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Freshwater Fish
Freshwater fish are fish species that spend some or all of their lives in bodies of fresh water such as rivers, lakes, ponds and inland wetlands, where the salinity is less than 1.05%. These environments differ from marine habitats in many ways, especially the difference in levels of osmolarity. To survive in fresh water, fish need a range of physiological adaptations. 41.24% of all known species of fish are found in fresh water. This is primarily due to the rapid speciation that the scattered habitats make possible. When dealing with ponds and lakes, one might use the same basic models of speciation as when studying island biogeography. Physiology Freshwater fish differ physiologically from saltwater fish in several respects. Their gills must be able to diffuse dissolved gases while keeping the electrolytes in the body fluids inside. Their scales reduce water diffusion through the skin: freshwater fish that have suffered too much scale loss will die. They also have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gill
A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are kept moist. The microscopic structure of a gill presents a large surface area to the external environment. Branchia (: branchiae) is the zoologists' name for gills (from Ancient Greek ). With the exception of some aquatic insects, the filaments and lamella (surface anatomy), lamellae (folds) contain blood or Coelom#Coelomic fluid, coelomic fluid, from which gases are exchanged through the thin walls. The blood carries oxygen to other parts of the body. Carbon dioxide passes from the blood through the thin gill tissue into the water. Gills or gill-like organs, located in different parts of the body, are found in various groups of aquatic animals, including Mollusc, molluscs, crustaceans, insects, fish, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Catadromous Fish
Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres. Such migrations are usually done for better feeding or to reproduce, but in other cases the reasons are unclear. Fish migrations involve movements of schools of fish on a scale and duration larger than those arising during normal daily activities. Some particular types of migration are ''anadromous'', in which adult fish live in the sea and migrate into fresh water to spawn; and ''catadromous'', in which adult fish live in fresh water and migrate into salt water to spawn. Marine forage fish often make large migrations between their spawning, feeding and nursery grounds. Their movements are associated with ocean currents and with the availability of food in different areas at different times of the year. The migratory m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anguillidae
The Anguillidae are a family of ray-finned fish that contains the freshwater eels. All the extant species and six subspecies in this family are in the genus ''Anguilla'', and are elongated fish of snake-like bodies, with long dorsal, caudal and anal fins forming a continuous fringe. They are catadromous, spending their adult lives in freshwater, but migrating to the ocean to spawn. Eels are an important food fish and some species are now farm-raised, but not bred in captivity. Many populations in the wild are now threatened, and Seafood Watch recommend consumers avoid eating anguillid eels. Physical description Adult freshwater eels are elongated with tubelike, snake-shaped bodies. They have large, pointed heads and their dorsal fins are usually continuous with their caudal and anal fins, to form a fringe lining the posterior end of their bodies. They have relatively well developed eyes and pectoral fins compared to saltwater eels that they use to navigate and maneuver thro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Three-spined Stickleback
The three-spined stickleback (''Gasterosteus aculeatus'') is a fish native to most inland and coastal waters north of 30°N. It has long been a subject of scientific study for many reasons. It shows great morphological variation throughout its range, ideal for questions about evolution and population genetics. Many populations are anadromous (they live in seawater but breed in fresh or brackish water) and very tolerant of changes in salinity, a subject of interest to physiologists. It displays elaborate breeding behavior (defending a territory, building a nest, taking care of the eggs and fry) and it can be social (living in shoals outside the breeding season) making it a popular subject of inquiry in fish ethology and behavioral ecology. Its antipredator adaptations, host-parasite interactions, sensory physiology, reproductive physiology, and endocrinology have also been much studied. Facilitating these studies is the fact that the three-spined stickleback is easy to find in nat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trout
Trout (: trout) is a generic common name for numerous species of carnivorous freshwater ray-finned fishes belonging to the genera '' Oncorhynchus'', ''Salmo'' and ''Salvelinus'', all of which are members of the subfamily Salmoninae in the family Salmonidae. The word ''trout'' is also used for some similar-shaped but non-salmonid fish, such as the spotted seatrout/speckled trout (''Cynoscion nebulosus'', which is actually a croaker). Trout are closely related to salmon and have similar migratory life cycles. Most trout are strictly potamodromous, spending their entire lives exclusively in freshwater lakes, rivers and wetlands and migrating upstream to spawn in the shallow gravel beds of smaller headwater creeks. The hatched fry and juvenile trout, known as ''alevin'' and ''parr'', will stay upstream growing for years before migrating down to larger waterbodies as maturing adults. There are some anadromous species of trout, such as the steelhead (a coastal subs ... [...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] |
Anadromous
Fish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres. Such migrations are usually done for better feeding or to reproduce, but in other cases the reasons are unclear. Fish migrations involve movements of schools of fish on a scale and duration larger than those arising during normal daily activities. Some particular types of migration are ''anadromous'', in which adult fish live in the sea and migrate into fresh water to spawn; and ''catadromous'', in which adult fish live in fresh water and migrate into salt water to spawn. Marine forage fish often make large migrations between their spawning, feeding and nursery grounds. Their movements are associated with ocean currents and with the availability of food in different areas at different times of the year. The migratory ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sturgeon
Sturgeon (from Old English ultimately from Proto-Indo-European language, Proto-Indo-European *''str̥(Hx)yón''-) is the common name for the 27 species of fish belonging to the family Acipenseridae. The earliest sturgeon fossils date to the Late Cretaceous, and are descended from other, earlier Acipenseriformes, acipenseriform fish, which date back to the Early Jurassic period, some 174 to 201 million years ago. They are one of two living families of the Acipenseriformes alongside paddlefish (Polyodontidae). The family is grouped into five genera: ''Acipenser'', ''Huso'', ''Scaphirhynchus,'' ''Sinosturio'', and ''Pseudoscaphirhynchus''. Two species (''Adriatic sturgeon, H. naccarii'' and ''Dabry's sturgeon, S. dabryanus'') may be extinct in the wild, and one (''Syr Darya sturgeon, P. fedtschenkoi'') may be entirely extinct. Sturgeons are native to subtropical, temperate and sub-Arctic rivers, lakes and coastlines of Eurasia and North America. A Maastrichtian-age fossil found i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Excretion
Excretion is elimination of metabolic waste, which is an essential process in all organisms. In vertebrates, this is primarily carried out by the lungs, Kidney (vertebrates), kidneys, and skin. This is in contrast with secretion, where the substance may have specific tasks after leaving the Cell (biology), cell. For example, placental mammals expel urine from the bladder through the urethra, which is part of the excretory system. Unicellular organisms discharge waste products directly through the surface of the cell. During life activities such as cellular respiration, several chemical reactions take place in the body. These are known as metabolism. These chemical reactions produce waste products such as carbon dioxide, water, Salt (chemistry), salts, urea and uric acid. Accumulation of these wastes beyond a level inside the body is harmful to the body. The excretory organs remove these wastes. This process of removal of metabolic waste from the body is known as excretion. Proce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kidney
In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal artery, renal arteries; blood exits into the paired renal veins. Each kidney is attached to a ureter, a tube that carries excreted urine to the urinary bladder, bladder. The kidney participates in the control of the volume of various body fluids, fluid osmolality, Acid-base homeostasis, acid-base balance, various electrolyte concentrations, and removal of toxins. Filtration occurs in the glomerulus (kidney), glomerulus: one-fifth of the blood volume that enters the kidneys is filtered. Examples of substances reabsorbed are solute-free water, sodium, bicarbonate, glucose, and amino acids. Examples of substances secreted are hy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
