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Effects of variation in the abundance and distribution of prey on the foraging success of central place foragers
Author(s) -
Boyd Charlotte,
Grünbaum Daniel,
Hunt George L.,
Punt André E.,
Weimerskirch Henri,
Bertrand Sophie
Publication year - 2017
Publication title -
journal of applied ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.503
H-Index - 181
eISSN - 1365-2664
pISSN - 0021-8901
DOI - 10.1111/1365-2664.12832
Subject(s) - foraging , predation , abundance (ecology) , seabird , forage fish , forage , ecology , optimal foraging theory , fishery , biology , marine ecosystem , ecosystem
SummarySeabirds and pinnipeds are vulnerable to reductions in prey availability, especially during the breeding season when spatial constraints limit their adaptive capacity. There are growing concerns about the effects of fisheries on prey availability in regions where large commercial fisheries target forage fish. For breeding seabirds and pinnipeds, prey availability depends on a combination of abundance, accessibility, patchiness and distance from the colony. An understanding of the aspects of prey availability that determine foraging success is essential for the design of effective management responses. We used a mechanistic individual‐based foraging model based on observed data for two seabird species, the Peruvian Booby Sula variegata and Guanay Cormorant Phalacrocorax bougainvilliorum , to simulate the foraging patterns of seabirds feeding on schooling fish. We ran the model over simulated prey fields representing eight possible combinations of high or low prey abundance, shallow or deep prey, and broadly distributed or spatially concentrated prey. The results highlight the importance of the accessibility of prey. Depth distribution was the primary factor determining modelled foraging success for both species, followed by abundance, and then spatial configuration. Synthesis and applications . The individual‐based foraging model provides a spatially explicit framework for assessing the effects of fisheries on the foraging success of seabirds and other central place foragers, and for evaluating the potential effectiveness of marine‐protected areas and other fisheries management strategies for safeguarding central place foragers in dynamic ecosystems. Our analysis indicates that broad‐scale fisheries management strategies that maintain forage fish above critical biomass levels are essential, but may need to be supplemented by targeted actions, such as time–area closures, when environmental conditions lead to low prey abundance or reduce prey accessibility for seabirds or pinnipeds of conservation concern. The individual‐based foraging model is adaptable and could be reconfigured for application to other species and systems.