Neocalanus cristatus, that reaches almost 1 cm in body length, is a large copepod distributed in the subarctic North Pacific Ocean. This species occupy approximately 30% on the zooplankton biomass in the Oyashio region and is an important prey for fish, cetaceans, and seabirds. This species develops in the surface layer during spring, and after accumated energy as lipid inside their body, descent to depths greater than 1,000 m. Between summer and winter, they stay in the deep layer for their diapause. Reproduction occurs at the deep layer, and the hatched nauplii with large amounts of lipid return to the surface. This species has a one-year life cycle.