Euphausia Pacifica, commonly known as the Pacific krill, is a small, shrimp-like crustacean that belongs to the family Euphausiidae. This species is widely distributed in the eastern North Pacific Ocean and is an important food source for a variety of marine organisms, including fish, whales, and seabirds. There are a few synonyms for this species, such as Thysanoessa spinifera, Euphausia spinifera, and Nyctiphanes spinifera. These synonyms were previously used to refer to different morphological types of Euphausia Pacifica, but recent research has found that they are all the same species. As such, Euphausia Pacifica remains the accepted name for this important marine organism.