Neocalanus plumchrus is a large species of copepod found in the Pacific and Arctic Oceans.

[1] It was eventually moved by Janet Bradford and John Jillett in 1974 from the genus Calanus to its current placement in Neocalanus.

[2] Neocalanus plumchrus is considered a large copepod,[3] with females generally ranging from about 4 to 6.3 millimetres (0.16 to 0.25 in) in length.

In stage V copepodites, the colouration and the second from medial caudal seta (or II bristle) can be used to distinguish this species and N. flemingeri.

[8] Stage V copepodites enter diapause at depths of below 250 metres (820 ft)[5] during late summer.

[9] It is able to uptake glucose directly from seawater from its dermal glands and midgut, which arthropods were thought to be incapable of due to their rigid exoskeleton.