Krill are small marine crustaceans that live in the polar oceanic regions. Krill are usually found in large swarms covering an area of up to several hundred square kilometres. Together with plankton, they form the largest percentage of biomass in the world. They serve as a food source for a wide range of marine animals, including seals and penguins. Krill is also commercially processed for the needs of the pharmaceutical, food and feed industry. It is especially prized for its high content of omega-3 unsaturated fatty acids and astaxanthin. Astaxanthin is considered one of the most effective antioxidants of all. It reduces the oxidation process in the body by limiting the activity of oxygen radicals and protecting cells from damage that can lead to cancerous growth.