Marine Science Researcher Studies Tiger Sharks
Public perception of sharks is often negative as the sea creatures are typically viewed as aggressive eating machines. This perception, however, displays a lack of awareness of the important role sharks play in maintaining a balance in our ocean Indeed, sharks play a vital role in the ocean’s food web, and scientists worldwide are working to better understand, protect and conserve sharks in a number of ways. Their low reproductive rates and the high demand in Asian markets for many sharks have threatened their global viability. ecosystem.
Dr. Marcus Drymon, Research Assistant Professor in Marine Biology, studies sharks. According to Dryman, “With the public’s support, we are able to start reversing the global declines being reported for some shark populations.” He adds that “Understanding what they eat is a necessary step in the process.” At the the Dauphin Island Sea Lab, Drymon recently started studying what the local shark populations consume on Alabama’s Gulf Coast. When he and his team caught a small tiger shark coughing up a mass of feathers, he realized that small tiger sharks in the northern Gulf of Mexico were consuming birds. Further examination of these feathers revealed they were from land, rather than marine, birds. Since then, Drymon and his team have recorded as many as three-fourths of the tiger sharks in the Gulf of Mexico with remains of terrestrial birds in their stomachs. The terrestrial birds being eaten by the sharks include, Drymon says, “kingbirds, thrashers, wrens, flycatchers, coots, doves, among other species.”
The first step in this research project, Dryman says, was to document how often these small tiger sharks interact with land birds. The second step was to use DNA bar-coding to identify the bird remains from the tiger sharks to the lowest possible level (species). The third and final step centers on understanding where these tiger sharks gain access to these birds. According to Drymon, having detailed information on what the tiger sharks eat is crucial to the conservation of the threatened sharks. However, linked to this is the fact that many bird species using Dauphin Island as an important stopover during their annual migrations become prey necessary for the sharks’ survival. “Knowing what an individual species eats and how it varies within a population is important to know so we can manage and conserve all species,” Drymon said. To view a video about Drymon’s project and to donate to this program, visit www.experiment.com/tigersharks.