''Neocalanus cristatus'' is a species of

copepod Copepods (; meaning 'oar-feet') are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (living in the water column), some are benthos, benthic (living on the sedimen ...

found primarily in the northern Pacific.

Description

The female usually ranges in length from about . The male usually is between about in length.

Distribution

''Neocalanus cristatus'' is found in the northern Pacific and, in lesser numbers, in the

Chukchi Sea The Chukchi Sea (, ), sometimes referred to as the Chuuk Sea, Chukotsk Sea or the Sea of Chukotsk, is a marginal sea of the Arctic Ocean. It is bounded on the west by the Long Strait, off Wrangel Island, and in the east by Point Barrow, Alaska, ...

and the Arctic Sea. It has also been recorded off of the coast of

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

Ecology

Life cycle and reproduction

Although ''N. cristatus'' breeds year round, it peaks in terms of reproductive activity from October to December. Breeding occurs at depth; at Station P, adults reproduce at depths below . At Site H, off of the east coast of

Hokkaido is the list of islands of Japan by area, second-largest island of Japan and comprises the largest and northernmost prefectures of Japan, prefecture, making up its own list of regions of Japan, region. The Tsugaru Strait separates Hokkaidō fr ...

, adults reproduce at depths below . Here, adults are usually located from about in depth. After being spawned, the nauplii ascend to the surface. During this ascent, they develop into stage VI nauplii or stage I copepodites. According to studies in a laboratory with water at , it takes about 40 days for this development to happen. The nauplii feed off of their large yolk during their growth. Stage I through IV copepodites are found in the top of depth. During a period of the year, stage I through IV copepodites may be found from the

thermocline A thermocline (also known as the thermal layer or the metalimnion in lakes) is a distinct layer based on temperature within a large body of fluid (e.g. water, as in an ocean or lake; or air, e.g. an atmosphere) with a high gradient of distinct te ...

to between about ; in some areas, this is correlated with high temperatures near the surface. It takes about four months to develop from a stage I to a stage V copepodite. Stage V copepodites migrate below of depth in July and August and enter diapause, emerging as adults after September. Overall, the life cycle of ''N. cristatus'' is annual, like the rest of its genus.

References

{{Taxonbar, from=Q7676621 Calanoida Copepods of the Pacific Ocean Crustaceans of the Arctic Ocean Taxa named by Henrik Nikolai Krøyer Crustaceans described in 1848