About This Project

Growing concern for declining shark populations is driving the need for effective conservation and management plans. An important, yet often missing, component of these plans is accurate dietary data. Tiger sharks are iconic predators, notorious for the wide variety of prey they consume. Using satellite tags, our goal is to investigate the link between oil platforms and the prevalence of an intriguing prey item common to tiger sharks in the northern Gulf of Mexico: terrestrial birds.

Ask the Scientists

What is the context of this research?

Tiger sharks are infamous for the variety of prey items they consume, including marine mammals, fish, squid, sea turtles, and occasionally, birds. In 2010, we began investigating the diet of tiger sharks in the northern Gulf of Mexico. Our findings show that tiger sharks in our region consume fish, squid, and birds, all items previously described in their diet; however, we were shocked by two findings: the prevalence and identity of the birds consumed. Surprisingly, birds were common in tiger shark diets. Even more surprising, DNA barcoding of the bird remains identified them as terrestrial species like kingbirds, flycatchers, thrashers, coots, wrens, woodpeckers, doves and yellowthroats! Currently, this link between tiger sharks and the backyard birds they consume is a mystery.

What is the significance of this project?

Recent estimates suggest that the global biomass of predatory fish has declined by two thirds over the past 100 years. Understanding the diet of apex predators such as tiger sharks is critical for their management, and for predicting how changes in their populations will impact the resilience of the ecosystems they occupy.

What are the goals of the project?

The goal of this project is to investigate the link between oil platforms and the unusually high prevalence of terrestrial birds in the diet of juvenile tiger sharks in the northern Gulf of Mexico.

In the fall of 2015, our objective is to tag four juvenile tiger sharks with satellite tags that transmit locations when the animal comes to the surface.

These data will allow us to test the idea that tiger sharks are surfacing more frequently in the vicinity of oil platforms to take advantage of terrestrials birds attracted to the platform lights and too weak to return to land.