Euphausiacea, commonly known as krill, are small, shrimp-like crustaceans found in oceans worldwide. They play a crucial role in the marine ecosystem as a primary food source for many larger animals, including whales, seals, and penguins. Krill are known for their bioluminescence, which helps them evade predators and communicate.

Euphausiacea, commonly known as krill, are found in oceans worldwide. They inhabit the waters surrounding every continent, from the polar regions to temperate and tropical zones. Major concentrations of krill are found in the Southern Ocean (Antarctica) and the Northern Pacific Ocean.

Krill typically inhabit cold oceanic waters, with the highest densities occurring within nutrient-rich upwelling zones and polar regions. They are generally found at varying depths, depending on the species, and can be located from the surface to depths of over 2000 meters. The temperature range for krill habitats often spans from sub-zero waters in polar regions to moderate temperatures in temperate zones.

Krill play a crucial role in marine ecosystems as primary consumers, feeding on phytoplankton and, to a lesser extent, zooplankton. They serve as a key food source for many marine animals, including fish, birds, and mammals such as whales and seals. Krill are adapted to a pelagic lifestyle, often forming large swarms that can extend over several kilometers, which aids in their feeding and protection from predators.