Calanus pacificus

Taxon-Order: 
Calanoida

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Distribution: 
California Current System, for the subspecies C. pacificus californicus.
Habitat: 
Surface to 500-800 m depth.
Size: 
Female 2.6-3.4 mm; male 2.5-3.1 mm
Diet: 
Omnivorous.
Predators: 
Carnivorous zooplankton and fish.
Useful Facts or Characters: 

Posterior corners of prosome without spines; 1st antennae as long as the body.

Natural History: 

Among the more abundant copepods off Southern California.

"Biphasic" life history in Southern California; year-round reproduction in surface waters by part of the population, while another part of the population remains dormant in deeper waters through the winter.

References: 

http://www.marinespecies.org/copepoda/aphia.php?p=taxdetails&id=362749

http://copepodes.obs-banyuls.fr/en/fichesp.php?sp=508

Nuwer, M.L., Frost, B.W., and Armbrust, E.V. (2008) Population structure of the planktonic copepod Calanus pacificus in the North Pacific Ocean. Marine Biology 156, 107-115.  doi 10.1007/s00227-008-1068-y.

Ohman, M.D., Drits, A.V., Clarke, M.E., and Plourde, S. (1998) Differential dormancy of co-occurring copepods. Deep-Sea Research II 45: 1709-1740.