Every winter, billions of sardines off the coast of South Africa embark on their annual breeding migration. "The Ocean’s Greatest Feast" premieres Wednesday, February 16th at 8/7c on PBS. [VID: Sardines by the billions live here year-round, swimming and feeding together in loose shoals of hundreds of thousands of individuals. Then, in late April, ocean currents undergo a subtle shift. As the southern winter approaches, upwellings and eddies force a tendril of cold water toward the east. The warm

South Africa's annual sardine run is one of the planet's biggest migrations, with billions of fish heading north to Mozambique. But the greatest shoal on Earth is under threat from the climate crisis: https://cnn.it/2J8mSh1 #CallToEarth | CNN