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Eel Life History
The eel is a long, thin bony fish of the order Anguilliformes. The species has a catadromous life cycle, that is: at different stages of development migrating between inland waterways and the deep ocean. Because fishermen never caught anything they recognized as young eels, the life cycle of the eel was a mystery for a very long period of scientific history. Past studies of eels The European eel (''Anguilla anguilla'') was historically the one most familiar to Western scientists, beginning with Aristotle, who wrote the earliest known inquiry into the natural history of eels. He speculated that they were born of "earth worms", which he believed were formed of mud, growing from the "guts of wet soil" rather than through sexual reproduction. Many centuries passed before scientists were able to demonstrate that such spontaneous generation does not occur in nature. In 1777, the Italian Carlo Mondini located an eel's ovaries and demonstrated that eels are a kind of fish. In 1876, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leptocephalus
Leptocephalus (meaning "slim head") is the flat and transparent larva of the eel, marine eels, and other members of the superorder Elopomorpha. This is one of the most diverse groups of teleosts, containing 801 species in 4 orders, 24 families, and 156 genera. This group is thought to have arisen in the Cretaceous period over 140 million years ago.Inuoe, Jun, M. Miya, et al. “Mitogenomic evidence for the monophyly of elopomorph fishes (Teleostei) and the evolutionary origin of the leptocephalus larva.” Molecular Phylogenetics and Evolution 32 (2004): 274-286. Web. 2 Nov. 2012. Fishes with a leptocephalus larval stage include the most familiar eels such as the conger, moray eel, and garden eel as well as members of the family Anguillidae, plus more than 10 other families of lesser-known types of marine eels. These are all true eels of the order Anguilliformes. Leptocephali of eight species of eels from the South Atlantic Ocean were described by Meyer-Rochow The fishes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spawn (biology)
Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquatic mammals and reptiles, reproduce through the process of spawning. Spawn consists of the reproductive cells (gametes) of many aquatic animals, some of which will become fertilized and produce offspring. The process of spawning typically involves females releasing ova (unfertilized eggs) into the water, often in large quantities, while males simultaneously or sequentially release spermatozoa ( milt) to fertilize the eggs. Most fish reproduce by spawning, as do most other aquatic animals, including crustaceans such as crabs and shrimps, molluscs such as oysters and squid, echinoderms such as sea urchins and sea cucumbers, amphibians such as frogs and newts, aquatic insects such as mayflies and mosquitoes and corals, which are actually sma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bermuda
) , anthem = "God Save the King" , song_type = National song , song = "Hail to Bermuda" , image_map = , map_caption = , image_map2 = , mapsize2 = , map_caption2 = , subdivision_type = Sovereign state , subdivision_name = , established_title2 = English settlement , established_date2 = 1609 (officially becoming part of the Colony of Virginia in 1612) , official_languages = English , demonym = Bermudian , capital = Hamilton , coordinates = , largest_city = Hamilton , ethnic_groups = , ethnic_groups_year = 2016 , government_type = Parliamentary dependency under a constitutional monarchy , leader_title1 = Monarch , leader_name1 = Charles III , leader_title2 = Governor , leader_name2 = Rena Lalgie , leader_title3 = Premier , leader_name3 = Edward David Burt , legislature = Parliament , upper_house = Senate , lower_house = House of Assembly , area_km2 = 53.2 , area_sq_mi = 20.54 , area_rank = , percent_water = 27 , elevation_max_m = 7 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sargasso Sea
The Sargasso Sea () is a region of the Atlantic Ocean bounded by four currents forming an ocean gyre. Unlike all other regions called seas, it has no land boundaries. It is distinguished from other parts of the Atlantic Ocean by its characteristic brown '' Sargassum'' seaweed and often calm blue water. The sea is bounded on the west by the Gulf Stream, on the north by the North Atlantic Current, on the east by the Canary Current, and on the south by the North Atlantic Equatorial Current, the four together forming a clockwise-circulating system of ocean currents termed the North Atlantic Gyre. It lies between 20° and 35° north and 40° and 70° west and is approximately wide by long. Bermuda is near the western fringes of the sea. While all of the above currents deposit marine plants and refuse into the sea, ocean water in the Sargasso Sea is distinctive for its deep blue color and exceptional clarity, with underwater visibility of up to 61 m (200 ft). It is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe and Asia from the "New World The term ''New World'' is often used to mean the majority of Earth's Western Hemisphere, specifically the Americas."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: Oxford University Press, p. ..." of the Americas in the European perception of Earth, the World. The Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Europe and Africa to the east, and North America, North and South America to the west. As one component of the interconnected World Ocean, it is connected in the north to the Arctic Ocean, to the Pacific Ocean in the southwest, the Indian Ocean in the southeast, and the Southern Ocean in the south (other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carlsberg Foundation
Carlsberg Foundation ( da, Carlsbergfondet) was founded by J. C. Jacobsen in 1876, by allocating some of his shares in the Carlsberg Brewery to fund and operate the Carlsberg Laboratory and the Museum of National History at Frederiksborg Palace. The foundation has since expanded to fund scientific research, to manage the Ny Carlsberg Glyptotek, and via the Tuborg Foundation to fund social works. it owned 30.3% of the shares in Carlsberg Group and controlled 74.2% of the voting power. History The foundation was started to run Carlsberg Laboratory. To finance its works the foundation received a portion of shares in Carlsberg Brewery. J.C. Jacobsen's wish was to create a foundation with firm obligations to the natural sciences and direct responsibility for the running of a corporate enterprise. In 1878 the foundation started to manage and fund the Museum of National History at Frederiksborg Palace. In 1882 after the death of J. C. Jacobsen the foundation inherited the remaining ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dana Expeditions
The Dana expeditions were four Danish research expeditions undertaken by the ''Dana I'' and ''Dana'' ''II''. They were funded in part by the Carlsberg Foundation and led by Johannes Schmidt. The first three expeditions took place from 1920 to 1922 and the fourth and final was from 1928 to 1930. They centered around investigating the breeding of eels. The first two expeditions allowed Schmidt to prove his theory that European eels migrate to the Sargasso Sea to spawn. The final expedition traveled to the Indian Ocean and gathered numerous samples. First expeditions (1920–1922) Planning From 1920 to 1922, ''Dana'' undertook a series of three expeditions that were led by the marine biologist Johannes Schmidt. Schmidt and C. F. Dreschel had first proposed an expedition that would explore the deep sea of the Atlantic Ocean in 1916. Although the two men originally envisioned a single large expedition, in January 1917 Schmidt had suggested instead running two expeditions w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
North Atlantic
The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe and Asia from the "New World" of the Americas in the European perception of the World. The Atlantic Ocean occupies an elongated, S-shaped basin extending longitudinally between Europe and Africa to the east, and North and South America to the west. As one component of the interconnected World Ocean, it is connected in the north to the Arctic Ocean, to the Pacific Ocean in the southwest, the Indian Ocean in the southeast, and the Southern Ocean in the south (other definitions describe the Atlantic as extending southward to Antarctica). The Atlantic Ocean is divided in two parts, by the Equatorial Counter Current, with the North(ern) Atlantic Ocean and the South(ern) Atlantic Ocean split at about 8°N. Scientific explorations of the Atlan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Johannes Schmidt (biologist)
Ernst Johannes Schmidt (2 January 1877 – 21 February 1933) was a Danish biologist credited with discovering in 1920 that European eels migrate to the Sargasso Sea to spawn. Before this people in North America and Europe had wondered where the small glass eels, or elvers, came from. Biography Schmidt was born at Jægerspris, Denmark, son of Ernst Schmidt and Camilla Ellen Sophie Schmidt (born Kjeldall and sister to the chemist Johan Kjeldahl). Schmidt began his studies of natural history at the University of Copenhagen under professor of botany Eugen Warming (1841–1924), and obtained an MS degree in biology in 1898. He obtained a grant from the Carlsberg Foundation to study the flora of the coastal areas of Ko Chang in then Siam, including both mangrove trees and microalgae. He made his doctoral thesis in biology and botany, on shoot architecture of mangrove trees and Eugen Warming served as faculty opponent in October 1903. Schmidt then more or less switched to marine zool ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Denmark
) , song = ( en, "King Christian stood by the lofty mast") , song_type = National and royal anthem , image_map = EU-Denmark.svg , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of Denmark , established_title = Consolidation , established_date = 8th century , established_title2 = Christianization , established_date2 = 965 , established_title3 = , established_date3 = 5 June 1849 , established_title4 = Faroese home rule , established_date4 = 24 March 1948 , established_title5 = EEC accession , established_date5 = 1 January 1973 , established_title6 = Greenlandic home rule , established_date6 = 1 May 1979 , official_languages = Danish , languages_type = Regional languages , languages_sub = yes , languages = GermanGerman is recognised as a protected minority language in the South Jutland area of Denmark. , demonym = , capital = Copenhagen , largest_city = capital , coordinates = , ethnic_groups = , ethnic_g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rostrata
Rostratus (masculine), rostrata (feminine) or rostratum (neuter) is a Latin adjective meaning "beaked, curved, hooked, with a crooked point, or with a curved front". In marine warfare, the term ''beak'' (''rostrum'') referred to the ram bows on warships, which were metal or metal-covered beams projecting from ships' bows, used to pierce enemy vessels by ramming. Roman usage Columna rostrata (Rostral column) After the Battle of Mylae in 260 BC during the First Punic War, a ''columna rostrata'' (a victory column), was placed in the Roman Forum in honour of Gaius Duilius. It was so called because it was adorned with the beaks (ram bows) of the captured Carthaginian vessels. The ''columna rostrata'' became a favourite site for speeches. Corona rostrata A ''corona rostrata'' was a golden wreath, decorated with small golden prow and beak of a ship. These were awarded to commanders who were victorious in naval warfare. Modern usage In modern usage the adjective is used in L ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
