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Euryhaline
Euryhaline organisms are able to adapt to a wide range of salinities. An example of a euryhaline fish is the short-finned molly, '' Poecilia sphenops'', which can live in fresh water, brackish water, or salt water. The green crab ('' Carcinus maenas'') is an example of a euryhaline invertebrate that can live in salt and brackish water. Euryhaline organisms are commonly found in habitats such as estuaries and tide pools where the salinity changes regularly. However, some organisms are euryhaline because their life cycle involves migration between freshwater and marine environments, as is the case with salmon and eels. The opposite of euryhaline organisms are stenohaline ones, which can only survive within a narrow range of salinities. Most freshwater organisms are stenohaline, and will die in seawater, and similarly most marine organisms are stenohaline, and cannot live in fresh water. Osmoregulation Osmoregulation is the active process by which an organism maintains its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brackish Water
Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuary, estuaries, or it may occur in brackish Fossil water, fossil aquifers. The word comes from the Middle Dutch root '':wikt:brak#Dutch, brak''. Certain human activities can produce brackish water, in particular civil engineering projects such as dikes and the flooding of coastal marshland to produce brackish water pools for freshwater prawn farming. Brackish water is also the primary waste product of the Osmotic power, salinity gradient power process. Because brackish water is hostile to the growth of most terrestrial plant species, without appropriate management it can be damaging to the environment (see article on shrimp farming, shrimp farms). Technically, brackish water contains between 0.5 and 30 grams of salt per litre—more ofte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Round Goby
The round goby (''Neogobius melanostomus'') is a euryhaline bottom-dwelling species of fish of the family (biology), family Gobiidae. It is native to Central Eurasia, including the Black Sea and the Caspian Sea. Round gobies have established large non-native populations in the Baltic Sea, several major Eurasian rivers, and the North American Great Lakes. Characteristics Round gobies are small, soft-bodied fish characterized by a distinctive black spot on the first dorsal fin. The eyes are large and protrude slightly from the top of the head and, like most gobies, the pelvic fins are fused to form a single disc (shaped like a suction cup) on the belly. Round gobies range in length from , with a maximum size of . They weigh between , their weight increasing with age. Male round gobies are larger than females. Juvenile round gobies (less than one year old) are grey. Upon maturation, round gobies become mottled with grey, black, brown, and olive green markings. Adult male round gobies ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osmoconformer
Osmoconformers are marine organisms that maintain an internal environment which is isotonic to their external environment. This means that the osmotic pressure of the organism's cells is equal to the osmotic pressure of their surrounding environment. By minimizing the osmotic gradient, this subsequently minimizes the net influx and efflux of water into and out of cells. Even though osmoconformers have an internal environment that is isosmotic to their external environment, the types of ions in the two environments differ greatly in order to allow critical biological functions to occur. An advantage of osmoconformation is that such organisms don’t need to expend as much energy as osmoregulators in order to regulate ion gradients. However, to ensure that the correct types of ions are in the desired location, a small amount of energy is expended on ion transport. A disadvantage to osmoconformation is that the organisms are subject to changes in the osmolarity of their envi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salinity
Salinity () is the saltiness or amount of salt (chemistry), salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal to per mille, ‰). Salinity is an important factor in determining many aspects of the chemistry of natural waters and of biological processes within it, and is a state function, thermodynamic state variable that, along with temperature and pressure, governs physical characteristics like the density and heat capacity of the water. A contour line of constant salinity is called an ''isohaline'', or sometimes ''isohale''. Definitions Salinity in rivers, lakes, and the ocean is conceptually simple, but technically challenging to define and measure precisely. Conceptually the salinity is the quantity of dissolved salt content of the water. Salts are compounds like sodium chloride, magnesium sulfate, potassium nitrate, and sod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stenohaline
Stenohaline describes an organism, usually fish, that cannot tolerate a wide fluctuation in the salinity of water. Stenohaline is derived from the words: "''steno''" meaning narrow, and "''haline''" meaning salt. Many fresh water fish, such as goldfish (''Carassius auratus''), tend to be stenohaline and die in environments of high salinity such as the ocean. Many marine fish, such as haddock, are also stenohaline and die in water with lower salinity. Alternatively, fish living in coastal estuaries and tide pools are often euryhaline (tolerant to changes in salinity), as are many species which have life cycle requiring tolerance to both fresh water and seawater environments such as salmon and herring. See also *Fish migration *Osmoconformer *Osmoregulation *Euryhaline Euryhaline organisms are able to adapt to a wide range of salinities. An example of a euryhaline fish is the short-finned molly, '' Poecilia sphenops'', which can live in fresh water, brackish water, or sal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moonyfish
Monodactylidae is a family of perciform bony fish commonly referred to as monos, moonyfishes or fingerfishes. All are strongly laterally compressed with disc-shaped bodies and tall anal and dorsal fins. Unusually for fish, scales occur on their dorsal fins and sometimes on the anal fins. The pelvic fins are small, sometimes vestigial. They are of moderate size, typically around in length, and ''Monodactylus sebae'' can be taller than it is long, measuring up to from the tip of the dorsal fin down to the tip of the anal fin. These long, scaly fins have given them the name "fingerfishes". Most are silvery with yellow and black markings; the juveniles are especially attractive, and most species are popular as aquarium fish. The family contains six extant species in two genera, ''Monodactylus'' and ''Schuettea''. They are distributed along the coastlines of Africa, India, and southern Asia, and as far west as Australia. Species of ''Monodactylus'' in particular commonly occur in est ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Big-scale Sand Smelt
The big-scale sand smelt (''Atherina boyeri'') is a species of fish in the family Atherinidae. It is a euryhaline amphidromous fish, up to 20 cm in length. Description It is a small pelagic fish species which occurs near the surface in the littoral estuarine zone: in lagoons, salt marshes (77 psu), shallow brackish areas (2 psu) and inland waters which are rather unsuitable for other fish species, due to their high ionic strength and salinity. Body is rather long, slender, moderately flattened. Eyes are large. Head and body are scaly. Mouth is protractible, upwardly directed, with small teeth. Lower jaw has an upper expansion within mouth (high dentary bone). There are two separate dorsal fins, with all rays of first and 1–2 anterior rays of second dorsal fin being unsegmented. The anal fin is similar to the second dorsal fin, while the caudal fin is forked. The first dorsal fin has 6–10 flexible spines. It is an omnivorous species feeding on zoo-plankton and small bott ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Longnose Stingray
The longnose stingray (''Hypanus guttatus'') is a species of stingray in the family Dasyatidae, native to the western Atlantic Ocean from the southern Gulf of Mexico to Brazil. Found in coastal waters no deeper than , this demersal species favors muddy or sandy habitats. The longnose stingray is characterized by its angular, rhomboid pectoral fin disc, moderately projecting snout, and whip-like tail with a dorsal keel and ventral fin fold. It typically grows to across and is brownish above and light-colored below. Longnose stingrays feed mainly on bottom-dwelling invertebrates and small bony fishes. Reproduction is aplacental viviparous, with females bearing two litters of 1–2 pups per year. The young are born in relatively fresh water, move into saltier water as juveniles, and then back into fresher water as adults. This species is valued by commercial and recreational fishers in many parts of its range, and utilized for meat, gelatin, oil, and even the aquarium trade. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atlantic Stingray
The Atlantic stingray (''Hypanus sabinus'') is a species of Myliobatiformes, stingray in the family (biology), family Dasyatidae, common along the Atlantic coast of North America from Chesapeake Bay to Mexico, including brackish and freshwater habitats. It may be distinguished from other stingrays in the area by its relatively elongated snout. This species is of little Commercial fisheries, commercial importance, other than for sale in the aquarium industry. Taxonomy and phylogeny The Atlantic stingray was described by French naturalist Charles Alexandre Lesueur as ''Trygon sabina'', in an 1824 volume of the ''Journal of the Academy of Natural Sciences of Philadelphia''. He based his account on a damaged male specimen collected by American naturalist Titian Ramsay Peale during the Academy of Natural Sciences, Academy's 1817 expedition to Florida. Since then, various authors have included this species in the obsolete genera ''Pastinaca'', ''Dasybatus'' (or the variants ''Dasibatis' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osmoregulation
Osmoregulation is the active regulation of the osmotic pressure of an organism's body fluids, detected by osmoreceptors, to maintain the homeostasis of the organism's water content; that is, it maintains the fluid balance and the concentration of electrolytes ( salts in solution which in this case is represented by body fluid) to keep the body fluids from becoming too diluted or concentrated. Osmotic pressure is a measure of the tendency of water to move into one solution from another by osmosis. The higher the osmotic pressure of a solution, the more water tends to move into it. Pressure must be exerted on the hypertonic side of a selectively permeable membrane to prevent diffusion of water by osmosis from the side containing pure water. Although there may be hourly and daily variations in osmotic balance, an animal is generally in an osmotic steady state over the long term. Organisms in aquatic and terrestrial environments must maintain the right concentration of solutes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salmon
Salmon (; : salmon) are any of several list of commercially important fish species, commercially important species of euryhaline ray-finned fish from the genera ''Salmo'' and ''Oncorhynchus'' of the family (biology), family Salmonidae, native to tributary, tributaries of the North Atlantic (''Salmo'') and North Pacific (''Oncorhynchus'') basins. ''Salmon'' is a colloquial or common name used for fish in this group, but is not a scientific name. Other closely related fish in the same family include trout, Salvelinus, char, Thymallus, grayling, Freshwater whitefish, whitefish, lenok and Hucho, taimen, all coldwater fish of the subarctic and cooler temperate regions with some sporadic endorheic populations in Central Asia. Salmon are typically fish migration, anadromous: they hatch in the shallow gravel stream bed, beds of freshwater headstreams and spend their juvenile fish, juvenile years in rivers, lakes and freshwater wetlands, migrate to the ocean as adults and live like sea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carcinus Maenas
''Carcinus maenas'' is a common littoral crab. It is known by different names around the world. In the British Isles, it is generally referred to as the shore crab or green shore crab. In North America and South Africa, it bears the name European green crab. ''C. maenas'' is a widespread invasive species, listed among the 100 of the World's Worst Invasive Alien Species. It is native to the north-east Atlantic Ocean and Baltic Sea, but has colonised similar habitats in Australia, South Africa, South America, and both Atlantic and Pacific Ocean, Pacific Coasts of North America. It grows to a carapace width of , and feeds on a variety of Mollusca, mollusks, worms, and small crustaceans, affecting a number of fisheries. Its successful dispersal has occurred by a variety of mechanisms, such as on ships' hulls, sea planes, packing materials, and bivalves moved for aquaculture. Description ''C. maenas'' has a carapace up to long and wide, but can be larger outside its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
