| Euphausia lucens | |
|---|---|
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Order: | Euphausiacea |
| Family: | Euphausiidae |
| Genus: | Euphausia |
| Species: | E. lucens |
| Binomial name | |
| Euphausia lucens Hansen, 1905 | |
| Synonyms [1] | |
| |
Euphausia lucens is a species of krill endemic to the temperate waters of the Southern Hemisphere.
Euphausia lucens is an epipelagic species restricted to the Southern Hemisphere, where it has a circumpolar distribution including parts of the Atlantic, Indian and Pacific Oceans. [2] [3] It is most common in the temperate waters between 41°S and 45°S, avoiding the cooler waters of the Southern Ocean, but may be found as far north as 37°S and as far south as 52°S. [2] [3] It prefers water temperatures between 5–18 °C (41–64 °F) and typically occurs in waters no shallower than 100 m (330 ft) deep; it is generally not encountered closer to the coast. [2] [4]
In the eastern South Pacific, Euphausia lucens occupies the area directly north of the range of Euphausia vallentini . [3]
Adult Euphausia lucens measure 10–18 mm (0.39–0.71 in) long. [5] The eyes are large and spherical and the rostrum is noticeably short. There is a small tooth on the lower edge of the carapace, but the abdomen lacks any spines. Adults may closely resemble Euphausia vallentini. [3]
Euphausia lucens is a diurnal vertical migrator, with adults and juveniles spending the day at depths of up to 300 m (980 ft) and moving towards the surface at night, [5] [6] [7] though it has also been observed swarming at the surface during the day at some locations. [4] It is an opportunistic omnivore, known to feed on diatoms, dinoflagellates, tintinnids, fish larvae, copepods, and other zooplankton and phytoplankton. [7] [6] [8] [9] It aggregates in swarms and is a food source for baleen whales, seabirds, and several commercially valuable fish species including Engraulis capensis , Merluccius capensis , Merluccius paradoxus , Sardinops sagax , and Thyrsites atun . [5] [9] [10]
Euphausia lucens is a continuous spawner, with spawning most intense from late winter to early spring. [11] Mature females are capable of releasing a batch of eggs approximately every other day and may be reproductively active for up to eight to ten months per year. [11] [12] Eggs and nauplii remain near the surface and do not migrate vertically throughout the water column, with older larva in the calyptopis and furcilia stages engaging in some vertical migration while largely remaining in the upper layers of the water column. Post-larval juveniles and adults are capable of migrating from the bottom layers of the water column to the surface, [13] with individuals reaching sexual maturity at around six months of age. [11]
Antarctic krill is a species of krill found in the Antarctic waters of the Southern Ocean. It is a small, swimming crustacean that lives in large schools, called swarms, sometimes reaching densities of 10,000–30,000 animals per cubic metre. It feeds directly on minute phytoplankton, thereby using the primary production energy that phytoplankton originally derive from the sun in order to sustain its pelagic life cycle. It grows to a length of 6 centimetres (2.4 in), weighs up to 2 grams (0.071 oz), and can live for up to six years. A key species in the Antarctic ecosystem and in terms of biomass, E. superba is one of the most abundant animal species on the planet, with a cumulative biomass of approximately 500 million metric tons.
Krill(Euphausiids) are small and exclusively marine crustaceans of the order Euphausiacea, found in all the world's oceans. The name "krill" comes from the Norwegian word krill, meaning "small fry of fish", which is also often attributed to species of fish.
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The krill fishery is the commercial fishery of krill, small shrimp-like marine animals that live in the oceans world-wide. The present estimate for the biomass of Antarctic krill is 379 million tonnes. The total global harvest of krill from all fisheries amounts to 150–200,000 tonnes annually, mainly Antarctic krill and North Pacific krill.
Maurolicus muelleri, commonly referred to as Mueller's pearlside,Mueller's bristle-mouth fish, or the silvery lightfish, is a marine hatchetfish in the genus Maurolicus, found in deep tropical, subtropical and temperate waters of the Pacific Ocean and the Atlantic Ocean, from the surface to depths of 1,500 metres (4,900 ft). It can grow to a maximum total length of 8 centimetres (3.1 in).
The Ross Gyre is one of three gyres that exists within the Southern Ocean around Antarctica, the others being the Weddell Gyre and Balleny Gyre. The Ross Gyre is located north of the Ross Sea, and rotates clockwise. The gyre is formed by interactions between the Antarctic Circumpolar Current and the Antarctic Continental Shelf. The Ross Gyre is bounded by the Polar Front of the Antarctic Circumpolar Current to the north, the Antarctic Slope Current to the south, the Balleny Gyre to the west, and a variable boundary to the east from semiannual changes in sea surface height (SSH) in the Amundsen Sea. Circulation in the Ross Gyre has been estimated to be 20 ± 5 Sverdrup (Sv) and plays a large role in heat exchange in this region.
Euphausia crystallorophias is a species of krill, sometimes called ice krill, crystal krill, or Antarctic coastal krill. It lives in the coastal waters around Antarctica, further south than any other species of krill. The specimens for the species' original description were collected through holes cut in the ice by Robert Falcon Scott's Discovery Expedition, several thousand having been donated by Thomas Vere Hodgson.
Merluccius merluccius or the European hake is a merluccid hake of the genus Merluccius. Other vernacular names include Cornish salmon and herring hake. It is a predatory species, which was often netted alongside one of its favoured prey, the Atlantic herring, hence the latter common name. It is found in the eastern Atlantic from Norway and Iceland south to Mauritania and into the Mediterranean Sea. It is an important species in European fisheries and is heavily exploited, with some populations being fished unsustainably.
Stephanasterias albula is a species of starfish in the family Asteriidae. It is the only species in its genus, Stephanasterias, which was described by Verrill in 1871. It has a circumboreal distribution and is found in the north west Atlantic Ocean, the north east Pacific Ocean, the Barents Sea and European waters. It usually has eight arms and is white with a rough upper surface. It has been trawled from depths of 267 metres.
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