Thysanoessa raschii

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Thysanoessa raschii
Thysanoessa raschii.jpg
Scientific classification
T. raschii
Binomial name
Thysanoessa raschii
M. Sars, 1864

Rhoda jardineanaSim, 1872
Euphausia raschii G. O. Sars, 1883
Boreophausia raschiiNorman, 1886
Rhoda raschii Stebbing, 1893

Thysanoessa raschii, sometimes known as Arctic krill, is one of the most common euphausiid species of the subarctic and Arctic seas. They may reach 20–25 millimetres (0.8–1.0 in) long, and are sexually mature above 14 mm (0.6 in). [1]

Krill order of crustaceans

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.

Subarctic The region from 50°N to 70°N with a subarctic climate

The subarctic is a region in the Northern Hemisphere immediately south of the true Arctic and covering much of Alaska, Canada, Iceland, the north of Scandinavia, Siberia, the Shetland Islands, and the Cairngorms. Generally, subarctic regions fall between 50°N and 70°N latitude, depending on local climates. Precipitation is low, and vegetation is characteristic of the taiga.

Arctic Ocean The smallest and shallowest of the worlds five major oceans, located in the north polar regions

The Arctic Ocean is the smallest and shallowest of the world's five major oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, although some oceanographers call it the Arctic Sea. It is classified as an estuary of the Atlantic Ocean, and it is also seen as the northernmost part of the all-encompassing World Ocean.

T. raschii is a major prey item of several taxa, planktivorous fishes and marine mammals. It is also a common prey item of seabirds, including shearwaters. [2]

Marine mammal Mammals that live in the ocean

Marine mammals are aquatic mammals that rely on the ocean and other marine ecosystems for their existence. They include animals such as seals, whales, manatees, sea otters and polar bears. They do not represent a distinct taxon or systematic grouping, and are unified only by their reliance on the marine environment for feeding.

Seabird Birds that have adapted to life within the marine environment

Seabirds are birds that are adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution, as the same environmental problems and feeding niches have resulted in similar adaptations. The first seabirds evolved in the Cretaceous period, and modern seabird families emerged in the Paleogene.

Shearwater medium-sized long-winged seabirds, common name for a subgroup of the family Procellariidae

Shearwaters are medium-sized long-winged seabirds. There are more than 30 species of shearwaters, a few larger ones in the genus Calonectris and many smaller species in the genus Puffinus. The Procellaria petrels and Bulweria were believed to belong to this group, but are only distantly related based on more recent studies, while the Pseudobulweria and Lugensa "petrels" are more closely related. The genus Puffinus can be divided into a group of small species close to Calonectris and a few larger ones more distantly related to both.

This species goes through a number of stages in its development. Roderick Macdonald defined the characteristics of fourteen stages, or 'furcilia'. [3]

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Arctic fox species of mammal

The Arctic fox, also known as the white fox, polar fox, or snow fox, is a small fox native to the Arctic regions of the Northern Hemisphere and common throughout the Arctic tundra biome. It is well adapted to living in cold environments, and is best known for its thick, warm fur that is also used as camouflage. On average, Arctic foxes only live 3–4 years in the wild. Its body length ranges from 46 to 68 cm, with a generally rounded body shape to minimize the escape of body heat.

Ecology Scientific study of the relationships between living organisms and their environment

Ecology is a branch of biology that studies the interactions among organisms and their biophysical environment, which includes both biotic and abiotic components. Topics of interest include the biodiversity, distribution, biomass, and populations of organisms, as well as cooperation and competition within and between species. Ecosystems are dynamically interacting systems of organisms, the communities they make up, and the non-living components of their environment. Ecosystem processes, such as primary production, pedogenesis, nutrient cycling, and niche construction, regulate the flux of energy and matter through an environment. These processes are sustained by organisms with specific life history traits.

Walrus Species of marine mammal

The walrus is a large flippered marine mammal with a discontinuous distribution about the North Pole in the Arctic Ocean and subarctic seas of the Northern Hemisphere. The walrus is the only living species in the family Odobenidae and genus Odobenus. This species is subdivided into two subspecies: the Atlantic walrus which lives in the Atlantic Ocean and the Pacific walrus which lives in the Pacific Ocean.

Narwhal Medium-sized toothed whale that lives year-round in the Arctic

The narwhal, or narwhale, is a medium-sized toothed whale that possesses a large "tusk" from a protruding canine tooth. It lives year-round in the Arctic waters around Greenland, Canada, and Russia. It is one of two living species of whale in the family Monodontidae, along with the beluga whale. The narwhal males are distinguished by a long, straight, helical tusk, which is an elongated upper left canine. The narwhal was one of many species described by Carl Linnaeus in his publication Systema Naturae in 1758.

Pinniped Infraorder of mammals

Pinnipeds, commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic marine mammals. They comprise the extant families Odobenidae, Otariidae, and Phocidae. There are 33 extant species of pinnipeds, and more than 50 extinct species have been described from fossils. While seals were historically thought to have descended from two ancestral lines, molecular evidence supports them as a monophyletic lineage. Pinnipeds belong to the order Carnivora and their closest living relatives are believed to be bears and the superfamily of musteloids, having diverged about 50 million years ago.

Procellariidae A family of seabirds which includes petrels, shearweters and prions

The family Procellariidae is a group of seabirds that comprises the fulmarine petrels, the gadfly petrels, the prions, and the shearwaters. This family is part of the bird order Procellariiformes, which also includes the albatrosses, the storm petrels, and the diving petrels.

Fin whale Baleen whale, and second-largest mammal species

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-largest species 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."

Ringed seal species of mammal

The ringed seal, also known as the jar seal, as netsik or nattiq by the Inuit and as Ньиэрпэ by the Yakut, is an earless seal inhabiting the Arctic and sub-Arctic regions. The ringed seal is a relatively small seal, rarely greater than 1.5 m in length, with a distinctive patterning of dark spots surrounded by light grey rings, hence its common name. It is the most abundant and wide-ranging ice seal in the Northern Hemisphere: ranging throughout the Arctic Ocean, into the Bering Sea and Okhotsk Sea as far south as the northern coast of Japan in the Pacific, and throughout the North Atlantic coasts of Greenland and Scandinavia as far south as Newfoundland, and include two freshwater subspecies in northern Europe. Ringed seals are one of the primary prey of polar bears and killer whales, and have long been a component of the diet of indigenous people of the Arctic.

Manx shearwater species of bird

The Manx shearwater is a medium-sized shearwater in the seabird family Procellariidae. The scientific name of this species records a name shift: Manx shearwaters were called Manks puffins in the 17th century. Puffin is an Anglo-Norman word for the cured carcasses of nestling shearwaters. The Atlantic puffin acquired the name much later, possibly because of its similar nesting habits.

Arctic wolf Subspecies of the gray wolf found in the Canadian arctic, Alaska and parts of Greenland

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Spongivore organism that feeds primarily on sea sponges

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<i>Clione limacina</i> species of mollusc

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In ecology, a priority effect is the impact that a particular species can have on community development due to prior arrival at a site.

<i>Limacina helicina</i> species of mollusc

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Intraguild predation

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A food chain is a linear network of links in a food web starting from producer organisms and ending at apex predator species, detritivores, or decomposer species. A food chain also shows how the organisms are related with each other by the food they eat. Each level of a food chain represents a different trophic level. A food chain differs from a food web, because the complex network of different animals' feeding relations are aggregated and the chain only follows a direct, linear pathway of one animal at a time. Natural interconnections between food chains make it a food web. A common metric used to the quantify food web trophic structure is food chain length. In its simplest form, the length of a chain is the number of links between a trophic consumer and the base of the web and the mean chain length of an entire web is the arithmetic average of the lengths of all chains in a food web.


  1. M. J. de Kluijver & S. S. Ingalsuo. "Thysanoessa raschii". Macrobenthos of the North Sea. Universiteit van Amsterdam. Archived from the original on July 17, 2011. Retrieved December 7, 2006.
  2. J. R. Lovvorn; C. L. Baduini & G. L. Hunt (2001). "Modelling underwater visual and filter feeding by planktivorous shearwaters in unusual sea conditions". Ecology . 82 (8): 2342–2356. doi:10.1890/0012-9658(2001)082[2342:MUVAFF]2.0.CO;2. ISSN   0012-9658.
  3. R. Macdonald (1928). "The life history of Thysanoessa raschii". Journal of the Marine Biological Association of the United Kingdom . 15 (1): 57–80. doi:10.1017/S0025315400055533. Archived from the original on 2007-03-11.