The diet of the largest animal ever known, the blue whale, is mainly composed of one of the smallest: krill.

The Predator

Blue whales, weighing around 200 tons, feed exclusively on krill and require massive amounts to sustain their large size. Having been hunted to near extinction by historical whaling, blue whales now need krill to fuel their reproduction to recover their populations.

The Prey

Krill are small, pink, translucent, shrimp-like crustaceans that congregate in large, dense masses called swarms or clouds. Krill serve as a critical link in the food web as many animals rely upon them as a food source. They are present in all the oceans of the world.

The Threats

Krill fisheries, operating in the Southern Ocean and around Japan, harvest krill for human consumption and aquaculture feed. Increasing demand for new products, such as krill oil, may further reduce krill populations and stress blue whale survival.