Ecosystems Impacts of Overfishing

Project Title: Assessing the cascading ecosystem impacts of marine predator declines as a result of overfishing

Overview

Overfishing is among the greatest threats facing marine biodiversity. Many species of top ocean predators, such as billfish, tunas and sharks, are experiencing unprecedented population declines worldwide. Sharks are among the most threatened marine animals worldwide. Recent estimates suggest that populations of many large sharks have declined by 90% or more in areas where they were once abundant. We are conducting a series of integrated field and laboratory studies in the Florida Keys to understand the ecosystem role of marine predators and the potential cascading effects of their declines on fish communities. This work will provide insights for predicting how both predators and prey are likely to respond to overfishing with implications for developing effective conservation and management strategies.

Some of the primary questions of this work include:

  1. Can changes in the presence and absence of sharks impact the community structure of coral reef fishes?
  2. Can changes in the abundance or movements of sharks effect the feeding behaviors and diets of coral reef fishes?
  3. Can changes in the abundance or behavior of sharks effect the physiology and/or reproductive behavior of coral reef fishes?


This project will increase our understanding of how predators can influence coral reef ecosystems. Such an understanding will aid scientists and managers in predicting how ecosystems may change following declines or recoveries of marine predators.



Investigators

Project Lead:
Dr. N Hammerschlag
Co-Investigators & Collaborators:
D Shiffman
• B Shelton
• Dr. G Trussell
• Dr. L Kaufman
• Dr. J Sulikowski