|
Cryodraco Antarcticus
''Cryodraco antarcticus'', the long-fingered icefish, is a demersal species of marine ray-finned fish belonging to the family Channichthyidae, the crocodile icefishes. It occurs only in deep waters of the Southern Ocean. Taxonomy ''Cryodraco antarcticus'' was first formally described in 1900 by the Belgian palaeontologist Louis Dollo with the type locality given as 71°22'S, 88°38'W, or 71°18'S, 88°02'W. It is the type species of the genus ''Cryodraco'', which is known as ''Pagetodes'' by some authorities. Description ''Cryodraco antarcticus'' is pale greyish-brown with 5-6 dark cross-bars on its body and dusky-tipped pelvic fins. It is distinguished by the elongate shape of its pelvic fins, which are blackish in the pelagic juveniles. This species can grow up to . Distribution and habitat ''Cryodraco antarcticus'' is found near the South Orkney Islands, the Antarctic Peninsula, the Weddell, Bellinghausen, Ross and Davis seas at depths of 90 to 600 m (295 to 1970 ft). Bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ichthyologist
Ichthyology is the branch of zoology devoted to the study of fish, including bony fish ( Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 33,400 species of fish had been described as of October 2016, with approximately 250 new species described each year. Etymology The word is derived from the Greek words ἰχθύς, ''ikhthus'', meaning "fish"; and λογία, ''logia'', meaning "to study". History The study of fish dates from the Upper Paleolithic Revolution (with the advent of "high culture"). The science of ichthyology was developed in several interconnecting epochs, each with various significant advancements. The study of fish receives its origins from humans' desire to feed, clothe, and equip themselves with useful implements. According to Michael Barton, a prominent ichthyologist and professor at Centre College, "the earliest ichthyologists were ''hunters and gatherers'' who had learned how to obtain the most usef ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weddell Sea
The Weddell Sea is part of the Southern Ocean and contains the Weddell Gyre. Its land boundaries are defined by the bay formed from the coasts of Coats Land and the Antarctic Peninsula. The easternmost point is Cape Norvegia at Princess Martha Coast, Queen Maud Land. To the east of Cape Norvegia is the King Haakon VII Sea. Much of the southern part of the sea is covered by a permanent, massive ice shelf field, the Filchner-Ronne Ice Shelf. The sea is contained within the two overlapping Antarctic territorial claims of Argentine Antarctica, the British Antarctic Territory, and also resides partially within the Antarctic Chilean Territory. At its widest the sea is around across, and its area is around . Various ice shelves, including the Filchner-Ronne Ice Shelf, fringe the Weddell sea. Some of the ice shelves on the east side of the Antarctic Peninsula, which formerly covered roughly of the Weddell Sea, had completely disappeared by 2002. The Weddell Sea has been deemed by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Described In 1900
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthropods. Mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cryodraco
''Cryodraco'' is a genus of marine ray-finned fish belonging to the family Channichthyidae, the crocodile icefishes. They are found in the Southern Ocean. While ''C. antarcticus'' has minor commercial importance, ''C. atkinsoni'' and ''C. pappenheimi'' are of no interest to commercial fisheries. Taxonomy ''Cryodraco'' was first formally described as a monotypic genus in 1900 by the Belgian palaeontologist Louis Dollo when he was describing ''Cryodraco antarctica''. Although FishBase uses the genus name ''Cryodraco'', Catalog of Fishes uses ''Pagetodes'' as the genus name and treats ''Cryodraco'' as a synonym, following Sheiko. The name ''Pagetodes'' was applied to a fish which was washed onto the bow of HMS ''Terror'' and frozen in place. The fish was carefully removed from the ice, allowing the ship's surgeon John Robertson to create a rough sketch, but a cat took the fish and ate it before it could be preserved in alcohol. In 1844 John Richardson described the genus ''Pag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commercial Fisheries
Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often pursue fish far into the ocean under adverse conditions. Large-scale commercial fishing is also known as industrial fishing. The major fishing industries are not only owned by major corporations but by small families as well. In order to adapt to declining fish populations and increased demand, many commercial fishing operations have reduced the sustainability of their harvest by fishing further down the food chain. This raises concern for fishery managers and researchers, who highlight how further they say that for those reasons, the sustainability of the marine ecosystems could be in danger of collapsing. Commercial fishermen harvest a wide variety of animals. However, a very small number of species support the majority of the world' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scotia Arc
The Scotia Arc is the island arc system forming the north, east and south border of the Scotia Sea. The northern border, the North Scotia Ridge, comprises (from west to east) Isla de los Estados at the tip of Tierra del Fuego, the Burdwood, Davis, and Aurora Banks; the Shag, South Georgia Island and Clerke Rocks. The eastern border comprises the volcanic South Sandwich Islands flanked by the South Sandwich Trench. The southern border, the South Scotia Ridge, (east to west) comprises Herdman, Discovery, Bruce, Pirie, and Jane Banks; the South Orkney Islands and Elephant Island. The Bransfield Strait, finally, separates the arc from the South Shetland Islands and James Ross Island flanking the tip of the Antarctic Peninsula. The Scotia Arc surrounds the small Scotia and South Sandwich Plates. The arc is formed by continental fragments that once formed a land bridge between South America and Antarctica, once part of the subduction margin that still forms the Andes. An ancestral arc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meristics
Meristics is an area of ichthyology and herpetology which relates to counting quantitative features of fish and reptiles, such as the number of fins or scales. A meristic (countable trait) can be used to describe a particular species of fish, or used to identify an unknown species. Meristic traits are often described in a shorthand notation called a ''meristic formula''. Meristic characters are the countable structures occurring in series (e.g. myomeres, vertebrae, fin rays) in fish. These characters are among the characters most commonly used for differentiation of species and populations. In the salmonids, scale counts have been most widely used for the differentiation of populations within species. In rainbow and steelhead trout the most notable differences among populations occur in counts of scales. Meristic characters are used in many other fields, such as in botany or in zoology. Meristic comparison is used in phenetic and cladistic analysis. Meristic analysis A meristic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blackfin Icefish
The blackfin icefish (''Chaenocephalus aceratus''), also known as the Scotia Sea icefish, is a species of crocodile icefish belonging to the family Channichthyidae. The blackfin icefish belongs to Notothenioidei, a suborder of fishes that accounts for 90% of the fish fauna on the Antarctic continental shelf. Icefishes, also called white-blooded fishes, are a unique family in that they are the only known vertebrates to lack haemoglobin, making their blood oxygen carrying capacity just 10% that of other teleosts. Icefishes have translucent blood and creamy white gills. Taxonomy The blackfin icefish was first formally described as ''Chaenichthys aceratus'' in 1906 by the Swedish zoologist Einar Lönnberg with the type locality given as South Georgia Island. In 1913 the English ichthyologist Charles Tate Regan described a new subgenus of ''Channichthys'', ''Chaenocephalus'' with the blackfin icefish as its only species, its type species by monotypy. ''Chaenocephalus'' is now ge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The larva's appearance is generally very different from the adult form (''e.g.'' caterpillars and butterflies) including different unique structures and organs that do not occur in the adult form. Their diet may also be considerably different. Larvae are frequently adapted to different environments than adults. For example, some larvae such as tadpoles live almost exclusively in aquatic environments, but can live outside water as adult frogs. By living in a distinct environment, larvae may be given shelter from predators and reduce competition for resources with the adult population. Animals in the larval stage will consume food to fuel their transition into the adult form. In some organisms like polychaetes and barnacles, adults are immobil ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Krill
Antarctic krill (''Euphausia superba'') 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 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 (open ocean) life cycle. It grows to a length of , weighs up to , 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 (approximately 500 million tons, corresponding to 300 to 400 trillion individuals). Life cycle The main spawning season of Antarctic krill is from January to March, both above the continental shelf and also in the upper region of deep sea oceanic areas. In the typical way of all krill, the male attaches a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Krill
Krill are small crustaceans of the order Euphausiacea, and are found in all the world's oceans. The name "krill" comes from the Norwegian Norwegian, Norwayan, or Norsk may refer to: *Something of, from, or related to Norway, a country in northwestern Europe * Norwegians, both a nation and an ethnic group native to Norway * Demographics of Norway *The Norwegian language, including ... word ', meaning "small fry of fish", which is also often attributed to species of fish. Krill are considered an important trophic level connection – near the bottom of the food chain. They feed on phytoplankton and (to a lesser extent) zooplankton, yet also are the main source of food for many larger animals. In the Southern Ocean, one species, the Antarctic krill, ''Euphausia superba'', makes up an estimated biomass (ecology), biomass of around 379,000,000 tonnes, making it among the species with the largest total biomass. Over half of this biomass is eaten by whales, Pinniped, seals, pen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish
Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts. Fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators. The first fish with jaws appeared in the Silurian period, after which many (such as sharks) became formidable marine predators rather than just the prey of arthropods. Mos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
