Long-beaked common dolphin pod and diving Cape gannets hunting sardines off the Eastern Cape, South Africa

© Pete Oxford/Minden Picture

The buffet is open. World Oceans Day

On World Oceans Day, you're invited to dinner below the sea, hosted by these long-beaked common dolphins. This pod, off the Eastern Cape in South Africa, is employing an ingenious hunting technique, herding a school of frantic sardines toward the surface of the water so they have no escape, essentially driving them against a wall. Once pinned near the surface, the sardines are easy pickings for the hungry dolphins and any other lucky bystanders, like these dive-bombing Cape gannets who are quick to pounce on the opportunity. The technique requires teamwork of course but that comes easy to dolphins, known for their intelligence and tight familial bonds.

World Oceans Day has been officially recognized by the UN since 2008, in an effort to create awareness and understanding of the oceans and their vital role in supporting all life on the planet, not just marine life. The oceans are under pressure like never before from pollution and climate change. As habitats become dangerously altered, many species are facing extinction, signs that the vast oceans are more fragile than we once thought.

Lest we ignore the bit players here, the smallest fish, like anchovies, herring, and these sardines, fill an essential role in the food chain. Mass feedings like this occur all over the oceans. Scientists even have a name for it: multi-species feeding associations. One massive shoal of small fish can feed many larger creatures, demonstrating how life in the sea is interconnected and how every organism has a part to play.