Sharks have been around, essentially unchanged, for 400 million years. Their size, power, and massive jaws fill us with terror and fascination. And even though sharks kill fewer people than dogs each year, media coverage and movies of shark attacks have portrayed them as insatiable killing machines.

They may rule the ocean, but sharks are vulnerable. They grow slowly, produce few young, and are exceptionally susceptible to overfishing. Sharks are being depleted faster than they can reproduce. This threatens the stability of marine ecosystems around the world. A healthy and abundant ocean depends on predators like sharks keeping ecosystems balanced.

Sharks migrating between California and Baja California, Mexico, are threatened by commercial fishing activity in both countries. Join Scripps shark expert Dan Cartamil as he explores the ecology and behaviors of these fascinating animals, and discusses the issues relevant to the sustainability of our local shark populations.

Watch Sharks Without Borders: A Binational Effort to Study and Conserve Threatened Shark Species.

Browse more programs in the Perspectives on Ocean Science series, taped at Birch Aquarium at Scripps since 2001.