Date Awarded

2022

Document Type

Thesis

Degree Name

Master of Science (M.Sc.)

Department

Biology

Advisor

Bryan Watts

Committee Member

Mary Fabrizio

Committee Member

Matthias Leu

Committee Member

John Swaddle

Abstract

The Atlantic States Marine Fisheries Commission (ASMFC), the governing body responsible for managing fisheries on the U.S. East Coast, formally adopted the use of Ecological Reference Points (ERPs) for Atlantic menhaden, Brevoortia tyrannus. Scientists and stakeholders have long recognized the importance of menhaden and predators such as ospreys, Pandion haliaetus, that support the valuable ecotourism industry and hold cultural significance. Landings in the reduction fishery are at their lowest levels and menhaden is facing potential local depletion. Mobjack Bay, located within the lower Chesapeake Bay, has been a focus of osprey research since 1970 and represents a barometer for the relationship between osprey breeding performance and menhaden availability. Since local levels of menhaden abundance were not available, we conducted a supplemental feeding experiment on osprey pairs during the 2021 breeding season. Our main objective was to determine if the delivery rate of menhaden had an influence on nest success and productivity. Nest success (χ2 = 5.5, df = 1, P = 0.02) and productivity (β = 0.88, SE = 0.45, pseudo r2 = 0.14, CI = 0.049, 1.825, P = 0.048) were significantly higher within the treatment group. The added average biomass/d/nest (β = 0.03, SE = 0.009, pseudo r2 = 0.59, CI = 0.01, 0.05, P = 0.02) and energy content/d/nest (β = 0.02, SE = 0.005, pseudo r2 = 0.64, CI = 0.006, 0.03, P = 0.02) had an influence on pairs reaching maintenance reproductive rates (1.15 young/pair). Reproductive rates within the control group were low and unsustainable suggesting that current menhaden availability is too low to support a demographically stable osprey population.

DOI

https://dx.doi.org/10.21220/s2-7xng-am50

Rights

© The Author

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