Krill More than 85 species of krill inhabit the world's oceans and they are usually 2-3 cm in size, living anywhere from six months to several years. Krill have two antennae, which are used for sensing touch, heat, vibration, smell and taste. They have several pairs of legs that have different purposes. For swimming, krill use legs called “swimmerets” that look like small feathers and act like fins. They also have modified feeding legs that separate food from the water as they swim. Krill generally feed on phytoplankton, microscopic ocean plants at the foundation of the marine food chain. When food resources are scarce, adult krill have the amazing ability to shrink in size. Krill typically concentrate into large groups, sometimes swarming into groups as dense as 1,000 to 100,000 krill per cubic meter. Such behavior acts as a defense mechanism, confusing some predators that prefer to take single individuals, but paradoxically welcoming bigger predators to a feast. Other defense mechanisms include the krill’s ability to instantly molt, in which they leave behind their floating exoskeletons as a decoy to confuse predators. Often times, large groupings of krill can be located by observing the behavior of more easily visible animals such as seabirds and whales. Flocks of diving pelicans or gulls help fishing boats locate salmon feeding on krill below the ocean surface. Even though it makes them more vulnerable to predators, the krill that inhabit the waters off the California coast spend most daylight hours in the warmer waters near the surface. It is unknown why they do this since it puts them in such danger. Some researchers believe the krill are involuntarily driven to surface waters by overpowering ocean currents. Other researchers believe they swarm to the surface to take advantage of better feeding opportunities, and because reproductive rates are higher in warmer waters. Seabirds and filter feeders like the humpback whale exploit this strange behavior of the krill. A single humpback whale may eat up to a ton of krill in a single day. The most common commercial uses of krill include aquaculture and aquarium feed, but they are harvested for other reasons such as human consumption, pharmaceutical uses, and bait for sport fishing. In Japan, krill used for human food is known as okiami. Usually it is only the tail meat that is sold and it is used in soups, seafood salads, and in restaurant entrees. Their taste is described as salty and stronger than shrimp. In health food stores, krill oil is marketed as a nutritional supplement and is believed to be beneficial for joints and the immune system. In Antarctic waters the annual catch of krill tops out at around 100,000 tons, and in Japan, slightly less, at about 70,000. Because of over fishing in the eighties, the Commission for the Conservation of Antarctic Marine Living Resources in 1993 set regulations on the krill fishing industry, ensuring a sustainable future for krill populations. Concern about krill surfaced in 2004 when the managers of the Monterey Bay, Gulf of the Farallones and Cordell Banks National Marine Sanctuaries in California raised concerns about krill harvesting since they are a vital part of the food chain. Washington, Oregon, and California already have a state ban against netting krill, up to their boundaries of 3 miles offshore. The Pacific Fishery Management Council, an advisory board to the National Marine Fisheries Service, recommended a federal krill harvest ban in March for federal waters which reach 200 miles offshore. The recommendation must now be approved by the National Marine Fisheries Service. http://www.farallones.org/e_newsletter/2006-04/Krill.htm