Demographic response of osprey within the lower Chesapeake Bay to fluctuations in menhaden stock
-
Published:2024-01-08
Issue:
Volume:10
Page:
-
ISSN:2296-7745
-
Container-title:Frontiers in Marine Science
-
language:
-
Short-container-title:Front. Mar. Sci.
Author:
Watts Bryan D.,Stinson Christine H.,McLean Peter K.,Glass K. Andrew,Academia Michael H.,Byrd Mitchell A.
Abstract
Forage fish support the largest fisheries in the world and play a vital role in marine food webs by transferring energy from plankton to consumers within higher trophic levels. Growing commercial demand for these species and concern for the impact of over harvest on predator populations has driven a paradigm shift in management objectives from maximizing economic return to the establishment of ecosystem-based limits on harvest rates. How well current harvest policy supports noncommercial species like piscivorous birds remains poorly understood. We investigated the relationship between osprey breeding performance within the lower Chesapeake Bay and a menhaden stock index during a period (1974-2021) when the menhaden index fluctuated over 35-fold. Reproductive rate (young/pair/year), brood provisioning (fish/10-h) and the proportion of menhaden in the diet all declined during the study period. Indicators of food stress including brood reduction and nest failure increased during the study period. The population transitioned from reproductive surplus (demographic source) to reproductive deficit (demographic sink). A significant relationship between reproductive rate and the menhaden index suggests that osprey population viability requires that the menhaden stock be restored to 1980s levels. Current ecological reference points based on the food requirements of predatory fish are unlikely to protect the osprey population. We suggest the establishment of menhaden or reproductive thresholds designed to allow osprey to meet demographic targets (1.15 young/pair/year).
Publisher
Frontiers Media SA
Subject
Ocean Engineering,Water Science and Technology,Aquatic Science,Global and Planetary Change,Oceanography
Reference79 articles.
1. Food supplementation increases reproductive performance of ospreys in the lower Chesapeake Bay;Academia;Front. Mar. Sci.,2023
2. Population biology and life history of the North American menhadens. Brevoortia spp;Ahrenholz;Mar. Fisheries Rev.,1991
3. Forage fish: From ecosystems to markets;Alder;Annu. Rev. Environ. Resour.,2008
4. The path to an ecosystem approach for forage fish management: A case study of Atlantic menhaden;Anstead;Front. Mar. Sci.,2021