlantic menhaden was the primary prey of striped bass in Chesapeake Bay in the early 1950s. Analysis of historical data using current techniques provided valuable tool of comparison that will be useful in understanding the current striped bass predator-prey relationship in Chesapeake Bay.