There are over 33,000 extant species of fish, easily the largest group of vertebrates and more than all species of the other traditional classes, namely amphibians, reptiles, birds, and mammals, combined. Most fish belong to the classActinopterygii, the ray-finned fishes, which accounts for approximately half of all living vertebrates.
Though often used interchangeably, in biologyfish andfishes have different meanings.Fish is used as a singular noun, or as a plural to describe multiple individuals from a single species.Fishes is used to describe different species or species groups.[5][6][7]
During theDevonian, fish diversity greatly increased, including among the placoderms, lobe-finned fishes, and early sharks, earning the Devonian the epithet "the age of fishes".[16][17]
Phylogeny
Fishes are aparaphyletic group, since anyclade containing all jawed fish (Gnathostomata) or all bony fish (Osteichthyes) also contains the clade oftetrapods (four-limbed vertebrates, mostly terrestrial), which are usually not considered fish.[18][19] Some tetrapods, such ascetaceans andichthyosaurs, havesecondarily acquired a fish-like body shape throughconvergent evolution.[20] On the other hand,Fishes of the World comments that "it is increasingly widely accepted that tetrapods, including ourselves, are simply modified bony fishes, and so we are comfortable with using the taxon Osteichthyes as a clade, which now includes all tetrapods".[19]
Thebiodiversity of extant fish is unevenly distributed among the various groups;teleosts, bony fishesable to protrude their jaws, make up 96% of fish species.[21][19] Thecladogram[22] shows theevolutionary relationships of all groups of living fishes (with their respective diversity[19]) and the tetrapods.[23]Extinct groups are marked with adagger (†); groups of uncertain placement[22] are labelled with a question mark (?) and dashed lines (- - - - -). Groups with over 25,000 species are inboldface.
Fishes (without tetrapods) are aparaphyletic group and for this reason, the class Pisces seen in older reference works is no longer used in formal classifications. Traditional classification divides fish into threeextantclasses ("Agnatha",Chondrichthyes, and "Osteichthyes"), and with extinct forms sometimes classified within those groups, sometimes as their own classes.[24]
Fish account for more than half of vertebrate species. As of 2016, there are over 32,000 described species of bony fish, over 1,100 species of cartilaginous fish, and over 100 hagfish and lampreys. A third of these fall within the nine largest families; from largest to smallest, these areCyprinidae,Gobiidae,Cichlidae,Characidae,Loricariidae,Balitoridae,Serranidae,Labridae, andScorpaenidae. About 64 families aremonotypic, containing only one species.[19]
Swimming performance varies from fish such as tuna,salmon, andjacks that can cover 10–20 body-lengths per second to species such aseels andrays that swim no more than 0.5 body-lengths per second.[28]
A typical fish iscold-blooded, has astreamlined body for rapid swimming, extracts oxygen from water using gills, has two sets of paired fins, one or two dorsal fins, an anal fin and a tail fin, jaws, skin covered withscales, and lays eggs. Each criterion has exceptions, creating a wide diversity in body shape and way of life. For example, some fast-swimming fish are warm-blooded, while some slow-swimming fish have abandoned streamlining in favour of other body shapes.[29]
Different fish species are adapted to a wide variety of freshwater and marine habitats.
Fish species are roughly divided equally betweenfreshwater and marine (oceanic) ecosystems; there are some 15,200 freshwater species and around 14,800 marine species.[30]Coral reefs in theIndo-Pacific constitute the center of diversity for marine fishes,[31] whereas continental freshwater fishes are most diverse in largeriver basins oftropical rainforests, especially theAmazon,Congo, andMekong basins.[32] More than 5,600 fish species inhabitNeotropical freshwaters alone, such thatNeotropical fishes represent about 10% of allvertebrate species on the Earth.[33]
Fish are abundant in most bodies of water. They can be found in nearly all aquatic environments, from highmountain streams (e.g.,char andgudgeon) to theabyssal and evenhadal depths of the deepest oceans (e.g.,cusk-eels andsnailfish), although none have been found in the deepest 25% of the ocean.[34] The deepest living fish in the ocean so far found is a cusk-eel,Abyssobrotula galatheae, recorded at the bottom of thePuerto Rico Trench at 8,370 m (27,460 ft).[35]
In terms of temperature,Jonah's icefish live in cold[a] waters of the Southern Ocean, including under theFilchner–Ronne Ice Shelf at a latitude of 79°S,[37] whiledesert pupfish live in desert springs, streams, and marshes, sometimes highly saline, with water temperatures as high as 36 C.[38][39]
Like other animals, fish suffer fromparasitism. Some species usecleaner fish to remove external parasites. The best known of these are thebluestreak cleaner wrasses ofcoral reefs in theIndian andPacific oceans. These small fish maintain cleaning stations where other fish congregate and perform specific movements to attract the attention of the cleaners.[45] Cleaning behaviors have been observed in a number of fish groups, including an interesting case between two cichlids of the same genus,Etroplus maculatus, the cleaner, and the much largerE. suratensis.[46]
The body of a typical fish is adapted for efficient swimming by alternately contracting paired sets ofmuscles on either side of the backbone. These contractions form S-shaped curves that move down the body. As each curve reaches the tail fin, force is applied to the water, moving the fish forward. The other fins act ascontrol surfaces like an aircraft's flaps, enabling the fish to steer in any direction.[49]
Anatomy of a typical fish (lanternfish shown): 1)gill cover 2)lateral line 3) dorsal fin 4) fat fin 5) caudal peduncle 6) caudal fin 7) anal fin 8) photophores 9) pelvic fins 10) pectoral fins
Since body tissue is denser than water, fish must compensate for the difference or they will sink. Many bony fish have an internal organ called aswim bladder that allows them to adjust theirbuoyancy by increasing or decreasing the amount of gas it contains.[50]
Thescales of fish provide protection frompredators at the cost of adding stiffness and weight.[51] Fish scales are often highly reflective; thissilvering provides camouflage in the open ocean. Because the water all around is the same colour, reflecting an image of the water offers near-invisibility.[52]
Silveredscales of arohu provide protection and camouflage.
Circulation
The fish heart pumps blood to the gills, where it picks up oxygen. The blood then flows without further pumping to the body, from where it returns to the heart.
Fish have aclosed-loop circulatory system. Theheart pumps the blood in a single loop throughout the body; for comparison, the mammal heart has two loops, one for the lungs to pick up oxygen, one for the body to deliver the oxygen. In fish, the heart pumps blood through the gills. Oxygen-rich blood then flows without further pumping, unlike in mammals, to the body tissues. Finally, oxygen-depleted blood returns to the heart.[53]
Fish exchange gases usinggills on either side of thepharynx. Gills consist of comblike structures called filaments. Each filament contains acapillary network that provides a largesurface area for exchangingoxygen andcarbon dioxide. Fish exchange gases by pulling oxygen-rich water through their mouths and pumping it over their gills. Capillary blood in the gills flows in the opposite direction to the water, resulting in efficientcountercurrent exchange. The gills push the oxygen-poor water out through openings in the sides of the pharynx. Cartilaginous fish have multiple gill openings: sharks usually have five, sometimes six or seven pairs; they often have to swim to oxygenate their gills. Bony fish have a single gill opening on each side, hidden beneath a protective bony cover oroperculum. They are able to oxygenate their gills using muscles in the head.[54]
Some 400 species of fish in 50 families can breathe air, enabling them to live in oxygen-poor water or to emerge on to land.[55] The ability of fish to do this is potentially limited by their single-loop circulation, as oxygenated blood from their air-breathing organ will mix with deoxygenated blood returning to the heart from the rest of the body. Lungfish, bichirs, ropefish, bowfins, snakefish, and the African knifefish have evolved to reduce such mixing, and to reduce oxygen loss from the gills to oxygen-poor water.[55]
Bichirs and lungfish have tetrapod-like paired lungs, requiring them to surface to gulp air, and making them obligate air breathers. Many other fish, including inhabitants ofrock pools and theintertidal zone, are facultative air breathers, able to breathe air when out of water, as may occur daily atlow tide, and to use their gills when in water. Some coastal fish likerockskippers andmudskippers choose to leave the water to feed in habitats temporarily exposed to the air.[55] Some catfish absorb air through their digestive tracts.[56]
Digestion
The digestive system consists of a tube, the gut, leading from the mouth to the anus. The mouth of most fishes contains teeth to grip prey, bite off or scrape plant material, or crush the food. Anesophagus carries food to the stomach where it may be stored and partially digested. A sphincter, the pylorus, releases food to the intestine at intervals. Many fish have finger-shaped pouches,pyloric caeca, around the pylorus, of doubtful function. Thepancreas secretes enzymes into the intestine to digest the food; other enzymes are secreted directly by the intestine itself. Theliver producesbile which helps to break up fat into an emulsion which can be absorbed in the intestine.[57]
Excretion
Most fish release their nitrogenous wastes asammonia. This may be excreted through the gills orfiltered by thekidneys. Salt is excreted by the rectal gland.[58] Saltwater fish tend to lose water byosmosis; their kidneys return water to the body, and produce a concentrated urine. The reverse happens infreshwater fish: they tend to gain water osmotically, and produce a dilute urine. Some fish have kidneys able to operate in both freshwater and saltwater.[59]
Fish have small brains relative to body size compared with other vertebrates, typically one-fifteenth the brain mass of a similarly sized bird or mammal.[60] However, some fish have relatively large brains, notablymormyrids andsharks, which have brains about as large for their body weight as birds andmarsupials.[61] At the front of the brain are theolfactory lobes, a pair of structures that receive and process signals from thenostrils via the twoolfactory nerves.[60]
Fish that hunt primarily by smell, such as hagfish and sharks, have very large olfactory lobes. Behind these is thetelencephalon, which in fish deals mostly with olfaction. Together these structures form the forebrain. Connecting the forebrain to the midbrain is thediencephalon; it works withhormones andhomeostasis. Thepineal body is just above the diencephalon; it detects light, maintainscircadian rhythms, and controls color changes.[60]
Thelateral line system is a network of sensors in the skin which detects gentle currents and vibrations, and senses the motion of nearby fish, whether predators or prey.[62] This can be considered both a sense oftouch and ofhearing.Blind cave fish navigate almost entirely through the sensations from their lateral line system.[63] Some fish, such as catfish and sharks, have theampullae of Lorenzini,electroreceptors that detect weak electric currents on the order of millivolt.[64]
Hearing too is an important sensory system in fish. Fish sense sound using their lateral lines andotoliths in their ears, inside their heads. Some can detect sound through the swim bladder.[69]
Some fish, including salmon, are capable ofmagnetoreception; when the axis of a magnetic field is changed around a circular tank of young fish, they reorient themselves in line with the field.[70][71] The mechanism of fish magnetoreception remains unknown;[72] experiments in birds imply a quantumradical pair mechanism.[73]
The cognitive capacities of fish includeself-awareness, as seen inmirror tests.Manta rays andwrasses placed in front of a mirror repeatedly check whether their reflection's behavior mimics their body movement.[74][75]Choerodon wrasse,archerfish, andAtlantic cod can solve problems and invent tools.[76] Themonogamous cichlidAmatitlania siquia exhibits pessimistic behavior when prevented from being with its partner.[77] Fish orient themselves using landmarks; they may use mental maps based on multiple landmarks. Fish are able to learn to traverse mazes, showing that they possess spatial memory and visual discrimination.[78] Behavioral research suggests that fish aresentient, capable of experiencingpain.[79]
Most fish are exclusively cold-blooded orectothermic. However, theScombroidei arewarm-blooded (endothermic), including thebillfishes and tunas.[82] Theopah, alampriform, uses whole-body endothermy, generating heat with its swimming muscles to warm its body while countercurrent exchange minimizes heat loss.[83] Among the cartilaginous fishes, sharks of the familiesLamnidae (such as the great white shark) andAlopiidae (thresher sharks) are endothermic. The degree of endothermy varies from the billfishes, which warm only their eyes and brain, to thebluefin tuna and theporbeagle shark, which maintain body temperatures more than 20 °C (68 °F) above the ambient water.[82][84][85]
The primary reproductive organs are pairedtesticles andovaries.[86] Eggs are released from the ovary to theoviducts.[87] Over 97% of fish, including salmon and goldfish, areoviparous, meaning that the eggs are shed into the water and develop outside the mother's body.[88] The eggs are usually fertilized outside the mother's body, with the male and female fish shedding theirgametes into the surrounding water. In a few oviparous fish, such as theskates, fertilization is internal: the male uses anintromittent organ to deliver sperm into the female's genital opening of the female.[89]
Marine fish release large numbers of small eggs into the open water column. Newly hatched young of oviparous fish areplanktonic larvae. They have a largeyolk sac and do not resemble juvenile or adult fish. The larval period in oviparous fish is usually only some weeks, and larvae rapidly grow andchange in structure to become juveniles. During this transition, larvae must switch from their yolk sac to feeding onzooplankton prey.[89] Some fish such assurf-perches,splitfins, andlemon sharks areviviparous or live-bearing, meaning that the mother retains the eggs and nourishes the embryos via a structure analogous to theplacenta to connect the mother's blood supply with the embryo's.[89]
DNA repair
Embryos of externally fertilized fish species are directly exposed during their development to environmental conditions that maydamage their DNA, such as pollutants,UV light andreactive oxygen species.[90] To deal with such DNA damages, a variety of differentDNA repair pathways are employed by fish embryos during their development.[90] In recent yearszebrafish have become a useful model for assessing environmental pollutants that might be genotoxic, i.e. cause DNA damage.[91]
Fish have both non-specific and immune defenses against disease. Non-specific defenses include the skin and scales, as well as the mucus layer secreted by theepidermis that traps and inhibits the growth ofmicroorganisms. Ifpathogens breach these defenses, theinnate immune system can mount aninflammatory response that increases blood flow to the infected region and deliverswhite blood cells that attempt to destroy pathogens, non-specifically. Specific defenses respond to particular antigens, such asproteins on the surfaces ofpathogenic bacteria, recognised by theadaptive immune system.[92] Immune systems evolved indeuterostomes as shown in the cladogram.[93]
Cartilaginous fish have three specialized organs that contain immune system cells: the epigonal organs around the gonads,Leydig's organ within the esophagus, and aspiral valve in their intestine, while theirthymus andspleen have similar functions to those of the same organs in the immune systems of tetrapods.[94] Teleosts have lymphocytes in the thymus, and other immune cells in the spleen and other organs.[95][96]
Ashoal is a loosely organised group where each fish swims and forages independently but is attracted to other members of the group and adjusts its behaviour, such as swimming speed, so that it remains close to the other members of the group. Aschool is a much more tightly organised group, synchronising its swimming so that all fish move at the same speed and in the same direction.[98] Schooling is sometimes anantipredator adaptation, offering improved vigilance against predators.[97]
It is often more efficient to gather food by working as a group, and individual fish optimise their strategies by choosing to join or leave a shoal. When a predator has been noticed, prey fish respond defensively, resulting in collective shoal behaviours such as synchronised movements. Responses do not consist only of attempting to hide or flee; antipredator tactics include for example scattering and reassembling. Fish also aggregate in shoals to spawn.[97] Thecapelin migrates annually in large schools between its feeding areas and its spawning grounds.[99]
Fish communicate by transmitting acoustic signals (sounds) to each other. This is most often in the context of feeding, aggression or courtship.[100] The sounds emitted vary with the species and stimulus involved. Fish can produce either stridulatory sounds by moving components of the skeletal system, or can produce non-stridulatory sounds by manipulating specialized organs such as the swimbladder.[101]
Some fish produce sounds by rubbing or grinding their bones together. These sounds are stridulatory. InHaemulon flavolineatum, the French grunt fish, as it produces a grunting noise by grinding its teeth together, especially when in distress. The grunts are at a frequency of around 700 Hz, and last approximately 47 milliseconds.[101] The longsnout seahorse,Hippocampus reidi produces two categories of sounds, 'clicks' and 'growls', by rubbing their coronet bone across the grooved section of their neurocranium.[102] Clicks are produced during courtship and feeding, and the frequencies of clicks were within the range of 50 Hz-800 Hz. The frequencies are at the higher end of the range during spawning, when the female and male fishes were less than fifteen centimeters apart. Growls are produced when theH. reidi are stressed. The 'growl' sounds consist of a series of sound pulses and are emitted simultaneously with body vibrations.[103]
Some fish species create noise by engaging specialized muscles that contract and cause swimbladder vibrations.Oyster toadfish produce loud grunts by contracting sonic muscles along the sides of the swim bladder.[104] Female and male toadfishes emit short-duration grunts, often as a fright response.[105] In addition to short-duration grunts, male toadfishes produce "boat whistle calls".[106] These calls are longer in duration, lower in frequency, and are primarily used to attract mates.[106] The various sounds have frequency range of 140 Hz to 260 Hz.[106] The frequencies of the calls depend on the rate at which the sonic muscles contract.[107][104]
The red drum,Sciaenops ocellatus, produces drumming sounds by vibrating its swimbladder. Vibrations are caused by the rapid contraction of sonic muscles that surround the dorsal aspect of the swimbladder. These vibrations result in repeated sounds with frequencies from 100 to >200 Hz.S. ocellatus produces different calls depending on the stimuli involved, such as courtship or a predator's attack. Females do not produce sounds, and lack sound-producing (sonic) muscles.[108]
Conservation
The 2024IUCNRed List names 2,168 fish species that are endangered or critically endangered.[109] Included are species such asAtlantic cod,[110]Devil's Hole pupfish,[111]coelacanths,[112] andgreat white sharks.[113] Because fish live underwater they are more difficult to study than terrestrial animals and plants, and information about fish populations is often lacking. Freshwater fish seem particularly threatened because they often live in relatively small water bodies. For example, the Devil's Hole pupfish occupies only a single 3 by 6 metres (10 by 20 ft) pool.[114]
TheFood and Agriculture Organization reports that "in 2017, 34 percent of the fish stocks of the world's marine fisheries were classified as overfished".[116] Overfishing is a major threat to edible fish such as cod andtuna.[117][118] Overfishing eventually causesfish stocks to collapse, because the survivors cannot produce enough young to replace those removed. Such commercial extinction does not mean that the species is extinct, merely that it can no longer sustain a fishery. In the case of thePacific sardine fishery off the California coast, the catch steadily declined from a 1937 peak of 800,000 tonnes to an economically inviable 24,000 tonnes in 1968.[119]
In thecase of the Atlantic northwest cod fishery, overfishing reduced the fish population to 1% of its historical level by 1992.[115]Fisheries scientists and thefishing industry have sharply differing views on the resiliency of fisheries to intensive fishing. In many coastal regions the fishing industry is a major employer, so governments are predisposed to support it.[120][121] On the other hand, scientists and conservationists push for stringent protection, warning that many stocks could be destroyed within fifty years.[122][123]
Other threats
A key stress on both freshwater and marine ecosystems ishabitat degradation includingwater pollution, the building of dams, removal of water for use by humans, and the introduction ofexotic species including predators.[124] Freshwater fish, especially ifendemic to a region (occurring nowhere else), may be threatened with extinction for all these reasons, as is the case for three of Spain's ten endemic freshwater fishes.[125] River dams, especially major schemes like theKariba Dam (Zambezi river) and theAswan Dam (River Nile) on rivers with economically important fisheries, have caused large reductions in fish catch.[126]
Industrial bottom trawlingcan damage seabed habitats, as has occurred on theGeorges Bank in the North Atlantic.[127] Introduction of aquaticinvasive species is widespread. It modifies ecosystems, causing biodiversity loss, and can harm fisheries. Harmful species include fish but are not limited to them;[128] the arrival of acomb jelly in the Black Sea damaged theanchovy fishery there.[129][128] The opening of theSuez Canal in 1869 made possibleLessepsian migration, facilitating the arrival of hundreds of Indo-Pacific marine species of fish, algae and invertebrates in theMediterranean Sea, deeply impacting its overall biodiversity[130] and ecology.[131]
The predatoryNile perch was deliberately introduced toLake Victoria in the 1960s as a commercial and sports fish. The lake had high biodiversity, with some 500endemic species ofcichlid fish. It drastically altered the lake's ecology, andsimplified the fishery from multi-species to just three: the Nile perch, thesilver cyprinid, and another introduced fish, theNile tilapia. Thehaplochromine cichlid populations have collapsed.[132][133]
Throughout history, humans have usedfish as a food source fordietary protein. Historically and today, most fish harvested for human consumption has come by means of catching wild fish. However, fish farming, which has been practiced since about 3,500 BCE in ancient China,[134] is becoming increasingly important in many nations. In 2007, about one-sixth of the world's protein was estimated to be provided by fish.[135]
Fishing is a large global business which provides income for millions of people.[135] As of 2020, over 65 million tonnes (Mt) of marine fish and 10 Mt of freshwater fish were captured, while some 50 Mt of fish, mainly freshwater, were farmed. Of the marine species captured in 2020,anchoveta represented 4.9 Mt,Alaska pollock 3.5 Mt,skipjack tuna 2.8 Mt, andAtlantic herring andyellowfin tuna 1.6 Mt each; eight more species had catches over 1 Mt.[136]
Fish have been recognized as a source of beauty for almost as long as used for food, appearing incave art, being raised asornamental fish in ponds, and displayed inaquariums in homes, offices, or public settings. Recreational fishing is fishing primarily for pleasure or competition; it can be contrasted with commercial fishing, which is fishing for profit, orartisanal fishing, which is fishing primarily for food. The most common form of recreational fishing employs arod,reel,line,hooks, and a wide range ofbaits. Recreational fishing is particularly popular in North America and Europe; government agencies often actively manage target fish species.[137][138]
Fish were sacred to the Syrian goddessAtargatis[140] and, during her festivals, only her priests were permitted to eat them.[140] In theBook of Jonah, the central figure, aprophet namedJonah, is swallowed by a giant fish after being thrown overboard by the crew of the ship he is travelling on.[141]Early Christians used theichthys, a symbol of a fish, to represent Jesus.[140][142] Among thedeities said to take the form of a fish areIkatere of thePolynesians,[143]the shark-godKāmohoaliʻi ofHawaiʻi,[144]andMatsya of the Hindus.[145] The constellationPisces ("The Fishes") is associated with a legend from Ancient Rome thatVenus and her sonCupid were rescued by two fishes.[146]
Fish feature prominently in art,[147] in films such asFinding Nemo[148] and books such asThe Old Man and the Sea.[149] Large fish, particularly sharks, have frequently been the subject ofhorror movies andthrillers, notably the novelJaws, made into a film which in turn has been parodied and imitated many times.[150] Piranhas are shown in a similar light to sharks in films such asPiranha.[151]
^The temperature is often around 0 °C. The freezing point of seawater at the surface is −1.85 °C, falling to −2.62 °C at a depth of 1000 metres. However, the water can besupercooled somewhat below these temperatures.[36]
^Buck, Carl Darling (1949). "section 3.65".A Dictionary of Selected Synonyms in the Principal Indo-European Languages. p. 184.
^Pauly, Daniel (13 May 2004)."Fish(es)".Darwin's Fishes: An Encyclopedia of Ichthyology, Ecology, and Evolution. Cambridge University Press. p. 77.ISBN978-1-139-45181-9.Archived from the original on 8 February 2016.
^Davis, R. W. (2019). "Return to the Sea: The Evolution of Marine Mammals". In Davis, R. W. (ed.).Marine Mammals: Adaptations for an Aquatic Life. New York:Springer International Publishing. pp. 7–27.ISBN978-3-3199-8278-6.
^Haumann, F. Alexander; Moorman, Ruth; Riser, Stephen C.; Smedsrud, Lars H.; Maksym, Ted; et al. (28 October 2020). "Supercooled Southern Ocean Waters".Geophysical Research Letters.47 (20) e2020GL090242.Bibcode:2020GeoRL..4790242H.doi:10.1029/2020GL090242.hdl:1912/26495.
^Shrode, Joy B.; Gerking, Shelby D. (1977). "Effects of Constant and Fluctuating Temperatures on Reproductive Performance of a Desert Pupfish,Cyprinodon n. nevadensis".Physiological Zoology.50 (1):1–10.doi:10.1086/physzool.50.1.30155710.S2CID82166135.
^Henderson, P.A.; Walker, I. (1990). "Spatial organization and population density of the fish community of the litter banks within a central Amazonian blackwater stream".Journal of Fish Biology.37 (3):401–411.Bibcode:1990JFBio..37..401H.doi:10.1111/j.1095-8649.1990.tb05871.x.
^Helfman, G.S. (2007).Fish Conservation: A Guide to Understanding and Restoring Global Aquatic Biodiversity and Fishery Resources.Island Press. pp. 41–42.ISBN978-1-55963-595-0.
^Wyman, Richard L.; Ward, Jack A. (1972). "A Cleaning Symbiosis between the Cichlid FishesEtroplus maculatus andEtroplus suratensis. I. Description and Possible Evolution".Copeia.1972 (4):834–838.doi:10.2307/1442742.JSTOR1442742.
^Quan, Haocheng; Yang, Wen; Lapeyriere, Marine; Schaible, Eric; Ritchie, Robert O.; Meyers, Marc A. (2020). "Structure and Mechanical Adaptability of a Modern Elasmoid Fish Scale from the Common Carp".Matter.3 (3):842–863.doi:10.1016/j.matt.2020.05.011.
^Maetz, J. (20 August 1971). "Fish gills: mechanisms of salt transfer in fresh water and sea water".Philosophical Transactions of the Royal Society of London B.262 (842):209–249.Bibcode:1971RSPTB.262..209M.doi:10.1098/rstb.1971.0090.
^abAlbert, J. S.; Crampton, W. G. (2006). "Electroreception and Electrogenesis". In Lutz, P. L. (ed.).The Physiology of Fishes. Boca Raton, Florida:CRC Press. pp. 429–470.ISBN978-0-8493-2022-4.
^Hawryshyn, Craig W. (2010). "Ultraviolet Polarization Vision and Visually Guided Behavior in Fishes".Brain, Behavior and Evolution.75 (3):186–194.doi:10.1159/000314275.PMID20733294.
^Ari, Csilla; D'Agostino, Dominic P. (1 May 2016). "Contingency checking and self-directed behaviors in giant manta rays: Do elasmobranchs have self-awareness?".Journal of Ethology.34 (2):167–174.doi:10.1007/s10164-016-0462-z.S2CID254134775.
^Canedo, Aryelle; Rocha, Thiago Lopes (2021). "Zebrafish (Danio rerio) using as model for genotoxicity and DNA repair assessments: Historical review, current status and trends".Science of the Total Environment.762 144084.Bibcode:2021ScTEn.76244084C.doi:10.1016/j.scitotenv.2020.144084.PMID33383303.
^Zapata, A.G.; Chiba, A.; Vara, A. (1996). "Cells and tissues of the immune system of fish". In Iwama, G. Iwama; Nakanishi, T. (eds.).The Fish Immune System: Organism, Pathogen and Environment. Fish Immunology. Vol. 15. New York: Academic Press. pp. 1–55.doi:10.1016/S1546-5098(08)60271-X.ISBN978-0-12-350439-5.
^Oliveira, T.P.R.; Ladich, F.; Abed-Navandi, D.; Souto, A.S.; Rosa, I.L. (26 June 2014). "Sounds produced by the longsnout seahorse: a study of their structure and functions".Journal of Zoology.294 (2):114–121.doi:10.1111/jzo.12160.
^Knowler, D.; Barbier, E.B. (2000). "The Economics of an Invading Species: a Theoretical Model and Case Study Application". In Perrings, C.; Williamson, M.; Dalmazzone, S. (eds.).The Economics of Biological Invasions. Cheltenham: Edward Elgar. pp. 70–93.doi:10.4337/9781781008645.00013.ISBN978-1-78100-864-5.
^Coulter, George W.; Allanson, Brian R.; Bruton, Michael N.; Greenwood, P. Humphry; Hart, Robert C.; Jackson, Peter B. N.; Ribbink, Anthony J. (1986). "Unique qualities and special problems of the African Great Lakes".Environmental Biology of Fishes.17 (3).Springer Science and Business Media:161–183.Bibcode:1986EnvBF..17..161C.doi:10.1007/bf00698196.
^abHelfman, Gene S. (2007).Fish Conservation: A Guide to Understanding and Restoring Global Aquatic Biodiversity and Fishery Resources.Island Press. p. 11.ISBN978-1-59726-760-1.
^Beard, T. Douglas, ed. (2011).The Angler in the Environment: Social, Economic, Biological, and Ethical Dimensions. Bethesda, Maryland:American Fisheries Society. p. 365.ISBN978-1-934874-24-0.
^Hickley, Phil; Tompkins, Helena, eds. (1998).Recreational Fisheries: Social, Economic and Management Aspects.Wiley-Blackwell. p. 328.ISBN978-0-852-38248-6.
^Alabaster, Jay (2023). "The Goofy Great White: Jaws and Our Love for an Apex Predator". In Jackson, Kathy Merlock; Simpson, Philip L. (eds.).This shark, swallow you whole": Essays on the Cultural Influence of Jaws.McFarland. pp. 124–.ISBN978-1-4766-7745-3.
.jpg)
.svg)
.gif)
.png)
.jpg)
.jpg)
.JPG)
.jpg)
.jpg)
.jpg)
.jpg)
.svg)
%2c_islas_Azores%2c_Portugal%2c_2020-07-27%2c_DD_40.jpg)
.png)
