In the vast, open ocean with no place to hide, sardines group together for protection. When they cannot rely on speed to escape, the sardines' best chance is to outmaneuver the predator altogether.

Is there bycatch? What about emissions? Are sardines overfished? If we care about the health of the ocean, can we keep eating sardines? Featuring Jeannie Bartlett, Malin Pinsky, and Zach Koehn.

Sharks, those legendary "swimming noses," were never far from the sardine supply. They had a knack for materializing out of seemingly empty ocean. You would think you were alone—and then there ...