Sharks: Stewards of the Reef

In this trailer, experts discuss the importance of sharks to the health of coral reefs. Marine ecologist Enric Sala of Scripps Institution of Oceanography talks about the role of sharks as top predators in ocean ecosystems. Peter Knight, executive director of WildAid, and Sonja Fordham of the Ocean Conservancy detail the decline of shark populations worldwide as a result of fishing pressure (03:23)