Neocalanus cristatus

Neocalanus cristatus is a species of copepod found primarily in the northern Pacific.

Neocalanus cristatus
Scientific classification
Kingdom:
Animalia
Phylum:
Arthropoda
Subphylum:
Crustacea
Class:
Hexanauplia
Subclass:
Copepoda
Order:
Calanoida
Family:
Calanidae
Genus:
Neocalanus
Species:
N. cristatus
Binomial name
Neocalanus cristatus
(Krøyer, 1848)
Synonyms
  • Calanus cristatus Krøyer, 1848

Description

The female usually ranges in length from about 7.6 to 10.4 millimetres (0.30 to 0.41 in). The male usually is between about 6.7 and 9.6 millimetres (0.26 and 0.38 in) in length.[1]

Distribution

N. cristatus is found in the northern Pacific and, in lesser numbers, in the Chukchi Sea and the Arctic Sea.[2] It has also been recorded off of the coast of Chile.[1]

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 250 metres (820 ft).[3] At Site H, off of the east coast of Hokkaido, adults reproduce at depths below 500 metres (1,600 ft). Here, adults are usually located from about 500 to 1,500 metres (1,600 to 4,900 ft) in depth.[4] After being spawned, the nauplii ascend to the surface. During this ascent, they develop into stage VI nauplii or stage I copepodites.[5] According to studies in a laboratory with water at 2 °C (36 °F), it takes about 40 days for this development to happen.[6] The nauplii feed off of their large yolk during their growth.[3] Stage I through IV copepodites are found in the top 250 metres (820 ft) of depth.[4] During a period of the year, stage I through IV copepodites may be found from the thermocline to between about 200 and 250 metres (660 and 820 ft);[7] 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 250 metres (820 ft) of depth in July and August and enter diapause, emerging as adults after September. Overall, the life cycle of N. cristatus is annual,[4] like the rest of its genus.[8]

References
  1. Razouls C.; de Bovée F.; Kouwenberg J.; Desreumaux N. (2018). "Diversity and Geographic Distribution of Marine Planktonic Copepods". Sorbonne Université, CNRS. Retrieved 16 July 2018.
  2. "Neocalanus cristatus" at the Encyclopedia of Life
  3. Miller, Charles B.; Frost, Bruce W.; Batchelder, Harold P.; Clemons, Martha J.; Conway, Richard E. (1984). "Life histories of large, grazing copepods in a subarctic ocean gyre: Neocalanus plumchrus, Neocalanus cristatus, and Eucalanus bungii in the Northeast Pacific". Progress in Oceanography. 13 (2): 201–243. doi:10.1016/0079-6611(84)90009-0. ISSN 0079-6611.
  4. Kobari, T.; Ikeda, T. (1999). "Vertical distribution, population structure and life cycle of Neocalanus cristatus (Crustacea: Copepoda) in the Oyashio region, with notes on its regional variations". Marine Biology. 134 (4): 683–696. doi:10.1007/s002270050584. ISSN 0025-3162. S2CID 85038743.
  5. Dagg, Michael (1993). "Sinking particles as a possible source of nutrition for the large calanoid copepod Neocalanus cristatus in the subarctic Pacific Ocean". Deep Sea Research Part I: Oceanographic Research Papers. 40 (7): 1431–1445. doi:10.1016/0967-0637(93)90121-I. ISSN 0967-0637.
  6. Tsuda, Atsushi; Saito, Hiroaki; Kasai, Hiromi (2004). "Life histories of Eucalanus bungii and Neocalanus cristatus (Copepoda: Calanoida) in the western subarctic Pacific Ocean". Fisheries Oceanography. 13 (s1): 10–20. doi:10.1111/j.1365-2419.2004.00315.x. ISSN 1054-6006.
  7. Tsuda, Atsushi; Saito, Hiroaki; Kasai, Hiromi; Nishioka, Jun; Nakatsuka, Takeshi (2015). "Vertical segregation and population structure of ontogenetically migrating copepods Neocalanus cristatus, N. flemingeri, N. plumchrus, and Eucalanus bungii during the ice-free season in the Sea of Okhotsk". Journal of Oceanography. 71 (3): 271–285. doi:10.1007/s10872-015-0287-3. ISSN 0916-8370. S2CID 133032694.
  8. Conover, R. J. (1988). "Comparative life histories in the genera Calanus and Neocalanus in high latitudes of the Northern Hemisphere". Hydrobiologia. 167 (1): 127–142. doi:10.1007/BF00026299. ISSN 0018-8158. S2CID 30898474.
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