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Mayaheros Mayorum
''Mayaheros'' is a genus of cichlid fish that is native to Mexico and northern Central America. This genus has a disjunct distribution, with the ''M. urophthalmus'' group being found in the Atlantic drainages of southeastern Mexico (southern Veracruz east to the Yucatán Peninsula and southwards), Belize, eastern Guatemala, northern Honduras and northeastern Nicaragua, while ''M. beani'' is the northernmost cichlid in the Pacific drainage, ranging from Jalisco to Sonora in northwestern Mexico. Both inhabit a wide range of habitats such as freshwater rivers, streams, lakes, ponds, pools and marshes, as well as brackish waters like estuaries, lagoons and mangrove, with members of the ''M. urophthalmus'' group sometimes even occurring in caves or coastal marine waters. They are medium-sized to large cichlids that are omnivorous, feeding mostly on small animals, but also plants and detritus. ''Mayaheros'' cichlids are sometimes kept in aquariums and commonly caught for food ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estuaries
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environments and are an example of an ecotone. Estuaries are subject both to marine influences such as tides, waves, and the influx of saline water, and to fluvial influences such as flows of freshwater and sediment. The mixing of seawater and freshwater provides high levels of nutrients both in the water column and in sediment, making estuaries among the most productive natural habitats in the world. Most existing estuaries formed during the Holocene epoch with the flooding of river-eroded or glacially scoured valleys when the sea level began to rise about 10,000–12,000 years ago. Estuaries are typically classified according to their geomorphological features or to water-circulation patterns. They can have many different names, such as bays, har ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mérida, Yucatán
Mérida () is the capital of the Mexican state of Yucatán, and the largest city in southeastern Mexico. The city is also the seat of the eponymous Municipality. It is located in the northwest corner of the Yucatán Peninsula, about 35 km (22 mi) inland from the coast of the Gulf of Mexico. In 2020 it had a population of 921,770 while its metropolitan area, which also includes the cities of Kanasín and Umán, had a population of 1,316,090. The city's rich cultural heritage is a product of the syncretism of the Maya and Spanish cultures during the colonial era. It was the first city to be ever named American Capital of Culture and is the only city that has received the title twice. The Cathedral of Mérida, Yucatán was built in the late 16th century with stones from nearby Mayan ruins and is known to be the oldest cathedral in the mainland Americas. In addition, the city has the third largest old town district on the continent. In 2007, the city was visited by former U.S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cavefish
Cavefish or cave fish is a generic term for fresh and brackish water fish adapted to life in caves and other underground habitats. Related terms are subterranean fish, troglomorphic fish, troglobitic fish, stygobitic fish, phreatic fish and hypogean fish.Romero, Aldemaro, editor (2001). ''The Biology of Hypogean Fishes.'' Developments in Environmental Biology of Fishes. Helfman, G.S. (2007). ''Fish Conservation: A Guide to Understanding and Restoring Global Aquatic Biodiversity and Fishery Resources'', pp. 41–42. Island Press. There are more than 200 scientifically described species of obligate cavefish found on all continents, except Antarctica. Although widespread as a group, many cavefish species have very small ranges and are seriously threatened.Fenolio, D.B.; Zhao, Y.; Niemiller, M.L.; and Stout, J. (2013). ''In-situ observations of seven enigmatic cave loaches and one cave barbel from Guangxi, China, with notes on conservation status.'' Speleobiology Notes 5: 19-33.Proud ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa, where a species presumed extinct abruptly "reappears" (typically in the fossil record) after a period of apparent absence. More than 99% of all species that ever lived on Earth, amounting to over five billion species, are estimated to have died out. It is estimated that there are currently around 8.7 million species of eukaryote globally, and possibly many times more if microorganisms, like bacteria, are included. Notable extinct animal species include non-avian dinosaurs, saber-toothed cats, dodos, m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cenote
A cenote ( or ; ) is a natural pit, or sinkhole, resulting from the collapse of limestone bedrock that exposes groundwater. The regional term is specifically associated with the Yucatán Peninsula of Mexico, where cenotes were commonly used for water supplies by the ancient Maya, and occasionally for sacrificial offerings. The term derives from a word used by the lowland Yucatec Maya——to refer to any location with accessible groundwater. Similar rock-sided sinkholes like cenotes are common geological forms in low-altitude regions, particularly on islands, coastlines, and platforms with young post-Paleozoic limestone with little soil development. The term ''cenote'' has also been used to describe similar karst features in other countries such as Cuba and Australia. Definition and description Cenotes are surface connections to subterranean water bodies. While the best-known cenotes are large open-water pools measuring tens of meters in diameter, such as those at Chichen It ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. Other ways of defining species include their karyotype, DNA sequence, morphology, behaviour or ecological niche. In addition, paleontologists use the concept of the chronospecies since fossil reproduction cannot be examined. The most recent rigorous estimate for the total number of species of eukaryotes is between 8 and 8.7 million. However, only about 14% of these had been described by 2011. All species (except viruses) are given a two-part name, a "binomial". The first part of a binomial is the genus to which the species belongs. The second part is called the specific name or the specific epithet (in botanical nomenclature, also sometimes i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Introduced Species
An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there by human activity, directly or indirectly, and either deliberately or accidentally. Non-native species can have various effects on the local ecosystem. Introduced species that become established and spread beyond the place of introduction are considered naturalized. The process of human-caused introduction is distinguished from biological colonization, in which species spread to new areas through "natural" (non-human) means such as storms and rafting. The Latin expression neobiota captures the characteristic that these species are ''new'' biota to their environment in terms of established biological network (e.g. food web) relationships. Neobiota can further be divided into neozoa (also: neozoons, sing. neozoon, i.e. animals) and neophyt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Overfishing
Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in the species becoming increasingly underpopulated in that area. Overfishing can occur in water bodies of any sizes, such as ponds, wetlands, rivers, lakes or oceans, and can result in resource depletion, reduced biological growth rates and low biomass levels. Sustained overfishing can lead to critical depensation, where the fish population is no longer able to sustain itself. Some forms of overfishing, such as the overfishing of sharks, has led to the upset of entire marine ecosystems. Types of overfishing include: growth overfishing, recruitment overfishing, ecosystem overfishing. The ability of a fishery to recover from overfishing depends on whether its overall carrying capacity and the variety of ecological conditions are suitable for t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IUCN
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natural resources. It is involved in data gathering and analysis, research, field projects, advocacy, and education. IUCN's mission is to "influence, encourage and assist societies throughout the world to conserve nature and to ensure that any use of natural resources is equitable and ecologically sustainable". Over the past decades, IUCN has widened its focus beyond conservation ecology and now incorporates issues related to sustainable development in its projects. IUCN does not itself aim to mobilize the public in support of nature conservation. It tries to influence the actions of governments, business and other stakeholders by providing information and advice and through building partnerships. The organization is best known to the wider ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Least Concern
A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. They do not qualify as threatened, near threatened, or (before 2001) conservation dependent. Species cannot be assigned the "Least Concern" category unless they have had their population status evaluated. That is, adequate information is needed to make a direct, or indirect, assessment of its risk of extinction based on its distribution or population status. Evaluation Since 2001 the category has had the abbreviation "LC", following the IUCN 2001 Categories & Criteria (version 3.1). Before 2001 "least concern" was a subcategory of the "Lower Risk" category and assigned the code "LR/lc" or lc. Around 20% of least concern taxa (3261 of 15636) in the IUCN database still use the code "LR/lc", which indicates they have not been re-evaluate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fish Farming
upright=1.3, Salmon farming in the sea (mariculture) at Loch Ainort, Isle of Skye">mariculture.html" ;"title="Salmon farming in the sea (mariculture">Salmon farming in the sea (mariculture) at Loch Ainort, Isle of Skye, Scotland Fish farming or pisciculture involves commercial animal husbandry, breeding of fish, usually for food, in fish tanks or artificial pen (enclosure), enclosures such as fish ponds. It is a particular type of aquaculture, which is the controlled cultivation and harvesting of aquatic animals such as fish, crustaceans, molluscs and so on, in natural or pseudo-natural environment. A facility that releases juvenile fish into the wild for recreational fishing or to supplement a species' natural numbers is generally referred to as a fish hatchery. Worldwide, the most important fish species produced in fish farming are carp, catfish, salmon and tilapia. Global demand is increasing for dietary fish protein, which has resulted in widespread overfishing in wild ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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