A Comparison of Spatial and Movement Patterns between Sympatric Predators: Bull Sharks (Carcharhinus leucas) and Atlantic Tarpon (Megalops atlanticus)
Open Access
- 26 September 2012
- journal article
- research article
- Published by Public Library of Science (PLoS) in PLOS ONE
- Vol. 7 (9), e45958
- https://doi.org/10.1371/journal.pone.0045958
Abstract
Predators can impact ecosystems through trophic cascades such that differential patterns in habitat use can lead to spatiotemporal variation in top down forcing on community dynamics. Thus, improved understanding of predator movements is important for evaluating the potential ecosystem effects of their declines. We satellite-tagged an apex predator (bull sharks, Carcharhinus leucas) and a sympatric mesopredator (Atlantic tarpon, Megalops atlanticus) in southern Florida waters to describe their habitat use, abundance and movement patterns. We asked four questions: (1) How do the seasonal abundance patterns of bull sharks and tarpon compare? (2) How do the movement patterns of bull sharks and tarpon compare, and what proportion of time do their respective primary ranges overlap? (3) Do tarpon movement patterns (e.g., straight versus convoluted paths) and/or their rates of movement (ROM) differ in areas of low versus high bull shark abundance? and (4) Can any general conclusions be reached concerning whether tarpon may mitigate risk of predation by sharks when they are in areas of high bull shark abundance? Despite similarities in diet, bull sharks and tarpon showed little overlap in habitat use. Bull shark abundance was high year-round, but peaked in winter; while tarpon abundance and fishery catches were highest in late spring. However, presence of the largest sharks (>230 cm) coincided with peak tarpon abundance. When moving over deep open waters (areas of high shark abundance and high food availability) tarpon maintained relatively high ROM in directed lines until reaching shallow structurally-complex areas. At such locations, tarpon exhibited slow tortuous movements over relatively long time periods indicative of foraging. Tarpon periodically concentrated up rivers, where tracked bull sharks were absent. We propose that tarpon trade-off energetic costs of both food assimilation and osmoregulation to reduce predation risk by bull sharks.This publication has 38 references indexed in Scilit:
- An analytical and hypothesis‐driven approach to elasmobranch movement studiesJournal of Fish Biology, 2012
- Habitat use and movement patterns of bull sharks Carcharhinus leucas determined using pop‐up satellite archival tagsJournal of Fish Biology, 2010
- Patterns and ecosystem consequences of shark declines in the oceanEcology Letters, 2010
- Improving conservation planning for an endangered sawfish using data from acoustic telemetryBiological Conservation, 2010
- Home range, residency and movements of Diplodus sargus and Diplodus vulgaris in a coastal lagoon: Connectivity between nursery and adult habitatsEstuarine, Coastal and Shelf Science, 2009
- A movement ecology paradigm for unifying organismal movement researchProceedings of the National Academy of Sciences of the United States of America, 2008
- Migration patterns of white sharks Carcharodon carcharias tagged at Guadalupe Island, Mexico, and identification of an eastern Pacific shared offshore foraging areaMarine Ecology Progress Series, 2008
- Life history patterns shape energy allocation among fishes on coral reefsOecologia, 2007
- How to reliably estimate the tortuosity of an animal's path:: straightness, sinuosity, or fractal dimension?Journal of Theoretical Biology, 2004
- Rapid worldwide depletion of predatory fish communitiesNature, 2003