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Favorable Fish Findings :: Diet, Omega-3 Fatty Acids, Fish worldgym.com | Fishing Singles, Fishing Dating, Fishing Clubs fitness-singles.com | Fish Oils/Fish annieappleseedproject.org | Fish Oil - 180 EPA/120 DHA, Ultra-Pure Fish Oil shop-enzymatictherapy.com |
 Fish are very diverse and are categorised in many ways. This article is an overview of some of the more common types of fish. Although most fish species have probably been discovered and described, about 250 new species are still discovered every year. According to FishBase, 31,200 species of fish had been described by May 2009,[4] That is more species than the combined total of all other vertebrates: mammals, amphibians, reptiles and birds.
[edit] By species
Fish systematics is the formal description and organisation of fish taxa into systems. It is complex, very much alive and evolving, and controversies over "arcane, but important, details of classification are still quietly raging."[5] The term "fish" describes any non-tetrapod chordate, (i.e., an animal with a backbone), that has gills throughout life and has limbs, if any, in the shape of fins.[6] Unlike groupings such as birds or mammals, fish are not a single clade but a paraphyletic collection of taxa, including jawless, cartilaginous and skeletal types.[7][8] [edit] Jawless fishJawless fish are the most primitive type of fish. There is current debate over whether these are really fish at all. They have no jaw, no scales, no paired fins, and no bony skeleton. Their skin is smooth and soft to the touch, and they are very flexible. Instead of a jaw, they possess an oral sucker. They use this to fasten on to other fish, and then use their rasp-like teeth to rasp through their host's skin into the viscera. Jawless fish inhabit both fresh and salt water environments. Some are anadromous, moving between both fresh and salt water habitats. Extant jawless fish are either lamprey or hagfish. Juvenile lamprey feed by sucking up mud containing micro-organisms and organic debris. The lamprey has well developed eyes, while the hagfish has only primitive eyespots. The hagfish coats itself, and any carcasses it finds, with noxious slime to deter predators, and periodically ties itself into a knot to scrape the slime off. It is the only fish that is not a vertebrate, and the only animal which has a skull but no vertebral column.[9] It has four hearts, two brains, and a paddle-like tail.[10]
[edit] Cartilaginous fishCartilaginous fish have a cartilaginous skeleton. However, their ancestors were bony animals, and were the first fish to develop paired fins. Cartilaginous fish don't have swim bladders. Their skin is covered in denticles, which makes it as rough as sandpaper. Because cartilaginous fish do not have bone marrow, red blood cells are produced in the spleen and special tissue around the gonads. Some cartilaginous fishes possess an organ called Leydig's Organ which also produces red blood cells. There are over 980 species of cartilaginous fish. They include sharks, rays and chimaera.
[edit] Bony fishBony fish include the lobe finned fish and the ray finned fish. The lobe finned fish is the class of fleshy finned, lobe finned fishes, consisting of lungfish, and coelacanths. They are bony fish with fleshy, lobed paired fins, which are joined to the body by a single bone [11]. These fins evolved into legs of the first tetrapod land vertebrates, amphibians. They are called ray finned because they possess lepidotrichia or "fin rays", their fins being webs of skin supported by bony or horny spines ("rays"). There are three types of ray finned fishes: the chondrosteans, holosteans, and teleosts. The chondrosteans and holosteans are primitive fishes sharing a mixture of characteristics of teleosts and sharks. In comparison with the other chondrosteans, the holosteans are closer to the teleosts and further from sharks.
[edit] TeleostsTeleosts are the most advanced or "modern" fishes. They are overwhelmingly the dominant class of fishes (or for that matter, vertebrates) with nearly 30,000 species, covering about 96 percent of all extant fish species. They are ubiquitous throughout fresh water and marine environments from the deep sea to the highest mountain streams. Included are nearly all the important commercial and recreational fishes.[12] Teleosts have a movable maxilla and premaxilla and corresponding modifications in the jaw musculature. These modifications make it possible for teleosts to protrude their jaws outwards from the mouth.[13][14] The caudal fin is homocercal, meaning the upper and lower lobes are about equal in size. The spine ends at the caudal peduncle, distinguishing this group from those in which the spine extends into the upper lobe of the caudal fin.[13]
[edit] By size
The smallest known species of fish is Paedocypris progenetica, a type of minnow. It is also the smallest known vertebrate. The smallest reported mature female had a standard length of 7.9 millimetres (.31 in). The largest reported individual is 10.3 mm (.41 in). They live in the dark coloured peat swamps of the Indonesian island of Sumatra.[15][16][17] Other near contenders for smallest fish are the male anglerfish, Photocorynus spiniceps,[18] and the stout infantfish, a type of goby.[19] According to the Guinness Book of World Records, the sinarapan, another type of goby, is the world's smallest commercially harvested fish.[20] Found in the Philippines, they have an average length of 12.5 millimetres, and are threatened by overfishing.[17] The largest fish species is the whale shark. It is a slow moving filter feeding shark with a maximum published length of 20 metres (66 ft) and a maximum published weight of 34 tonnes. Whale sharks can live up to 70 years.[21] The heaviest bony fish is the ocean sunfish. It can weigh up to 2,300 kg (5,100 lb). It is found in all warm and temperate oceans.[22] The longest bony fish is the king of herrings. Its total length can reach 11 metres (36 ft), and it can weigh up to 272 kilograms (600 lb). It is a rarely seen oarfish found in all the world's oceans, at depths of between 20 metres (66 ft) and 1,000 metres (3,300 ft).[23]
[edit] By life spanSome of the shortest lived fish species are found among gobies, which are small coral reef-dwelling fish. Some of the longest lived fish species are found among rockfish - some rockfish species are very long lived. The shortest lived fish species is the seven-figure pygmy goby, which lives for at most 59 days. This is the shortest lifespan for any vertebrate.[24] Short lived fish have particular value in genetic studies on ageing. In particular, the short-lived ram cichlid is used in laboratory studies because of its ease of breeding and predictable pattern of ageing.[25][26] The longest life span reported for a fish is the 205 years reported for the rougheye rockfish, Sebastes aleutianus, found offshore in the North Pacific at depths between 25 and 900 metres. This fish exhibits negligible senescence.[27][28][29] There are stories about Japanese Koi goldfish passed from generation to generation for 300 years. Scientists are sceptical. Counting growth lines on the scales of fish confined to ponds or bowls is unreliable, since they lay down extra lines.[30][31] The maximum reliably reported age for a goldfish is 41 years[32]
The longest living commercial fish may be the orange roughy, with a maximum reported age of 149 years.[34] One of the longest living sport fish is the Atlantic tarpon, with a maximum reported age of 55 years."[35][36][37] Some of the longest living fish are living fossils, such as the green sturgeon. This species is among the longest living species found in freshwater, with a maximum reported age of 60 years. They are also among the largest fish species found in freshwater, with a maximum reported length of 2.50 metres and a maximum reported weight of 159 kg.[38][39][40] Another living fossil is the Australian lungfish. An Australian lungfish has lived in an aquarium for 75 years, and is the oldest fish in captivity. According to fossil records, the Australian lungfish has hardly changed for 380 million years.[41][42][43] [edit] By habitatFish can live in saltwater or freshwater. There is 10,000 times more saltwater in the oceans than there is freshwater in the lakes and rivers. However, only 58 percent of extant fish species are saltwater. A disproportionate 41 percent are freshwater fish (the remaining one percent are anadromous).[44] This diversity in freshwater species is, perhaps, not surprising, since thousands of separate lake habitats would promote speciation.[45]
Fish can also be demersal or pelagic. Demersal fish live on or near the bottom of oceans and lakes, while pelagic fish inhabit the water column away from the bottom. Habitats can also be vertically stratified, with epipelagic fish occupying the sunlight surface waters down to 200 metres, mesopelagic fish occupying the deeper twilight waters down to 1000 metres, and bathypelagic fish inhabiting the cold and pitch black depths below 1000 metres. In the ocean, most species (78 percent, which is 44 percent of all fish species), are found near the shoreline. These are the coastal fish, which live on or above the relatively shallow continental shelf. Only 13 percent of all fish species live in the open ocean, off the shelf. Of these, 1 percent are epipelagic fish, 5 percent are deep water pelagic fish, and 7 percent are deep water demersal fish.[44] Fish are found in nearly all the aquatic habitats on earth.[51] Most fish, whether by species count or abundance, live in warmer environments, where temperatures do not fluctuate a lot.[45] However, some species can live in temperatures up to 44.6 degrees Celsius, while others can cope with salinities greater than 10 percent.[51] The world's deepest living fish, Abyssobrotula galatheae, a species of cusk eel, was found in the Puerto Rico Trench at a depth of 8,372 metres.[51][52] At the other extreme, the Tibetan stone loach lives at altitudes over 5,200 metres in the Himalayas.[51][53] Some marine pelagic fish range over vast areas, such as the blue shark found in all oceans. At the other extreme are fish confined to very small living spaces, such as isolated cave fish like Lucifuga in the Bahamas and Cuba,[54] or equally isolated desert pupfish living in small desert spring systems in Mexico and the southwest USA, or bythitid vent fish like Thermichthys hollisi, living around thermal vents 2,400 metres deep.[51][55]
[edit] By breeding behaviourGrouper are protogynous hermaphrodites, who school in harems of three to fifteen females. When no male is available, the most aggressive and largest females shift sex to male, probably as a result of behavioural triggers. In very deep waters, it is not easy for a fish to find a mate. There is no light, so some species depend on bioluminescence. Others are hermaphrodites, which doubles their chances of producing both eggs and sperm when an encounter does occur.[56] The female anglerfish releases pheromones to attract tiny males. When a male finds her, he bites on to her and never lets go. When a male of the anglerfish species Haplophryne mollis bites into the skin of a female, he release an enzyme that digests the skin of his mouth and her body, fusing the pair to the point where the two circulatory systems join up. The male then atrophies into nothing more than a pair of gonads. This extreme sexual dimorphism ensures that, when the female is ready to spawn, she has a mate immediately available.[57]
[edit] By feeding behaviourThere are three basic methods by which food is gathered into the mouths of fish: by suction feeding, by ram feeding, and by manipulation or biting.[62] Nearly all fish species use one of these styles, and most use two.[63]
Early fish lineages had inflexible jaws limited to little more than opening and closing. Modern telosts have evolved protusible jaws that can reach out to engulf prey.[64][65] An extreme example is the protusible jaw of the slingjaw wrasse. Its mouth extends into a tube half as long as its body, and with a strong suction it catches it prey. The equipment is tucked away under its body when it is not in use.[66][67] In practice, feeding modes lie on a spectrum, with suction and ram feeding at the extremes. Many fish capture their prey using both suction pressure combined with a forward motion of the body or jaw.[68] The cookiecutter shark is a small dogfish which derives its name from the way it removes small circular plugs, looking as though cut with a cookie cutter, from the flesh and skin of cetaceans and larger fish, including other sharks. The cookiecutter attaches to its larger prey with its suctorial lips, and then protrudes its teeth to remove a symmetrical scoop of flesh.[69]
Most fish are food opportunists, or generalists. They eat whatever is most easily available.[70] For example, the blue shark feeds on dead whales and nearly everthing else that wriggles: other fish, cephalopods, gastropods, ascidians, crustaceans.[71][72] Ocean sunfish prefer jellyfish.[22]
.png) Other fish have developed extreme specialisations. Silver arowana, also called monkey fish, can leap two metres out of the water to capture prey. They usually swim near the surface of the water waiting for potential prey. Their main diet consist of crustaceans, insects, smaller fishes and other animals that float on the water surface, for which its draw-bridge-like mouth is exclusively adapted for feeding. The remains of small birds, bats, and snakes have also been found in their stomachs.[73] Archerfish are known for their habit of preying on land based insects and other small animals by literally shooting them down with water droplets from their specialized mouths. Archerfish are remarkably accurate in their shooting; adult fish almost always hit the target on the first shot. They can bring down an insect that includes grasshoppers,[74] spiders and butterflies on a branch of an overhanging tree,[75] 3 m above the water's surface.[76] This is partially due to their good eyesight, but also having ability to compensate for light refraction when aiming for their prey.[77] Triggerfish also use jets of water, but to uncover sand dollars buried in sand or overturn sea urchins.[78]
Doctor fish (nibble fish) live and breed in the outdoor pools of some Turkish spas, where they feed on the skin of patients with psoriasis. The fish are like cleaner fish in that they only consume the affected and dead areas of the skin, leaving the healthy skin to recover. [edit] By swimming abilitySee also: Fish locomotion The slowest-moving fishes are the sea horses. The slowest of these, the dwarf seahorse, attains about five feet per hour.[79] The fasted sprinter is the Indo-Pacific sailfish. It has been recorded in a burst of over 110 km/h (68 mph), equivalent to 12 to 15 fish lengths per second. The wahoo is perhaps the fastest fish for its size, attaining a speed of 19 fish length per second (78 km/h). The shortfin mako shark is fast enough and agile enough to chase down and kill an adult swordfish, but they don't always win. Sometimes in the struggle with a shark a swordfish can kill it by ramming it in the gills or belly. The shortfin mako's speed has been recorded at 50 km/h (31 mph), and there are reports that it can achieve bursts of up to 74 km/h (46mph).[80] It can jump up to 9m (28ft.) in the air. Due to its speed and agility, this high-leaping fish is sought as game worldwide. This shark is highly migratory. Its exothermic constitution partly accounts for its relatively great speed.[81] The northern bluefin tuna is capable of sustained high speed cruising, and can maintain high muscle temperatures so it can can cruise in arctic waters.
A number of fish species fish jump while swimming near the surface, skimming the water.  Although not exactly a "swimming" ability, flying fish have unusually large pectoral fins, which enable the fish to take short gliding flights through air, above the surface of the water, in order to escape from predators. Their glides are typically around 50 meters (160 ft), but they can use updrafts at the leading edge of waves to cover distances of at least 400 meters (1,300 ft).[82] In May 2008, a flying fish was filmed off the coast of Japan (see video). The fish spent 45 seconds in flight, and was able to stay aloft by occasionally beating the surface of the water with its caudal (tail) fin.[83] The previous record was 42 seconds.[83]. [edit] By toxicityToxic fish are fish which contain strong toxins in their bodies. There is a distinction between poisonous fish and venomous fish. Both types of fish contain strong toxins, but the difference is in the way the toxin is delivered. Venomous fish deliver their toxins (called venom) by biting, stinging, or stabbing, causing an envenomation. Venomous fish don't necessarily cause poisoning if they are eaten, since the venom is often destroyed in the digestive system. By contrast, poisonous fish contain strong toxins which are not destroyed by the digestive system. This makes them poisonous to eat.[84] The most poisonous fish is the puffer fish. It is the second most poisonous vertebrate after the golden dart frog. It paralyses the diaphragm muscles of human victims, who can die from suffocation. In Japan, skilled chefs use parts of a closely related species, the blowfish to create a delicacy called "fugu", including just enough toxin for that "special flavour". The spotted trunkfish is a reef fish which secretes a colourless ciguatera toxin from glands on its skin when touched. The toxin is only dangerous when ingested, so there's no immediate harm to divers. However, predators as large as nurse sharks can die as a result of eating a trunkfish.[85] The giant moray is a reef fish at the top of the food chain. Like many other apex reef fish, it is likely to cause ciguatera poisoning if eaten.[86][87] Outbreaks of ciguatera poisoning in the 11th to 15th centuries from large, carnivorous reef fish, caused by harmful algal blooms, could be a reason why Polynesians migrated to Easter Island, New Zealand, and possibly Hawaii.[88][89]
A 2006 study found that there are at least 1200 species of venomous fish.[90] There are more venomous fish than venomous snakes. In fact, there are more venomous fish than the combined total of all other venomous vertebrates.[90] Venomous fish are found in almost all habitats around the world, but mostly in tropical waters. They wound over 50,000 people every year.[91] They carry their venom in venom glands and use various delivery systems, such as spines or sharp fins, barbs or spikes, and fangs. Venomous fish tend to be either very visible, using flamboyant colours to warn enemies, or skilfully camouflaged and maybe buried in the sand. Apart from the defence or hunting value, venom might have value for bottom dwelling fish by killing the bacteria that try to invade their skin. Few of these venoms have been studied. They are a yet to be tapped resource for bioprospecting to find drugs with medical uses.[92]
The most venomous known fish is the reef stonefish.[93][97] It has a remarkable ability to camouflage itself amongst rocks. It is an ambush predator that sits on the bottom waiting for prey to come close. It does not swim away if disturbed, but erects 13 venomous spines along its back. For defence, it can shoot venom from each or all of these spines. Each spine is like a hypodermic needle, delivering the venom from two sacs attached to the spine. The stonefish has control over whether to shoot its venom, and does so when provoked or frightened.[92] The venom results in severe pain, paralysis and tissue death, and can be fatal if not treated. Despite its formidable defence, the stonefish does have predators. Some bottom feeding rays and sharks with crushing teeth feed on them, as does the Stokes' seasnake[98] Unlike the stonefish which can shoot venom, the lionfish can only release venom when something strikes its spines. Although not native to the US coast, lionfish have appeared around Florida and have spread up the coast to New York. They are attractive aquarium fish, sometimes used to stock ponds, and may have been washed into the sea during a hurricane. Lionfish can aggressively dart at scuba divers and attempt to puncture the facemask with their venomous spines.[92] The stargazer buries itself and can deliver electric shocks as well as venom. It is a delicacy in some cultures (the venom is destroyed when it is cooked), and can be found for sale in some fish markets with the electric organ removed. They have been called "the meanest things in creation"[92]  Stingray envenomations can occur to people who wade in shallow water and tread on them. This can be avoided by shuffling through the sand or stamping on the bottom, as the rays detect this and swim away. The stinger usually breaks off in the wound. It is barbed, so it can easily penetrate but not so easily be removed. The stinger causes local trauma from the cut itself, pain and swelling from the venom, and possible later infection from bacteria. Occasionally severed arteries or death can result.[99] Treatment for venom stings usually includes the application of heat, using water at temperatures of about 45 degrees Celsius, since heat breaks down most complex venom proteins. [edit] By human use Fish are sought by humans for their value as commercial food fish, recreational sport fish and decorative aquarium fish. Throughout human history, important fisheries have been based on forage fish.[100] Forage fish are small schooling fish which are preyed on by larger predators for food. Typical ocean forage fish feed near the bottom of the food chain on plankton, often by filter feeding. They include the fishes of the family Clupeidae (herrings, sardines, menhaden, hilsa, shad and sprats), as well as anchovies, capelin and halfbeaks. Important herring fisheries have existed for centuries in the North Atlantic and the North Sea. Likewise, important traditional fisheries for anchovies and sardines have operated in the Pacific, the Mediterranean, and the southeast Atlantic.[101] The world annual catch of forage fish in recent years has been around 25 million tonnes, or one quarter of the world's total catch. Higher in the food chain, Gadidae (cod, pollock, haddock, saithe, hake and whiting also support important fisheries. Once the Atlantic cod was one of the world's great fisheries. Concentrated initially in the North Sea, cod was one Europe's oldest fisheries. Later the fishery was extended to the Grand Banks,[102] Declining numbers led to international cod wars and eventually the virtual abandonment of these fisheries. These days the Alaska pollock supports an important fishery in the Bering Sea and the north Pacific. Each year, Alaska pollock yields about 6 million tonnes, while all species of cod together amount to about 9 million tonnes.[101]
Recreational and sport fishing is big business[103] Just the saltwater fishers in the USA spend about $30 billion annually and support 350,000 jobs.[104] Some of the more popular recreational and sport fish include bass, marlin, porgie, shad, mahi-mahi, smelt whiting, swordfish, walleye. Fishkeeping is another popular pastime, and there is a large international trade for aquarium fish. [edit] By vulnerability
[edit] Other typesFish hold the records for the relative brain weights of vertebrates. Most vertebrate species have brains that weigh about the same in proportion to their total body mass. The deep sea bathopelagic cusk-eel Acanthonus armatus,[105] is an ambush predator with a huge head. This fish has the smallest relative brain of all known vertebrates.[106] At the other extreme, the elephantnose fish, an African freshwater fish, has the largest relative brain of all known vertebrates.[107] There are also hallucinogenic fish. Sarpa salpa, a species of bream, recognisable by the golden stripes running the length of its body, can induce LSD-like hallucinations if it is eaten.[108] These widely distributed coastal fish[109] were used as a recreational drug during the Roman Empire, and are called "the fish that make dreams" in Arab. Other hallucinogenic fish are Siganus spinus,[110] called "the fish that inebriates" in Reunion Island, and Mulloidichthys samoensis,[111] called "the chief of ghosts" in Hawaii.[112] [edit] Notes
[edit] References
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