Meganyctiphanes norvegica
FAMILY
Euphausiidae
TAXONOMY
Meganyctiphanes norvegica M. Sars, 1857.
OTHER COMMON NAMES
English: Northern krill.
PHYSICAL CHARACTERISTICS
Length about 1.2–1.5 in (3–4 cm); relatively short legs. Weighs about 0.017 oz (0.5 g) at maturity. Gut appears red because of a diet of copepods.
DISTRIBUTION
North Atlantic, Arctic Ocean, and Mediterranean Sea.
HABITAT
Wide climactic range, from sub-Arctic zones around Greenland and Scandinavia down to North Carolina and the Mediterranean Sea. Pelagic, found from the surface to a depth of 984 ft (300 m).
BEHAVIOR
Surface swarms may contain almost 800,000 individuals per 35 cubic ft (cubic m) and extend for more than 1,075 ft2 (100 m2). Swarms may be segregated by sex. Like most other krill species, it rises to the surface at night to feed. This endogenous rhythm has been found to be influenced by moonlight and synchronized to the lunar cycle; perturbations associated with the lunar eclipse have been observed.
FEEDING ECOLOGY AND DIET
Feeds mainly on copepods; surveys in the Northeast Atlantic found C. finmarchicus making up 85–95% of prey mass. Will also consume other foods, including phytoplankton and other euphausiids. Predators include marine mammals, fishes, and birds.
REPRODUCTIVE BIOLOGY
Spawning occurs in the winter in the Mediterranean, but in colder waters in the summer. Maturity occurs after about a year, and individuals generally participate in two breeding seasons. Lifespan is about 2.5 years.
CONSERVATION STATUS
Not listed by the IUCN.
SIGNIFICANCE TO HUMANS
Commercial fisheries in Canada, and small-scale harvesting in the Mediterranean.
