10. Taimen (6′ 11″ – 231 lbs)
The taimen is distributed from the Volga and Pechora River basins east to the Yana River in the north to the Amur River in the south. On a larger scale, this includes parts of the Caspian and Arctic drainages in Eurasia and portions of the Pacific drainage in Mongolia and Russia (the Amur River). In Mongolia, the taimen is found in both the Arctic and Pacific drainages, specifically the Yenisei/Selenga, the Lena, and the Amur River Basins. The taimen lives in flowing water and is only occasionally found in lakes, usually near the mouth of a tributary. The taimen is not anadromous, but does show increased movement rates during the spawning season. The average home range size of taimen in the E.g.-Uur River of Mongolia is 23 kilometres (14 mi), but some tagged individuals show home ranges up to 93 kilometres (58 mi).Some authors consider the taimen to be a subspecies of the huchen, i.e. Hucho hucho taimen.
Coloration varies geographically, but is generally olive green on the head blending to reddish brown in the tail. Adipose, anal, and caudal fins are often dark red. The belly ranges from nearly white to dark gray. The taimen is one of the largest salmonids in the world. Most mature fish caught weigh from 15 to 30 kg (33 to 66 lb). The average length is from 70 to 120 cm (28 to 47 in). The maximum size is not assured, but supposedly a fish caught in the Kotui River in Russia in 1943 with a length of 210 cm (83 in) and a weight of 105 kg (231 lb) is the largest size recorded. The maximum length is about 150 to 180 cm (59 to 71 in). The IGFA world record is 92.5 lb or 41.95 kg with a length of 156 cm. It can reach at least 55 years of age.
9. Alligator Gar (10 ft – 327 lbs)
Alligator gar (Atractosteus spatula) are ray-finned euryhaline fish related to bowfin in the infraclass Holostei (ho’-las-te-i). The fossil record traces their existence to the Early Cretaceous over a hundred million years ago. They are the largest species in the gar family, and among the largest freshwater fishes in North America. Gars are often referred to as “primitive fishes“, or “living fossils” because they have retained some morphologicalcharacters of their earliest ancestors, such as a spiral valve intestine which is also common to the digestive system of sharks, and they can breathe both air and water. Their common name was derived from their resemblance to American alligator, particularly their broad snout and long sharp teeth. Anecdotal evidence in several scientific reports suggest that an alligator gar can grow up to 10 ft (3.0 m) in length and weigh as much as 300 lb (140 kg); however in 2011 the largest alligator gar ever caught and officially recorded was 8 ft 5 1⁄4 in (2.572 m) long, weighed 327 lb (148 kg), and was 47 in (120 cm) around the girth.
The body of an alligator gar is torpedo shaped, usually brown or olive fading to a lighter gray or yellow ventral surface. Their scales are not like the scales of other fishes, rather they have ganoid scales which are hard, enamel-like, diamond-shaped scales, often with serrated edges. Ganoid scales are nearly impenetrable and have served the fish well as protection against predation. Unlike other gar species, the upper jaw of an alligator gar has a dual row of large sharp teeth which are used to impale and hold prey. Alligator gar are stalking, ambush predators, primarily piscivores, but they will also ambush and eat water fowl and small mammals they find floating on the water’s surface.
Populations of alligator gar have been extirpated from much of their historic range as a result of habitat destruction, indiscriminate culling, and unrestricted harvests. Populations are now located primarily in the southern portions of the United States extending into Mexico. They are considered euryhaline because they can adapt to varying salinities ranging from freshwater lakes and swamps to brackish marshes, estuaries, and bays along the Gulf of Mexico.
For nearly a half-century, alligator gar were considered “trash fish”, or a “nuisance species” detrimental to sport fisheries; therefore, were targeted for elimination by state and federal authorities in the United States. The 1980s brought a better understanding of the ecological balance necessary to sustain an ecosystem, and eventually an awareness that alligator gar were no less important than any other living organism in the ecosystemsthey inhabit. Over time, alligator gar were afforded some protection by state and federal resource agencies. They are also protected under the Lacey Act which makes it illegal to transport certain species of fish in interstate commerce when in violation of state law or regulation. Several state and federal resource agencies are monitoring populations in the wild, and have initiated outreach programs to educate the public. Alligator gar are beingcultured in ponds, pools, raceways and tanks by federal hatcheries for mitigation stocking, by universities for research purposes, and in Mexico for consumption.
8. Nile Perch (6 ft – 440 lbs)
The Nile perch (Lates niloticus) is a species of freshwater fish in family Latidae of order Perciformes. It is widespread throughout much of the Afrotropic ecozone, being native to the Congo, Nile, Senegal, Niger, and Lake Chad,Volta, Lake Turkana, and other river basins. It also occurs in the brackish waters of Lake Maryut in Egypt. Originally described as Labrus niloticus, among the marine wrasses, the species has also been referred to as Centropomus niloticus. Common names include African snook, Victoria perch (a misleading trade name, as the species is not native to Lake Victoria), and a large number of local names in various African languages, such as the Luo name mbuta or mputa. In Tanzania, it is called sangara, sankara or chenku. In Francophone African countries, it is known as capitaine and in Egypt/Sudan as am’kal. Its name in the Hausa language is giwan ruwa, meaning “water elephant”.
Lates niloticus is silver in colour with a blue tinge. It has distinctive dark-black eyes, with a bright-yellow outer ring. One of the largest freshwater fish, it reaches a maximum length of nearly 2 m (more than 6 ft), weighing up to 200 kg (440 lb). Mature fish average 121–137 cm (47.5–54 in), although many fish are caught before they can grow this large.
7. Arapaima (15 ft – 440 lbs)
The arapaima, pirarucu, or paiche are any large species of bonytongue in the genus Arapaima native to the Amazon and Essequibo basins of South America. Genus Arapaima is the type genus of the familyArapaimidae. They are an important food fish. They have declined in the native range due to overfishing and habitat loss. In contrast, arapaima have been introduced to several tropical regions outside the native range (within South America and elsewhere) where they are sometimes considered invasive species. Its local name, pirarucu, derives from the indigenous words for “pira” meaning “fish” and “urucum” meaning “red”.
Arapaima can reach lengths of more than 2 m (6 ft 7 in), in some exceptional cases even more than 2.5 m (8 ft 2 in) and over 100 kg (220 lb). The maximum recorded weight for the species is 200 kg (440 lb), while the longest recorded length was 4.52 m (15 ft). As a result of overfishing, large arapaima of more than 2 m (6 ft 7 in) are seldom found in the wild.
6. Bull Shark (13 ft – 694 lbs)
The bull shark (Carcharhinus leucas), also known as the Zambezi shark or, unofficially, as Zambi in Africa and Nicaragua shark in Nicaragua, is a requiem shark commonly found worldwide in warm, shallow waters along coasts and in rivers. The bull shark is known for its aggressive nature, predilection for warm shallow water, and presence in brackish and freshwater systems including estuaries and rivers.
Bull sharks can thrive in both saltwater and freshwater and can travel far up rivers. They have been known to travel as far up the Mississippi River as Illinois, although there have been few recorded freshwater human-shark interactions. They are probably responsible for the majority of near-shore shark attacks, including many bites attributed to other species.
Bull sharks are large and stout, with females being larger than males. The bull shark can be up to 81 cm (2.66 ft) in length at birth. Adult female bull sharks average 2.4 m (7.9 ft) long and typically weigh 130 kg (290 lb), whereas the slightly smaller adult male averages 2.25 m (7.4 ft) and 95 kg (209 lb). While a maximum size of 3.5 m (11 ft) is commonly reported, there is a questionable record of a female specimen of exactly 4 m (13 ft). The maximum recorded weight of a bull shark was 315 kg (694 lb) but may be larger. Bull sharks are wider and heavier than other requiem sharks of comparable length, and are grey on top and white below. The second dorsal fin is smaller than the first. The bull shark’s caudal fin is longer and lower than that of the larger sharks, and it has a small snout, and lacks an interdorsal ridge.
Bull sharks have a bite force of up to 5,914 newtons (1,330 lbf), weight for weight the highest among all investigated cartilaginous fishes.
5. Mekong Giant Catfish (9.8 ft – 770 lb)
The Mekong giant catfish, Pangasianodon gigas (Thai: ปลาบึก, rtgs: pla buek, pronounced [plāː bɯ̀k]; Khmer: ត្រីរាជ /trəy riec/; Vietnamese: cá tra dầu), is a very large, critically endangered species of catfish (orderSiluriformes) in the shark catfish family (Pangasiidae), native to the Mekong basin in Southeast Asia and adjacent China. In Thai folklore, this fish is regarded with reverence, and special rituals are followed and offerings are made before fishing it.
Grey to white in colour and lacking stripes, the Mekong giant catfish is distinguished from other large catfish species in this river by the near-total lack of barbels and the absence of teeth. The Mekong giant catfish currently holds the Guinness Book of World Records‘ position for the world’s largest freshwater fish. Attaining an unconfirmed length of 3 m (9.8 ft), the Mekong giant catfish grows extremely quickly, reaching a mass of 150 to 200 kg (330 to 440 lb) in six years. It can reportedly weigh up to 350 kg (770 lb). The largest catch recorded in Thailand since record-keeping began in 1981 was a female measuring 2.7 m (8 ft 10 in) in length and weighing 293 kg (646 lb). This specimen, caught in 2005, is widely recognized as the largest freshwater fish ever caught (although the largest sturgeon species can far exceed this size, they are anadromous). Thai Fisheries officials stripped the fish of its eggs as part of a breeding programme, intending then to release it, but the fish died in captivity and was sold as food to local villagers.
4. Chinese Paddle Fish (23 ft – 1,100 lbs)
Paddlefish (family Polyodontidae) are basal Chondrostean ray-finned fish. They have been referred to as “primitive fish” because they have evolved with few morphological changes since the earliest fossil records of theLate Cretaceous, seventy to seventy-five million years ago. Polyodontids are exclusively North American with the exception of the genus Psephurus, which includes solely the Chinese paddlefish (Psephurus gladius).
There are five known taxa: three extinct taxa from western North America, and two extant taxa, including the American paddlefish (Polyodon spathula) which is native to the Mississippi River basin in the U.S. and the critically endangered Chinese paddlefish (Psephurus glades) which is endemic to the Yangtze River Basin in China. Chinese paddlefish are also commonly referred to as “Chinese swordfish”, or “elephant fish”.
Paddlefish populations have declined dramatically throughout their historic range as a result of overfishing, pollution, and the encroachment of human development, including the construction of dams that have blocked their seasonal upward migration to ancestral spawning grounds. Other detrimental effects include alterations of rivers which have changed natural flows resulting in the loss of spawning habitat and nursery areas. Chinese paddlefish have not been seen in the wild since 2003, and may now be extinct for many of the same reasons that have plagued the American species.
The largest Chinese paddlefish on record measured 23 feet (7.0 m) in length, and weighed over several thousand pounds. They commonly reach 9.8 feet (3.0 m) and 1,100 pounds (500 kg). Although the American paddlefish is one of the largest freshwater fishes in North America, their recorded lengths and weights fall short in comparison to the larger Chinese paddlefish. American paddlefish commonly reach 5 feet (1.5 m) or more in length and can weigh more than 60 pounds (27 kg). The largest American paddlefish on record weighed 144 pounds (65 kg), and was caught by Clinton Boldridge in the Atchison Watershed in Kansas.
3. Giant Freshwater Stingray (16 ft – 1,300 lbs)
The giant freshwater stingray (Himantura polylepis, also widely known by the junior synonym H. chaophraya) is a species of stingray in the family Dasyatidae. It is found in large rivers and estuaries in Indochina and Borneo, though historically it may have been more widely distributed in South and Southeast Asia. It has a relatively thin, oval pectoral fin disc that is widest anteriorly, and a sharply pointed snout with a protruding tip. Its tail is thin and whip-like, and lacks fin folds. This species is uniformly grayish brown above and white below; the underside of the pectoral and pelvic fins bear distinctive wide, dark bands on their posterior margins.
The giant freshwater stingray reaches at least 1.9 m (6.2 ft) in width and 5.0 m (16.4 ft) in length, and can likely grow larger. With reports from the Mekong and Chao Phraya Rivers of individuals weighing 500–600 kg (1,100–1,300 lb), it ranks among the largest freshwater fishes in the world.
Bottom-dwelling in nature, the giant freshwater stingray inhabits sandy or muddy areas and preys on small fishes and invertebrates. Females give live birth to litters of one to four pups, which are sustained to term by maternally produced histotroph (“uterine milk”). This species faces heavy fishing pressure for meat, recreation, and aquarium display, as well as extensive habitat degradation and fragmentation. These forces have resulted in substantial population declines in at least central Thailand and Cambodia. As a result, the International Union for Conservation of Nature (IUCN) has assessed the giant freshwater stingray as Endangered.
2. White Sturgeon (20 ft – 1,799 lbs)
The white sturgeon (Acipenser transmontanus), also known as the Pacific sturgeon, Oregon sturgeon, Columbia sturgeon, Sacramento sturgeon, and California white sturgeon, is a sturgeon (a fish of the familyAcipenseridae) which lives along the west coast of North America from the Aleutian Islands to Central California.
It is the largest freshwater fish in North America and is the third-largest species of sturgeon, after the beluga and the kaluga. The white sturgeon is known to reach a maximum size of 816 kg (1,799 lb) and 6.1 m (20 ft).
1. Beluga Sturgeon (24 ft – 3,463 lbs)
The beluga /bəˈluːɡə/ or European sturgeon (Huso huso) is a species of anadromous fish in the sturgeon family (Acipenseridae) of order Acipenseriformes. It is found primarily in the Caspian and Black Sea basins, and occasionally in the Adriatic Sea. Heavily fished for the female’s valuable roe—known as beluga caviar— the beluga is a huge and late-maturing fish that can live for 118 years. The species’ numbers have been greatly reduced by overfishing and poaching, prompting many governments to enact restrictions on its trade. The most similar to the Huso huso beluga is the Huso dauricus kaluga, also referred to as the “river beluga”.
The largest accepted record is of a female taken in 1827 in the Volga estuary at 1,571 kg (3,463 lb) and 7.2 m (24 ft). Several other records of aged sturgeon exceed 5 m (16 ft). These great sizes mark the beluga as thelargest freshwater fish in the world. A few other species of sturgeon can attain great sizes but none match the maximum sizes known for the beluga, like Chinese, Pacific White, Oceanic European, Atlantic, Baikalian, andKaluga, the latter a close cousin which can obtained a maximum weight of 1,000 kg (2,200 lb), thus attaining the second largest sturgeon size. It may be considered as a rival in size to the ocean sunfish among all extant bony fishes although that marine, passive giant has not been nearly as heavily fished nor takes as long to attain great sizes as does the beluga so more regularly attain massive weights. The Beluga also rivals the great white shark, the Greenland shark, and the tiger shark for the title of largest actively predatory fish, only the great white easily exceeding the beluga’s maximum size. The giant belugas are much larger than the Mekong giant catfish, the arapaima or other sizable rivals for the title of largest freshwater fish. Nevertheless, some scientists still consider the Mekong giant catfish to be the largest true freshwater fish, owing to sturgeons’ ability to survive in seawater and that it spends much of its life in brackish environments.
Beluga of such great sizes are very old (continuing to grow throughout life) and have become increasingly rare in recent decades due to the heavy fishing of this species. Today, belugas that are caught are generally 142–328 cm (4.66–10.76 ft) long and weigh 19–264 kg (42–582 lb). The female beluga is typically 20% larger than the male.