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Totoaba Macdonaldi
The totoaba or totuava (''Totoaba macdonaldi'') is a species of marine fish, a very large member of the drum family Sciaenidae that is endemic to the Gulf of California in Mexico. It is the only species in the genus ''Totoaba''. Formerly abundant and subject to an intensive fishery, the totoaba has become rare, and is listed on CITES Appendix I, and as endangered under the Endangered Species Act. Life cycle The totoaba can grow up to in length and in weight, making it the largest species in the drum family, together with the similar-sized Chinese bahaba (''Bahaba taipingensis'') and meagre (''Argyrosomus regius''). The totoabas' diet consists of finned fish and crustaceans. Individuals may live up to 15 years, but sexual maturity is usually not reached until the fish are 6–7 years old. As totoabas spawn only once a year, population growth is slow, with a minimum population doubling time of 4.5 to 15 years. The totoaba spawn in the Colorado River Delta, which also serves ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Henry Gilbert
Charles Henry Gilbert (December 5, 1859 in Rockford, Illinois – April 20, 1928 in Palo Alto, California) was a pioneer ichthyologist and Fisheries science, fishery biologist of particular significance to natural history of the western United States. He collected and studied fishes from Central America north to Alaska and described many new species. Later he became an expert on Pacific salmon and was a noted conservation movement, conservationist of the Pacific Northwest. He is considered by many as the intellectual founder of American fisheries biology. He was one of the 22 "pioneer professors" (founding faculty) of Stanford University. Early life and education Born in Rockford, Illinois, Gilbert spent his early years in Indianapolis, Indiana, where he came under the influence of his high school teacher, David Starr Jordan (1851‒1931). When Jordan became Professor of Natural History at Butler University in Indianapolis, Gilbert followed and received his B.A. degree in 187 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doubling Time
The doubling time is the time it takes for a population to double in size/value. It is applied to population growth, inflation, resource extraction, consumption of goods, compound interest, the volume of malignant tumours, and many other things that tend to grow over time. When the relative growth rate (not the absolute growth rate) is constant, the quantity undergoes exponential growth and has a constant doubling time or period, which can be calculated directly from the growth rate. This time can be calculated by dividing the natural logarithm of 2 by the exponent of growth, or approximated by dividing 70 by the percentage growth rate (more roughly but roundly, dividing 72; see the rule of 72 for details and derivations of this formula). The doubling time is a characteristic unit (a natural unit of scale) for the exponential growth equation, and its converse for exponential decay is the half-life. For example, given Canada's net population growth of 0.9% in the year 2006, di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enrique Peña Nieto
Enrique Peña Nieto (; born 20 July 1966), commonly referred to by his initials EPN, is a Mexican politician who served as the 64th president of Mexico from 1 December 2012 to 30 November 2018. A member of the Institutional Revolutionary Party (PRI), he previously served as Governor of the State of Mexico from 2005 to 2011, local deputy from 2003 to 2004, and Secretary of Administration from 2000 to 2002. Born in Atlacomulco and raised in Toluca, Peña Nieto attended Panamerican University, graduating with a B.A. in legal studies. After attaining a MBA from ITESM, he began his political career by joining the Institutional Revolutionary Party (PRI) in 1984. After serving as a public notary in Mexico City, he began an ascent through local political ranks in the late 1990s, culminating in his 2005 campaign for Governor of the State of Mexico. As governor, he pledged to deliver 608 ''compromisos'' (commitments) to his constituency to varying levels of success. His tenure was mar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endangered Species Act Of 1973
The Endangered Species Act of 1973 (ESA or "The Act"; 16 U.S.C. § 1531 et seq.) is the primary law in the United States for protecting imperiled species. Designed to protect critically imperiled species from extinction as a "consequence of economic growth and development untempered by adequate concern and conservation", the ESA was signed into law by President Richard Nixon on December 28, 1973. The Supreme Court of the United States described it as "the most comprehensive legislation for the preservation of endangered species enacted by any nation"."Tennessee Valley Authority v. Hill" 437 U.S. 153 (1978) Retrieved 24 November 2015. The purposes of the ESA are two-fold: to prevent extinction and to recover species to the point where the law's protections are not needed. It therefo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gillnets
Gillnetting is a fishing method that uses gillnets: vertical panels of netting that hang from a line with regularly spaced floaters that hold the line on the surface of the water. The floats are sometimes called "corks" and the line with corks is generally referred to as a "cork line." The line along the bottom of the panels is generally weighted. Traditionally this line has been weighted with lead and may be referred to as "lead line." A gillnet is normally set in a straight line. Gillnets can be characterized by mesh size, as well as colour and type of filament from which they are made. Fish may be caught by gillnets in three ways: # Wedged – held by the mesh around the body. # Gilled – held by mesh slipping behind the opercula. # Tangled – held by teeth, spines, maxillaries, or other protrusions without the body penetrating the mesh. Most often fish are gilled. A fish swims into a net and passes only part way through the mesh. When it struggles to free ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vaquita
The vaquita ( ; ''Phocoena sinus'') is a species of porpoise endemic to the northern end of the Gulf of California in Baja California, Mexico. Averaging (females) or (males) in length, it is the smallest of all living cetaceans. The species is currently on the brink of extinction, and currently listed as Critically Endangered by the IUCN Red List; the steep decline in abundance is primarily due to bycatch in gillnets from the illegal totoaba fishery. Taxonomy The vaquita was defined as a species by two zoologists, Kenneth S. Norris and William N. McFarland, in 1958 after studying the morphology of skull specimens found on the beach. It was not until nearly thirty years later, in 1985, that fresh specimens allowed scientists to describe their external appearance fully. The genus ''Phocoena'' comprises four species of porpoise, most of which inhabit coastal waters (the spectacled porpoise is more oceanic). The vaquita is most closely related to Burmeister's porpoise (''Phoco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hong Kong
Hong Kong ( (US) or (UK); , ), officially the Hong Kong Special Administrative Region of the People's Republic of China ( abbr. Hong Kong SAR or HKSAR), is a city and special administrative region of China on the eastern Pearl River Delta in South China. With 7.5 million residents of various nationalities in a territory, Hong Kong is one of the most densely populated places in the world. Hong Kong is also a major global financial centre and one of the most developed cities in the world. Hong Kong was established as a colony of the British Empire after the Qing Empire ceded Hong Kong Island from Xin'an County at the end of the First Opium War in 1841 then again in 1842.. The colony expanded to the Kowloon Peninsula in 1860 after the Second Opium War and was further extended when Britain obtained a 99-year lease of the New Territories in 1898... British Hong Kong was occupied by Imperial Japan from 1941 to 1945 during World War II; British administration resume ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KNSD
KNSD (channel 39) is a television station in San Diego, California, United States, airing programming from the NBC network. It is owned and operated by the network's NBC Owned Television Stations alongside Poway-licensed Telemundo outlet KUAN-LD (channel 48). KNSD and KUAN-LD share studios on Granite Ridge Drive in the Serra Mesa section of San Diego; through a channel sharing agreement, the two stations transmit using KNSD's spectrum from an antenna southeast of Spring Valley. KNSD's on-air branding, NBC 7 San Diego, is derived from its cable channel position in the market on Charter Spectrum, Cox Communications and AT&T U-verse. The station is also available on channel 39 on satellite providers DirecTV and Dish Network. History Early history The station first signed on the air on November 14, 1965, as KAAR, owned by San Diego Telecasters. It was the first television station in the San Diego market to operate on the UHF band and was the market's first independent station. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Swim Bladder
The swim bladder, gas bladder, fish maw, or air bladder is an internal gas-filled Organ (anatomy), organ that contributes to the ability of many bony fish (but not cartilaginous fish) to control their buoyancy, and thus to stay at their current water depth without having to expend energy in swimming. Also, the Dorsum (biology), dorsal position of the swim bladder means the center of mass is below the centroid, center of volume, allowing it to act as a stabilizing agent. Additionally, the swim bladder functions as a resonator, resonating chamber, to produce or receive sound. The swim bladder is evolutionarily Homology (biology), homologous to the lungs. Charles Darwin remarked upon this in ''On the Origin of Species''.Darwin, Charles (1859''Origin of Species''Page 190, reprinted 1872 by D. Appleton. Darwin reasoned that the lung in air-breathing vertebrates had derived from a more primitive swim bladder. In the embryonic stages, some species, such as Ophioblennius atlanticus, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poaching
Poaching has been defined as the illegal hunting or capturing of wild animals, usually associated with land use rights. Poaching was once performed by impoverished peasants for subsistence purposes and to supplement meager diets. It was set against the hunting privileges of nobility and territorial rulers. Since the 1980s, the term "poaching" has also been used to refer to the illegal harvesting of wild plant species. In agricultural terms, the term 'poaching' is also applied to the loss of soils or grass by the damaging action of feet of livestock, which can affect availability of productive land, water pollution through increased runoff and welfare issues for cattle. Stealing livestock as in cattle raiding classifies as theft, not as poaching. The United Nations' Sustainable Development Goal 15 enshrines the sustainable use of all wildlife. It targets the taking of action on dealing with poaching and trafficking of protected species of flora and fauna to ensure their avail ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glen Canyon Dam
Glen Canyon Dam is a concrete arch-gravity dam on the Colorado River in northern Arizona, United States, near the town of Page, Arizona, Page. The high dam was built by the U.S. Bureau of Reclamation (USBR) from 1956 to 1966 and forms Lake Powell, one of the largest man-made reservoirs in the U.S. with a capacity of more than . The dam is named for Glen Canyon, a series of deep sandstone canyon, gorges now flooded by the reservoir; Lake Powell is named for John Wesley Powell, who in 1869 led the first expedition to traverse the Colorado River's Grand Canyon by boat. A dam in Glen Canyon was studied as early as 1924, but these plans were initially dropped in favor of the Hoover Dam (completed in 1936) which was located in the Black Canyon of the Colorado, Black Canyon. By the 1950s, due to rapid population growth in the seven U.S. and two Mexico, Mexican states comprising the Colorado River Basin, the Bureau of Reclamation deemed the construction of additional reservoirs necessar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hoover Dam
Hoover Dam is a concrete arch-gravity dam in the Black Canyon of the Colorado River, on the border between the U.S. states of Nevada and Arizona. It was constructed between 1931 and 1936 during the Great Depression and was dedicated on September 30, 1935, by President Franklin D. Roosevelt. Its construction was the result of a massive effort involving thousands of workers, and cost over one hundred lives. It was referred to as Hoover Dam after President Herbert Hoover in bills passed by Congress during its construction; it was named Boulder Dam by the Roosevelt administration. The Hoover Dam name was restored by Congress in 1947. Since about 1900, the Black Canyon and nearby Boulder Canyon had been investigated for their potential to support a dam that would control floods, provide irrigation water and produce hydroelectric power. In 1928, Congress authorized the project. The winning bid to build the dam was submitted by a consortium named Six Companies, Inc., which began ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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