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Rainbow trout
Oncorhynchus mykiss
It is a species of fish in the genus Salmon
[1]
Also known as water fine scale, waterfall fish, seven color fish
[6
]
. Rainbow trout body length of about 260-465mm, adult weight up to 2.8 kg, body flat side, large mouth, oblique crack, end position. The snout is round and blunt, and the upper jaw has fine teeth. The dorsal fin has a short base, followed by a small lipid fin. Pectoral fins are medium and slightly pointed at the end. The ventral fins are smaller and away from the anal fin. Sexually mature individuals have a wide, bright red rainbow band of purple and peach along the lateral line, straight along the base of the caudal fin
[6-7
]
.
Native to the Pacific coast of North America and the Kamchatka Peninsula, the Kessilam River in Alaska and the western side of the Rocky Mountains in Canada, the United States and northwestern Mexico are natural areas of rainbow trout distribution. After being widely introduced into the world to breed, most of the global distribution
[2]
[13
]
. Since its introduction to China in 1959, the breeding of Chinese rainbow trout has spread across more than 20 provinces (municipalities and autonomous regions) in China.
[14
]
. In the natural environment, rainbow trout live in cold and clear upstream headwaters, streams, rivers to rivers or lakes, can also be found in the anadroit spawning coastal rivers, almost in the water temperature of 9-18°C can be seen its population, but in the summer temperature of more than 25°C water bodies and ponds with low oxygen content is rare
[2]
. Rainbow trout feed on aquatic insects and larvae, crustaceans, fish and shrimp, tadpoles, and land insects that fall into the water. Androgynous, in vitro fertilization, rapid growth, strong adaptability. Spawning ground In gravel rivers or tributaries, female fish dig spawning pits, male fish protection, egg settling
[5
]
.
The International Union of Nature's (IUCN) Invasion Expert Panel lists rainbow trout as one of the world's 100 invasive species
[9
]
. The introduction of rainbow trout has also brought a host of problems such as the spread of disease and competition with native species
[8]
.
- Chinese name
- Rainbow trout
- Latin name
- Oncorhynchus mykiss [1]
- alias
- fallfish [6 ] , heptachys , Water scale-up
- Foreign name
- rainbow trout [1]
- world
- animalia [1]
- The door
- Chordate phylum [1]
- The outline
- Osteopichthys [1]
- Orders,
- Salmoniformes [1]
- Families,
- Salmonid [1]
- Belong to
- Pacificus (Salmon) [1]
- Kind of
- Rainbow trout
- subspecies
- 8 subspecies [1]
- Distribution area
- Native to the Pacific coast of North America and the Kamchatka Peninsula, the Kessilam River in Alaska and the western side of the Rocky Mountains in Canada, the United States and northwestern Mexico are natural areas of rainbow trout distribution. After being widely introduced into the world to breed, most of the global distribution [2] [13 ]
- Namers and years
- Walbaum, 1792 [1]
- habitat
- It inhabits cold and clear upstream headwaters, streams, rivers to rivers or lakes, and can also be found in coastal rivers that adduce eggs [2]
catalogue
- oneHistory of zoology
- ▪Taxonomic history
- ▪Discovery and naming
- 2Morphological characteristics
- 3habitat
- 4Distribution range
- 5Life habit
- ▪Feeding habits
- ▪run
- ▪Events
- 6Growth and reproduction
- ▪copulation
- ▪Juvenile growth
- 7Artificial breeding
- ▪Breeding status
At the June 1988 meeting of the American Association of Ichthyologists and Herpetologists, the AFS-ASIH Committee on Fish Names, after reviewing the evidence, proposed a number of species that had previously been classified into the genus Salmonid (Salmonid).
Salmo
Some species are even considered to be actually subspecies of rainbow trout, especially some species that live in the Pacific Basin. The committee voted unanimously to accept Oncorhynchus as the generic name, remaining
Salmo
As a genus of trout (including Atlantic salmon), the species name rainbow trout is taken from
gairdnerit changed
for
mykiss
The scientific name of the rainbow trout was changed to the naming method adopted by John Julius Wollbaum in 1792, i.e
Oncorhynchus mykiss
. Historically, it has also been used to name rainbow trout species such as
irideus
,
gaardneri
Etc was adopted as a subspecies name
[10
]
.
In 1792, the German naturalist and taxonomist Johann Julius Wollbaum (
Johann Julius Walbaum
Rainbow trout was named after type specimens from the Kamchatka Peninsula in Siberia
Oncorhynchus mykiss
[10
]
.
Rainbow trout are named for having a clear rainbow trail on one side of their body. Body length 260-465mm, adult weight up to 2.8 kg. Body flat side, large mouth, oblique cleft, terminal. The snout is round and blunt, and the upper jaw has fine teeth. The dorsal fin has a short base, followed by a small lipid fin. Pectoral fins are medium and slightly pointed at the end. The ventral fins are smaller and away from the anal fin. The scales are small and round. The back and top of the head are blue-green, yellow-green and brown, and the sides and belly are silver-white, white and off-white. The head, sides, back and fins are irregularly dotted with small black spots. Sexually mature individuals have a wide, bright red rainbow band of purple and peach along the lateral line, straight to the base of the tail fin, especially showy during the breeding period
[6
]
. The main appearance of the rainbow trout is based on the head. The one with the large head and pointed snout is the male fish, and the one with blunt snout is the female fish
[7
]
.
The body color of rainbow trout will change with the habitat, fish size and sex status: the fish of stream type and anadroit type are black and the color is stronger; The lake-type species are lighter and more bright and silvery. When rainbow trout leave the lake to spawn, they become darker in color
[8]
.
Juveniles have an olive-green patch on the back and a silver olive high on the side of the body. There are 8-13 oval patches along the edge, and there may be small dark spots along these patches. Between the oval patches, there are rose-red - yellow markings along the lateral line. As the young grow, they gradually take on the color of the adult fish
[8]
.
Rainbow trout
Rainbow trout in the natural environment, mostly live in cold and clear upstream headwaters, streams, rivers to rivers or lakes, can also be found in the anadroit spawning coastal rivers, almost in the water temperature of 9-18 ° C can be seen its population, but in the summer temperature of more than 25 ° C water bodies and ponds with low oxygen content is rare
[2]
. The most suitable growth temperature is 16~18 ° C, when the water temperature is lower than 7 ° C or higher than 20 ° C, the appetite decreases, the growth slows down, the feeding stops at more than 24 ° C, and then gradually weakens and dies
[11
]
.
There are three types of rainbow trout: landlocked type, descending type and lake type
[12
]
Landlocked rainbow trout live in the upper and middle waters with clear water quality and gravel bottom, and is the main type used for artificial culture; Saltwater rainbow trout includes two groups which enter the sea in winter and summer. Lake type rainbow trout live in relatively deep cold water and its coastal waters
[13
]
.
Rainbow trout [21]
Native to the Pacific coast of North America and the Kamchatka Peninsula, the Kessilam River in Alaska and the western side of the Rocky Mountains in Canada, the United States and northwestern Mexico are natural areas of rainbow trout distribution. After being widely introduced into the world to breed, most of the global distribution
[2]
[13
]
.
After more than one hundred years of artificial cultivation exploration, rainbow trout artificial cultivation has spread to five continents in the world, becoming one of the most widely distributed farmed fish in the world today
[13
]
. China's farmed rainbow trout was introduced from the DPRK in 1959 and is distributed in Heilongjiang, Jilin, Liaoning, Shandong, Hebei, Shaanxi, Gansu, Zhejiang, Xinjiang, Sichuan, Guizhou, Hubei, Yunnan and other provinces and autonomous regions
[14
]
.
Rainbow trout temperament is very lively, can jump to take bait, mainly aquatic insects and larvae, crustaceans, fish and shrimp, tadpoles and land insects fell into the water to feed, larval stage to zooplankton, benthic animals, aquatic insects; Adult fish feed on fish, crustaceans, shellfish, terrestrial and aquatic insects, as well as aquatic plant leaves and seeds
[5
]
. In the sea they feed on small fish and cephalopods. They migrate small distances, or long distances if they are anadromous or lake-based species
[2]
.
Steelhead trout are migratory species of rainbow trout that hatch and grow in fresh water, then spend most of their lives in the ocean before returning to freshwater rivers to breed
[15]
.
There is very little communication between rainbow trout and steelhead trout. Once the fry emerge from the gravel, they turn against each other and compete for habitat. Larger fish generally win the best habitat and food sources, and all trout species have size classes present in aquatic systems. Potential mates communicate via visual cues before laying eggs. Rainbow trout individuals are visual predators, relying on keen vision to spot prey. Trout species use chemical signals and detection of the Earth's magnetic field to travel to and from their natal streams and oceans
[16]
.
Rainbow trout are solitary fish that leave the brood once they hatch from their eggs. As adults, they compete with a variety of trout and salmon for food and habitat. The biggest trout often have the best habitat. Rainbow trout have a smaller territorial area, but also disperse from areas with higher fish densities in search of food
[16]
.
Rainbow trout [21]
Rainbow trout is male and female, female fish began to mature sexually at 3 years old, male fish began to mature sexually at 2 years old, in vitro fertilization during reproduction. Mature female fish prefer to choose the riverbed with gravel or pebble bottom, clear water quality and faster water flow as spawning ground. Female fish dig spawning pit, male fish protection, egg settling. Each spawning pit usually contains 800-1000 fertilized eggs, and individuals carry 10,000-13,000, orange-colored eggs, which are then fertilized by males, covered with gravel, and produced several times; there are known instances of the same individual reproducing five times
[7
]
[8]
. The breeding season of rainbow trout is winter and early spring, and the water temperature is between 6-13 ° C. The spawning period was greatly affected by water temperature and light. Rainbow trout fertilized eggs have a longer incubation time, taking about 30 days to hatch small fish at 10 ° C
[22
]
.
As they grow, young freshwater rainbow trout need to feed and grow in the lake before migrating downstream after about a year
[8]
. Rainbow trout growth due to water temperature, environmental conditions, feeding amount has a great difference. Rainbow trout mature age is usually two years for male fish, three years for female fish. Mature individuals vary between 15 and 40 cm. Under the conditions of breeding environment, the life span of male fish is 5-6 years and that of female fish is 6-8 years
[23
]
.
Steelhead trout (migratory rainbow trout) undergo a series of metamorphical development processes, from freshwater to saltwater environment undergoing significant physical and physiological changes to prepare for life in the ocean, where they spend two to three years of adult life, reaching maturity and swimming back to spawning tributaries, most of which return to their native tributaries. However, some lake populations may lay their eggs directly in the gravel of the lake shore without returning to the tributaries
[16]
.
Rainbow trout is one of the first economic fish in the world to be artificially domesticated. It is a typical carnivorous and cold-water fish. The United States began the artificial breeding of rainbow trout in 1874, and it is the first country in the world to artificially raise rainbow trout. After more than one hundred years of artificial cultivation exploration, rainbow trout artificial culture has spread across the five continents of the world, becoming one of the most widely distributed farmed fish in the world today. With the continuous expansion of farming areas, farming output continues to increase, and the farming method has also been developed from a single pond running water aquaculture to seawater, freshwater cages, fence aquaculture and lake and reservoir aquaculture. Relatively speaking, China's artificial breeding of rainbow trout started relatively late (nearly 100 years later than foreign countries). It was first started in 1959 when President Kim Il-sung of North Korea presented Premier Mei with 50,000 eggs and 6,000 fish of the same year. Heilongjiang Fisheries Research Institute was responsible for successful trial breeding and established the first rainbow trout test site in China. Thus, the rainbow trout farming in China began
[13
]
.
The world production of rainbow trout is 920,000 tons (2020 Food and Agriculture Organization of the United Nations), and China's annual output is close to 40,000 tons (2022 China Huaihe Industry Statistical Yearbook), mainly from inland freshwater, mariculture has not yet formed statistical production
[17]
.
According to the different growth stages of rainbow trout, there are young ponds, fry ponds, seed ponds, adult ponds, parent ponds and reserve parent ponds, which account for 0.5%, 1.0%, 12.5%, 80%, 3.0% and 3.0% of the total area respectively. Where conditions exist, a small number of quarantine ponds should be set up to prepare sick fish for quarantine and quarantine.
Young fish ponds, fish fry ponds, fish seed ponds to stone or concrete structure is better, adult fish ponds and parent ponds can be either earth, stone or concrete structure. According to the terrain, each row of fish ponds should have a certain drop, in order to facilitate natural water.
The inlet drainage system of rainbow trout pond is an important part in the construction of the pond. Each fish pond should have its own water inlet, water outlet and sewage outlet. The inlet and outlet should be set up fish barrier to prevent escape fish. The fence should be tight, and the size of the spacing should be determined according to the size of the fish.
[3
]
The water used for rainbow trout aquaculture is seepage water and well water under the dam of Lanying Reservoir. The water source is pollution-free, the water quality of aquaculture water meets the water quality standards of fisheries, the annual water temperature is not higher than 24℃, the dissolved oxygen is rich, and the water quality is weak alkaline. There are 4 cement ponds for breeding, 20 meters long and 4.5 meters wide. There are 2 earth ponds of 3335 square meters each. The inlet and drainage system is independent and complete, and the power generation and oxygen enhancement facilities are complete.
[3
]
The breeding process of rainbow trout can be divided into several stages, including the larval stage (from hatching to feeding for two months), the fry stage (from two months to six months after feeding), the seed stage (from nine months after feeding to the end of the year) and the adult stage (from the next January to sale).
- one
Larval stage: Within 20 days after incubation, there is no need to bait, the fry are tender and weak, dark and afraid of light, slow activity, and maintain their growth by absorbing nutrients in the yolk sac, and the stocking density is about 10,000 to 50,000 tail/square meter. After 20 days, the feed begins, and the boiled egg yolk can initially be mixed into slurry water and dropped into the water surface with fish upstream of the fish pond. One month after feeding, the stocking density is 500 ~ 1000 tail/square meter, and the cooked egg yolk can be squeezed out with gauze and dropped in water in a fine granular form. You can also use animal liver, fresh small mixed fish ground into paste, drop into the water to feed. Feed 6 to 8 times a day. The daily feeding amount can account for about 12% of the fish's body weight.
- 2.
Fry stage: After two months of feeding, the weight of the larvae has reached about 1 gram, and it has entered the fry period, and the stocking density is 200 to 500 tail/square meter, and pellet feed or broken material can be fed. More than 80% animal content in feed. The daily feeding amount can account for about 9% of the fish's body weight. Daily feeding times 4 times.
- 3.
Fish breeding period: half a year after feeding, until the end of the year, for the fish breeding period, stocking density 50 ~ 200 tail/square meter. Feed can be fed to adult fish, the amount of bait can account for about 5% of the body weight of fish. The daily feeding times are 3 ~ 4 times.
- 4.
Adult fish stage: stocking density of 15 ~ 50 fish, water depth of 1 ~ 2 meters. Animal feed accounts for 30 ~ 40% of the feed. Feed feeding adhere to the four principles, 80% full is appropriate, feed twice a day, feed the amount of fish body weight of 2 ~ 3%. [3 ]
Rainbow trout culture requires fresh water quality, high dissolved oxygen, and a water environment with micro running water. Cultured rainbow trout have micro water injected into the pool every day to increase dissolved oxygen in the water and prevent floating head. In the management of the first to maintain sufficient water and set up oxygen equipment, once the oxygen shortage, immediately supplement. In July and August, when the temperature is high, the well water is regularly filled at noon every day. A way to lower the water temperature by putting a shade over the pond. The water temperature of the pond is controlled not to exceed 22℃ all year round.
[3
]
In May 2023, the Ministry of Agriculture and Rural Affairs issued the Notice on the Announcement of the First Batch of National Aquaculture Breeding Joint Research Plan, which selected seven important aquaculture varieties such as rainbow trout as research objects and deployed the national aquaculture breeding joint research plan
[4]
.
- one
Patrol ponds regularly and keep a pond log: Record the water temperature, water quantity, dissolved oxygen and feeding amount of the fish every day, and pay attention to observe the activities and food intake of the fish in the pond. Especially in the summer high temperature season, pay attention to measuring water temperature (not more than 22 ° C), dissolved oxygen (not more than 5 mg/l), ammonia nitrogen (not more than 0.0075 mg/L).
- 2.
And time pool: With the growth of fish fry, it is necessary to often separate ponds and adjust the density of feeding. After one month of breeding, there will be an uneven size phenomenon, and it must be screened in time. Catch large and leave small, catch and sell adult fish that have reached food standards in time, and select individuals with obvious differences for feeding in separate ponds.
- 3.
Do a good job of cleaning: Timely decontamination and removal of impurities; Remove foreign bodies in the inlet and outlet, and insist on cleaning once a day to ensure that the inlet and drainage are smooth. [3 ]
According to the "Technical Specifications for the Prevention and Control of Rainbow Trout Disease" issued by China in 2021, common diseases of rainbow trout mainly include infectious hematopoietic organ necrosis, water mildew, bacterial fin rot, and ectoparasitosis. Symptoms and pathological changes of infectious hematopoietic organ necrosis: black body color, bulging eyeball, abdominal enlargement, body wall congestion, bleeding; There is often a slime stool in the anus; Severe necrosis of hematopoietic tissue in kidney and spleen; Symptoms and pathological changes of water mycosis: in the early stage of the disease, the injured part of the fish will be red, swollen and inflamed, and in the middle stage, the wound and mycelium will further expand and develop, and the mycelium will invade the muscle, and the surface of the infected fish will form gray white cotton. With the expansion of the lesion area, the skin of the fish develops ulcerative tissue necrosis, swimming disorder, loss of appetite, and eventually die of weakness
[18
]
.
Comprehensive control measures should be taken to control rainbow trout disease, including: keeping water quality fresh; Prevent frostbite, mechanical damage, sudden change of water temperature; Remove dead fish (or eggs) in time. Strict quarantine, do not use IPN, IHNV parent fish sperm collection, egg collection, do not buy fish eggs and seedlings from the epidemic area; Do not contact with aquatic animals and other pollutants that may carry viruses, and do not mix with other types of fish that have not been quarantined
[18
]
.
|
Chinese name
|
Scientific name
|
Namers and years
|
|---|---|---|
|
Rainbow trout eagle Lake subspecies
|
Oncorhynchus mykiss aquilarum
|
Snyder, 1917
|
|
Rainbow trout Columbia River subspecies
|
Oncorhynchus mykiss gairdnerii
|
Richardson, 1836
|
|
Rainbow trout Kern River subspecies
|
Oncorhynchus mykiss gilberti
|
Jordan,1894
|
|
Rainbow trout coastal subspecies
|
Oncorhynchus mykiss irideus
|
Gibbons, 1955
|
|
Rainbow trout named subspecies
|
Oncorhynchus mykiss mykiss
|
Walbaum, 1792
|
|
Rainbow trout Baja California subspecies
|
Oncorhynchus mykiss nelsoni
|
Evermann, 1908
|
|
Rainbow trout Sacramento subspecies
|
Oncorhynchus mykiss stonei
|
Jordan, 1894
|
|
Rainbow trout small golden subspecies
|
Oncorhynchus mykiss whitei
|
Evermann, 1906
|
|
Reference materials:
[1]
|
||
Human activities pose threats to the survival of some subspecies of rainbow trout, such as the California Rainbow trout subspecies, including habitat degradation, reduced spawning routes due to DAMS and other diversions. Siltation from forestry activities and erosion from urban and agricultural development also affect spawning beds
[16]
.
The National Oceanic and Atmospheric Administration's Fisheries Service reconnects the upper domain by removing or modifying DAMS and other fish passage obstructions; Restoring the flow of main and tributaries; Restoration of riparian and estuarine habitats; Control of non-native invasive plants and aquatic predators; Reducing excessive groundwater extraction and other measures to protect the local residual rainbow trout population
[19
]
.
In Southern California, where a prolonged drought poses a continuing threat to the entire rainbow trout population, the Endangered Species Act requires that listed species (protected West Coast salmon and rainbow trout species) be reviewed at least every five years to determine whether their listed endangered species status is accurate or should be changed. And take critical and effective conservation actions for Southern California steelhead trout based on monitoring conditions
[19
]
.
Rainbow trout is a kind of fish with high economic value, its meat is fresh and tender, delicious, no smell, especially small bone spurs, no scaling when eating. Rainbow trout meat is rich in unsaturated fatty acids and amino acids, which is conducive to human absorption and nutritional balance. Among them, unsaturated fatty acids can prevent and cure cardiovascular diseases, and are also necessary nutrients for the brain, retina and nervous system, and play an important role in the brain development of fetuses and young children. At the same time, unsaturated fatty acids can also effectively fight chronic diseases, diabetes
[7
]
.
In addition, the rainbow trout body contains DHA, EPA, known as "brain gold", much higher than other fish, has a good medicinal and edible value, can reduce the concentration of cholesterol in the blood, prevent cardiovascular disease caused by arteriosclerosis, reduce inflammation, prevent the spread of cancer, but also improve brain function. Rainbow trout also contain a lot of B vitamins, especially vitamin B
twelve
And small amounts of vitamin D, vitamin A and vitamin E. In addition, rainbow trout fish contains trace elements that have an important role in human metabolism, such as selenium, iodine, fluorine and so on. Rainbow trout fish is rich in fat, making it tender and refreshing. The red fresh meat is sweet and delicious, called the "king of fish", whether eaten raw or smoked, the taste is better, so it is very popular in the market. Rainbow trout eggs, grains as large as soybeans, rich in highly unsaturated fatty acids and egg protein, is a world-renowned high-grade nutritional food
[7
]
.
