Bite Size: Bull Shark Predation of Tarpon
Neil Hammerschlag, University of Miami
Gareth Burghes, Lagomorph Films
Predators can impact ecosystems through trophic cascades. Both bull sharks and tarpon are large predatory fish in tropical waters. They occupy similar inshore habitats and having similar diets; but, if given the opportunity, bull sharks will catch and consume tarpon. However, it remains unknown if tarpon adjust their movements to avoid being killed by the sharks. In this study, both bull sharks and tarpon were satellite tagged to track their movements in South Florida waters. The results showed that tarpon avoided the areas where bull sharks aggregated. In fact, tarpon appeared to forfeit some of the best feeding spots to reduce their chances of being killed by sharks. These results suggest that overfishing of bull shark could impact the behaviors of tarpon, subsequently triggering trophic cascades.
Hammerschlag N, Luo J, Irschick DJ, Ault JS (2012) A Comparison of Spatial and Movement Patterns between Sympatric Predators: Bull Sharks (Carcharhinus leucas) and Atlantic Tarpon (Megalops atlanticus). PLoS ONE 7(9): e45958. doi:10.1371/journal.pone.0045958
Follow Dr. Hammerschlag's research on his website: www.SharkTagging.com