Sharks on Coral Reefs
Predators play important roles in natural ecosystems, often determining the abundances of other species and how the ecosystem itself functions. Across the world’s oceans; however, many predator populations have been substantially depleted through overfishing. Sharks are a prime example of these threatened predators. Although ferocious predators, sharks are actually quite vulnerable to fishing pressure because they take years to reach maturity and have few pups, leaving them with low population growth rates. Despite this vulnerability, shark exploitation has increased substantially because of escalating demand for shark fins. With sharks largely eliminated from reefs over the past several centuries, many of the world’s remaining populations are now found on remote Pacific islands. Even these remote islands are now coming under pressure from fishing.
Given these mounting threats, there is a critical need to evaluate the status of reef shark populations and to forecast the threats posed to their persistence by human activities. This Working Group research aims to understand what ecological, physical, and anthropogenic factors determine the abundance of sharks and other predators on reefs across the Pacific by integrating data into statistical models. Census data from divers will be integrated with oceanographic, diversity, human population and fishing data. Models will then be used to predict predator distributions and abundances across the Pacific to estimate past abundances of these species, and to forecast potential changes in their populations over the coming decades based on alternative management scenarios.
This research is timely, given the recent designation of many remote Pacific reefs as U.S. national monuments. Research findings will be communicated to NOAA scientists and conservation practitioners with the aim of informing policy decisions for shark conservation.