| Nyctiphanes | |
|---|---|
 | |
| Nyctiphanes australis | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Crustacea |
| Class: | Malacostraca |
| Order: | Euphausiacea |
| Family: | Euphausiidae |
| Genus: | Nyctiphanes G. O. Sars, 1883 |
| Species [1] | |
| |
Nyctiphanes is a genus of krill, comprising four species with an anti-tropical distribution. [2] Based on molecular phylogenetic analyses of the cytochrome oxidase gene and 16S ribosomal DNA, Nyctiphanes is believed to have evolved during the Miocene. [2]
Antarctic krill is a species of krill found in the Antarctic waters of the Southern Ocean. It is the dominant animal species of Earth. It is a small, swimming crustacean that lives in large schools, called swarms, sometimes reaching densities of 10,000–30,000 individual animals per cubic metre. It feeds directly on minute phytoplankton, thereby using the primary production energy that the phytoplankton originally derived from the sun in order to sustain their 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. It is a key species in the Antarctic ecosystem and in terms of biomass, is one of the most abundant animal species on the planet.
The biomass is the mass of living biological organisms in a given area or ecosystem at a given time. Biomass can refer to species biomass, which is the mass of one or more species, or to community biomass, which is the mass of all species in the community. It can include microorganisms, plants or animals. The mass can be expressed as the average mass per unit area, or as the total mass in the community.
Northern krill, Meganyctiphanes norvegica, is a species of krill that lives in the North Atlantic Ocean. It is an important component of the zooplankton, providing food for whales, fish and birds. M. norvegica is the only species recognised in the genus Meganyctiphanes, although it has been known by several synonyms:
The fin whale, also known as finback whale or common rorqual and formerly known as herring whale or razorback whale, is a cetacean belonging to the parvorder of baleen whales. It is the second-longest species of cetacean on Earth after the blue whale. The largest reportedly grow to 27.3 m (89.6 ft) long with a maximum confirmed length of 25.9 m (85 ft), a maximum recorded weight of nearly 74 tonnes, and a maximum estimated weight of around 114 tonnes. American naturalist Roy Chapman Andrews called the fin whale "the greyhound of the sea ... for its beautiful, slender body is built like a racing yacht and the animal can surpass the speed of the fastest ocean steamship."
Krill are small crustaceans of the order Euphausiacea, and are 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.
The crabeater seal, also known as the krill-eater seal, is a true seal with a circumpolar distribution around the coast of Antarctica. They are medium- to large-sized, relatively slender and pale-colored, found primarily on the free-floating pack ice that extends seasonally out from the Antarctic coast, which they use as a platform for resting, mating, social aggregation and accessing their prey. They are by far the most abundant seal species in the world. While population estimates are uncertain, there are at least 7 million and possibly as many as 75 million individuals. This success of this species is due to its specialized predation on the abundant Antarctic krill of the Southern Ocean, for which it has uniquely adapted, sieve-like tooth structure. Indeed, its scientific name, translated as "lobe-toothed (lobodon) crab eater (carcinophaga)", refers specifically to the finely lobed teeth adapted to filtering their small crustacean prey. Despite its name, crabeater seals do not eat crabs. As well as being an important krill predator, the crabeater seal's pups are an important component of the diet of leopard seals, which are responsible for 80% of all crabeater pups deaths.
Krill oil is an extract prepared from a species of Antarctic krill, Euphausia superba. Processed krill oil is commonly sold as a dietary supplement. Two components of krill oil are omega-3 fatty acids similar to those in fish oil, and phospholipid-derived fatty acids (PLFA), mainly phosphatidylcholine.
Eucarida is a superorder of the Malacostraca, a class of the crustacean subphylum, comprising the decapods, krill, Amphionides and Angustidontida. They are characterised by having the carapace fused to all thoracic segments, and by the possession of stalked eyes.
Bentheuphausia amblyops, the deep sea krill is a species of krill. B. amblyops is the only species within its genus, which in turn is the only genus within the family Bentheuphausiidae. All the 85 other species of krill known are classified in the family Euphausiidae.
Euphausia is the largest genus of krill, and is placed in the family Euphausiidae. There are 31 species known in this genus, including Antarctic krill and ice krill from the Southern Ocean, and North Pacific krill in the Pacific Ocean.
Nematoscelis is a genus of krill, containing the following species:
Stylocheiron is a genus of krill, containing the following species:
Thysanoessa is a genus of krill, containing the following species:
Thysanopoda is a genus of krill, containing the following species:
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.
Metanauplius is an early larval stage of some crustaceans such as krill. It follows the nauplius stage.
The true seal tribe Lobodontini, collectively known as the antarctic seals or lobodontin seals, consist of four species of seals in four genera: the crabeater seal, the leopard seal, the Weddell seal, and the Ross seal. All lobodontine seals have circumpolar distributions surrounding Antarctica. They include both the world's most abundant seal and the only predominantly mammal-eating seal. While the Weddell seal prefers the shore-fast ice, the other species live primarily on and around the off-shore pack ice. Thus, though they are collectively the most abundant group of seals in the world, the combination of remote range and inaccessible habitat make them among the least well studied of the world's seals.
Crustaceans form a large, diverse arthropod taxon which includes such animals as crabs, lobsters, crayfish, shrimp, krill, prawns, woodlice, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata; because of recent molecular studies it is now well accepted that the crustacean group is paraphyletic, and comprises all animals in the clade Pancrustacea other than hexapods. Some crustaceans are more closely related to insects and the other hexapods than they are to certain other crustaceans.
Bettina Meyer is a German Antarctic researcher, best known for her work on the ecology and physiology of invertebrates in the pelagic zone. She is the head of the ecophysiology of pelagic key species working group at the Alfred Wegener Institute for Polar and Marine Research (AWI).
The clade Multicrustacea constitutes the largest superclass of crustaceans, containing approximately four-fifths of all described crustacean species, including crabs, lobsters, crayfish, shrimp, krill, prawns, woodlice, barnacles, copepods, amphipods, mantis shrimp and others. The largest branch of multicrustacea is the class Malacostraca.
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