1.
Albacore
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The albacore, known also as the bonito or longfin tuna, is a species of tuna of the order Perciformes. It is found in temperate and tropical waters across the globe in the epipelagic and mesopelagic zones, there are six distinct stocks known globally in the Atlantic, Pacific, and Indian oceans, as well as the Mediterranean Sea. The albacore has an elongate, fusiform body with a snout, large eyes. Its body is a deep blue dorsally and shades of silvery white ventrally, individuals can reach up to 1.4 m in length. Albacore are pelagic predators that eat a variety of foods, including fish, crustaceans and they are unique among tuna in that their primary food source is cephalopods, with fish making up a much smaller portion of their diet. Reproduction usually occurs from November to February and is oviparous, an adult female can release over 2 million eggs in a single cycle. Fry generally stay near where they were spawned for about a year moving on. Albacore form schools based on their stage in the cycle, but also combine with other tuna like the skipjack tuna, yellowfin tuna. Once grown, schools are highly migratory, the albacore is a very economically important fish and is a target of commercial and recreational fisheries. It was originally the basis for the United States tuna-canning industry and is no less important today and it is listed as Near Threatened by the International Union for the Conservation of Nature because of the threat of overfishing. Several stocks are in significant decline and the overall population trend is decreasing. The first scientific description of the albacore was authored in 1788 by Pierre Joseph Bonnaterre in the illustrated encyclopedia Tableau encyclopédique et methodique des trois règnes de la nature and he originally placed it in the mackerel genus Scomber. It was assigned to the genus Thunnus by ichthyologists Bruce B, collette and Cornelia E. Nauen in 1983. It is a member of the Thunnus subgenus, also known as the bluefin group, populations of albacore differ genetically by region, with Atlantic, Pacific, and Mediterranean groups each showing differences in mitochondial and nuclear DNA. The albacore has an streamlined, fusiform body with a snout, large mouth. Its body is blue dorsally, shades of silvery white ventrally. Like the fishs body, the fins are blue on top. The first dorsal fin is a yellow and the second
2.
Atlantic bluefin tuna
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The Atlantic bluefin tuna is a species of tuna in the family Scombridae. It is variously known as the bluefin tuna, giant bluefin tuna. Atlantic bluefin are native to both the western and eastern Atlantic Ocean, as well as the Mediterranean Sea, Atlantic bluefin have become extinct in the Black Sea. The Atlantic bluefin tuna is a relative of the other two bluefin tuna species—the Pacific bluefin tuna and the southern bluefin tuna. Atlantic bluefin tuna may exceed 450 kg in weight, and rival the black marlin, blue marlin, throughout recorded history, the Atlantic bluefin tuna has been highly prized as a food fish. Besides their commercial value as food, the size, speed, and power they display as apex predators has attracted the admiration of fishermen, writers. The Atlantic bluefin tuna has been the foundation of one of the worlds most lucrative commercial fisheries, medium-sized and large individuals are heavily targeted for the Japanese raw fish market, where all bluefin species are highly prized for sushi and sashimi. This commercial importance has led to severe overfishing, on 16 October 2009, Monaco formally recommended Endangered Atlantic bluefin tuna for an Appendix I CITES listing and international trade ban. In early 2010, European officials, led by the French ecology minister, European Union nations, who are responsible for most bluefin tuna overfishing, later abstained from voting to protect the species from international trade. Most bluefin are captured commercially by fishermen using longlines, purse seines, assorted hook-and-line gear, heavy rods and reels. Recreationally, bluefin has been one of the most important big-game species sought by sports fishermen since the 1930s, particularly in the United States, but also in Canada, Spain, France and Italy. It is most closely related to the Pacific bluefin tuna and the southern bluefin tuna, and more distantly to the other large tunas of the genus Thunnus – the bigeye tuna and the yellowfin tuna. For many years, the Pacific and Atlantic bluefin tuna species were considered to be the same, or subspecies and this name occasionally gives rise to some confusion, as the longtail tuna can in Australia sometimes be known under the name northern bluefin tuna. This is also true in New Zealand and Fiji, Bluefin tuna were often referred to as the common tunny, especially in the UK, Australia, and New Zealand. In some languages, the red color of the meat is included in its name, as in atún rojo and tonno rosso. The body of the Atlantic bluefin tuna is rhomboidal in profile, the head is conical and the mouth rather large. The head contains a window that allows the fish to navigate over its multiple thousands-of-miles range. The color is blue above and gray below, with a gold coruscation covering the body
3.
Skipjack tuna
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The skipjack tuna, Katsuwonus pelamis, is a medium-sized perciform fish in the tuna family, Scombridae. It is otherwise known as the aku, arctic bonito, mushmouth, oceanic bonito, striped tuna and it grows up to 1 m in length. It is a pelagic fish found in tropical and warm-temperate waters. It is an important species for fisheries. It is an important prey species for large pelagic fishes and sharks and it has no scales, except on the lateral line and the corselet. It commonly reaches fork lengths up to 80 cm and a weight of 8–10 kg and its maximum fork length is 108 cm and maximum weight is 34.5 kg. Ageing skipjack tuna is difficult, and the estimates of its potential lifespan range between 8 and 12 years, skipjack tuna is a batch spawner. Spawning occurs year-round in equatorial waters, but it gets more seasonal further away from the equator, fork length at first spawning is about 45 cm. It is also known for its potent smell and it is an important commercial and game fish, usually caught using purse seine nets, and is sold fresh, frozen, canned, dried, salted, and smoked. With reported landings of almost 2.6 million tonnes, it was only to the Peruvian anchoveta as the worlds most important capture fish species in 2009. Countries recording large amounts of skipjack catches include the Maldives, France, Spain, Malaysia, Sri Lanka, skipjack is the most fecund of the main commercial tunas, and its population is considered sustainable against its current consumption. Its fishing is controversial due to the methodology, with rod. Purse seine methods are considered unsustainable by some due to excess bycatch. These considerations have led to the availability of canned skipjack marked with the method used to catch it. Skipjack is considered to have moderate mercury contamination, as a result, pregnant women are advised against eating large quantities. In addition, skipjacks livers were tested globally for tributyltin contamination, TBT is an organotin compound introduced into marine ecosystems through antifouling paint used on ship hulls, and has been determined to be very toxic. About 90% of skipjack tested positive for contamination, especially in Southeast Asia, skipjack tuna is used extensively in Japanese cuisine, where it is known as katsuo. Besides being eaten seared and raw in sushi and sashimi, it is smoked and dried to make katsuobushi
4.
Yellowfin tuna
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The yellowfin tuna is a species of tuna found in pelagic waters of tropical and subtropical oceans worldwide. Yellowfin is often marketed as ahi, from the Hawaiian ʻahi, the second dorsal fin and the anal fin, as well as the finlets between those fins and the tail, are bright yellow, giving this fish its common name. The second dorsal and anal fins can be long in mature specimens, reaching almost as far back as the tail. The pectoral fins are longer than the related bluefin tuna. The main body is a dark metallic blue, changing to silver on the belly. Reported sizes in the literature have ranged as high as 2.4 m in length and 200 kg in weight, the International Game Fish Association record for this species stands at 176 kg for a fish caught in 1977 near San Benedicto Island in the Pacific waters of Mexico. In 2010, a 184-kg yellowfin was caught off the tip of Mexicos Baja Peninsula,2. 2-metre long with a girth of 1.5 m, the catch is still pending verification by the IGFA. In 2012, a fisherman in Baja California caught a 193-kg yellowfin, if the catch is confirmed by the IGFA, the fisherman will receive a prize of $1 million. Yellowfin tuna are epipelagic fish that inhabit the surface layer of the ocean above the thermocline. An individual tagged in the Indian Ocean with an archival tag spent 85% of its time in depths shallower than 75 m, although mainly found in deep offshore waters, yellowfin tuna may approach shore when suitable conditions exist. Yellowfin may venture well inshore of the shelf when water temperature and clarity are suitable. Yellowfin tuna often travel in schools with similarly sized companions and they sometimes school with other tuna species and mixed schools of small yellowfin, and skipjack tuna, in particular, are commonplace. They are often associated with species of dolphins or porpoises, as well as with larger marine creatures such as whales. They also associate with drifting flotsam such as logs and pallets, Hawaiian yellowfins associate with anchored fish aggregation devices and with certain sections of the 50-fathom curve. Yellowfin tuna prey include fish, pelagic crustaceans, and squid. Like all tunas, their shape is particularly adapted for speed, enabling them to pursue and capture fast-moving baitfish such as flying fish, sauries. Schooling species such as myctophids or lanternfish and similar pelagic driftfish, anchovies, large yellowfins prey on smaller members of the tuna family such as frigate mackerel and skipjack tuna. In turn, yellowfin are preyed upon when young by other pelagic hunters, including tuna, seabirds, and predatory fishes such as wahoo, shark
5.
Bigeye tuna
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Bigeye tuna, Thunnus obesus, is an important food fish and prized recreational game fish. It is a tuna of the genus Thunnus, belonging to the wider mackerel family Scombridae. In Hawaiian, it is one of two known as ʻahi, the other is yellowfin tuna. Bigeye tuna are found in the waters of all tropical and temperate oceans. Bigeye tuna can grow up to 250 centimetres in length, maximum weight of individuals probably exceeds 180 kg, with the all-tackle angling record standing at 178 kg. They are large, deep-bodied, streamlined fish with large heads, the pectoral fins are very long, reaching back beyond the start of the second dorsal fin in juveniles and the space between the first and second dorsal fin in adults. They have 13 or 14 dorsal spines, bigeye tuna have a unique physiology which allows them to forage in deeper colder waters and tolerate oxygen-poor waters. Vascular counter-current heat exchangers maintain body temperatures above ambient water temperature, the eyes of bigeye tuna are well developed and with a large spherical lens allowing their vision to function well in low light conditions. Conventional tagging data and counts of growth increments in otoliths of bigeye tuna have recorded a maximum age of 16 years and this translates to an age of maturity of 2 –4 years. Differences in methods of studies may contribute to this variability, spawning takes place across most months of the year in tropical regions of the Pacific Ocean, becoming seasonal at higher latitudes when sea surface temperatures are above 24 °C. In the northwestern tropical Atlantic spawning occurs in June and July, and in January and February in the Gulf of Guinea, which is the only known Atlantic nursery area. Bigeye tuna undertake a distinct shift in vertical behaviour, generally descending at dawn to deeper, cooler waters. During the day they can undertake vertical movements into waters of 300–500 m depth that can be as low as 20 °C than surface temperatures, individuals undertake thermoregulatory behaviour whilst at depth, periodically returning from deeper, cooler waters to shallower, warmer waters to re-warm. These suggest that bigeye tuna are tracking an optimum temperature which is shallower in the eastern Pacific Ocean than in the western Pacific Ocean, the diel shift in the vertical behaviour of bigeye tuna has been suggested to be associated with the diel migration of their prey. Typical vertical behaviour of bigeye tuna shifts when fish associate with seamounts, buoys and fish aggregating devices, association with objects has been observed to occur over periods of approximately 10–30 days. Results from tagging studies show that bigeye tuna are capable of traversing ocean basins, one study suggested an annual migration influenced by water temperature, specifically that near the surface. Central Pacific bigeye migrate from subtropical waters in September to tropical waters in March, the fish also briefly travel outside these thermal ranges. Other data indicate similar Pacific-wide variations, bigeye tuna primarily feed on epipelagic and mesopelagic fish, crustaceans and cephalopods
6.
Taxonomy (biology)
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Taxonomy is the science of defining groups of biological organisms on the basis of shared characteristics and giving names to those groups. The exact definition of taxonomy varies from source to source, but the core of the remains, the conception, naming. There is some disagreement as to whether biological nomenclature is considered a part of taxonomy, the broadest meaning of taxonomy is used here. The word taxonomy was introduced in 1813 by Candolle, in his Théorie élémentaire de la botanique, the term alpha taxonomy is primarily used today to refer to the discipline of finding, describing, and naming taxa, particularly species. In earlier literature, the term had a different meaning, referring to morphological taxonomy, ideals can, it may be said, never be completely realized. They have, however, a value of acting as permanent stimulants. Some of us please ourselves by thinking we are now groping in a beta taxonomy, turrill thus explicitly excludes from alpha taxonomy various areas of study that he includes within taxonomy as a whole, such as ecology, physiology, genetics, and cytology. He further excludes phylogenetic reconstruction from alpha taxonomy, thus, Ernst Mayr in 1968 defined beta taxonomy as the classification of ranks higher than species. This activity is what the term denotes, it is also referred to as beta taxonomy. How species should be defined in a group of organisms gives rise to practical and theoretical problems that are referred to as the species problem. The scientific work of deciding how to define species has been called microtaxonomy, by extension, macrotaxonomy is the study of groups at higher taxonomic ranks, from subgenus and above only, than species. While some descriptions of taxonomic history attempt to date taxonomy to ancient civilizations, earlier works were primarily descriptive, and focused on plants that were useful in agriculture or medicine. There are a number of stages in scientific thinking. Early taxonomy was based on criteria, the so-called artificial systems. Later came systems based on a complete consideration of the characteristics of taxa, referred to as natural systems, such as those of de Jussieu, de Candolle and Bentham. The publication of Charles Darwins Origin of Species led to new ways of thinking about classification based on evolutionary relationships and this was the concept of phyletic systems, from 1883 onwards. This approach was typified by those of Eichler and Engler, the advent of molecular genetics and statistical methodology allowed the creation of the modern era of phylogenetic systems based on cladistics, rather than morphology alone. Taxonomy has been called the worlds oldest profession, and naming and classifying our surroundings has likely been taking place as long as mankind has been able to communicate
7.
Animal
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Animals are multicellular, eukaryotic organisms of the kingdom Animalia. The animal kingdom emerged as a clade within Apoikozoa as the group to the choanoflagellates. Animals are motile, meaning they can move spontaneously and independently at some point in their lives and their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later in their lives. All animals are heterotrophs, they must ingest other organisms or their products for sustenance, most known animal phyla appeared in the fossil record as marine species during the Cambrian explosion, about 542 million years ago. Animals can be divided broadly into vertebrates and invertebrates, vertebrates have a backbone or spine, and amount to less than five percent of all described animal species. They include fish, amphibians, reptiles, birds and mammals, the remaining animals are the invertebrates, which lack a backbone. These include molluscs, arthropods, annelids, nematodes, flatworms, cnidarians, ctenophores, the study of animals is called zoology. The word animal comes from the Latin animalis, meaning having breath, the biological definition of the word refers to all members of the kingdom Animalia, encompassing creatures as diverse as sponges, jellyfish, insects, and humans. Aristotle divided the world between animals and plants, and this was followed by Carl Linnaeus, in the first hierarchical classification. In Linnaeuss original scheme, the animals were one of three kingdoms, divided into the classes of Vermes, Insecta, Pisces, Amphibia, Aves, and Mammalia. Since then the last four have all been subsumed into a single phylum, in 1874, Ernst Haeckel divided the animal kingdom into two subkingdoms, Metazoa and Protozoa. The protozoa were later moved to the kingdom Protista, leaving only the metazoa, thus Metazoa is now considered a synonym of Animalia. Animals have several characteristics that set apart from other living things. Animals are eukaryotic and multicellular, which separates them from bacteria and they are heterotrophic, generally digesting food in an internal chamber, which separates them from plants and algae. They are also distinguished from plants, algae, and fungi by lacking cell walls. All animals are motile, if only at life stages. In most animals, embryos pass through a stage, which is a characteristic exclusive to animals. With a few exceptions, most notably the sponges and Placozoa and these include muscles, which are able to contract and control locomotion, and nerve tissues, which send and process signals
8.
Chordate
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Chordates are deuterostomes, as during the embryo development stage the anus forms before the mouth. They are also bilaterally symmetric coelomates, in the case of vertebrate chordates, the notochord is usually replaced by a vertebral column during development, and they may have body plans organized via segmentation. There are also additional extinct taxa, the Vertebrata are sometimes considered as a subgroup of the clade Craniata, consisting of chordates with a skull, the Craniata and Tunicata compose the clade Olfactores. Of the more than 65,000 living species of chordates, the worlds largest and fastest animals, the blue whale and peregrine falcon respectively, are chordates, as are humans. Fossil chordates are known from at least as early as the Cambrian explosion, Hemichordata, which includes the acorn worms, has been presented as a fourth chordate subphylum, but it now is usually treated as a separate phylum. The Hemichordata, along with the Echinodermata, form the Ambulacraria, the Chordata and Ambulacraria form the superphylum Deuterostomia, composed of the deuterostomes. Attempts to work out the relationships of the chordates have produced several hypotheses. All of the earliest chordate fossils have found in the Early Cambrian Chengjiang fauna. Because the fossil record of early chordates is poor, only molecular phylogenetics offers a prospect of dating their emergence. However, the use of molecular phylogenetics for dating evolutionary transitions is controversial and it has also proved difficult to produce a detailed classification within the living chordates. Attempts to produce family trees shows that many of the traditional classes are paraphyletic. While this has been known since the 19th century, an insistence on only monophyletic taxa has resulted in vertebrate classification being in a state of flux. Although the name Chordata is attributed to William Bateson, it was already in prevalent use by 1880, ernst Haeckel described a taxon comprising tunicates, cephalochordates, and vertebrates in 1866. Though he used the German vernacular form, it is allowed under the ICZN code because of its subsequent latinization, among the vertebrate sub-group of chordates the notochord develops into the spine, and in wholly aquatic species this helps the animal to swim by flexing its tail. In fish and other vertebrates, this develops into the spinal cord, the pharynx is the part of the throat immediately behind the mouth. In fish, the slits are modified to form gills, a muscular tail that extends backwards behind the anus. This is a groove in the wall of the pharynx. In filter-feeding species it produces mucus to gather food particles, which helps in transporting food to the esophagus and it also stores iodine, and may be a precursor of the vertebrate thyroid gland
9.
Actinopterygii
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Actinopterygii /ˌæktᵻnˌɒptəˈrɪdʒi. aɪ/, or the ray-finned fishes, constitute a class or subclass of the bony fishes. These actinopterygian fin rays attach directly to the proximal or basal skeletal elements, the radials, numerically, actinopterygians are the dominant class of vertebrates, comprising nearly 99% of the over 30,000 species of fish. They are ubiquitous throughout freshwater and marine environments from the sea to the highest mountain streams. Extant species can range in size from Paedocypris, at 8 mm, to the ocean sunfish, at 2,300 kg. Ray-finned fishes occur in variant forms. The main features of a typical ray-finned fish are shown in the diagram at the left. In nearly all ray-finned fish, the sexes are separate, development then proceeds with a free-swimming larval stage. However other patterns of ontogeny exist, with one of the commonest being sequential hermaphroditism, in most cases this involves protogyny, fish starting life as females and converting to males at some stage, triggered by some internal or external factor. This may be advantageous as females become less prolific as they age while male fecundity increases with age, protandry, where a fish converts from male to female, is much less common than protogyny. Most families use external rather than internal fertilization, of the oviparous teleosts, most do not provide parental care. Viviparity is relatively rare and is found in about 6% of teleost species, male territoriality preadapts a species for evolving male parental care. There are a few examples of fish that self-fertilise, the mangrove rivulus is an amphibious, simultaneous hermaphrodite, producing both eggs and spawn and having internal fertilisation. This mode of reproduction may be related to the habit of spending long periods out of water in the mangrove forests it inhabits. Males are occasionally produced at temperatures below 19 °C and can fertilise eggs that are spawned by the female. This maintains genetic variability in a species that is otherwise highly inbred, the earliest known fossil actinopterygiian is Andreolepis hedei, dating back 420 million years. Remains have been found in Russia, Sweden, and Estonia, actinopterygians are divided into the subclasses Chondrostei and Neopterygii. The Neopterygii, in turn, are divided into the infraclasses Holostei and Teleostei, during the Mesozoic and Cenozoic the teleosts in particular diversified widely, and as a result, 96% of all known fish species are teleosts. The cladogram shows the groups of actinopterygians and their relationship to the terrestrial vertebrates that evolved from a related group of fish
10.
Scombridae
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The Scombridae family of the mackerels, tunas, and bonitos includes many of the most important and familiar food fishes. The family consists of 51 species in 15 genera and two subfamilies, all species are in the subfamily Scombrinae, except the butterfly kingfish, which is the sole member of subfamily Gasterochismatinae. Scombrids have two fins and a series of finlets behind the rear dorsal fin and anal fin. The caudal fin is divided and rigid, with a slender. The first dorsal fin and the fins are normally retracted into body grooves. Species lengths vary from the 20 cm of the island mackerel to the 4.58 m recorded for the immense Atlantic bluefin tuna, scombrids are generally predators of the open ocean, and are found worldwide in tropical and temperate waters. They are capable of speed, due to a highly streamlined body. Some members of the family, in particular the tunas, are notable for being partially endothermic, other adaptations include a large amount of red muscle, allowing them to maintain activity over long periods. Two of the fastest recorded scombrids are the wahoo and the yellowfin tuna, a compendium of fossil marine animal genera. Media related to Scombridae at Wikimedia Commons Skaphandrus. com Scombridae
11.
Allothunnus
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The slender tuna, Allothunnus fallai, is a species of tuna, the only species in the genus Allothunnus, found around the world in the southern oceans between latitudes 20° and 50° South. Its length is up to one metre, froese, Rainer and Pauly, Daniel, eds. Tony Ayling & Geoffrey Cox, Collins Guide to the Sea Fishes of New Zealand,2007 IUCN Red List of Threatened Species
12.
Auxis
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Auxis is a genus of ocean-dwelling ray-finned bony fish in the family Scombridae, and tribe Thunnini, also known as the tunas. Auxis, commonly and collectively called the frigate tunas, is one of five genera of tunas which comprise the Thunnini tribe, there are two species in the genus Auxis, each with two subspecies. A. rochei, marusōda ssp. A. rochei rochei, ssp. A. rochei eudorax Collette et Aadland,1996, Eastern Pacific. A. thazard, hirasōda ssp. A. thazard thazard, distributed tropic and subtropic Atlantic, Indian, ssp. A. thazard brachydorax Collette et Aadland,1996, Eastern Pacific. Auxis can reach a length of 50–65 millimetres and they have a strong, fusiform body with a sharpened head. The teeth are small and conical, the two dorsal fins are separated by a wide gap. They have a dark, blue-black back, the top of the head may be purple or almost black. The belly is whitish and without streaks or spots and these fishes are widespread in all tropical and subtropical seas and oceans, and both mentioned species are present in the Mediterranean Sea with their subspecies. In Japan the two species in the genus are collectively called sōdagatsuo, and this is also the genus name. g. Although fresh fish might be eaten as sashimi or grilled, it has a lot of dark-red meat, and it degrades quickly so shipment out to market is limited. The frigate tuna is considered superior between the two, fossils of Auxis have been found in the Pliocene of Italy and United States. Froese, Rainer, and Daniel Pauly, eds
13.
Thunnus
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Thunnus is a genus of ocean-dwelling ray-finned bony fish from the Scombridae family. More specifically, Thunnus is one of five genera which make up the Thunnini tribe – a tribe that is known as the tunas. Also called the true tunas or real tunas, Thunnus consists of eight species of tuna, the word Thunnus is the Middle Latin form of the Ancient Greek, θύννος tunny-fish – which is in turn derived from θύνω, to rush, to dart. The first written use of the word was by Homer and their coloring, metallic blue on top and shimmering silver-white on the bottom, helps camouflage them from above and below. Atlantic bluefin tuna, the largest member of genus, can grow to 15 feet long. All tunas are extremely strong swimmers, and the Yellowfin tuna is known to reach speeds of up to 50 miles per hour when pursuing prey. As with all tunas, members of this genus are warm-blooded, which is a rare trait among fish, this enables them to tolerate cold waters. Bluefin tunas, for example, are found in Newfoundland and Iceland, and also in the waters of the Gulf of Mexico and the Mediterranean Sea. Due to overfishing, the range of this genus has declined significantly, having been effectively expirated from the Black Sea and this genus has eight species in two subgenera, Subgenus Thunnus, Albacore, T. alalunga. Subgenus Thunnus, Yellowfin tuna, T. albacares, until recently, it was thought that there were seven Thunnus species, and that Atlantic bluefin tuna and Pacific bluefin tuna were subspecies of a single species. In 1999 Collette established that based on molecular and morphological considerations, they are in fact distinct species. The genus Thunnus is further classified into two subgenera, Thunnus, and Thunnus, International agreements and conventions are good faith agreements and are difficult to monitor or enforce. On December 30,2012, a 222-kilogram bluefin tuna caught off northeastern Japan, was sold at the Tsukiji fish market in Tokyo for a record 155.4 million yen – a unit price of JP¥1.274 million/kg. The End of the Line, How Overfishing Is Changing the World, molly E. Lutcavage, Tony J. Pitcher. Atlantic Bluefin Tuna in the Gulf of Maine, I, Estimation of Seasonal Abundance Accounting for Movement, School, froese, Rainer, and Daniel Pauly, eds. Nutritional benefits of tunadead link] The International Commission for the Conservation of Atlantic Tunas
14.
Fish
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A fish is any member of a group of animals that consist of all gill-bearing aquatic craniate animals that lack limbs with digits. They form a group to the tunicates, together forming the olfactores. Included in this definition are the living hagfish, lampreys, and cartilaginous, tetrapods emerged within lobe-finned fishes, so cladistically they are fish as well. However, traditionally fish are rendered obsolete or paraphyletic by excluding the tetrapods, because in this manner the term fish is defined negatively as a paraphyletic group, it is not considered a formal taxonomic grouping in systematic biology. The traditional term pisces is considered a typological, but not a phylogenetic classification, the earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period. Although they lacked a true spine, they possessed notochords which allowed them to be more agile than their invertebrate counterparts, fish would continue to evolve through the Paleozoic era, diversifying into a wide variety of forms. Many fish of the Paleozoic developed external armor that protected them from predators, the first fish with jaws appeared in the Silurian period, after which many became formidable marine predators rather than just the prey of arthropods. Fish are abundant in most bodies of water and they can be found in nearly all aquatic environments, from high mountain streams to the abyssal and even hadal depths of the deepest oceans. With 33,100 described species, fish exhibit greater species diversity than any group of vertebrates. Fish are an important resource for humans worldwide, especially as food, commercial and subsistence fishers hunt fish in wild fisheries or farm them in ponds or in cages in the ocean. They are also caught by fishers, kept as pets, raised by fishkeepers. Fish have had a role in culture through the ages, serving as deities, religious symbols, fish do not represent a monophyletic group, and therefore the evolution of fish is not studied as a single event. Early fish from the record are represented by a group of small, jawless. Jawless fish lineages are mostly extinct, an extant clade, the lampreys may approximate ancient pre-jawed fish. The first jaws are found in Placodermi fossils, the diversity of jawed vertebrates may indicate the evolutionary advantage of a jawed mouth. It is unclear if the advantage of a hinged jaw is greater biting force, improved respiration, fish may have evolved from a creature similar to a coral-like sea squirt, whose larvae resemble primitive fish in important ways. The first ancestors of fish may have kept the form into adulthood. Fish are a group, that is, any clade containing all fish also contains the tetrapods
15.
Tribe (biology)
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In biology, a tribe is a taxonomic rank above genus, but below family and subfamily. It is sometimes subdivided into subtribes, in zoology, some examples include the tribes Caprini, Hominini, Bombini, and Thunnini. The standard ending for the name of a tribe is -ini. The tribe Hominini is divided into subtribes by some scientists, subtribe Hominina then comprises humans, the standard ending for the name of a zoological subtribe is -ina. In botany, examples include the tribes Acalypheae and Hyacintheae, the standard ending for the name of a botanical tribe is -eae. The tribe Hyacintheae is divided into subtribes, including the subtribe Massoniinae, the standard ending for the name of a botanical subtribe is -inae. In bacteriology, the form of names is as in botany, e. g. Pseudomonadeae
16.
Species
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In biology, a species is the basic unit of biological classification and a taxonomic rank. A species is defined as the largest group of organisms in which two individuals can produce fertile offspring, typically by sexual reproduction. While this definition is often adequate, looked at more closely it is problematic, for example, with hybridisation, in a species complex of hundreds of similar microspecies, or in a ring species, the boundaries between closely related species become unclear. Other ways of defining species include similarity of DNA, morphology, all species 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. For example, Boa constrictor is one of four species of the Boa genus, Species were seen from the time of Aristotle until the 18th century as fixed kinds that could be arranged in a hierarchy, the great chain of being. In the 19th century, biologists grasped that species could evolve given sufficient time, Charles Darwins 1859 book The Origin of Species explained how species could arise by natural selection. Genes can sometimes be exchanged between species by horizontal transfer, and species may become extinct for a variety of reasons. In his biology, Aristotle used the term γένος to mean a kind, such as a bird or fish, a kind was distinguished by its attributes, for instance, a bird has feathers, a beak, wings, a hard-shelled egg, and warm blood. A form was distinguished by being shared by all its members, Aristotle believed all kinds and forms to be distinct and unchanging. His approach remained influential until the Renaissance, when observers in the Early Modern period began to develop systems of organization for living things, they placed each kind of animal or plant into a context. Many of these early delineation schemes would now be considered whimsical, animals likewise that differ specifically preserve their distinct species permanently, one species never springs from the seed of another nor vice versa. In the 18th century, the Swedish scientist Carl Linnaeus classified organisms according to shared physical characteristics and he established the idea of a taxonomic hierarchy of classification based upon observable characteristics and intended to reflect natural relationships. At the time, however, it was widely believed that there was no organic connection between species, no matter how similar they appeared. However, whether or not it was supposed to be fixed, by the 19th century, naturalists understood that species could change form over time, and that the history of the planet provided enough time for major changes. Jean-Baptiste Lamarck, in his 1809 Zoological Philosophy, described the transmutation of species, proposing that a species could change over time, in 1859, Charles Darwin and Alfred Russel Wallace provided a compelling account of evolution and the formation of new species. Darwin argued that it was populations that evolved, not individuals and this required a new definition of species. Darwin concluded that species are what appear to be, ideas
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Genus
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A genus is a taxonomic rank used in the biological classification of living and fossil organisms in biology. In the hierarchy of classification, genus comes above species. In binomial nomenclature, the name forms the first part of the binomial species name for each species within the genus. Felis catus and Felis silvestris are two species within the genus Felis, Felis is a genus within the family Felidae. The composition of a genus is determined by a taxonomist, the standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. Moreover, genera should be composed of units of the same kind as other genera. The term comes from the Latin genus, a noun form cognate with gignere, linnaeus popularized its use in his 1753 Species Plantarum, but the French botanist Joseph Pitton de Tournefort is considered the founder of the modern concept of genera. The scientific name of a genus may be called the name or generic epithet. It plays a role in binomial nomenclature, the system of naming organisms. The rules for the names of organisms are laid down in the Nomenclature Codes. The standard way of scientifically describing species and other lower-ranked taxa is by binomial nomenclature, the generic name forms its first half. For example, the gray wolfs binomial name is Canis lupus, with Canis being the name shared by the wolfs close relatives. The specific name is written in lower-case and may be followed by names in zoology or a variety of infraspecific names in botany. Especially with these names, when the generic name is known from context. Because animals are typically only grouped within subspecies, it is written as a trinomen with a third name. Dog breeds, meanwhile, are not scientifically distinguished, there are several divisions of plant species and therefore their infraspecific names generally include contractions explaining the relation. For example, the genus Hibiscus includes hundreds of other species apart from the Rose of Sharon or common garden hibiscus, Rose of Sharon doesnt have subspecies but has cultivars that carry desired traits, such as the bright white H. syriaca Diana. Hawaiian hibiscus, meanwhile, includes several separate species, since not all botanists agree on the divisions or names between species, it is common to specify the source of the name using author abbreviations
18.
Bullet tuna
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The bullet tuna, Auxis rochei rochei, is a subspecies of tuna, in the family Scombridae, found circumglobally in tropical oceans in open surface waters to depths of 50 m. Its maximum length is 50.0 cm, sometimes called bullet mackerel, the bullet tuna is a comparatively small and slender tuna. It has a triangular first dorsal fin, widely separated from the dorsal fin. There are the usual finlets of the tuna, there is a small corselet of small scales around the pectoral region of the body. Bullet tunas are blue-black on the back with a pattern of dark markings on the upper hind body. They feed on fish, squid, planktonic crustaceans. Froese, Rainer and Pauly, Daniel, eds
19.
Opah
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Opahs are large, colorful, deep-bodied pelagic lampriform fishes comprising the small family Lampridae. Only two living species occur in a genus, Lampris. One species is found in tropical to temperate waters of most oceans, while the other is limited to a distribution in the Southern Ocean. Two additional species, one in the genus Lampris and the other in the monotypic Megalampris, are known from fossil remains. The extinct family, Turkmenidae, from the Paleogene of Central Asia, is closely related, opah specimens are rarely caught by recreational anglers. They are prized trophies for deep-water anglers as their large size, opahs are frequently caught as bycatch in many longline tuna fisheries. Opah is becoming popular in seafood markets. It first became popular as a sushi and sashimi in the late 1980s, the meat is lightly flavored and lends itself well to a variety of preparations, principally sauté. Opah flesh has a light-pink to orange color, but turns white when cooked and it is popular in Hawaii, especially in restaurants. An average of 35% of a weight is consumable, with the remaining 65% being bone. The opah is the first fish discovered to have a warm heart, the opah can keep most of its body consistently at a temperature above the water temperature. Opahs are deeply keeled, compressed, discoid fish with conspicuous coloration, both the median and paired fins are a bright vermilion. The large eyes stand out, as well, ringed with golden yellow, the body is covered in minute cycloid scales and its silvery, iridescent guanine coating is easily abraded. Opahs closely resemble in shape the unrelated butterfish, both have falcated pectoral fins and forked, emarginated caudal fins. The pectorals of opahs are also inserted horizontally rather than vertically, the anterior portion of an opahs single dorsal fin is greatly elongated, also in a falcated profile similar to the pelvic fins. The anal fin is about as high and as long as the portion of the dorsal fin. The snout is pointed and the small, toothless. The lateral line forms an arch over the pectoral fins before sweeping down to the caudal peduncle
20.
Lamniformes
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The Lamniformes are an order of sharks commonly known as mackerel sharks. It includes some of the most familiar species of sharks, such as the white shark, as well as more unusual representatives, such as the goblin shark. Members of the order are distinguished by possessing two dorsal fins, a fin, five gill slits, eyes without nictitating membranes. Also, unlike sharks, they maintain a higher body temperature than the surrounding water
21.
Pelagic zone
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Any water in a sea or lake that is neither close to the bottom nor near the shore can be said to be in the pelagic zone. The word pelagic is derived from Greek πέλαγος, meaning open sea, the pelagic zone can be thought of in terms of an imaginary cylinder or water column that goes from the surface of the sea almost to the bottom. Conditions differ deeper in the water such that as pressure increases with depth. Depending on the depth, the column, rather like the Earths atmosphere. The pelagic zone occupies 1,330 million km3 with a depth of 3.68 km. Pelagic life decreases with increasing depth and it is affected by light intensity, pressure, temperature, salinity, the supply of dissolved oxygen and nutrients, and the submarine topography, which is called bathymetry. In deep water, the zone is sometimes called the open-ocean zone. In other contexts, coastal water not near the bottom is still said to be in the pelagic zone, the pelagic zone can be contrasted with the benthic and demersal zones at the bottom of the sea. The benthic zone is the region at the very bottom of the sea. It includes the sediment surface and some subsurface layers, Marine organisms living in this zone, such as clams and crabs, are called benthos. The demersal zone is just above the benthic zone and it can be significantly affected by the seabed and the life that lives there. Demersal fish are known as bottom feeders and groundfish. Depending on how deep the sea is, the zone can extend over up to five horizontal layers in the ocean. From the top down, these are, From the surface down to around 200 m This is the zone at the surface of the sea where enough light is available for photosynthesis. Nearly all primary production in the ocean occurs here, consequently, plants and animals are largely concentrated in this zone. Examples of organisms living in this zone are plankton, floating seaweed, jellyfish, tuna, many sharks, from 200 m down to around 1,000 m The name for this zone stems from Greek μέσον, meaning middle. Although some light penetrates this second layer it is insufficient for photosynthesis, at about 500 m the water also becomes depleted of oxygen. Organisms survive this environment by having more efficient gills or by minimizing movement, examples of animals that live here are swordfish, squid, Anarhichadidae or wolffish and some species of cuttlefish
22.
Overfishing
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Overfishing is a form of overexploitation where fish stocks are reduced to below acceptable levels. Overfishing can occur in bodies of any sizes, such as ponds, rivers, lakes or oceans. Sustained overfishing can lead to critical depensation, where the population is no longer able to sustain itself. Some forms of overfishing, for example the overfishing of sharks, has led to the upset of entire marine ecosystems, the ability of a fishery to recover from overfishing depends on whether the ecosystems conditions are suitable for the recovery. For example, once trout have been overfished, carp might take over in a way makes it impossible for the trout to re-establish a breeding population. Overfishing occurs when fish are caught than the population can replace through natural reproduction. Gathering as many fish as possible may seem like a profitable practice, the results not only affect the balance of life in the oceans, but also the social and economic well-being of the coastal communities who depend on fish for their way of life. Overfishing has significantly affected many fisheries around the world, as much as 85% of the worlds fisheries may be over-exploited, depleted, fully exploited or in recovery from exploitation. Significant overfishing has been observed in pre-industrial times, in particular, the overfishing of the western Atlantic Ocean from the earliest days of European colonisation of the Americas has been well documented. Following World War Two, industrial fishing rapidly expanded with rapid increases in worldwide fishing catches, however, many fisheries have either collapsed or degraded to a point where increased catches are no longer possible. Daniel Pauly, a fisheries scientist known for pioneering work on the impacts on global fisheries, has commented. We are gradually winning this war to exterminate them, and to see this destruction happen, for nothing really – for no reason – that is a bit frustrating. Examples of overfishing exist in such as the North Sea, the Grand Banks of Newfoundland. In these locations, overfishing has not only proved disastrous to fish stocks, the Peruvian coastal anchovy fisheries crashed in the 1970s after overfishing and an El Niño season largely depleted anchovies from its waters. Anchovies were a natural resource in Peru, indeed,1971 alone yielded 10.2 million metric tons of anchovies. However, the five years saw the Peruvian fleets catch amount to only about 4 million tons. This was a loss to Perus economy. The collapse of the cod fishery off Newfoundland, and the 1992 decision by Canada to impose a moratorium on the Grand Banks, is a dramatic example of the consequences of overfishing
23.
Southern bluefin tuna
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The southern bluefin tuna, Thunnus maccoyii, is a tuna of the family Scombridae found in open southern Hemisphere waters of all the worlds oceans mainly between 30°S and 50°S, to nearly 60°S. At up to 2.5 metres and weighing up to 260 kilograms, Southern bluefin tuna, like other pelagic tuna species, are part of a group of bony fishes that can maintain their body core temperature up to 10 degrees above the ambient temperature. This advantage enables them to high metabolic output for predation. The southern bluefin tuna is a feeder, preying on a wide variety of fish, crustaceans, cephalopods, salps. The southern bluefin tuna is an organism with a high metabolic need. These are pelagic animals, but migrate vertically through the water column and they also migrate between tropical and cool temperate waters in the search for food. The seasonal migrations are between waters off the coast of Australia and the Indian Ocean. Although the preferred temperature range for souther bluefin tuna is from 18-20 °C, they can endure temperatures as low as 3 °C at low depths, and as high as 30 °C, when spawning. This wide range of temperature and depth changes poses a challenge to the respiratory and circulatory systems of the southern bluefin tunas, tunas swim continuously and at high speeds and, therefore, have a high demand for oxygen. The oxygen concentration in the changes with the change in temperature. Tunas are, however, driven by the availability of food, Bluefin tunas, unlike other species of tunas, maintain a fairly constant red muscle temperature over a wide range of ambient temperatures. So, in addition to being endotherms, bluefin tunas are also thermoregulators, the species is listed as critically endangered by the IUCN. Respiratory systems of southern bluefin tunas are adapted to their oxygen demand. Bluefin tunas are obligate ram ventilators, they drive water into the cavity through their mouth, then over the gills. Therefore, unlike most other teleost fish, the bluefin tuna does not require a separate pump mechanism to pump water over the gills. All species of tuna in general have lost the opercular pump, therefore, if they stop swimming, tunas suffocate due to a lack of water flow over the gills. The oxygen need and oxygen uptake of the bluefin tuna are directly related. As the tuna increases its metabolic need by swimming faster, water flows into the mouth and over the more quickly
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Extinction
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In biology and ecology, extinction is the end of an organism or of a group of organisms, normally a species. The moment of extinction is considered to be the death of the last individual of the species, although the capacity to breed. Because a species range may be very large, determining this moment is difficult. This difficulty leads to such as Lazarus taxa, where a species presumed extinct abruptly reappears after a period of apparent absence. More than 99 percent of all species, amounting to five billion species. Estimates on the number of Earths current species range from 10 million to 14 million, of which about 1.2 million have been documented and over 86 percent have not yet been described. More recently, in May 2016, scientists reported that 1 trillion species are estimated to be on Earth currently with only one-thousandth of one percent described, the relationship between animals and their ecological niches has been firmly established. Mass extinctions are relatively rare events, however, isolated extinctions are quite common, only recently have extinctions been recorded and scientists have become alarmed at the current high rate of extinctions. Most species that become extinct are never scientifically documented, some scientists estimate that up to half of presently existing plant and animal species may become extinct by 2100. A dagger symbol next to a name is often used to indicate its extinction. A species is extinct when the last existing member dies, Extinction therefore becomes a certainty when there are no surviving individuals that can reproduce and create a new generation. Pinpointing the extinction of a species requires a definition of that species. If it is to be declared extinct, the species in question must be distinguishable from any ancestor or daughter species. Extinction of a plays a key role in the punctuated equilibrium hypothesis of Stephen Jay Gould. In ecology, extinction is often used informally to refer to local extinction, in which a species ceases to exist in the area of study. This phenomenon is known as extirpation. Local extinctions may be followed by a replacement of the species taken from other locations, species which are not extinct are termed extant. Those that are extant but threatened by extinction are referred to as threatened or endangered species, currently an important aspect of extinction is human attempts to preserve critically endangered species
25.
Predatory fish
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Predatory fish are fish that prey upon other fish or animals. Some predatory fish include perch, muskie, pike, walleye, levels of large predatory fish in the global oceans were estimated to be about 10% of their pre-industrial levels by 2003. Large predatory fish are most at risk of extinction, there was a level of large predatory fish extinctions during the Cretaceous–Paleogene extinction event 66 million years ago. Creation of marine reserves has been found to restore populations of predatory fish such as the Serranidae — groupers. Predatory fish switch between types of prey in response to variations in their abundance, such changes in preference are disproportionate and are selected for as evolutionarily efficient. Predatory fish may become a pest if they are introduced into an ecosystem in which they become a new top predator, an example, which has caused much trouble in Maryland and Florida, is the snakehead fish. Predators are an important factor to consider in managing fisheries, and methods for doing so are available, feeding frenzy Scale eating Shark attack Shark feeding Predatory fish on AquaticCommunity. com Predator fish in oceans on alarming decline, experts say Washington Post,21 February 2011
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Billfish
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The term billfish refers to a group of predatory fish characterised by prominent bills, or rostra, and by their large size, some are longer than 4 m. Billfish include sailfish and marlin, which make up the family Istiophoridae and they are apex predators which feed on a wide variety of smaller fish, crustaceans, and cephalopods. Billfish are pelagic and highly migratory and they are found in all oceans, although they usually inhabit tropical and subtropical waters, swordfish are found in temperate waters, as well. Billfish use their long spears or sword-like upper beaks to slash at and their bills can also be used to spear prey, and have been known to spear boats, but they are not normally used in that way. They are highly valued as gamefish by sports fishermen, the term billfish refers to the fishes of the families Xiphiidae and Istiophoridae. These large fishes are characterized by the prolongation of the jaw, much beyond the lower jaw into a long rostrum which is flat and sword-like or rounded. The 12 species of true billfish are divided into two families and five genera, one family, Xiphiidae, contains only one species, the swordfish Xiphias gladius, and the other family, Istiophoridae contains 11 species in four genera, including marlin, spearfish, and sailfish. Controversy exists about whether the Indo-Pacific blue marlin, Makaira mazara, is the species as the Atlantic blue marlin. FishBase follows Nakamura in recognizing M. mazara as a distinct species, a number of other fishes have pronounced bills or beaks, and are sometimes referred to as billfish. However, they are not true billfish, halfbeaks look somewhat like miniature billfish, and the sawfish and sawshark, which are cartilaginous fishes with spectacular rostrums shaped like a chain saw. Paddlefish have elongated rostrums containing electroreceptors that can detect weak electrical fields, paddlefish are filter feeders and may use their rostrum to detect zooplankton. Billfish have a long, bony, spear-shaped bill, sometimes called a snout, the swordfish has the longest bill, about one-third its body length. Like a true sword, it is smooth, flat, pointed, the bills of other billfish are shorter and rounder, more like spears. Billfish normally use their bills to slash at schooling fish and they swim through the fish school at high speed, slashing left and right, and then circle back to eat the fish they stunned. Adult swordfish have no teeth, and other billfish have only small file-like teeth and they swallow their catch whole, head-first. Billfish dont normally spear with their bills, though occasionally a marlin will flip a fish into the air, given the speed and power of these fish, when they do spear things the results can be dramatic. Predators of billfish, such as white and mako sharks, have been found with billfish spears embedded in them. Pelagic fish generally are fascinated by floating objects, and congregate about them, Billfish can accidentally impale boats and other floating objects when they pursue the small fish that aggregate around them
27.
Bonito
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Bonitos are a tribe of medium-sized, ray-finned predatory fish in the family Scombridae – a family it shares with the mackerel, tuna, and Spanish mackerel tribes, and also the butterfly kingfish. Also called the Sardini tribe, it consists of eight species across four genera, bonito is an adjective that means pretty applied to males or masculine objects both in Portuguese and Spanish, but it is unclear whether the name of the fish is related to this. However, it is said to be derived of the Italian buono, the bonito has a moderate fat content. Bonito may not be marketed as tuna in all countries, however, the Atlantic bonito is also found in the Mediterranean and the Black Sea, where it is a popular food fish, eaten grilled, pickled, or baked. Other fish sometimes called bonito include skipjack tuna, Katsuwonus pelamis Sardini
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Mackerel
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Mackerel is a common name applied to a number of different species of pelagic fish, mostly, but not exclusively, from the family Scombridae. They are found in temperate and tropical seas, mostly living along the coast or offshore in the oceanic environment. Mackerel typically have stripes on their backs and deeply forked tails. Many species are restricted in their ranges, and live in separate populations or fish stocks based on geography. Some stocks migrate in schools along the coast to suitable spawning grounds. After spawning they return the way they came, in smaller schools, from there they may move offshore into deeper waters and spend the winter in relative inactivity. Smaller mackerel are forage fish for larger predators, including larger mackerel, flocks of seabirds, as well as whales, dolphins, sharks and schools of larger fish such as tuna and marlin follow mackerel schools and attack them in sophisticated and cooperative ways. Mackerel is high in oils and is intensively harvested by humans. In 2009, over five tons were landed by commercial fishermen. Sport fishermen value the fighting abilities of the king mackerel, over thirty different species, principally belonging to the family Scombridae, are commonly referred to as mackerel. The term mackerel means marked or spotted, the term mackerel derives from the Old French maquerel, c.1300, meaning a pimp or procurer. The connection is not altogether clear, but mackerel spawn enthusiastically in shoals near the coast, about 21 species in the family Scombridae are commonly called mackerel. The type species for the mackerel is the Atlantic mackerel. Until recently, it was thought that Atlantic chub mackerel and Indo-Pacific chub mackerel were subspecies of the same species, in 1999 Collette established, on molecular and morphological considerations, that these are separate species. Mackerel are smaller with shorter life cycles than their relatives, the tuna. The true mackerels belong to the tribe Scombrini, the tribe consists of seven species, each belonging to one of two genera, Scomber and Rastrelliger. The Spanish mackerels belong to the tribe Scomberomorini, which is the tribe of the true mackerels. This tribe consists of 21 species in all—18 of those are classified into the genus Scomberomorus, in addition, a number of species with mackerel-like characteristics in the families Carangidae, Hexagrammidae and Gempylidae are commonly referred to as mackerel
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Salmon
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Salmon /ˈsæmən/ is the common name for several species of ray-finned fish in the family Salmonidae. Other fish in the family include trout, char, grayling. Salmon are native to tributaries of the North Atlantic and Pacific Ocean, many species of salmon have been introduced into non-native environments such as the Great Lakes of North America and Patagonia in South America. Salmon are intensively farmed in parts of the world. Typically, salmon are anadromous, they are born in water, migrate to the ocean. However, populations of species are restricted to fresh water through their lives. Various species of salmon display anadromous life strategies while others display freshwater resident life strategies, folklore has it that the fish return to the exact spot where they were born to spawn, tracking studies have shown this to be mostly true. A portion of a salmon run may stray and spawn in different freshwater systems. The percent of straying depends on the species of salmon, homing behavior has been shown to depend on olfactory memory. The term salmon comes from the Latin salmo, which in turn may have originated from salire, the nine commercially important species of salmon occur in two genera. The genus Salmo contains the Atlantic salmon, found in the north Atlantic, the genus Oncorhynchus contains eight species which occur naturally only in the North Pacific. As a group, these are known as Pacific salmon, Chinook salmon have been introduced in New Zealand and Patagonia. Coho, freshwater sockeye, and Atlantic salmon have established in Patagonia. † Both the Salmo and Oncorhynchus genera also contain a number of species referred to as trout, within Salmo, additional minor taxa have been called salmon in English, i. e. the Adriatic salmon and Black Sea salmon. The steelhead anadromous form of the rainbow trout migrates to sea, also a number of other species have common names which refer to them as being salmon. The British Columbia salmon fossil provides evidence that the divergence between Pacific and Atlantic salmon had not yet occurred 40 million years ago, Both the fossil record and analysis of mitochondrial DNA suggest the divergence occurred by 10 to 20 million years ago. This independent evidence from DNA analysis and the fossil record rejects the theory of salmon divergence. Atlantic salmon reproduce in northern rivers on both coasts of the Atlantic Ocean, landlocked salmon live in a number of lakes in eastern North America and in Northern Europe, for instance in lakes Sebago, Onega, Ladoga, Saimaa, Vänern, and Winnipesaukee
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Shark
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Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha and are the group to the rays. Under this broader definition, the earliest known sharks date back to more than 420 million years ago, acanthodians are often referred to as spiny sharks, though they are not part of Chondrichthyes proper, they are a paraphyletic assemblage leading to cartilaginous fish as a whole. Since then, sharks have diversified into over 500 species, Sharks are found in all seas and are common to depths of 2,000 metres. They generally do not live in freshwater although there are a few exceptions, such as the bull shark and the river shark. Sharks have a covering of dermal denticles that protects their skin from damage and they have numerous sets of replaceable teeth. Well-known species such as the white shark, tiger shark, blue shark, mako shark. Many shark populations are threatened by human activities, until the 16th century, sharks were known to mariners as sea dogs. The etymology of the shark is uncertain. One theory is that it derives from the Yucatec Maya word xok, however, the Middle English Dictionary records an isolated occurrence of the word shark in a letter written by Thomas Beckington in 1442, which rules out a New World etymology. Evidence for the existence of sharks dates from the Ordovician period, 450–420 million years ago, before land vertebrates existed and before many plants had colonized the continents. Only scales have been recovered from the first sharks and not all agree that these are from true sharks. The oldest generally accepted shark scales are from about 420 million years ago, the first sharks looked very different from modern sharks. The majority of sharks can be traced back to around 100 million years ago. Most fossils are of teeth, often in large numbers, partial skeletons and even complete fossilized remains have been discovered. Estimates suggest that sharks grow tens of thousands of teeth over a lifetime, the teeth consist of easily fossilized calcium phosphate, an apatite. When a shark dies, the decomposing skeleton breaks up, scattering the apatite prisms, preservation requires rapid burial in bottom sediments. Among the most ancient and primitive sharks is Cladoselache, from about 370 million years ago, which has been found within Paleozoic strata in Ohio, Kentucky, and Tennessee
31.
Tuna
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A tuna is a saltwater fish that belongs to the tribe Thunnini, a sub-grouping of the mackerel family – which together with the tunas, also includes the bonitos, mackerels, and Spanish mackerels. Thunnini comprises fifteen species across five genera, the sizes of which vary greatly, the bluefin averages 2 m, and is believed to live for up to 50 years. Tuna and mackerel sharks are the species of fish that can maintain a body temperature higher than that of the surrounding water. An active and agile predator, the tuna has a sleek, streamlined body, found in warm seas, it is extensively fished commercially, and is popular as a game fish. As a result of over-fishing, stocks of tuna species such as the southern bluefin tuna have been reduced dangerously close to the point of extinction. The term tuna ultimately derives from Thunnus, the Middle Latin form of the Ancient Greek, θύννος tunny-fish – which is in turn derived from θύνω, rush, the following cladogram illustrates the relationship between the tunas and other tribes of the family Scombridae. The true tunas are those that belong to the genus Thunnus, until recently, it was thought that there were seven Thunnus species, and that Atlantic bluefin tuna and Pacific bluefin tuna were subspecies of a single species. In 1999, Collette established that based on molecular and morphological considerations, they are in fact distinct species. The genus Thunnus is further classified into two subgenera, Thunnus, and Thunnus, the Thunnini tribe also includes seven additional species of tuna across four genera. They are, The tuna is a sleek and streamlined fish and it has two closely spaced dorsal fins on its back, The first is depressible – it can be laid down, flush, in a groove that runs along its back. Seven to ten yellow finlets run from the fins to the tail. The caudal peduncle, to which the tail is attached, is quite thin, the tunas dorsal side is generally a metallic dark blue, while the ventral side, or underside, is silvery or whitish, for camouflage. Thunnus are widely but sparsely distributed throughout the oceans of the world, generally in tropical, all tunas are able to maintain the temperature of certain parts of their body above the temperature of ambient seawater. For example, bluefin can maintain a body temperature of 25–33 °C. However, unlike typical endothermic creatures such as mammals and birds, tunas achieve endothermy by conserving the heat generated through normal metabolism. In all tunas, the heart operates at ambient temperature, as it receives cooled blood, also unlike most fish, which have white flesh, the muscle tissue of tuna ranges from pink to dark red. The red myotomal muscles derive their color from myoglobin, an oxygen-binding molecule, the oxygen-rich blood further enables energy delivery to their muscles. For powerful swimming animals like dolphins and tuna, cavitation may be detrimental, even if they have the power to swim faster, dolphins may have to restrict their speed, because collapsing cavitation bubbles on their tail are too painful
32.
Forage fish
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Forage fish, also called prey fish or bait fish, are small pelagic fish which are preyed on by larger predators for food. Predators include other fish, seabirds and marine mammals. Typical ocean forage fish feed near the base of the chain on plankton. They include particularly fishes of the family Clupeidae, but also small fish, including halfbeaks, silversides, smelt such as capelin. Forage fish compensate for their size by forming schools. Some swim in synchronised grids with their mouths open so they can efficiently filter plankton and these schools can become immense shoals which move along coastlines and migrate across open oceans. The shoals are concentrated fuel resources for the marine predators. The ocean primary producers, mainly contained in plankton, produce energy from the sun and are the raw fuel for the ocean food webs. Forage fish transfer this energy by eating the plankton and becoming food themselves for the top predators, in this way, forage fish occupy the central positions in ocean and lake food webs. The fishing industry catches forage fish primarily for feeding to farmed animals, some fisheries scientists are expressing concern that this will affect the populations of predator fish that depend on them. Herrings are a preeminent forage fish, often marketed as sardines or pilchards, the term “forage fish” is a term used in fisheries, and is applied also to forage species that are not true fish, but play a significant role as prey for predators. Thus invertebrates such as squid and shrimp are also referred to as forage fish, even the tiny shrimp-like creatures called krill, small enough to be eaten by other forage fish, yet large enough to eat the same zooplankton as forage fish, are often classified as forage fish. Forage fish utilise the biomass of copepods, mysids and krill in the zone to become the dominant converters of the enormous ocean production of zooplankton. They are, in turn, central prey items for higher trophic levels, Forage fish may have achieved their dominance because of the way they live in huge, and often extremely fast cruising schools. Though forage fish are abundant, there are few species. There are more species of primary producers and apex predators in the ocean there are forage fish. Forage fish occupy central positions in the food webs. The position that a fish occupies in a web is called its trophic level
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Anchovy
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An anchovy is a small, common salt-water forage fish of the family Engraulidae. The 144 species are placed in 17 genera, they are found in the Atlantic, Indian, and Pacific Oceans, and in the Black Sea, Anchovies are usually classified as oily fish. Anchovies are small, green fish with blue reflections due to a longitudinal stripe that runs from the base of the caudal fin. They range from 2 to 40 cm in length. The snout is blunt with tiny, sharp teeth in both jaws, the snout contains a unique rostral organ, believed to be sensory in nature, although its exact function is unknown. The mouth is larger than that of herrings and silversides, two fish which anchovies closely resemble in other respects, the anchovy eats plankton and recently hatched fish. Anchovies are found in scattered areas throughout the oceans, but are concentrated in temperate waters. They are generally accepting of a wide range of temperatures. Large schools can be found in shallow, brackish areas with muddy bottoms, as in estuaries and they are abundant in the Mediterranean, particularly in the Alboran Sea, Aegean Sea and the Black Sea. The species is caught along the coasts of Crete, Greece, Sicily, Italy, France, Turkey. They are also found on the coast of northern Africa, the range of the species also extends along the Atlantic coast of Europe to the south of Norway. Spawning occurs between October and March, but not in water colder than 12 °C, the anchovy appears to spawn at least 100 km from the shore, near the surface of the water. The anchovy is a significant food source for almost every predatory fish in its environment, including the California halibut, rock fish, yellowtail, shark, chinook, and coho salmon. It is also important to marine mammals and birds, for example, breeding success of California brown pelicans. Anchovies, like most clupeoids, are filter-feeders that open their mouths as they swim, as water passes through the mouth and out the gills, food particles are sieved by gill rakers and transferred into the esophagus. * Type species On average, the Turkish commercial fishing fleet catches around 300,000 tons per year, the largest catch is in November and December. The Peruvian anchovy fishery is one of the largest in the world, in 1973 it collapsed catastrophically due to the combined effects of overfishing and El Niño and did not recover fully for two decades. A traditional method of processing and preserving anchovies is to gut and salt them in brine, allow them to mature and this results in a characteristic strong flavor and the flesh turns deep grey
34.
Herring
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Herring are forage fish, mostly belonging to the family Clupeidae. Herring often move in schools around fishing banks and near the coast. Three species of Clupea are recognised, and provide about 90% of all captured in fisheries. Most abundant of all is the Atlantic herring, providing half of all herring capture. Fishes called herring are found in India, in the Arabian Sea, Indian Ocean. Herring played a role in the history of marine fisheries in Europe. These oily fish also have a history as an important food fish. A number of different species, most belonging to the family Clupeidae, are referred to as herrings. The origins of the herring is somewhat unclear, though it may derive from the Old High German heri meaning a host, multitude. The type genus of the herring family Clupeidae is Clupea, Clupea contains three species, the Atlantic herring found in the north Atlantic, the Pacific herring found in the north Pacific, and the Araucanian herring found off the coast of Chile. Subspecific divisions have been suggested for both the Atlantic and Pacific herrings, but their biological basis remain unclear, in addition, a number of related species, all in the family Clupeidae, are commonly referred to as herrings. The table immediately below includes those members of the Clupeidae family referred to by FishBase as herrings which have been assessed by the International Union for Conservation of Nature. There are also a number of other species called herrings, which may be related to clupeids or just share some characteristics of herrings. Just which of these species are called herrings can vary with locality, some examples, The species of Clupea belong to the larger family Clupeidae, which comprises some 200 species that share similar features. These silvery-coloured fish have a dorsal fin, which is soft. They have no lateral line and have a lower jaw. At least one stock of Atlantic herring spawns in every month of the year, each spawns at a different time and place. Greenland populations spawn in 0–5 metres of water while North Sea herrings spawn at up to 200 metres in autumn
35.
Menhaden
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Menhaden, also known as mossbunker and bunker, are forage fish of the genera Brevoortia and Ethmidium, two genera of marine fish in the family Clupeidae. Menhaden is a blend of poghaden and an Algonquian word akin to Narragansett munnawhatteaûg, derived from munnohquohteau ‘he fertilizes’ and it is generally thought that Pilgrims were advised by Tisquantum to plant menhaden with their crops. Menhaden are flat, have soft flesh, and a forked tail. They rarely exceed 15 inches in length, and have a weight range. Gulf menhaden and Atlantic menhaden are small oily-fleshed fish, bright silver and they tend to have larger scales than Yellowfin menhaden and Finescale menhaden. In addition, Yellowfin menhaden tail rays are a yellow in contrast to those of the Atlantic menhaden. Recent taxonomic work using DNA comparisons have organized the North American menhadens into large-scaled and small-scaled designations, Menhaden have two main sources of food, phytoplankton and zooplankton. A menhaden’s diet varies considerably over the course of its lifetime, the smallest menhaden, typically those under one year old, eat primarily phytoplankton. After that age, adult menhaden gradually shift to a diet comprised almost exclusively of zooplankton, Menhaden are omnivorous filter feeders, feeding by straining plankton and algae from water. Along with oysters, which water on the sea bed, menhaden play a key role in the food chain in estuaries. Atlantic menhaden are an important link between plankton and upper level predators, because of their filter feeding abilities, menhaden consume and redistribute a significant amount of energy within and between Chesapeake Bay and other estuaries, and the coastal ocean. Because they play this role, and their abundance, menhaden are a prey species for many predatory fish, such as striped bass, bluefish, mackerel, flounder, tuna, drums. They are also an important food source for many birds, including egrets, ospreys, seagulls, northern gannets, pelicans. In 2012 the Atlantic States Marine Fisheries Commission declared that the Atlantic menhaden was depleted due to overfishing, the decision was driven by issues with water quality in the Chesapeake Bay and failing efforts to re-introduce predator species, due to lack of menhaden on which they could feed. Menhaden are not used directly for food and they are processed into fish oil and fish meal that are used as food ingredients, animal feed, and dietary supplements. It has a high fat content. Fish oil made from menhaden also is used as a raw material for such as lipstick. According to James Kirkley of the Virginia Institute of Marine Science, the first is known as a reduction fishery
36.
Sardine
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Sardine and pilchard are common names used to refer to various small, oily fish within the herring family of Clupeidae. The term sardine was first used in English during the early 15th century and may come from the Mediterranean island of Sardinia, the terms sardine and pilchard are not precise, and what is meant depends on the region. The United Kingdoms Sea Fish Industry Authority, for example, classifies sardines as young pilchards, one criterion suggests fish shorter in length than 15 cm are sardines, and larger fish are pilchards. Typically, sardines are caught with encircling nets, particularly purse seines, many modifications of encircling nets are used, including traps or weirs. The latter are stationary enclosures composed of stakes into which schools of sardines are diverted as they swim along the coast, the fish are caught mainly at night, when they approach the surface to feed on plankton. After harvesting, the fish are submerged in brine while they are transported to shore, sardines are commercially fished for a variety of uses, for bait, for immediate consumption, for drying, salting, or smoking, and for reduction into fish meal or oil. The chief use of sardines is for consumption, but fish meal is used as animal feed, while sardine oil has many uses, including the manufacture of paint, varnish. Sardines are commonly consumed by human beings, fresh sardines are often grilled, pickled or smoked, or preserved in cans. Sardines are rich in vitamins and minerals, a small serving of sardines once a day can provide 13 percent of vitamin B2, roughly one-quarter of niacin, and about 150 percent of the recommended daily value of vitamin B12. All B vitamins help to support proper nervous system function and are used for energy metabolism, also, sardines are high in the major minerals such as phosphorus, calcium, potassium, and some trace minerals including iron and selenium. Sardines are also a source of marine omega-3 fatty acids. Recent studies suggest that consumption of omega-3 fatty acids reduces the likelihood of developing Alzheimers disease. These fatty acids can also lower blood sugar levels and they are also a good source of vitamin D, calcium, vitamin B12, and protein. Because they are low in the chain, sardines are very low in contaminants such as mercury. Pilchard fishing and processing became an industry in Cornwall from around 1750 to around 1880. Catches varied from year to year and, in 1871 the catch was 47,000 hogsheads while in 1877 only 9,477 hogsheads, a hogshead contained 2,300 to 4,000 pilchards and, when filled with pressed pilchards, weighed 476 lbs. The pilchards were exported to Roman Catholic countries such as Italy. The chief market for the oil was Bristol where it is used on machinery, as of 2007, however, stocks are improving
37.
Alosinae
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The Alosinae, or the shads, are a subfamily of fishes in the herring family Clupeidae. The subfamily comprises seven genera worldwide, and about 30 species, the shads are pelagic schooling fish, of which many are anadromous or even landlocked. Several species are of importance, e. g. in the genus Alosa, Brevoortia. The Shad Foundation Shad Planking, a Virginia political gathering featuring the consumption of shad
38.
Sprat
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A sprat is the common name applied to a group of forage fish belonging to the genus Sprattus in the family Clupeidae. The term is applied to a number of other small sprat-like forage fish. Like most forage fishes, sprats are highly active small oily fish and they travel in large schools with other fish and swim continuously throughout the day. They are also recognized for their value as they contain high levels of polyunsaturated fats. Sprats are sometimes passed for other fish, products sold as having been prepared from anchovies and sardines are sometimes prepared from sprats and they are known for their smooth flavour and are easy to mistake for baby sardines. True sprats belong to the genus Sprattus in the family Clupeidae, * Type species The term is also commonly applied to a number of other small sprat-like forage fish which share characteristics of the true sprat. Apart from the true sprats, FishBase list another 48 species whose common names ends with sprat, the development of young larval sprat and reproductive success of the sprat have been largely influenced by environmental factors. Some of these factors that are affecting the sprat can be seen in the Baltic Sea, where specific gravity, water temperature, depth, and other such factors play a role in the success of the sprat. The amount of sprat over the last two decades has fluctuated due primarily to availability of zooplankton, a food source. Although the overall survival rates of the sprat decreased in the late 1980s and early 1990s, recent studies suggesting that there is a progression in the reproductive success of the sprat acknowledge that there has been a significant increase in spawning stock biomass. The metabolic rate of the sprat is highly influenced by factors such as water temperature. Several related fish such as the Atlantic Herring have a lower metabolic rate than that of the sprat. Fish of the different species of sprat are found in parts of the world including New Zealand, Australia. By far, the most highly studied location where the sprat, most commonly Sprattus sprattus, resides is the Baltic Sea, the Baltic Sea provides the sprat with a highly diverse environment, with spatial and temporal potential allowing for successful reproduction. One of the most well-known locations in the Baltic Sea where they forage for their food is the Bornholm Basin, although the Baltic Sea has undergone several ecological changes during the last two decades, the sprat has dramatically increased in population. In the Baltic Sea, cod, herring, and sprat are considered the most important species, cod is the top predator while the herring and sprat are recognized primarily as prey. This has been proven by many studies that analyze the contents of such fish. Although cod primarily feed on adult sprat, sprat tend to feed on cod before they have fully developed
39.
Demersal fish
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Demersal fish live and feed on or near the bottom of seas or lakes. They occupy the sea floors and lake beds, which usually consist of mud, sand, in coastal waters they are found on or near the continental shelf, and in deep waters they are found on or near the continental slope or along the continental rise. They are not generally found in the deepest waters, such as abyssal depths or on the abyssal plain, the word demersal comes from the Latin demergere, which means to sink. They can be contrasted with fish which live and feed away from the bottom in the open water column. Demersal fish fillets contain little fish oil, whereas pelagic fish can contain up to 30 percent. Demersal fish can be divided into two types, strictly benthic fish which can rest on the sea floor, and benthopelagic fish which can float in the water column just above the sea floor. As with other bottom feeders, a mechanism to deal with substrate is often necessary, with demersal fish the sand is usually pumped out of the mouth through the gill slit. Most demersal fish exhibit a ventral region so as to more easily rest their body on the substrate. The exception may be the flatfish, which are laterally depressed, also, many exhibit what is termed an inferior mouth, which means that the mouth is pointed downwards, this is beneficial as their food is often going to be below them in the substrate. Those bottom feeders with upward-pointing mouths, such as stargazers, tend to seize swimming prey, benthic fish, sometimes called groundfish, are denser than water, so they can rest on the sea floor. They either lie-and-wait as ambush predators, maybe covering themselves with sand or otherwise camouflaging themselves, benthic fish which can bury themselves include dragonets, flatfish and stingrays. Flatfish are an order of ray-finned benthic fishes which lie flat on the ocean floor, examples are flounder, sole, turbot, plaice, and halibut. The adult fish of many species have eyes on one side of the head. When the fish hatches, one eye is located on side of its head. But as the fish grows from the stage, one eye migrates to the other side of the body as a process of metamorphosis. The flatfish then changes its habits, and camouflages itself by lying on the bottom of the floor with both eyes facing upwards. The side on which the eye migrates depends on the species, flounder ambush their prey, feeding at soft muddy area of the sea bottom, near bridge piles, docks, artificial and coral reefs. Their diet consists mainly of fish spawn, crustaceans, polychaetes, the great hammerhead swings its head in broad angles over the sea floor to pick up the electrical signatures of stingrays buried in the sand
40.
Cod
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Cod is the common name for the genus Gadus of demersal fishes, belonging to the family Gadidae. Cod is also used as part of the name for a number of other fish species. Gadus morhua was named by Linnaeus in 1758, Cod is popular as a food with a mild flavour and a dense, flaky, white flesh. Cod livers are processed to make cod liver oil, an important source of vitamin A, vitamin D, vitamin E, young Atlantic cod or haddock prepared in strips for cooking is called scrod. In the United Kingdom, Atlantic cod is one of the most common ingredients in fish and chips, along with haddock, at various times in the past, taxonomists included many species in the genus Gadus. Most of these are now classified in other genera, or have been recognized as simply forms of one of three species. All these species have a number of names, most of them ending with the word cod, whereas other species. However, many other, unrelated species also have names ending with cod. The usage often changes with different localities and at different times, three species in the Gadus genus are currently called cod, Cod forms part of the common name of many other fish no longer classified in the genus Gadus. The tadpole cod family has now placed in Gadidae. Gadiformes include, Some fish have common names derived from cod, such as codling, Some fish commonly known as cod are unrelated to Gadus. Part of this confusion is market-driven. Severely shrunken Atlantic cod stocks have led to the marketing of cod replacements using culinary names of the form x cod, the common names for the following species have become well established, note that all inhabit the Southern Hemisphere. Most are better known as groupers, and belong to the family Serranidae, Some fish that do not have cod in their names are sometimes sold as cod. Haddock and whiting belong to the family, the Gadidae. Haddock Melanogrammus aeglefinus Whiting Merlangius merlangus Cods of the genus Gadus have three rounded dorsal and two anal fins, the pelvic fins are small, with the first ray extended, and are set under the gill cover, in front of the pectoral fins. The upper jaw extends over the jaw, which has a well-developed chin barbel. The eyes are medium-sized, approximately the same as the length of the chin barbel, Cod have a distinct white lateral line running from the gill slit above the pectoral fin, to the base of the caudal or tail fin
41.
Eel
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An eel is any fish belonging to the order Anguilliformes, which consists of four suborders,20 families,111 genera and about 800 species. The term eel is used for some other similarly shaped fish, such as electric eels and spiny eels. Eels are elongated fish, ranging in length from 5 cm in the eel to 4 m in the slender giant moray. Adults range in weight from 30 g to well over 25 kg and they possess no pelvic fins, and many species also lack pectoral fins. The dorsal and anal fins are fused with the caudal fin, eels swim by generating body waves which travel the length of their bodies. They can swim backwards by reversing the direction of the wave, most eels live in the shallow waters of the ocean and burrow into sand, mud, or amongst rocks. A majority of eel species are nocturnal, thus are rarely seen, sometimes, they are seen living together in holes, or eel pits. Some species of eels live in deeper water on the continental shelves. Only members of the Anguilla regularly inhabit fresh water, but they, too, the heaviest true eel is the European conger. The maximum size of species has been reported as reaching a length of 3 m. Other eels are longer, but do not weigh as much, such as the giant moray which reaches 4 m. Eels begin life as flat and transparent larvae, called leptocephali, Eel larvae drift in the surface waters of the sea, feeding on marine snow, small particles that float in the water. Eel larvae then metamorphose into glass eels and then become elvers before finally seeking out their juvenile, freshwater elvers travel upstream and are forced to climb up obstructions, such as weirs, dam walls, and natural waterfalls. Lady Colin Campbell found, at Ballisodare, the eel fisheries were greatly improved by the hanging of loosely plaited grass ladders over barriers and this classification follows FishBase in dividing the eels into 20 families. Additional families included in other classifications are noted below the family with which they are synomized in the Fish Base system, identifying the origin of the freshwater species has been problematic. Genomic studies indicate they are a group which originated among the deep-sea eels. The electric eel of South America is not a true eel, freshwater eels and marine eels are commonly used in Japanese cuisine, foods such as unadon and unajū are popular, but expensive. Eels are also popular in Chinese cuisine, and are prepared in many different ways
42.
Flatfish
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A flatfish is a member of the order Pleuronectiformes of ray-finned demersal fishes, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both lie on one side of the head, one or the other migrating through. Some species face their left sides upward, some face their right sides upward, many important food fish are in this order, including the flounders, soles, turbot, plaice, and halibut. Some flatfish can camouflage themselves on the ocean floor. Over 700 species are in the 11 families, the largest families are Bothidae, Cynoglossidae, Paralichthyidae, Pleuronectidae, and Soleidae, with more than 100 species each. Some families are the results of relatively recent splits, for example, the Achiridae were classified as a subfamily of Soleidae in the past, and the Samaridae were considered a subfamily of the Pleuronectidae. The Pleuronectidae may be split further still, as some authorities elevate Paralichthodinae, Poecilopsettinae, the taxonomy of some groups is in need of a review, as the last monograph covering the entire order was John Roxborough Normans Monograph of the Flatfishes published in 1934. New species are described with some regularity and undescribed species likely remain, hybrids are well known in flatfishes. The Pleuronectidae, of fishes, have the largest number of reported hybrids. Two of the most famous intergeneric hybrids are between the European plaice and European flounder in the Baltic Sea, and between the English sole and starry flounder in Puget Sound. The offspring of the species pair is popularly known as the hybrid sole and was initially believed to be a valid species in its own right. Flatfishes are found in worldwide, ranging from the Arctic, through the tropics. Most species are found in depths between 0 and 500 m, but a few have been recorded from depths in excess of 1,500 m, none have been confirmed from the abyssal or hadal zones. Among the deepwater species, Symphurus thermophilus lives in congregating around ponds of sulphur at hydrothermal vents on the seafloor, no other flatfish is known from hydrothermal vents. Many species will enter brackish or fresh water, and a number of soles. The most obvious characteristic of the flatfish is its asymmetry, with both eyes lying on the side of the head in the adult fish. In some families, the eyes are usually on the side of the body. The primitive spiny turbots include equal numbers of right- and left-sided individuals, other distinguishing features of the order are the presence of protrusible eyes, another adaptation to living on the seabed, and the extension of the dorsal fin onto the head
43.
Pollock
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Pollock is the common name used for either of the two species of North Atlantic marine fish in the genus Pollachius. Pollachius pollachius is referred to as pollock in both North America and the United Kingdom, while Pollachius virens today is known as coley in the British Isles. Other names for P. pollachius include the Atlantic pollock, European pollock, lieu jaune, the currently recognized species in this genus are, P. pollachius P. virens Both species can grow to 105 centimetres and can weigh up to 21 kilograms. P. virens has a defined, silvery lateral line running down the sides. Above the lateral line, the color is a greenish black, the belly is white, while P. pollachius has a distinctly crooked lateral line, grayish to golden belly, and a dark brown back. P. pollachius also has a strong underbite and it can be found in water up to 180 metres deep over rocks, and anywhere in the water column. One member of the genus Gadus is also referred to as Pollock. While related to the above pollock species, they are not members of the genus Pollachius, Alaska pollock generally spawn in late winter and early spring in the southeastern Bering Sea. The Alaska pollock is a significant part of the fishery in the Gulf of Alaska. Atlantic pollock is considered to be a whitefish, although it is a fairly strongly flavored one. Traditionally a popular source of food in countries, such as Norway, in the United Kingdom it has previously been largely consumed as a cheaper and versatile alternative to cod. However, in recent years, pollock has become popular due to overfishing of cod. It can now be found in most supermarkets as fresh fillets or prepared freezer items, for example, it is used minced in fish fingers or as an ingredient in imitation crab meat. Because of its gray color, pollock is often prepared, as in Norway, as fried fish balls, or if juvenile sized, breaded with oatmeal and fried. Year-old fish are split, salted, and dried over a peat hearth in Orkney. The fish can also be salted and smoked and achieve a salmon-like orange color, as is the case in Germany, in Korea, pollock may be repeatedly frozen and defrosted to create hwangtae, half-dried to create ko-da-ri, or fully dried and eaten as book-o. In 2009, U. K. supermarket Sainsburys briefly renamed pollock colin in a bid to boost ecofriendly sales of the fish as an alternative to cod. Sainsburys, which said the new name was derived from the French for cooked pollock, launched the product under the banner Colin, froese, Rainer, and Daniel Pauly, eds
44.
Batoidea
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Batoidea is a superorder of cartilaginous fish commonly known as rays. They and their relatives, the sharks, comprise the subclass Elasmobranchii. Rays are the largest group of fishes, with well over 600 species in 26 families. Rays are distinguished by their bodies, enlarged pectoral fins that are fused to the head. Batoids are flat-bodied, and, like sharks, are marine fish, meaning they have a boneless skeleton made of a tough. Most batoids have five ventral slot-like body openings called gill slits that lead from the gills, batoid gill slits lie under the pectoral fins on the underside, whereas a sharks are on the sides of the head. Most batoids have a flat, disk-like body, with the exception of the guitarfishes and sawfishes, many species of batoid have developed their pectoral fins into broad flat wing-like appendages. The eyes and spiracles are located on top of the head, Batoids have a ventrally located mouth and can considerably protrude their upper jaw away from the cranium to capture prey. The jaws have euhyostylic type suspension, which relies completely on the hyomandibular cartilages for support, bottom-dwelling batoids breathe by taking water in through the spiracles, rather than through the mouth as most fishes do, and passing it outward through the gills. Batoids reproduce in a number of ways, as is characteristic of elasmobranchs, batoids undergo internal fertilisation. All skates and some rays are oviparous while other rays are ovoviviparous, meaning that they give birth to young which develop in a womb but without involvement of a placenta. The eggs of oviparous skates are laid in egg cases that are commonly known as mermaids purses. Most species live on the sea floor, in a variety of geographical regions — mainly in coastal waters, most batoids have a cosmopolitan distribution, preferring tropical and subtropical marine environments, although there are temperate and cold-water species. Only a few species, like manta rays, live in the open sea, most batoids have developed heavy, rounded teeth for crushing the shells of bottom-dwelling species such as snails, clams, oysters, crustaceans, and some fish, depending on the species. The classification of batoids is currently undergoing revision, however, molecular evidence refutes the hypothesis that skates, nelsons 2006 Fishes of the World recognizes four orders. The Mesozoic Sclerorhynchoidea are basal or incertae sedis, they show features of the Rajiformes but have snouts resembling those of sawfishes, Rays are basically flattened sharks, adapted for feeding on the bottom. Guitarfish are somewhat between sharks and rays, and show characteristics of both, list of threatened rays Shark references. Database of bibliography of living/fossil sharks and rays with more than 15.000 listed papers, martin, R Aidan, Batoids, Sawfishes, Guitarfishes, Electric Rays, Skates, and Sting Rays, Elasmo research, ReefQuest Centre for Shark Research
45.
Carp
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Carp are various species of oily freshwater fish from the family Cyprinidae, a very large group of fish native to Europe and Asia. The cypriniformes are traditionally grouped with the Characiformes, Siluriformes, and Gymnotiformes to create the superorder Ostariophysi, the third anterior-most pair of ribs is in contact with the extension of the labyrinth and the posterior with the swim bladder. Most cypriniformes have scales and teeth on the pharyngeal bones which may be modified in relation to the diet. Tribolodon is the only cyprinid genus which tolerates salt water, several species move into brackish water but return to fresh water to spawn. All of the other cypriniformes live in waters and have a wide geographical range. Some consider all cyprinid fishes carp, and the family Cyprinidae itself is known as the carp family. Carp have long been an important food fish to humans, several species such as the various goldfish breeds and the domesticated common carp variety known as koi have been popular ornamental fishes. As a result, carp have been introduced to various locations, several species of carp are listed as invasive species by the U. S. Department of Agriculture, and, worldwide, large sums of money are spent on carp control. At least some species of carp are able to survive for months with no oxygen by metabolizing glycogen to form ethanol. Carp are variable in terms of angling value, in Europe, even when not fished for food, they are eagerly sought by anglers, being considered highly prized coarse fish that are difficult to hook. The UK has a thriving carp angling market, in the United States, carp are also classified as a rough fish, as well as damaging to naturalized exotic species, but with sporting qualities. Many states departments of natural resources are beginning to view the carp as a fish instead of a maligned pest. Various species of carp have been domesticated and reared as food fish across Europe and these various species appear to have been domesticated independently, as the various domesticated carp species are native to different parts of Eurasia. Aquaculture has been pursued in China for at least 2,400 years, a tract by Fan Li in the fifth century BC details many of the ways carp were raised in ponds. The common carp, Cyprinus carpio, is originally from Central Europe, several carp species were domesticated in East Asia. Carp that are originally from South Asia, for example catla, rohu and their hardiness and adaptability have allowed domesticated species to be propagated all around the world. Although the carp was an important aquatic food item, as fish species have become readily available for the table. Demand has declined, partly due to the appearance of more desirable fish such as trout and salmon through intensive farming
Near threatened[10]
Critically endangered[3]
Vulnerable[13]
Endangered[17]
Least concern[19]
Data deficient[21]
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Tuna pole and line fishing BBC Two
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