The galjoen, black bream, or blackfish is a species of marine fish found only along the coast of southern Africa from Angola to South Africa. Galjoen is the national fish of South Africa; the galjoen is indigenous to the coasts of southern Africa from Angola to South Africa, is found around reefs at shallow depths around 10 m near the shore. This species can reach a weight of 6.5 kg. The body is compressed, the fins are well developed, with prominent spines, 10 of them, with between 18 and 23 rays; the anal fin has three spines, 13 or 14 rays, the pelvic fins have 1 spine and 5 rays, the pectoral fins are shorter than the head. The body and head, with the except of the front of the snout, are covered in scales; the lips are thick, with strong curved incisors at the front of the mouth, with smaller teeth behind the front incisors. The species feeds on red and coraline seaweed and red bait, small mussels and barnacles found off rocky shores, appear in particular to be partial to the white mussels residing in the sandy beaches and inlets of the rocky outcrops along the southern coast.
In 2005, the movements of the species were extensively studied. Some 25,000 galjoen were tagged at four sites in reserves in South Africa and it was concluded that their overall movement remained localised, with some 95% of fish studied seeming to indicate a home area, it is important to local commercial fisheries and is popular as a game fish. Due to their abundance in the shores off South Africa, galjoen is common in South African cuisine. A notable dish is the fish is sprinkled with pepper and lemon, or with lemon and melted garlic butter and served with fresh bread and apricot jam. Galjoen is the national fish of South Africa; the suggestion to make it the national fish came from Margaret Smith, wife of the ichthyologist J. L. B. Smith, to find a marine equivalent to the Springbok; the scientific name of Coracinus capensis is a reference to its black colour when found in rocky areas, Coracinus meaning "raven" or "black coloured".
The Alaska blackfish is a species of freshwater fish in the esocid family of order Esociformes. It inhabits Arctic regions of Alaska as well as the Bering Sea islands. Alaska blackfish are small, with an average length of 108 mm, but have been known to reach 330 mm, they have an distinguishable morphology, with large, posterior dorsal fin and anal fins, lobed pectoral fins located just posterior to the operculum, a diphycercal caudal fin, small, pointy pelvic fins. The head is flat, with the trunk being long and slender; the color is dark green to brown on the dorsal side, pale below, with light-colored blotches appearing laterally. Males can be distinguished from females by the presence of a reddish fringe along the dorsal and anal fins; the Alaska blackfish is famous for its ability to breathe atmospheric oxygen through a modified esophagus. The esophagus of a blackfish can be subdivided into a non-respiratory and a respiratory section; the respiratory section can be identified by its extensive mucosal folding and vascularization, as well as widespread capillaries throughout the epithelium.
This respiratory structure implies selection pressures for the development of a purely respiratory organ and a purely hydrostatic organ. The interesting factor is the retention of the hydrostatic swim bladder, which seems unnecessary unless it is important in maintaining neutral buoyancy in the cold winter months under ice cover. Alaska blackfish can be found in the Bering Sea Islands and Alaska. In Alaska, they inhabit the Colville Delta south to the central Alaska Peninsula near Chignik as well as the upstream Yukon-Tanana drainage to near Fairbanks. Blackfish are found in vegetated swamps and ponds residing in rivers and densely-vegetated lakes, where in summer, water is stagnant. Spawning migrations are limited to inshore and upstream movements in the spring, reverse migrations to deeper water in the fall. In the winter-time, blackfish tend to reside in the benthic regions of lakes, although when oxygen availability reaches a certain minimum, blackfish move to the surface, grouping around breathing holes.
These breathing areas can be preexisting holes, such as those created by muskrats and fishermen, or thin layers of ice. Blackfish have been observed schooling below the ice, when swimming upwards to breathe, eat away at the ice and creating an audible snapping or sucking sound; the Alaska blackfish is known for its tolerance of cold water, has been reported to survive exposure to -20 °C for 40 minutes. Despite its hardiness, Alaska blackfish have been observed to suffer edema and mass mortality events during the winter; the principal source of food for blackfish is aquatic insects and invertebrates, although in Bristol Bay, larger blackfish have been observed to be cannibalistic, as well as predators of young pike. Blackfish are generalist feeders, have been analyzed to have contained algae, dipteran larvae, ostracods and caddis fly larvae in their stomachs. Spawning occurs from May with fish having the ability to spawn several times. A female, depending on her size, can release a total of 40-300 eggs at intervals during the spawning period, with the eggs attaching to vegetation and hatching in a short period of time.
When the young hatch, they are 6 mm in length, survive off the yolk sac for an average period of 10 days. Rate of growth varies throughout Alaska, with blackfish from Interior Alaska and the Anchorage area being about 108 mm at age 2, 138 mm at age 3, 178 mm at age 4. On the other hand, Bristol Bay blackfish are much slower growing and longer lived. Four-year-old fish are 64 mm in length, but can live up to 8 years. Female blackfish have been shown to reach sexual maturity at 80 mm; the Alaska blackfish is an important subsistence fish for Native communities residing in the Interior and Western Alaska those residing in Interior Alaska. Although small, their significance comes in their high nutritional value and large abundance in the winter, a lean time of year; when oxygen levels in the benthic regions of lakes becomes low, blackfish move to the surface to obtain atmospheric oxygen, thus making ice fishing an easy method of capture. Metabolic and survival studies have been conducted without successful replication of this observation.
The Alaska blackfish is not IUCN-listed as an threatened species. While blackfish are native to Western Alaska as well as the Interior, they were introduced to the Cook Inlet Basin of Alaska in the 1950s, have since become widespread. A study performed by Eidam et.al. in three study sites in the Cook Inlet Basin concluded that an insignificant portion of their diet was fish, meaning blackfish are unlikely to impact native and stocked fish in those populations. While that information is helpful for determining whether blackfish are invasive, it is not all-encompassing for other blackfish populations in the area. Further studies are warranted that estimate the abundance of introduced blackfish in lakes and streams in the Cook Inlet Basin as well as investigate potential dietary overlap with other fish. Molecular study of Alaska blackfish across its range has identified several
The Sacramento blackfish is a cyprinid fish of central California. It is the sole member of its genus. Blackfish are distinctive for their overall dark color. Younger individuals are darken as they age; the scales are unusually small. The forehead has a straight-line profile, the eyes are smallish, the terminal mouth slants upwards; the dorsal fin starts just behind the pelvic fins, has 9-11 rays, while the anal fin has 8-9 rays, the pelvic fins 10 rays. The pharyngeal teeth are long and knife-shaped, they have been recorded at up to 55 cm in length. Unlike most North American cyprinids, they feed on zooplankton, planktonic algae, floating detritus, including rotifers, cladocerans and the like. Younger fish pick at food items individually, while adults work by pumping large amounts of water through the oral cavity. Blackfish are denizens of the warm turbid waters found on the floor of the Central Valley, such as sloughs and oxbow lakes connected to the Sacramento and San Joaquin Rivers, they are common in Clear Lake, Pajaro River, Salinas River, the small creeks that feed into San Francisco Bay.
A population is present in the Russian River. They thrive in reservoirs, have been spread to a number of California reservoirs via the California Aqueduct, into Nevada via the Lahontan Reservoir where they have further colonized the Humboldt River drainage. Sacramento blackfish are of some commercial significance, are sold live at many Asian fish markets in California. Peter B. Moyle, Inland Fishes of California, pp. 144–146
Aquaculture known as aquafarming, is the farming of fish, molluscs, aquatic plants and other organisms. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, can be contrasted with commercial fishing, the harvesting of wild fish. Mariculture refers to aquaculture practiced in underwater habitats. According to the Food and Agriculture Organization, aquaculture "is understood to mean the farming of aquatic organisms including fish, molluscs and aquatic plants. Farming implies some form of intervention in the rearing process to enhance production, such as regular stocking, protection from predators, etc. Farming implies individual or corporate ownership of the stock being cultivated." The reported output from global aquaculture operations in 2014 supplied over one half of the fish and shellfish, directly consumed by humans. Further, in current aquaculture practice, products from several pounds of wild fish are used to produce one pound of a piscivorous fish like salmon.
Particular kinds of aquaculture include fish farming, shrimp farming, oyster farming, mariculture and the cultivation of ornamental fish. Particular methods include aquaponics and integrated multi-trophic aquaculture, both of which integrate fish farming and aquatic plant farming; the indigenous Gunditjmara people in Victoria, may have raised eels as early as 6000 BC. Evidence indicates they developed about 100 km2 of volcanic floodplains in the vicinity of Lake Condah into a complex of channels and dams, used woven traps to capture eels, preserve them to eat all year round. Aquaculture was operating in China circa 2000 BC; when the waters subsided after river floods, some fish carp, were trapped in lakes. Early aquaculturists fed their brood using nymphs and silkworm feces, ate them. A fortunate genetic mutation of carp led to the emergence of goldfish during the Tang dynasty. However, ancient Egyptians might have farmed fish from Lake Bardawil about 3,500 years ago, they traded them with Canaan.
Gim cultivation is the oldest aquaculture in Korea. Early cultivation methods used bamboo or oak sticks, which were replaced by newer methods that utilized nets in the 19th century. Floating rafts have been used for mass production since the 1920s. Japanese cultivated seaweed by providing bamboo poles and nets and oyster shells to serve as anchoring surfaces for spores. Romans bred fish in ponds and farmed oysters in coastal lagoons before 100 CE. In central Europe, early Christian monasteries adopted Roman aquacultural practices. Aquaculture spread in Europe during the Middle Ages since away from the seacoasts and the big rivers, fish had to be salted so they did not rot. Improvements in transportation during the 19th century made fresh fish available and inexpensive in inland areas, making aquaculture less popular; the 15th-century fishponds of the Trebon Basin in the Czech Republic are maintained as a UNESCO World Heritage Site. Hawaiians constructed oceanic fish ponds. A remarkable example is the "Menehune" fishpond dating from at least 1,000 years ago, at Alekoko.
Legend says. In the first half of the 18th century, German Stephan Ludwig Jacobi experimented with external fertilization of brown trouts and salmon, he wrote an article "Von der künstlichen Erzeugung der Forellen und Lachse". By the latter decades of the 18th century, oyster farming had begun in estuaries along the Atlantic Coast of North America; the word aquaculture appeared in an 1855 newspaper article in reference to the harvesting of ice. It appeared in descriptions of the terrestrial agricultural practise of subirrigation in the late 19th century before becoming associated with the cultivation of aquatic plant and animal species. In 1859, Stephen Ainsworth of West Bloomfield, New York, began experiments with brook trout. By 1864, Seth Green had established a commercial fish-hatching operation at Caledonia Springs, near Rochester, New York. By 1866, with the involvement of Dr. W. W. Fletcher of Concord, artificial fish hatcheries were under way in both Canada and the United States; when the Dildo Island fish hatchery opened in Newfoundland in 1889, it was the largest and most advanced in the world.
The word aquaculture was used in descriptions of the hatcheries experiments with cod and lobster in 1890. By the 1920s, the American Fish Culture Company of Carolina, Rhode Island, founded in the 1870s was one of the leading producers of trout. During the 1940s, they had perfected the method of manipulating the day and night cycle of fish so that they could be artificially spawned year around. Californians harvested wild kelp and attempted to manage supply around 1900 labeling it a wartime resource. Harvest stagnation in wild fisheries and overexploitation of popular marine species, combined with a growing demand for high-quality protein, encouraged aquaculturists to domesticate other marine species. At the outset of modern aquaculture, many were optimistic that a "Blue Revolution" could take place in aquaculture, just as the Green Revolution of the 20th century had revolutionized agriculture. Although land animals had long been domesticated, most seafood species were still caught from the wild.
Concerned about the impact of growing demand for seafood on the world's oceans, prominent ocean explorer Jacques Cousteau wrote in 1973: "With earth's burgeoning human populations to feed, we must turn to the sea with new understanding and new technology."About 430 of the species cultu
Encyclopedia Americana is one of the largest general encyclopedias in the English language. Following the acquisition of Grolier in 2000, the encyclopedia has been produced by Scholastic; the encyclopedia has more than 45,000 articles, most of them more than 500 words and many running to considerable length. The work's coverage of American and Canadian geography and history has been a traditional strength. Written by 6,500 contributors, the Encyclopedia Americana includes over 9,000 bibliographies, 150,000 cross-references, 1,000+ tables, 1,200 maps, 4,500 black-and-white line art and color images, it has 680 factboxes. Most articles are signed by their contributors. Long available as a 30-volume print set, the Encyclopedia Americana is now marketed as an online encyclopedia requiring a subscription. In March 2008, Scholastic said that print sales remained good but that the company was still deciding on the future of the print edition; the company did not produce an edition in 2007, a change from its previous approach of releasing a revised print edition each year.
The most recent print edition of the Encyclopedia Americana was published in 2006. The online version of the Encyclopedia Americana, first introduced in 1997, continues to be updated and sold; this work, like the print set from which it is derived, is designed for high school and first-year college students along with public library users. It is available to libraries as one of the options in the Grolier Online reference service, which includes the Grolier Multimedia Encyclopedia, intended for middle and high school students, The New Book of Knowledge, an encyclopedia for elementary and middle school students. Grolier Online is not available to individual subscribers. There have been three separate works using the title Encyclopedia Americana; the first began publishing in the 1820s by the German exile Francis Lieber. The 13 volumes of the first edition were completed in 1833, other editions and printings followed in 1835, 1836, 1847-1848, 1849 and 1858. Lieber's work was based upon and was in no small part a translation of the 7th edition of the well established Konversations-Lexikon of Brockhaus.
Some material from this set was carried over into the modern version, as well as the Brockhaus short article method. A separate Encyclopedia Americana was published by J. M. Stoddart between 1883 and 1889, as a supplement to American reprintings of the 9th edition of the Encyclopædia Britannica, it was four quarto volumes meant to "extend and complete the articles in Britannica". Stoddart's work, however, is not connected to the earlier work by Lieber. In 1902 a new version in 16 volumes was published under the title Encyclopedia Americana, under the editorial supervision of Scientific American magazine; the magazine's editor, Frederick Converse Beach, was editor-in-chief, was said to be assisted by hundreds of eminent scholars and authorities who served as consulting editors or authors. The first publisher was R. S. Peale & Co; the relationship with Scientific American was terminated in 1911. From 1907 to 1912, the work was published as The Americana. A major new edition appeared with George Edwin Rines as editor-in-chief.
An Annual or Yearbook was published each year beginning in 1923 and continuing until 2000. The encyclopedia was purchased by Grolier in 1945. By the 1960s, sales of the Americana and its sister publications under Grolier—The Book of Knowledge, the Book of Popular Science, Lands and Peoples—were strong enough to support the company's occupancy of a large building in Midtown Manhattan, at 575 Lexington Avenue. Sales during this period were accomplished through mail-order and door-to-door operations. Telemarketing and third-party distribution through their Lexicon division added to sales volumes in the 1970s. By the late 1970s, Grolier had moved its operations to Connecticut. In 1988 Grolier was purchased by the French media company Hachette, which owned a well-known French-language encyclopedia, the Hachette Encyclopedia. Hachette was absorbed by the French conglomerate the Lagardère Group. A CD-ROM version of the encyclopedia was published in 1995. Although the text and images were stored on separate disks, it was in keeping with standards current at the time.
More the work had been digitized, allowing for release of an online version in 1997. Over the next few years the product was augmented with additional features, supplementary references, Internet links, current events journal. A redesigned interface and reengineered product, featuring enhanced search capabilities and a first-ever ADA-compliant, text-only version for users with disabilities, was presented in 2002; the acquisition of Grolier by Scholastic for US$400 million, took place in 2000. The new owners projected a 30% increase in operating income, although Grolier had experienced earnings of 7% to 8% on income. Staff reductions as a means of controlling costs followed soon thereafter while an effort was made to augment the sales force. Cuts occurred every year between 2000 and 2007, leaving a much-depleted work force to carry out the duties of maintaining a large encyclopedia database. Today, Encyclopedia Americana lives on as an integral database within the Grolier Online product. Frederick Converse Beach, 1902–1917.
Engineer and editor of Scientific American magazine. George Edwin Rines, 1917–1920. Author and editor. A. H. McDannald, 1920–1948. Reporter and author
The Sparidae are a family of fish in the order Perciformes called sea breams and porgies. The sheepshead and red seabream are species in this family. Most sparids are deep-bodied compressed fish with a small mouth separated by a broad space from the eye, a single dorsal fin with strong spines and soft rays, a short anal fin, long pointed pectoral fins and rather large attached scales, they are bottom-dwelling carnivores. There are hermaphrodites in the Sparidae. Protogyny and protandry appear sporadically through this lineage of fish. Simultaneous hermaphrodites and bi-directional hermaphrodites do not appear as much since Sparidae are found in shallower waters. Species of fish that express a hermaphroditic condition "lack a genetic hardwire", therefore ecological factors play a role in sex determination. Most species possess molar-like teeth; some of the species, such as Polysteganus undulosus, have been subject to overfishing, or exploitation beyond sustainable recovery. The family Sparidae contains about 155 species in 38 genera: Acanthopagrus Peters, 1855 Amamiichthys Tanaka & Iwatsuki, 2015 Archosargus Gill, 1865 Argyrops Swainson, 1839 Argyrozona Smith, 1938 Boops Cuvier, 1814 Boopsoidea Castelnau, 1861 Calamus Swainson, 1839 Centracanthus Rafinesque, 1810 Cheimerius Smith, 1938 Chrysoblephus Swainson, 1839 Crenidens Valenciennes, 1830 Cymatoceps Smith, 1938 Dentex Cuvier, 1814 Diplodus Rafinesque, 1810 Evynnis Jordan & Thompson, 1912 Gymnocrotaphus Günther, 1859 Lagodon Holbrook, 1855 Lithognathus Swainson, 1839 Oblada Cuvier, 1829 Pachymetopon Günther, 1859 Pagellus Valenciennes, 1830 Pagrus Cuvier, 1816 Parargyrops Tanaka, 1916 Petrus Smith, 1938 Polyamblyodon Norman, 1935 Polysteganus Klunzinger, 1870 Porcostoma Smith, 1938 Pterogymnus Smith, 1938 Rhabdosargus Fowler, 1933 Sarpa Bonaparte, 1831 Sparidentex Munro, 1948 Sparodon Smith, 1938 Sparus Linnaeus, 1758 Spicara Rafinesque, 1810 Spondyliosoma Cantor, 1849 Stenotomus Gill, 1865 Virididentex Poll, 1971 The most celebrated of the breams in cookery are the gilt-head bream and the common dentex.
Gadopsis is a genus of temperate perches endemic to freshwater habitats in southeastern Australia. The genus was considered to be in a family of its own, Gadopsidae. There are two species in this genus: Gadopsis bispinosus Sanger, 1984 Gadopsis marmoratus J. Richardson, 1848