Predator-prey landscapes of large sharks in the Florida Keys
25 March 2022
Predator-prey landscapes of large sharks and game fishes in the Florida Keys
Lucas P Griffin, Grace A Casselberry, Susan K Lowerre-Barbieri, Alejandro Acosta, Aaron J Adams, Steven J Cooke, Alex Filous, Claudia Friess, Tristan L Guttridge, Neil Hammerschlag, Vital Heim, Danielle Morley, Mitchell J Rider, Gregory B Skomal, Matthew J Smukall, Andy J Danylchuk, Jacob W Brownscombe
ABSTRACT:
Interspecific interactions can play an essential role in shaping wildlife populations and communities. To date, assessments of interspecific interactions, and more specifically predator-prey dynamics, in aquatic systems over broad spatial and temporal scales (i.e., hundreds of km and multiple years) are rare due to constraints on our abilities to measure effectively at those scales. We applied new methods to identify space use overlap and potential predation risk to Atlantic tarpon (Megalops atlanticus) and permit (Trachinotus falcatus) from two known predators, great hammerhead (Sphyrna mokarran) and bull (Carcharhinus leucas) sharks over a three year period using acoustic telemetry in the coastal region of the Florida Keys (USA). By examining spatial-temporal overlap, as well as the timing and order of arrival at specific locations compared to random chance, we show that potential predation risk from great hammerhead and bull sharks to Atlantic tarpon and permit are heterogeneous across the Florida Keys. Additionally, we found that predator encounter rates with these game fishes are elevated at specific locations and times, including a pre-spawning aggregation site in the case of Atlantic tarpon. Further, using machine learning algorithms, we identify environmental variability in overlap between predators and their potential prey, including location, habitat, time of year, lunar cycle, depth, and water temperature. These predator-prey landscapes provide insights into fundamental ecosystem function and biological conservation, especially in the context of emerging fisheries-related depredation issues in coastal marine ecosystems.
Ecol Appl. 2022 Mar 25;e2584. DOI: 10.1002/eap.2584. Online ahead of print.