Thysanoessa longicaudata (Krøyer, 1846)
An subarctic Atlantic krill, maringally present in the Arctic
Size
- Eggs & nauplii 0.35-0.45 mm
- Adults 10-16 mm
Color & Characteristics
- 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
Habitat
- 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
Feeding
- Primarily predatory on smaller zooplankton, but can consume algae when abundant
- Prey item for fish and birds
Life cycle
- 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
Page Authors: Alexei Pinchuk & Russ Hopcroft
Created: Sept 3, 2010