Thysanoessa longicaudata (Krøyer 1846)

An subarctic Atlantic krill, maringally present in the Arctic

Primarily predatory on smaller zooplankton, but can consume algae when abundant; Prey item for fish and birds

Females lay several clutches of eggs during spring; Females require repeated mating after each molt to form new egg clutches; Life cycles is typcial: eggs, nauplius, metanauplius, followed by several stages of feeding calytopsis, and furcillia larvae; Juveniles resemble adults, and molt regularly while growing to adulthood over the first year of life; Life expectancy not known, likely 1-2 years

Transparent, yellowish if rich in lipids, females might develop blue hue when spawning; Eyes bi-lobed, rostrum pointed, photophores red; Anntennae lack lappet, carapace without denticle; Abdominal segments without spines on keel; 6th abdominal segment equal to the two preceding segments combined; second pair of thorathic legs elongated, but often broken during collection

Subarctic Atlantic in shelf-break habitats deeper than 200 m, amd some some isolated deep fjords; Transposted into the Chukchi Sea by currents; Undergo diel vertical migrations, spending daytime near bottom or typically 200-400 m , night-time 0-100 m

Boreal species. Found in the Barents Sea, Kara Sea, Laptev Sea, Arctic Basin.

The seconds pair of thoracopods is elongate; the last 2 segments are densely covered with setae. The length of the last abdominal segment is equal in length to the combined length of the previous 2. The endopodites of the uropods are longer than the exopodites and reach the end of the telson.

Length up to 12 mm.

Arctic to Gulf of Maine

upper and glacial epipelagic regions of the Gulf and estuary, and the upper Mesopelagic of the Gulf and estuary

depth in m: 0-400; horizontal distribution: N Atlantic, 35-70°N,