What organisms is a krill?

Krill are small, shrimp-like crustaceans belonging to the order Euphausiacea. They are primarily found in the ocean, particularly in polar regions, and serve as a crucial part of the marine food web, acting as a primary food source for various species, including whales, seals, and penguins. Krill play an essential role in the ecosystem by aiding in the transfer of energy from phytoplankton to larger marine animals. Their populations have significant ecological and commercial importance, particularly in fisheries.