Widespread reproductive deficits in Chesapeake Bay ospreys

Frontiers in Marine Science
By: , and 

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Abstract

Introduction: 

Ospreys (Pandion haliaetus) are well-known sentinels of aquatic ecosystem health and are indicators of both environmental contaminants and fish stocks. The Chesapeake Bay supports one of the largest osprey breeding populations in the world, but recent studies have documented declining reproductive performance and increasing food stress in some portions of the estuary.

Methods: 

We monitored osprey nests (N = 571) throughout the Chesapeake Bay during the 2024 breeding season and compared breeding metrics between high-salinity (>10 parts per thousand [ppt]) and low-salinity (<5 ppt) study areas. We also compared contemporary breeding performance within four high-salinity sites to historical data collected during the 1980s.

Results: 

Salinity was strongly associated with breeding performance and the likelihood that pairs achieved productivity levels required for population maintenance. All high-salinity study areas functioned as demographic sinks, whereas low-salinity areas functioned as demographic sources. Breeding metrics including the proportion of pairs breeding, clutch size, nesting failure, brood reduction, and nestling loss all suggested greater food stress within high-salinity areas. Temporal comparisons documented substantial declines in reproductive performance between the 1980s and 2024 within high-salinity study sites. High-salinity sites during the 1980s exhibited breeding performance comparable to low-salinity sites in 2024.

Discussion: 

Although several factors may influence osprey productivity within the Chesapeake Bay, we suggest that reduced availability of Atlantic menhaden (Brevoortia tyrannus) is a primary driver of poor reproductive performance within high-salinity waters.

Suggested Citation

Watts, B.D., Hines, C., Byrd, M., Lukei, R.F., Paxton, B.J., Duval, L., Spiewak, K., Kearns, G.D., Day, D.D., and Rattner, B., 2026, Widespread reproductive deficits in Chesapeake Bay ospreys: Frontiers in Marine Science, v. 13, 1685158, 15 p., https://doi.org/10.3389/fmars.2026.1685158.

ISSN: 2296-7745 (online)

Study Area

Publication type Article
Publication Subtype Journal Article
Title Widespread reproductive deficits in Chesapeake Bay ospreys
Series title Frontiers in Marine Science
DOI 10.3389/fmars.2026.1685158
Volume 13
Publication Date June 08, 2026
Year Published 2026
Language English
Publisher Frontiers Media
Contributing office(s) Eastern Ecological Science Center
Description 1685158, 15 p.
Country United States
State Maryland, Virginia
Other Geospatial Chesapeake Bay
Additional publication details