North Pacific Krill, Euphausia pacifica: The North Pacific Krill is a member of the Euphausiidae Family which has more than 80 members globally. Krill are more abundant than one might believe. They are shrimp-like creatures that swarm in huge clouds of significant biomass up to 2,000,000 metric tons with more than 1,000,000 animals per cubic meter, found in the upper water column.
Krill serve as a vital food source for a wide variety of marine life including sea birds, manta rays, mobula rays, and whales, with consumption rates estimated to be between 150,000,000 and 300,000,000 metric tons per annum.
For example, during the summer months in Alaskan waters Krill are consumed by Blue Whales at a level of 4 tons per day per individual. Each female Krill can produce many sets of 20,000 eggs per annum. There is also commercial interest in Krill with collections made using towed nets. Krill are used as a feed supplement for fish farms and aquariums, as well as for human consumption in Asia, where Krill consumption is estimated at 500,000 metric tons per annum.
Krill are believed to be the ocean’s richest source of protein and are also rich in vitamins. Krill undergo a daily vertical migration where they spend daylight hours in the twilight depths of the ocean, 100 to 300 feet deep, staying out of sight of predators. They are filter feeders and at night they rise to the surface to feed on phytoplankton.
North Pacific Krill, along with the species Thysanoessa spinifera, are the most common krill off the west coast of North America. They are about one-half inch in length and are characterized by having long antennae, no rostrum, spherical eyes, legs of similar appearance, no spines in the abdomen, and a prominent spine in the lateral part of the shell or carapace. The North Pacific Krill is found in all waters of the North Pacific.