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Eastern Freshwater Cod
The eastern freshwater cod (''Maccullochella ikei''), also known as the eastern cod or Clarence River cod, is a large predatory freshwater fish of the genus ''Maccullochella'' and the family Percichthyidae, that occur in the coastal Clarence River system of north-eastern New South Wales. Eastern freshwater cod are closely related to the Murray cod of the Murray-Darling River system, and are considered an icon of the Clarence River system. A long-lived, slow-growing species, eastern freshwater cod are threatened by poaching .e. illegal take habitat degradation, catastrophic natural events such as bushfires, and inbreeding from low genetic diversity. They are currently classified as endangered and protected by law from human exploitation of any kind. Range Eastern freshwater cod are native to the Clarence River system in northern New South Wales, Australia. The Clarence River system is an extensive East Coast drainage with many tributaries of differing size. By Australian stan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stuart J
Stuart may refer to: Names *Stuart (name), a given name and surname (and list of people with the name) Automobile *Stuart (automobile) Places Australia Generally *Stuart Highway, connecting South Australia and the Northern Territory Northern Territory *Stuart, the former name for Alice Springs (changed 1933) * Stuart Park, an inner city suburb of Darwin * Central Mount Stuart, a mountain peak Queensland *Stuart, Queensland, a suburb of Townsville *Mount Stuart, Queensland, a suburb of Townsville *Mount Stuart (Queensland), a mountain South Australia *Stuart, South Australia, a locality in the Mid Murray Council *Electoral district of Stuart, a state electoral district *Hundred of Stuart, a cadastral unit Canada * Stuart Channel, a strait in the Gulf of Georgia region of British Columbia United Kingdom *Castle Stuart United States * Stuart, Florida *Stuart, Iowa *Stuart, Nebraska *Stuart, Oklahoma *Stuart, Virginia *Stuart Township, Holt County, Nebraska * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natural Selection
Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations. Charles Darwin popularised the term "natural selection", contrasting it with selective breeding, artificial selection, which in his view is intentional, whereas natural selection is not. Genetic diversity, Variation exists within all populations of organisms. This occurs partly because random mutations arise in the genome of an individual organism, and their offspring can inherit such mutations. Throughout the lives of the individuals, their genomes interact with their environments to cause variations in traits. The environment of a genome includes the molecular biology in the Cell (biology), cell, other cells, other individuals, populations, species, as well as the abiotic environment. Because individuals with certain variants of the trait tend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trout Cod
The trout cod (''Maccullochella macquariensis'') or bluenose cod, is a large predatory freshwater fish of the genus ''Maccullochella'' and the family Percichthyidae, closely related to the Murray cod. It was originally widespread in the south-east corner of the Murray-Darling river system in Australia, but is now an endangered species. In the 19th and early 20th centuries, when trout cod were widely recognised as a separate species by commercial fishermen, recreational fishermen, riverside residents and fisheries scientists, they were generally known as bluenose cod or simply bluenose, particularly in Victoria. In some parts of New South Wales however they were also known as trout cod, and this common name was adopted when the species status of the fish was finally confirmed by genetic studies in the early 1970s. This choice of official common name was perhaps unfortunate; it has been suggested that bluenose cod is a more appropriate name as the name trout cod causes confus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cicada
The cicadas () are a superfamily, the Cicadoidea, of insects in the order Hemiptera (true bugs). They are in the suborder Auchenorrhyncha, along with smaller jumping bugs such as leafhoppers and froghoppers. The superfamily is divided into two families, the Tettigarctidae, with two species in Australia, and the Cicadidae, with more than 3,000 species described from around the world; many species remain undescribed. Cicadas have prominent eyes set wide apart, short antennae, and membranous front wings. They have an exceptionally loud song, produced in most species by the rapid buckling and unbuckling of drumlike tymbals. The earliest known fossil Cicadomorpha appeared in the Upper Permian period; extant species occur all around the world in temperate to tropical climates. They typically live in trees, feeding on watery sap from xylem tissue, and laying their eggs in a slit in the bark. Most cicadas are cryptic. The vast majority of species are active during the day as adults, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paratya
''Paratya'' is a genus of freshwater shrimp of the family Atyidae, found in various islands in the Pacific Ocean. The split between the North Pacific clade (Japan) and the South Pacific clade (New Zealand, Australia, New Caledonia, Lord Howe Island) has been estimated to have occurred . Species There are 14 species recognised in the genus: *'' Paratya annamensis'' Balss, 1924 *''Paratya australiensis'' Kemp, 1917 *'' Paratya boninensis'' Satake & Cai, 2005 *''Paratya borealis'' Volk, 1938 *''Paratya bouvieri'' Roux, 1926 *''Paratya caledonica'' Roux, 1926 *''Paratya compressa'' (De Haan, 1844) *''Paratya curvirostris'' (Heller, 1862) *''Paratya howensis'' Roux, 1926 *''Paratya improvisa'' Kemp, 1917 *''Paratya intermedia'' Roux, 1926 *''Paratya martensi'' Roux, 1925 *''Paratya norfolkensis'' Kemp, 1917 *''Paratya typa ''Paratya'' is a genus of freshwater shrimp of the family Atyidae, found in various islands in the Pacific Ocean. The split between the North Pacific clade ( Ja ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrobrachium
''Macrobrachium'' is a genus of freshwater prawns or shrimps characterised by the extreme enlargement of the second pair of pereiopods, at least in the male. Species It contains these species: *''Macrobrachium acanthochirus'' F. Villalobos, 1967 *''Macrobrachium acanthurus'' (Wiegmann, 1836) *''Macrobrachium acherontium'' Holthuis, 1977 *''Macrobrachium adscitum'' Riek, 1951 *''Macrobrachium aemulum'' (Nobili, 1906) *'' Macrobrachium agwi'' Klotz, 2008 *'' Macrobrachium ahkowi'' Chong & Khoo, 1987 *''Macrobrachium altifrons'' (Henderson, 1893) *''Macrobrachium amazonicum'' (Heller, 1862) *''Macrobrachium americanum'' Spence Bate, 1868 *''Macrobrachium amplimanus'' Cai & Dai, 1999 *'' Macrobrachium andamanicum'' (Tiwari, 1952) *'' Macrobrachium aracamuni'' Rodríguez, 1982 *'' Macrobrachium asperulum'' (von Martens, 1868) *'' Macrobrachium assamense'' (Tiwari, 1958) *'' Macrobrachium atabapense'' S. Pereira, 1986 *'' Macrobrachium atactum'' Riek, 1951 *'' Macrobrachium auratum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crustacean
Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can be treated as a subphylum under the clade Mandibulata. It is now well accepted that the hexapods emerged deep in the Crustacean group, with the completed group referred to as Pancrustacea. Some crustaceans (Remipedia, Cephalocarida, Branchiopoda) are more closely related to insects and the other hexapods than they are to certain other crustaceans. The 67,000 described species range in size from '' Stygotantulus stocki'' at , to the Japanese spider crab with a leg span of up to and a mass of . Like other arthropods, crustaceans have an exoskeleton, which they moult to grow. They are distinguished from other groups of arthropods, such as insects, myriapods and chelicerates, by the possession of biramous (two-parted) limbs, and by th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Territory (animal)
In ethology, territory is the sociographical area that an animal consistently defends against conspecific competition (or, occasionally, against animals of other species) using agonistic behaviors or (less commonly) real physical aggression. Animals that actively defend territories in this way are referred to as being territorial or displaying territorialism. Territoriality is only shown by a minority of species. More commonly, an individual or a group of animals occupies an area that it habitually uses but does not necessarily defend; this is called its home range. The home ranges of different groups of animals often overlap, and in these overlap areas the groups tend to avoid each other rather than seeking to confront and expel each other. Within the home range there may be a ''core area'' that no other individual group uses, but, again, this is as a result of avoidance. Function The ultimate function of animals inhabiting and defending a territory is to increase the indi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Diversity
Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is distinguished from ''genetic variability'', which describes the tendency of genetic characteristics to vary. Genetic diversity serves as a way for populations to adapt to changing environments. With more variation, it is more likely that some individuals in a population will possess variations of alleles that are suited for the environment. Those individuals are more likely to survive to produce offspring bearing that allele. The population will continue for more generations because of the success of these individuals. The academic field of population genetics includes several hypotheses and theories regarding genetic diversity. The neutral theory of evolution proposes that diversity is the result of the accumulation of neutral substitutions ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Kill
The term fish kill, known also as fish die-off, refers to a localized die-off of fish populations which may also be associated with more generalized mortality of aquatic life.University of Florida. Gainesville, FL (2005) ''Plant Management in Florida's Waters.'' The most common cause is reduced oxygen in the water, which in turn may be due to factors such as drought, algae bloom, overpopulation, or a sustained increase in water temperature. Infectious diseases and parasites can also lead to fish kill. Toxicity is a real but far less common cause of fish kill. Fish kills are often the first visible signs of environmental stress and are usually investigated as a matter of urgency by environmental agencies to determine the cause of the kill. Many fish species have a relatively low tolerance of variations in environmental conditions and their death is often a potent indicator of problems in their environment that may be affecting other animals and plants and may have a direct impact ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Population Bottleneck
A population bottleneck or genetic bottleneck is a sharp reduction in the size of a population due to environmental events such as famines, earthquakes, floods, fires, disease, and droughts; or human activities such as specicide, widespread violence or intentional culling, and human population planning. Such events can reduce the variation in the gene pool of a population; thereafter, a smaller population, with a smaller genetic diversity, remains to pass on genes to future generations of offspring through sexual reproduction. Genetic diversity remains lower, increasing only when gene flow from another population occurs or very slowly increasing with time as random mutations occur. This results in a reduction in the robustness of the population and in its ability to adapt to and survive natural selection, selecting environmental changes, such as Climate change (general concept), climate change or a shift in available resources. Alternatively, if survivors of the bottleneck are the i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Ages
An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and greenhouse periods, during which there are no glaciers on the planet. Earth is currently in the Quaternary glaciation. Individual pulses of cold climate within an ice age are termed ''glacial periods'' (or, alternatively, ''glacials, glaciations, glacial stages, stadials, stades'', or colloquially, ''ice ages''), and intermittent warm periods within an ice age are called ''interglacials'' or ''interstadials''. In glaciology, ''ice age'' implies the presence of extensive ice sheets in both northern and southern hemispheres. By this definition, Earth is currently in an interglacial period—the Holocene. The amount of anthropogenic greenhouse gases emitted into Earth's oceans and atmosphere is predicted to prevent the next glacial period for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
