Opening remarks
Fish are bony scales, gill breathing, fins as a motor organ and feeding on the upper and lower jaws of the warm aquatic vertebrates, belonging to the chordate phylum in the vertebrate subphylum, the average person divides the vertebrates into fish (53%), birds (18%), reptiles (12%), mammals (9%), amphibians (8%) five categories. According to the statistics of the late Canadian scholar "Nelson" in 1994, there are 24618 species of living species fish in the world, accounting for more than half of the named vertebrates, and new species of fish are constantly being discovered, with an average of about 150 species per year, which should have increased by more than 1500 species in more than a decade, and the current global named fish species are about 32100 species.
The first exhibition hall
【The World of Fish】
The World of Fish
First, the origin of fish
Fish are the lowest jaw and mouth animals, although many fish fossils have been found, but the question of when and what animals fish evolved from is still difficult to answer exactly, obviously, the evolution of jaw arch from the gill arch should be an important progress in the evolution of fish. From the fossil material, in the Devonian Period, about 400 million years ago, major taxa of fish have emerged, such as spiny fish, shield fish, cartilaginous fish and teleost fish. But it is generally believed that the appearance of jaws and the evolution of the earliest fish can be traced back to the Ordovicians.
According to fossil analysis, the number of spiny fish is less than that of contemporaneous shield fish, but the spiny fish live longer than the shield fish. Spiny fish may have appeared in the Ordovician, fossils found in strata about 450 million years old, peaking during the Silurian and Devonian periods, and extinction in the Carboniferous Period, about 300 million years ago. Based on the fact that spiny fish have shark-like teeth and crooked tails, and that the embryos of some sharks living in modern times have small echino-like rows of small ventral fins, it has been suggested that spiny fish are closer to cartilaginous fish. It has also been suggested that the spiny fish is closer to the ancestor of the teleost fish, the archaic cod, because it has bony scales and gill caps, as well as the inner bone of the hard bone.
The shield fish is covered with a shield-shaped bony deck , similar to the form of a turtle , but with an upper and lower jaw , pairs of nostril even fins , and a crooked tail , and the bones are cartilage. It contains many species, such as arthrodira, ptyctodontida, flatfish (Petalichthyida), rhenanida and so on. Fossils were found in the Silurian Period, where the Devonian period was more developed, mostly extinct by the end of the Devonian Period, and only a few continued into the Carboniferous Period. The kinship of the shield fish seems to be closer to that of the cartilaginous fish, but it has also been suggested that one branch of the shield fish evolved into a cartilaginous fish and the other evolved into a teleost fish.
Because cartilaginous fish fossils are less preserved than bony fish. According to the anatomical comparison of fossil sharks with contemporaneous spiny and shieldfish, the three appear to have originated from a common ancestor. The earliest fossils of cartilaginous fish were some Devonian carnivorous sharks, such as the Cla-doselache. During the Devonian period, cartilaginous fish developed in large quantities, and by the Carboniferous Period (about 280 million to 350 million years ago) it was common in freshwater and marine water, and many ancestral taxa subsequently became extinct and replaced by modern cartilaginous fish. Cartilaginous fish were very early divided into two major linear groups, namely the whole head and the shark rays. Shark rays have evolved in two directions due to their adaptation to different lifestyles, namely fast-swimming sharks and benthic, inactive rays. Cartilaginous fish have evolved to be quite conserved, with some species changing little over a period of about 200 million years, such as the modern Carcharodon carcharias, which have not changed much compared to their ancient fossil species Paleospinax, and the modern flat shark and six-gill shark compared to their Jurassic ancestors.
The three major taxa of teleost fish – lungfish , total fin fish ( including modern surviving coelacanths ) and rayfin fish — appear to have evolved from a common ancestor of jaws and even fins between 450 million and 425 million years ago.
Lungfish are a small group of specialized freshwater fish with only 3 extant species, distributed discontinuously in South America, Africa and Australia. This fact is enough to show that the range of life of lungfish in ancient times was very extensive. Sichuan, China, has found Ceratodus szechuanensis.
Paleotropic fish have inner nostrils, bladders that can be used as lungs, and fleshy leaf-like even fins that can move on land, which allows them to climb over dry mud puddles into new waters to live. Some species often crawl over land and breathe air in this way, and as a result develop into the original terrestrial vertebrates, that is, amphibians. Other species can not adhere to this life and migrate to the ocean, but in the sea they compete only with a large number of ancient cod and adaptability, and finally in the late Mesozoic Era, most of them were eliminated and extinct, and only a very small number of coelacanths such as speartails and maranfish remain to become "living fossils" today.
There is a type of osteolepis in the total finfish, and the arrangement of the skull pieces, the type of teeth, and the structure of the even fin bones are very similar to the ancient amphibians, so it can be considered that fish like the bone scale fish are likely to be the direct ancestors of amphibians.
The evolution of ray-finned fish from the Devonian period to the present has roughly gone through three stages of mutual succession: the earliest ray-finned fish are cartilaginous hard scales, represented by palaeoniscoidea, which appeared in the freshwater waters of the Devonian Period, the Carboniferous Period reached its heyday, and by the Triassic period it was replaced by the all-bone class, the whole bone class came from the cartilage hard scales, most of the Mesozoic period was the full bone flourishing period, branching and evolving in freshwater and seawater, and the modern all-bone class represented the finches and bowfin fish. In the early Mesozoic Era, eubony species developed from all-bone species, and the third stage of the evolution of ray-finned fish began, and true bone species have carried out a large amount of adaptive radiation since the late Mesozoic Era to the present, forming various ecological types. Despite the wide variety of species and morphologies of eukeletal fish, most ichthyologists believe that various eukeletal fish come from one of the whole bone order.
During the Devonian period 400 million years ago, the distribution of land and sea around the world underwent tremendous changes: many regions formed new mountain systems, plateaus and basins through orogeny and land-making, which also underwent huge changes in landforms and climates. The increase in the size of the continent and the dry and hot climate have caused changes in the biological world, and fish nature is no exception. At that time, fish, as freshwater habitats, often encountered the dilemma of depletion of lakes and marshes, river flow interruptions, and shrinking and heating of waters, and species that could not adapt were gradually extinct. Through natural selection, 2 adaptations were produced, allowing fish to be preserved, bred and multiplied to this day. The first is to move to the sea from the freshwater waters of the land; the second is to grow "lungs" in the body that can breathe, which can replace the function of gills if necessary.
Early cartilaginous fish adopted the first way of adaptation, that is, from fresh water into the sea, to live in the ocean. In this way, although a rich water environment has been obtained, but from fresh water to seawater, it is from a low-permeability water environment to a high-permeability water environment, and the first problem encountered by cartilaginous fish entering the sea is that the water in the body must continue to penetrate outward. Species that can prevent this infiltration can retain offspring, so that as a result of long-term adaptation, cartilaginous fish have a ability to regulate their own osmotic pressure, can convert nitrogen-containing metabolic waste into urea, and save it in the blood at a concentration of 2% to 2.5%, basically maintaining the balance of water regulation in the body and abroad, so it can continue life in the sea and reproduce races.
The eggs of cartilaginous fish still retain some of the original characteristics in fresh water, and their internal fluid is low-permeable compared with seawater, so cartilaginous fish cannot lay eggs unprotected in seawater. Their eggs are either wrapped in an impermeable egg shell at the time of their production, with fluid in the shell, in which the fertilized eggs develop, or they do not lay out at all and remain in the mother's body to develop, manifesting as oviviparous or (pseudo)viviparous. The males of cartilaginous fish have flippers and can undergo in vivo fertilization, which avoids direct contact between the eggs and the sea.
Early teleost fish adopted a second adaptation, that is, the pharynx grew a pair of cystic protrusions into the body cavity as primitive "lungs", which allowed for air breathing when the gills had difficulty breathing. Teleost fish are generally covered with scales, which in addition to having a protective effect, also have a drought-resistant effect.
Second, the geographical distribution of fish
The geographical distribution of animals has always been one of the central issues of concern to ichthyologists, and the methods of division have been expressed, and the more influential division methods are only introduced here.
In September 1954, Mr. Zhang Chunlin published an article entitled "Distribution of Freshwater Fish in China" in the Journal of Geography, arguing that the division of freshwater fish areas in China is not exactly the same as that of terrestrial animals and plants, and should be divided into five areas, such as Heilongjiang, Northwest Plateau, Jianghe Plain, Dongyang District and Nulan District, and analyzed the characteristics of unique fish or dominant species in each region.
1. Heilongjiang District: including Heilongjiang, Songhua River and Ussuri River, Tumen River, Yalu River basins. The main fish communities in the area are hardy species, such as three species of lamprey eels of the oratory order, 10 species of salmonids, 2 species of anchovy, 1 species of courgette family, 1 species of pike family, river cod, sturgeon, sturgeon, three-spinach of the order Spiny, etc., all of which are representative species unique to the region.
2. Northwest Plateau Region: This area includes Xinjiang, northern Tibet, Inner Mongolia, Qinghai, Gansu, Shaanxi, Shanxi and other places. The area is mainly plateau or mountainous, the fish that live in the area have special adaptation conditions, such as drought tolerance and alkali resistance, or can live in the bottom of the rapid water, so the species is relatively small, although the genus in the district is the least in the district, but some of the genus adapted to the living environment, the species are particularly numerous, becoming the dominant taxon. For example, there are about 70 species in the subfamily Schizothoptera and 110 species in the subfamily Loachidae that form endemic species in the region.
3, the river plain area: the area is a large plain, including the middle and lower reaches of the Yangtze River, the lower reaches of the Yellow River, the Huai River Basin and the lower reaches of the Liao River, in addition to the trunks and tributaries of the rivers, there are also Boyang Lake, Dongting Lake, Taihu Lake, Chao Lake and other large and small thousands of lakes, because of its flat terrain, slow water flow, the special adaptability of the main fish is that the general shape is the body side flat, the head and tail are pointed, slightly spindle-shaped, chest, abdomen, hips, tail fins are very developed. Most species and genera of the carp family are distributed in this area, such as carp, crucian carp, bream, grass, green, silver carp, bighead carp, red-eyed trout, trout, eel, anchovy, bream, crucian carp, drifting fish, wheat ear fish, copper fish, stick flower fish, mackerel and so on. There are not only a large number of cyprinids in the region, but also the individual production of their species is also abundant, which can be called the breeding center of the carp family in Asia.
4. Dongyang District: The area includes Guangdong, Guangxi, Hainan, eastern Yunnan, Guizhou, Fujian, Taiwan and other places, and most of the fish in the area are warm subtropical and tropical fish. Fish in the area live in high mountains and rivers, and due to the rapid flow of water, most of the fish inhabited have suction cups in the mouth or chest to survive in the rapids. The area is characterized by a wide variety of tropical organisms. Its fish community composition is similar to that of Vietnam, Thailand, Myanmar and India, and its representative species are mainly the Dan subfamily of the cyprinid family, the subfamily wild catfish, the subfamily catfish, the flatfin loach family, the catfishidae, the cyprinid family, the Cyprinidae, the Laminae family, the salmonidae, the catfish family, etc.
5. Nulan District: This area is the area through which the Brahmaputra, Nu, Lancang and Jinsha rivers flow, including southern and eastern Tibet, western Sichuan and western Yunnan. The rivers in the area flow in a north-south direction, so that fish in the Eastern Ocean Region and the Northwest Plateau Region coexist in the area through the exchange of rivers and waters. For example, the species of the wild loach subfamily, the loach genus of the loach family, the flatfin loach family, the loach family, the catfish genus of the catfish family, the yellow eel of the order Zygosteenidae, and the snakehead of the loach family are the same as those in the Eastern Ocean region; while the species of the schizothoptera subfamily and the subfamily of striped loach are the same as those in the northwest plateau region, and the mixture of fish in the two regions is the characteristic of the fish fauna in the region.
3. Classification and species of fish
There are about 20,000 species of fish in the world. Among them, there are about 73 species of round-mouthed fish, about 800 species of cartilaginous fish, and about 20,000 species of teleost fish. There are about 3,000 species of fish in China. Among them, there are about 2100 species of marine fish. There are about 1010 species of freshwater fish Common freshwater fish species.
1. General order of jawlessness
1. Hagfish
Hagfish myxiniformes - hagfish
2. Finned turtles
Order Arandaspidiformes †
Order Pteraspidiformes †
Thelodontiformes †
3. Head turtles
Lamprey eels Petromyzontiformes - Eight-eyed eels
Anaspidiformes †
Galeaspidiformes †
Cephalaspidiformes †
2. There is a general class of jaws
1. Shield fish
Rhenaniformes †
Carcass angustifolis Antiarchiformes †
Acanthothoraciformes †
Ptyctodontiformes †
Petalichthyiformes †
Phyllolepiformes †
Arthrodiriformes †
2. Cartilaginous fish
Holocephali
Superorder Paraselachimorpha †
Iniopterygiformes †
Petalodontiformes †
Order Eugeneodontiformes †
Orodontiformes †
Order Desmiodontiformes †
Clawtooth Helodontiformes †
Holocephalimorpha
Order Cochliodontiformes †
Order Menaspiformes †
Chimaeriformes
Suborder Elasmobranchii
Slittal Shark General Cladoselachimorpha †
Schizos (Cleft Shark) Cladoselachiformes †
Xenacanthimorpha †
Xenacanthiformes †
Euselachii (=Selachimorpha)
Order Ctenacanthiformes †
Hybodontiformes †
Heterodontiformes - Heterodontiformes
Orectolobiformes - Whale shark, nurse shark
White-eyed mackerel Carchariniformes - White-eyed mackerel, hammerhead shark
Mackerel Lamniformes - Great white shark, basking shark, longtail shark
Hexanchiformes
Horned Squaliformes
Squatiniformes - Flat sharks
Sawfish Pristiophoriformes - Sawsharks
Ray Rajiformes - Rays, rays, rays
3. Spiny fish
Climatiiformes †
Acanthodiformes †
Ischnacanthiformes †
4. Teleost fish
Suborder Sarcopterygii Coelacanthimorpha
Coelacanthiformes - Coelacanthiformes - Coelacialacene
Dipnotetrapodomorpha
Ceratodontiformes - Australian lungfish
Lepidosireniformes - American lungfish
Rhizodontimorpha †
Rhizodontiformes †
Osteolepimorpha †
Osteolepiformes †
The suborder Actinopterygii, a suborder of rayfin fish, Chondrostei
Order Cheirolepiformes †
Polypteriformes
Palaeonisciformes †
Order Tarrasiiformes †
Order Phanerorhynchiformes †
Saurichthyiformes †
Sturgeon Acipenseriformes - Sturgeon
Order Ptycholepiformes †
Order Pholidopleuriformes †
Order Perleidiformes †
Luganoiiformes †
Neopterygii
Whole bone fish pie Holostei
Semionotiformes - Finches
Bowfin fish order Amiiformes
Toothed fish Pycnodontiformes †
Aspidorhynchiformes †
Order Pachycormiformes †
Bonefish pie Teleostei
P.tilagora Pholidophoriformes †
Leptolepidiformes †
Order Tselfatiformes †
Osteoglossomorpha
Beggar Fish Eye Ichthyodectiformes †
Osteoglossiformes - Red dragon, elephant fish
Sea carp subacute Elopomorpha
Sea carp Elopiformes - Sea carp
Northern barracuda order Albuliformes - Northern barracuda
Anguilliformes - Freshwater eel, moray eel
Saccopharyngiformes
Order Crossognathiformes †
Herring subpay Clupeomorpha
Order Ellimmichthyiformes †
Herring order Clupeiformes - Sardines
Euteleostei
Superorder Ostariophusi
Anotophysi
Gonorynchiformes - Lice
Bone maw is Otophysi
Cypriniformes - Carp
Characiformes - Piranha
Catfish Siluriformes - Catfish
Gymnotiformes - Long knifefish, electric eel
Protacanthopterygii
Pike order Esociformes - Pike
Courgette fish order Osmeriformes - Courgette fish
Salmoniformes - Salmon, trout
Megalomanthus Stenopterygii
Megalomanth order Stomiiformes - Giant-mouthed fish
Braided fish order Ateleopodiformes
Round scales total Cyclosquamata
Fairy fish order Aulopiformes - Fairy fish
Lanternfish general order Scopelomorpha
Lanternfish Order Myctophiformes - Lanternfish
Moonfish General Order Lampridiomorpha
Lampridiformes - Moonfish
Silver-eyed seabream (general order Polymixiomorpha
Silver-eyed snapper (Whiskers) Polymixiiformes
Order Ctenothrissiformes †
Paracanthopterygii
Percopsiformes
Order Sphenocephaliformes †
Ferrets (Ferrets) Ophidiiformes - Ferrets
Cod Order Gadiformes - Cod
Toad order Batrachoidiformes
Lophiiformes - 鮟鱇
Spiny Fins Superorder Acanthopterygii
Mugilomorpha
Mugiliformes
Silverfish is Atherinomorpha
Silver-manned fish order Atheriniformes
Beloniformes - Needlefish, Saury
Cyprinodontiformes - mosquito-eating fish
Perch series Percomorpha
Odd gold-eyed snapper Stephanoberyciformes
Golden-eyed seabream Beryciformes - Golden-eyed seabream
Sea bream Zeiformes
Gasterosteiformes - Seahorse
Synbranchiformes - Yellow eel
Scorpaeniformes - Lionfish
Perciformes - Perciformes - Perciformes, bass, gobies, mackerel, pomfret, sailfish, tuna
Flounder Pleuronectiformes - Flounder
Tetraodontiformes (=Plectognathi) - pufferfish, sunfish
Endangered fish species
Parasitic eel - Japanese lamprey
A treasure of fish, Chinese sturgeon
Little Wax - Dashi Sturgeon
Seven-grain floating sturgeon comparable to bear paw
The longest freshwater fish, the white sturgeon
The lowest latitude salmon - Taiwan Masu Maha
Seven up and eight down Zheluo fish
Northwest Sichuan famous cat fish tiger Jia
Qinling precious flower fish - Qinling fine scale salmon
Xinjiang big white fish - northern salmon
Heilongjiang great white fish - Ussuri white salmon
Cold-water precious fish - Heilongjiang fennel
The king of freshwater fish, ayu
"Eel King" - Flower Eel
Four-gill perforated fish
Fire bream - cochineal
Taiwanese salmon - whiskered carp
Subtropical salmon - heterogeneous carp
Two-tailed - Chengdu carp
White cloud gold wire - Tang fish
Goldfish - Lin's crucian carp
Golden White Lady - Rare bass carp
Duck-billed eel - anchovy
Small white fish - Xinjiang Yaluo fish
Tropical knifefish - big fin fish
Taiwan bream - Taiwanese bream
Dianchi Lake small white fish - silver white fish
Dianchi red-tipped oil fish - Yunnan steamed bun
King of Europe , the European catfish
Fourth, the nutrition and efficacy of fish
First, the effect of fish and meat
The effect of fish: autumn and winter is a good time for the weak to supplement, and fish is a good aquatic food for supplementation, which is not only delicious in taste, but also has high nutritional value. Its protein content is twice that of pork, and it is a high-quality protein with a high absorption rate. Fish is rich in thiamine, riboflavin, niacin, vitamin D and a certain amount of calcium, phosphorus, iron and other minerals. Although the fat content of fish is low, the fatty acids in it have been confirmed to have hypoglycemic, cardiotonic and anti-cancer effects. The vitamins D, calcium and phosphorus in fish meat can effectively prevent osteoporosis.
Fish fat contains unsaturated fatty acids and has an anti-atherosclerotic effect, so it is quite beneficial for the prevention and treatment of cardiovascular and cerebrovascular diseases, enhancing memory, protecting vision, and eliminating inflammation. But the fish is not eaten as much as possible, this is due to the fact that the fatty acids of fish contain a large amount of eicosapentaenoic acid, which can inhibit the aggregation of platelets, long-term overdose, will reduce the cohesiveness of platelets and cause a variety of spontaneous bleeding, such as cerebral hemorrhage.
Second, eating contraindications
From the perspective of Traditional Chinese medicine, fish such as striped fish, silver carp, eel, etc. are warm foods, and eating too much can easily lead to the accumulation of internal fire, which is what people often call "fish making fire". Therefore, those with excessive internal heat and yin deficiency and strong physique should eat less warm fish. From the perspective of modern nutrition, fish is a high-protein food, if you eat too much, and lack of vitamin C-rich vegetables and fruits, will make the body collagen synthesis problems, resulting in gums, mucosal bleeding and other symptoms of fire. However, this is only for warm or hot fish, and a small number of flat or cool fish such as mullet, turtle, eel, carp and so on will not cause fire.
Ducks are born in water and are cold. Similarly, fish are also born in the water, but most fish will cause fire if they eat more, and Chinese medicine believes that fish are cold and hot in the water; ducks are on the surface of the water, that is, they are weak and cold. In other words, although fish are cold-blooded animals, in order to survive in the water, the body needs to have a mechanism to deal with low temperatures, which is why most fish meat is warm.
Third, nutritional value
Crucian carp: beneficial to qi and spleen, water and swelling, heat and detoxification, through the milk and other functions. Patients with ascites are cured with fresh crucian carp and red adzuki beans to cook soup. Simmered with fresh crucian carp and pig's trotters, and eaten with soup, it can cure maternal milk loss. Crucian carp oil is good for cardiovascular function, but also reduces blood viscosity and promotes blood circulation.
Carp: It has the effects of healthy spleen appetizer, diuresis and swelling reduction, cough and asthma, fetal milk, heat and detoxification. Carp and winter melon, green onion white boiled soup to treat nephritis edema. The large carp leaves the scales to remove the intestines and simmer it and serve it to cure jaundice. Use live carp and pig's trotter soup to treat maternal breast loss. Carp and Sichuan shellfish are boiled in a soup to cure cough and asthma.
Silver carp: it has the functions of warming the qi, warming the stomach, moisturizing the skin, etc., and is a warm and nourishing health food.
Blue fish: it has the functions of replenishing qi and nourishing the stomach, reducing dampness and water, dispelling wind and eliminating annoyance. Trace elements such as zinc and selenium can help fight cancer.
Blackfish: It has the functions of tonifying the spleen and water, removing stasis and regenerating, clearing heat and dispelling wind, tonifying the liver and benefiting the kidneys. Cooking blackfish, ginger and red dates has an auxiliary effect on the treatment of tuberculosis. Blackfish and brown sugar stew can cure nephritis. Maternal food steamed blackfish can promote lactation and blood replenishment.
Grass carp: it has the functions of warming the stomach, flattening the liver and dispelling the wind, and is a health food that replenishes the deficiency in temperature.
With fish: it has the functions of warming the stomach, replenishing deficiency, skin care, dispelling wind, killing insects, supplementing the five internal organs, etc., and can act on the auxiliary treatment of prolonged hepatitis and chronic hepatitis.
Eel: Beneficial qi and blood nourishment, soft muscles and sharp bones and other functions.
Yellow eel, into the liver, spleen and kidney three meridians, has the functions of tonic deficiency, rheumatism, strong muscles and bones, etc., and also has a certain regulatory effect on blood sugar. Those who are deficient in qi and blood can use shredded astragalus meat and astragalus (gauze packet) boiled in water to taste and take. Children with chancre and small shape and small food can use a yellow eel, cut into sections and add a little chicken gold to cook and eat. Internal hemorrhoidal bleeding and uterine prolapse can cook yellow eels, which are effective for a long time.
Loach has the functions of tonifying qi, removing dampness and evil, quenching thirst and sobering wine, removing poison and hemorrhoids, reducing swelling and protecting the liver. Loach and garlic are boiled over a high flame to cure malnutrition edema. Loach is fried in oil until brown and boiled in water to cure night sweats in children. Loach stewed tofu can cure hot and humid jaundice. Loach is cooked with shrimp yellow, which can cure impotence.
Third, the nutritional composition
1． Rich in complete protein. Fish contains a lot of protein, such as yellow croaker contains 17.6%, striped fish contains 18.1%, mackerel contains 21.4%, silver carp contains 18.6%, carp contains 17.3%, and crucian carp contains 13%.
2． It is low in fat and is mostly unsaturated fatty acids. The fat content of fish meat is generally relatively low, most of which are only 1% to 4%, such as yellow croaker containing 0.8%, striped fish containing 3.8%, mackerel containing 4%, silver carp containing 4.3%, carp containing 5% crucian carp containing 1.1% bighead carp (fathead fish) containing only 0.9%, cuttlefish containing only 0.7%.
3． Inorganic salts and vitamins are high. Marine fish and freshwater fish are rich in sulphur, but also contain phosphorus, calcium, iron and other inorganic salts. Fish also contains a lot of vitamin A, vitamin D, vitamin B1, niacin. These are the nutrients that the human body needs.
The benefits of eating fish
1． Brain health
2． Heart-protecting and lipid-lowering
3． Highly effective calcium supplementation
4． Blood nourishing products
5． Prevents diabetes and high blood pressure
6． Antioxidant, anti-distortion
4. Consumption practices
Steamed fish
1． Sprinkling salt
Wash the fish and control the drying, sprinkle with fine salt, evenly spread all over the fish, if it is a large fish, it should also be salted in the abdomen, marinated for half an hour, and then made. Fish that have been treated in this way are not easy to be steamed and not fragile, and the dishes can be flavored.
2． Add chicken fat method
When making steamed fish, in addition to putting the ingredients, put a piece of chicken fat on top of the fish, so that the fish absorbs the chicken fat, and after steaming, it is slippery and delicious.
3． Boiling water drawer method
When steaming fish, wait for the water to boil before steaming, and cover the pot tightly. In this way, the steamed fish will be fresh and delicious, and the aroma will be pure.
4． Apply dry powder method
When steaming fish, first apply some dry powder to the fish, and do not remove the lid when steaming. For example, if the weight of 250g of fish is the same thickness, steam for 8 to 10 minutes. For each 250g increase, steam for an additional 5 minutes.
5． Beer dip
When steaming fish with a large fishy taste, soak it in beer for 10 to 15 minutes and then steam it, not only the fishy taste is sharply reduced, but there will also be a crab flavor.
6． Leftover fish steaming method
If you can't finish steaming fish at one time, you can beat 1 egg when you eat it again, and make it into a fish steamed egg, so that the fish is not fishy.
7． Steamed small fish heads
Small fish heads are nutritious, but eat less meat. If you first put the fish head on the board, chop it into fine crumbs with a knife, enlarge the bowl, add an appropriate amount of flour and monosodium glutamate, cooking wine, pepper, chopped onion and ginger, stir well, and steam for more than 10 minutes on high heat, then the delicious fish head soup will be ready.
Carp soup
Ingredients: 5 grams of cumin, 1000 grams of fresh carp, 15 grams of Sichuan pepper, ginger, coriander, cooking wine, green onion, monosodium glutamate, vinegar.
method:
1． Descale the carp, dissect the abdomen, remove the internal organs, wash and cut into small pieces; ginger and green onion are washed and rinsed, patted and set aside.
2． Bring the mustard, carp, green onion and ginger to a boil, simmer over low heat for about 40 minutes, add parsley, cooking wine, monosodium glutamate and vinegar.
Dry-roasted crucian carp
Ingredients
600g crucian carp.
ingredient
Appropriate amount of oil, right amount of salt, right amount of soy sauce, right amount of balsamic vinegar, right amount of sugar, right amount of cooking wine, right amount of bean paste
method
Wash the crucian carp, cut a few knives on both sides of the fish, and soak it in cooking wine and soy sauce for 15 minutes.
Onion, ginger, garlic, chili pepper, celery, minced.
Heat the oil in a pan, fry the fish to a golden brown and set aside.
Put oil in the wok and sauté the chopped onion, ginger, garlic, chili pepper, celery, pixian bean paste and stir-fry evenly
Add crucian carp, add cooking wine, salt, soy sauce, sugar, water, bring to a boil, cover, simmer for 10 minutes on low heat, change the heat to collect the juice, add sesame oil and balsamic vinegar, and put it on the plate.
Precautions
Fry the fish to master the heat, do not fry the old.
Dried roasted fish will be very flavorful when added to the minced meat, and it is best to add minced beef.
Fifth, eating tips
Grilled fish anti-meat crumble: when cutting fish pieces should be stabbed by the fish knife; before burning, the fish should be wrapped in starch and fried in the pan, the temperature of the fried fish oil should be high, the soup should not be more when burning the fish, to the degree of just over the fish, the fire should not be too large, the soup should be simmered instead of a small fire after boiling, and the simmering sieve bone should be less turned over.
Fried fish anti-stick pan: clean the pot to heat, rub the pot with ginger, pour a little oil in the pot, heat and then add oil to the pot, drain the water of the fish hanging evenly after the egg paste into the hot oil pot, the egg paste in contact with heat quickly solidified, to prevent sticking to the pan.
Roasted fish should not be put ginger early: put ginger to remove fishiness, put ginger too early, the protein in the fish body leaching solution will hinder the fishy effect of ginger, you can cook for a while, wait for the protein to coagulate and then put ginger, you can also add some milk or rice vinegar or rice vinegar or wine to the soup to remove fishiness.
Flavor has a technique: before grilling the fish, marinate the fish (clean the fish control the water, the fish is evenly coated with fine salt); the frying time is not too long, so that the protein coagulation is not easy to taste.
Steamed fish with boiling water: when steaming fish, first boil the water in the pot and then put the fish, because when the fish is suddenly in high temperature, the external tissue solidifies, which can lock in the internal juice, and put a piece of chicken fat or lard on the fish before steaming, which can make the fish more smooth and tender.
There is a magic way to cook frozen fish: put some fresh milk in the soup, you can increase the umami taste of the fish, you can also put the frozen fish in a little brine to thaw, the protein in the frozen fish meat will slowly solidify when it meets salt, preventing it from spilling further from the cells.
Sixth, the wrong way to eat
1. Eating fish on an empty stomach is harmful
Eating fish on an empty stomach will increase the burden on the liver and kidneys. Protein is converted directly into energy, which produces a large amount of nitrogen-containing waste in the process of decomposition, increasing the burden on the liver and kidneys. Therefore, the practice of only eating fish and not eating staple foods not only wastes protein, but also increases the pressure of detoxification in the human body. Not only that, but eating fish on an empty stomach may also increase the risk of gout. The acidity of stomach acid is relatively high on an empty stomach, and without the help of carbohydrates, the protein decomposition of fish meat is incomplete, which will cause an increase in uric acid. Most fish are rich in purines themselves, and if they are consumed in large quantities on an empty stomach, but there are not enough carbohydrates to break down, they may induce gout or aggravate the condition of gout patients. If you add beer at this time, it will be "worse".
2, raw fish fillets are easy to get "liver fluke disease"
Many people like the tender and delicious sashimi, but they do not know that eating raw fish fillets is very unfavorable to the liver, and it is very easy to be infected with liver fluke disease, and even induce liver cancer.
According to experts in nutrition and health, hepatic fluke disease is a parasitic disease based on hepatobiliary lesions, and people eat raw or semi-cooked freshwater fish and shrimp containing liver fluke live cysts and freshwater snails with a very high probability of infection. Clinical symptoms are fatigue, epigastric discomfort, dyspepsia, abdominal pain, diarrhea, vague pain in the liver area, hepatomegaly, dizziness, etc. Are more common, and severely infected patients can cause liver stiffness and ascites in the advanced stage, and even death. In addition, eating raw or undercooked pork, beef, mutton, dog meat, etc., may be infected with parasitic diseases.
3. Excessive intake of fish gall will be poisoned
Chinese medicine believes that fish bile cold, bitter taste, diarrhea, blindness and other effects, the motherland medicine often use it to treat the eyes of the gallbladder, laryngeal paralysis, sores and other diseases, commonly used in the amount of 1 to 2.4 grams. However, if the dosage is too large, it will not only not cure the disease, but also may cause acute fish bile poisoning.
Fish bile contains a class of toxic substances, which are heat-resistant and cannot be destroyed by alcohol, so poisoning can occur whether the whole bile is cooked, swallowed raw, or sent down with wine. So, which fish galls cause acute poisoning? Fish galls such as bluefish, grass carp, anchovies, silver carp, bream, carp, etc. can cause poisoning. Among them, poisoning caused by bluefish, grass carp and anchovies is the most common and typical.
4, live fish killed now is not fresh and poisonous
Most people think that the fresher the fish is, the better, so they like to eat it alive, thinking that this can ensure the deliciousness and nutrition of the fish. But this is actually a misunderstanding. The reason why fish cannot be eaten now is that the fish protein that is killed is not completely decomposed, the taste is not delicious enough, and the nutritional content is not sufficient. Secondly, leave the caesarean section washed fish for a few hours, and the toxin volatilizes almost, which can reduce the harm of toxic substances to the body.
Seven, washing method
Washing after slaughtering live fish
In general, people can smoothly remove the bitter bile of the fish, and the problem is not big. Most people ask fish sellers to help slaughter live fish, they may not be cleaned up, and it is important to wash them thoroughly after taking them back, so as not to have a great fishy smell after cooking.
The gills must be completely removed from all gills to avoid sand and unpalatable fish heads after cooking.
The jaw scales are the scales at the junction of the fish's chin to the belly. Because this part of the scales is to protect the heart of the fish, it is firmly close to the skin and flesh, and the scales are small and not easy to be found, but it is the main reason for the fishy after the dish. Especially when processing crucian carp and most marine fish, the scales must be removed with a knife.
There is a layer of black clothes in the abdominal cavity of silver carp, crucian carp, carp and other fish, which not only affects the appearance, but also produces a fishy smell, and must be scraped clean when washing.
Blood tendons in the abdomen Some fish have a blood tendon hidden deep in the abdomen, under the vertebrae. When processing, it should be broken with a sharp knife and rinsed.
Fish fins retain the fins for the sake of aesthetics after cooking, if the fins are loose and loose, it is counterproductive, should be properly trimmed or cut all out.
Meat tendons Carp and other fish have a thin and long tendon on each side of the body, which should be removed during processing. After slaughtering and descaled, the fish body is smoothed out by hand in the direction from beginning to end, and a dark line can be seen on the side of the fish body, and the acid tendon is under this line. Cut a knife in the front of the fish near the gill cover, you can see the white tendons, while pinching the thin tendons with your hands and gently pulling them outwards, while tapping the fish body with the back of the knife, so that the acid tendons on both sides are withdrawn and then cooked.
8. Dietary medical treatment
1. Pharmacological effect of fish scales
Fish scales, accounting for 2% to 3% of the fish's body weight. The main characteristics of the scales: transparent from the appearance, like petals, and the edges are slightly curled; white luster; slightly fishy; the texture is firm and soft; the moisture content range is 16.4% to 17.8%, with an average of 17.5%. Nutritionists have found that fish scales are a special health food. It contains more lecithin, which decomposes fat balls into emulsions and water, which enhances human brain memory and delays cellular aging. Fish scales contain a variety of unsaturated fatty acids, which can reduce the deposition of cholesterol in the blood vessel wall, promote blood circulation, and play a role in preventing high blood pressure and heart disease.
Usefulness: Fish scales are also rich in a variety of trace minerals, especially high calcium and phosphorus content, which can prevent pediatric tenant disease and osteoporosis and fractures in the elderly.
Fish scales are the collagen produced by the collagen in the dermis layer of fish, scientifically known as fish scale hard protein. It has shown extraordinary effects in the fields of medicine and chemical industry. The 6 generation of guanine extracted from fish scales is clinically effective in the treatment of acute autohemorrhage, with an effective rate of 70% to 75%, and also has a miraculous effect on gastric cancer and lymphadenoma. Fish silver, a special industrial product extracted from fish scales, is an expensive biochemical reagent used in the pearl decoration industry and paint manufacturing industry, and is very popular in domestic and foreign markets.
Looking at the fish scales, a variety of nutritional and health care substances are integrated, so foreign countries have set off a "fish scale food therapy fever". The cooking method of fish scales is: first wash the fish body with water, scrape off the scale concentration, then rinse and drain with clean water, put it into a pressure cooker, add the appropriate amount of vinegar (except for fishy), cook on high heat for 10 minutes at the ratio of 500 grams of scales and 800 grams of water, then use low heat to cook for 20 minutes, turn off the heat and reduce pressure. The scales and debris are scooped out in a pot, the liquid is poured into the container, and it freezes into a color gelatin. Make a soup with slices of ginger, rice wine, salt and green onion, cut into pieces and boil. If eaten cold, take sugar, peppermint oil, osmanthus or tahini,
Spicy sesame oil as a seasoning, cut into pieces and stir. Eating fish scales can not only taste delicious dishes, but also get the benefits of nourishing fitness.
2. Pharmacological effect of fish maw
According to the Compendium of Materia Medica:
air bladder
[Synonyms]: Mackerel ("Qi Min Zhi Shu"), Squid, Fish White, Maw ("Materia Medica"), Fish Glue ("Three Factors"), White Maw ("Pu Ji Fang"), Fish Belly( "Outline"), Fish Belly ("Medical Forest Collection").
【Source】: It is a fish maw of the totoaba family, such as giant yellow croaker, small yellow fish or Chinese sturgeon and locust fish.
【Collection】: After obtaining the maw, cut open, remove the blood vessels and mucous membranes, wash, flatten, dry in the sun; or wash and use fresh. After melting, it condenses into a gelatin called "maw glue".
【Herbs】: Dried maw is pressed into long round flakes, pale yellow,, slightly shiny. The yellowfish is smaller , and the maws of sturgeon and locusts are large with 2 hanging bands. Tough texture, not easy to tear, fibrous at the fracture; easy to expand into water, boiling is almost completely dissolved, thick solution cooled into gelatin, viscosity is very strong. The smell is slightly fishy and the taste is light. The products are collectively referred to as fish maws. The mackerel of sturgeon and mackerel is called "yellow-lipped belly" or "yellow sturgeon gum". There are cut lines called "line fish glue".
Produced in Zhejiang, Fujian, Shanghai and other places.
【Preparation】: Bake soft, cut into sections, dry. Clam powder fried fish glue: first use clam powder in the pot to fry hot, and then pour the cut fish glue into it, stir-fry over low heat until the degree of loose foam, take out the sieve to remove the clam powder. (10 kg per fish gelatin, 2.5 kg with clam powder)
"The Book of The Book of Fengyuan": "Where the maw glue is added to the pill, cut into small pieces, and the clam powder is fried into beads, it can be ground." Honey refining mixture, must be used for cold, and can not be pounded, pounding is sticky, difficult for pills. ”
【Sexual taste】: sweet, flat.
Sea Medicine Materia Medica: "Non-toxic. ”
"Outline": "Gan, Ping, non-toxic." "Maw glue, sweet and salty, flat, non-toxic."
"New Edition of Materia Medica": "Sweet taste, temperature." ”
[Guijing]: "New Edition of Materia Medica": "Into the kidneys." ”
【Indications for function】: tonify the kidneys and improve sperm, nourish the muscles and veins, stop bleeding, disperse stasis, reduce swelling. Treatment of kidney deficiency and slippery sperm, postpartum spasm, tetanus, vomiting blood, blood collapse, trauma bleeding, hemorrhoids.
"Materia Medica": "The main bamboo wood into the flesh for a long time does not come out, take the white compress on the four sides of the sore, the flesh rotten is out of the thorn." ”
"Sea Medicine Materia Medica": "The main lunar eclipse sores, pubic sores, hemorrhoids, and burn ash." ”
"Drinking and Eating": "Wear it with wine, and eliminate tetanus." ”
"Outline": "Maw, stop the blood from the folding wounds; maw glue, burnt, treat women with dystocia, postpartum wind twitching, tetanus spasm, stop vomiting blood, disperse blood stasis, reduce swelling and poison." ”
"New Edition of Materia Medica": "Tonify Lean Blood." ”
"Materia Medica Seeks The Origin": "Nourish the veins, fix the hand to fight, and consolidate the essence." ”
【Usage and dosage】: Internal: decoction, 3 ~ 5 dollars; boiling paste or grinding into pills, loose. For external use: melting application.
【Should be avoided】: Stomach dull phlegm is contraindicated.
【Selection】:
Cure kidney water deficiency, yin deficiency and blood deficiency: one pound of fish maw (bran noodles fried, ground coarse powder, then fried and then ground), sand tribulus four two, angelica four two (wine washing), cistanche four two (descaled, wine washing), lotus whiskers, silk seeds four two (wine boiled). Honey pills, kiriko large. Two or three dollars per serving. ("Recipe for Excellence" Fish Maw Ball)
Cure kidney deficiency and storage is not solid, the dream is slippery: one pound of yellow fish maw gum (chopped, fried into beads with clam powder, and then stir-fried with soufflé), Shayuan Lingquan eight two (soaked in horse milk overnight, steamed in soup, roasted or dried), Schisandra two or two. Grind into fine powder, refined white honey added to the aged wine and then boiled, waiting for honey will be cold into pills, such as mung bean large. Take 80 or 90 pills per serving, and send it down with warm wine or salt soup on an empty stomach. ("The Criterion of Evidence" Concentrate Pill)
Treatment of postpartum twitching is strong, is the wind into the viscera, the same as tetanus: maw glue one or two. Sauté with snail powder, remove the powder, and end. Divide into three servings and fry cicadas under the soup. ("Treasure of Economic Effect")
Treatment of tetanus, mouth gag, rigidity: fish glue roasted seven points, retention, fine grinding, into a little musk. Two dollars per serving, under the wine, no drinking, under the rice soup. ("Three Causes")
Cure vomiting: maw glue is eight inches long, two inches wide, scorching yellow, scraping two dollars. Use thirty-five sugarcane knots and take the natural juice to mix it down. ("Empirical Side")
Cure the red and white collapse: three feet of fish xuan glue, roasted yellow grinding powder, pancakes with chicken, good wine to eat. (Compendium)
Treatment of menstrual blood retrograde: fish glue (cut, fried), new cotton (burnt ash). Two dollars per serving, rice drink down. ("Pluripotent")
Treatment of postpartum blood sickness: maw glue burning, wine and children urinating for three or five dollars. ("The Chronicle of the Ages")
Cure the stool poison swelling pain, has been large and soft: fish maw glue hot soup or vinegar fried soft, by the heat of the rotten paste. (Ren Zhai Zhi Fang)
Cure eight kinds of head wind: fish maw burning survival, for the end. Lying down with onion wine to serve three dollars. (Compendium)
Cure epilepsy: maw gum (micro-baked, hanging powder fried yellow), saponin (fried yellow) one or two each, cinnabar three dollars. Total is the end. Three dollars per serving, two servings under hot wine. ("Song Gui Zun Sheng" Bladder Scattered)
Treatment of esophageal cancer, stomach cancer: fish maw, fried crispy in sesame oil, crushed. Take 5 grams three times daily. (Inner Mongolia", "Selected Materials of the New Medical Law of Chinese Herbal Medicine")
【Famous Scholars' Discussion】
"Benjing Fengyuan": "Maw Gum HeshaYuan Tribulus Terrestris Name Jujing Pill, which is a solid essence medicine." Dan Fang also uses a taste of stir-frying, sugar mixing, daily service of a money dagger, the best treatment of hemorrhoids, after a long time hemorrhoids to dry themselves. Burn ash, cure postpartum wind shaking, tetanus spasm, take its nourishing meridians, and the virtual wind also rests. ”
"New Compilation of Materia Medica": "Fish maw gum thickening, into the kidney tonic, fear of stagnation, adding ginseng, to qi in it, then the essence is more beneficial, and there is no glue of the disadvantages." ”
Fish can't be eaten after killing
After the fish is slaughtered, although the breathing has stopped, the functions in the body are still undergoing a series of biochemical and physical changes, usually divided into stiffness, autolysis and decay. The fish is in a stiff stage when it first dies, its jawbone and gills are tightly closed, but the energy metabolism in the body is still going on, and the body temperature will even increase by a few degrees.
Because fish is rich in nutrients, tasteful food, and has a strong health care function for the human body, people generally love to eat fish. However, there are many kinds of fish, and different fish have different health care functions, which is not clear to everyone.
crucian
Beneficial qi and spleen, water and swelling, detoxification, circulation of milk and other functions.
Patients with ascites are effective in taking soup with fresh crucian carp and red adzuki beans. Simmering fresh crucian carp with pig's trotters and eating it with soup can cure maternal milk loss. Crucian carp oil is good for cardiovascular function, but also reduces blood viscosity and promotes blood circulation.
carp
It has the functions of healthy spleen and appetizer, diuretic and swelling reduction, cough and asthma, safe fetal milk, heat and detoxification.
silver carp
It has the functions of warming the qi, warming the stomach, moisturizing the skin, etc., and is a warm and nourishing health food.
herring
It has the functions of replenishing qi and nourishing the stomach, reducing dampness and water, dispelling wind and eliminating annoyance. Trace elements such as zinc and selenium help fight cancer.
snakehead
It has the functions of tonifying the spleen and water, removing stasis and regenerating new life, clearing heat and dispelling wind, and tonifying the liver and kidneys. Cooking blackfish and ginger dates has an auxiliary effect on the treatment of tuberculosis. Blackfish stewed with brown sugar can cure nephritis. Maternal food steamed blackfish can promote lactation and blood replenishment.
It has the functions of nourishing the liver and kidneys, replenishing qi and blood, clearing the stomach and removing heat. It is a health food for women, and has functions such as blood nourishment, blindness, menstruation, fetal safety, fertility, hemostasis, and prolactin.
Grass carp
It has the functions of warming the stomach and neutralizing the liver and dispelling the wind, and is a warm and weak health food.
hairtail
It has the functions of warming the stomach, replenishing deficiency, skin care, dispelling wind, killing insects, supplementing the five internal organs, etc., and can be used as an adjuvant treatment for prolonged hepatitis and chronic hepatitis. Hepatitis patients with fresh striped fish steamed and then take the upper layer of oil to eat, long-term service can improve symptoms.
eel
Beneficial qi nourishing blood, soft muscles and bone and other functions.
9. Related diseases
1. Rotten fin disease
The fins are damaged and discolored, dull, and there is a foreign body in the rot, or the transparent fin leaves are whitish and the white gradually expands; in severe cases, the fins are mutilated or cannot be stretched. The disease is more prevalent in summer. Tropical fish have thin fins and are susceptible to bruises and breaks. Treatment with table salt, antibiotics, etc. can be selected.
2. Cotton mouth disease
Also known as rotten mouth disease. The snout around the mouth of the sick fish is covered with white cotton-like mycelium like velvet, also known as white mouth disease. Algae fish commonly used to lick the wall of the mouth lick are susceptible to this disease and are easily infected. Sick fish are difficult to feed, swim slowly and weakly, and die. It should be treated in a timely manner. With penicillin or chlortetracycline solution, it is also possible to soak sick fish with 10 ppm oxytetracycline solution. Aquariums, fishing nets, tools, etc. are washed and disinfected with 0.1% formaldehyde solution.
3. Anchor head flea disease
Also known as needleworm disease; iron anchorworm disease. The head of the insect burrows into the skin muscles of the fish, and the insect body hangs on the fish body like a short needle, and the insect body is pulled out, and the iron anchor-like head is visible. The affected area is inflamed, red and swollen, with erythema and necrosis, and is easily invaded by pathogens. The sick fish is restless, the appetite is weakened, and the emaciated fish is emaciated.
4. Oral filariasis
Filaria oral filarial worms parasitize the skin and gills, and the gills and body surface have a layer of milky white mucus; cloudy, so also known as white cloud disease. The gills are reddish and the skin is inflamed and dull. Sick fish have difficulty breathing, swim slowly, gradually lose weight, and often die in large numbers
10. Relevant knowledge
1． Why are fishy?
Fish, especially cod, which inhabit cold water and on the surface of the water, contain a chemical called trimethylamine oxide. Although the substance itself is odorless, once the fish dies, the bacteria in the fish begin to break down trimethylamine oxide into derivatives of ammonia. It smells bad.
This is not the case with red meat because it does not contain a large amount of trimethylamine oxide. The reason why we find rotten fish products smell bad may be because our sense of smell has evolved to warn us of the dangers of eating fish that have been left there for a long time. Bacteria that produce a fishy smell can also cause severe food poisoning. Eating fish poisoning is much faster than eating beef or lamb poisoning.
2． Are fish affected by water pressure?
In the water, 1 atm is added for every 10 meters downwards. The Mariana Trench has more than 1,000 atmospheres underwater, but various types of fish and shrimp are observed underwater. Deepwater fish have a variety of sensory adaptations, such as a substance called trimethylamine oxide, which allows proteins to still fold into a normal 3D shape under water pressure.
3． How do fish go fishy?
After the fish is cleaned, fry them in oil, pour out the excess oil after frying, and then put the fried fish into the pan. When the pot is hot, add a little wine (preferably rice wine) and vinegar, cover the pot for about a few tens of seconds, and then remove the lid, and the fishy smell is removed. Then, with other spices such as soy sauce, you can cook a variety of delicious fish foods.
11. People who should not eat fish
1． Those taking certain drugs: those who take cough medicines should not eat fish, especially deep-sea fish, so as not to cause histamine allergic reactions, resulting in skin flushing, conjunctival congestion, dizziness, rapid heartbeat, urticaria and other uncomfortable symptoms. Many deep-sea fish contain histamine substances, once the amount of histamine in the human body exceeds the standard, the substance will enter the human blood circulation, resulting in histamine allergic reactions. The reason why eating deep-sea fish usually does not have the above uncomfortable symptoms is because there is a substance that inhibits the activity of histamine in the human intestines and liver - monoamine oxidase, which can prevent histamine from entering the blood. However, some cough medicines have monoamine oxidase inhibitors, which will inhibit the secretion of monoamine oxidase in the human stomach and liver, and it is very easy to eat deep-sea fish at this time to cause histamine substances to accumulate rapidly in the body.
In addition to cough suppressants, there are other drugs that can also inhibit monoamine oxidase. Antibacterial drugs, such as furazolidone (such as dysentery, etc.), ketoconazole, griseofulvin; antihypertensive drugs such as eugenic; selegiline for the treatment of Parkinson's; antidepressants such as moclobemide; antitumor drugs such as methyl benzylhydrazine. There are also drugs in traditional Chinese medicine that can inhibit the effect of monoamine oxidase, such as deer antler velvet, hawthorn, He Shou Wu and so on.
2． Gout patients: because fish contain purines, and gout is caused by disorders in the body's purine metabolism.
3． Patients with bleeding disorders: patients with bleeding disorders such as thrombocytopenia, hemophilia, vitamin K deficiency and other bleeding diseases should eat less or not eat fish, because the eicosapentaenoic acid (EPA) contained in fish can inhibit platelet aggregation, thereby aggravating the bleeding symptoms of patients with bleeding diseases. Patients with bleeding disorders should eat more foods rich in vitamin C.
4． Cirrhosis patients: cirrhosis of the body is difficult to produce coagulation factors, coupled with low platelets, easy to cause bleeding, if you eat sardines, bluefish, tuna rich in 20 carbon 5enoic acid, etc., will make the condition worse sharply, as if worse.
5． Tuberculosis patients: if you eat some fish when taking isoniazid, you are prone to allergic reactions, such as nausea, headache, skin flushing, conjunctival congestion, etc., and palpitations, lip and facial distension, rashes, diarrhea, abdominal pain, dyspnea, increased blood pressure, and even hypertensive crisis and cerebral hemorrhage.
6． Pregnant women: pregnant women should not eat sea fish regularly, often eat seafood, will consume too much methylmercury, the higher the amount of mercury exposed to the fetus in the womb, the greater the risk of slight delay in the development of other functions such as attention, memory, and language ability of young children. Scientists also warn that even if the mother does not ingest much mercury, the brain development of the fetus may be delayed. To this end, pregnant and lactating women should eat less seafood, up to 1 to 2 times a week, less than 100 grams each time, and do not eat tuna, swordfish and other marine fish with high mercury content, and can choose to eat fish raised in ponds that are not contaminated with mercury.
Introduction to fish system
Chondrichthyes
This family is the lowest class of fish in existence, with about 200 species worldwide and 140 species in China, the vast majority of which live in the sea.
Its main features are:
(1) There is no dura bone for life, and the inner bone is composed of cartilage.
(2) Most of the body surface is scaled.
(3) The gills are well spaced and there is no gill cover.
(4) Crooked caudal fin. The family is divided into two suborders, namely the suborder Plate gill and the full-headed subclass.
Second Exhibition Hall
【Treasures of Fish - Salmon】
Salmon is a species of salmon that is known as a cold-water spawning migratory fish. They are born in the fresh waters of rivers but grow up in the waters of the Pacific Ocean. Every autumn, these salmon can be seen in The Heilongjiang, Ussuri and Tumen rivers in China. Salmon are carnivorous fish, they are fierce by nature, and when they go to sea, they prey on other fish for a living. In the juvenile stage, it feeds on aquatic insects of benthic organisms in the water. Salmon can grow up to 6 kg, they are precious economic fish, loved by people, and their eggs are also famous aquatic products with high nutritional value. Known for its delicious meat and rich nutrition, it has always been regarded as a valuable fish. The Heilongjiang river in Fuyuan City, Heilongjiang Province, China, is rich in salmon and is the "hometown of salmon". Chinese scientific name "Da Ma Ha" fish, comes from a transliteration of the Hezhe language in Heilongjiang Province.
First, different naming
【Place names】Salmon, salmon, salmon, salmon, salmon, salmon,
【Common name】 Northern trout, Dafa salmon, Dafa salmon, Guoduo fish, Luo Pot fish, Gudong fish, Qimu fish, Qi Meng fish, spotted trout, flower trout.
[Foreign name] is also called calico salmon or dog salmon; Russian is Кета.
Salmonidae has a pale, fine-spotted North Pacific edible fish, scientifically named Oncorhynchus keta. Weighs up to 3.6 kg (8 lbs). During the autumn breeding season, it travels more than 3,200 kilometres (2,000 mi) along the Yukon River in North America. In the spring, juveniles hatch for several weeks before entering the sea.
Second, nutritional value
Salmon has a high economic value, the meat taste is very delicious, salmon generally weigh 3.5 kg, the largest more than 5 kg.
Salmon are spindle-like in shape, with a long mouth, a silvery-white abdomen, and 10 to 12 orange-red transverse spots on the side of the adult body. Due to its different reproductive habits, it is divided into two types: spring and autumn. The autumn type that entered China, so it is also known as autumn salmon, which is usually much larger than the average salmon, and the largest individual is 7.5 kg.
It is not only delicious meat, fish roe is more precious than fish meat, its diameter is about 7 mm, the color is red and transparent, like amber, the nutritional value is extremely high, 7 salmon roe is equivalent to an egg. The caviar made from it is served on the plate like a red pearl, sparkling, which can arouse people's appetite, so the "value" is extremely high. Therefore, it is very popular with the public in Europe and the United States.
Third, the living environment
There are more salmon in Lake Baikal and there are large catches.
Salmon is a river-retrospective fish distributed in the northern Pacific Ocean and the Arctic Ocean, with 6 main species: salmon, humpback salmon, red salmon, salmon, salmon, and silver salmon.
Among these species, except for the Mengsu salmon, which is only produced on the coast of Asia, the rest are distributed on both the coast of the Americas and the coast of Asia, and in terms of catch, whether it is the coast of Asia or the coast of the Americas, the humpback salmon occupies the first place.
Humpback salmon are widely distributed in the northern Pacific Ocean, but also widely off the coast of the Americas, from the Colvelli River in the Arctic Ocean to the St. Lorraine River in California.
Humpback salmon mainly feed on fish and crustaceans in the sea, the appetite is particularly delicious, the growth is also very fast, 2 to 4 years old can reach sexual maturity.
Upon sexual maturity, hunchback salmon begin to migrate into the river to spawn. During the migration, they gradually complete the development of sperm and eggs, and when they come to the spawning field, the sperm eggs have matured, the jaws are significantly enlarged, the back is significantly raised (hence the name of the hunchback salmon), and the body color changes. When laying eggs, a pit nest is built on the riverbed with a gravel bottom, and then the eggs are laid in it, and after laying, the eggs are buried with sand and gravel. Despite this, the eggs of the humpback salmon are swallowed in large numbers by ferocious fish such as red-spotted salmon, and because the ovary is dug up by the fish that arrives later, and the influence of unfavorable factors such as freezing, there are very few that can eventually hatch into juvenile fish. Humpback salmon produce very little eggs. Juveniles usually hatch in December of the same year and wait until the following spring to live in the ovary. After the juveniles leave the ovary, they begin to migrate into the sea, where they grow fat.
Roe and fry of salmon can only survive in freshwater, and they generally lay their eggs in gravel areas in the upper reaches of the rivers in freshwater systems. The eggs hatch out of the seedlings and grow for a period of time, then flow downstream into the ocean of the brackish water system, grow and develop in the materially rich ocean to accumulate energy, and after about 4 years of growth to reach sexual maturity, they will migrate to freshwater rivers to lay eggs. Salmon mainly inhabit the oceans of the Northern Hemisphere, with the largest number of seas such as the Sea of Okhotsk and the Bering Sea
Fourth, morphological characteristics
Salmon are generally about 60 cm long and flattened, slightly spindle-shaped; the head is gradually raised from the back of the head to the base of the dorsal fin, which starts at the highest point of the body, and from then on it gradually bends towards the tail. The side of the head is flattened, the snout is prominent, and slightly curved. The mouth is large and resembles a bird's beak, especially in the reproductive male, bending in the opposite direction like a pincer, so that the upper and lower jaws do not match. The maxilla is pronounced, free, and the posterior end extends to the posterior edge of the eye. There is a row of sharp teeth in the upper and lower jaws, the tooth shape is sharp and curved inward, except for the 4 pairs of teeth at the front of the lower jaw, the remaining teeth are small. The eyes are small, and the scales are also small, arranged in a tile-like arrangement. The adipotentic fins are small and the position is very backward. The caudal fin is deeply forked. When living in the ocean, the body color is silvery white, and soon after migrating into the river, the color becomes very bright, the back and side of the body first become yellow-green, gradually darkening, bluish black, and the abdomen is silvery white. There are 8-12 orange-red marriage-colored transverse stripes on the side of the body, the female fish is thicker, the male fish has larger stripe, the snout, jaw, gill cap and abdomen are bluish black or dark pale, and the fin and ventral fin are grayish white. When you arrive at the spawning grounds, your body color is darker. North American salmon, on the other hand, turn red when spawning.
【Original form】 Salmon, the body is slightly flattened, generally about 60 cm long. The head is large, the snout is long, prominent, slightly curved, especially the male fish during the reproductive period the snout is curved like a hook, so that the upper and lower jaws do not match. The eye distance to the snout end is closer than to the gill hole. The mouth is large, the teeth are flat and sharp, the apex is slightly curved inward, and the upper and lower jaws each have 1 row of large teeth. The gill holes are large, and the gill rakers are 19 to 25. The body is covered with small round scales. The lateral lines are obvious. Lateral scales 132 to 148 (19 to 26/18 to 24). The dorsal margin rises gradually from behind the head to the base of the dorsal fin. The dorsal fin is 3 to 4, 9 to 11, and the starting point is about equal to the base of the snout and the base of the caudal fin. The adipose fins are small, knotted with the fins, and the fins are 2 to 4, 12 to 15. Pectoral fins 1,41–16, small, low, ventral fins 1 to 2, 8 to 11. The caudal fin is forked. The dorsal and dorsal bodies are bluish-black, the abdomen is silvery-white, and there are 10 to 12 orange-red transverse spots on the side of the adult body. The and ventral fins are greyish white.
Fifth, life habits
Salmon are cold-water anthropositive spawning migratory fish. Originally inhabited in the northern Pacific Ocean, after living in the ocean for 3 to 5 years (usually 4 years of sexual maturity), they enter heilongjiang in groups in summer or autumn for reproductive migration, which can be divided into two biota, summer type and autumn type according to the river traceability time; only autumn type is traced into China. Most spawn downstream, with only a few arriving upstream. They go up the river, day and night, tirelessly, every day and night can advance 30 to 35 kilometers, whether it is encountering shoal canyons or rapids waterfalls, do not retreat, rush through the obstacles, until the destination. Adults do not feed after entering freshwater reproduction.
Salmon has strict requirements for the conditions of the spawning grounds, the environment should be secluded, the water quality should be clear, the water flow is urgent, the water temperature is 5 to 7 °C, and the substrate is gravel. The spawning period is from late October to mid-November. Before spawning, the male slaps the gravel with his tail fin and borrows the impact of the water flow to form a circular pit with a diameter of about 100 cm and a depth of about 30 cm, called "wozi"; the female lays eggs in the wozi, while the male ejaculates semen. The female repeatedly stirs the gravel with her tail fin to bury the eggs. After spawning, male and female fish linger around the spawning grounds for a long time. Due to their long and arduous migration, they no longer eat during the migration, coupled with the construction of "sleeping children" to lay eggs, physical exhaustion, after spawning cannabis salmon, dark body color, emaciation, full of injuries, has lost its edible value. Therefore, he died 7 to 14 days after laying his eggs, and painstakingly completed the task of reproducing offspring. It breeds only once in life and lays more than 4,000 eggs. The hatchlings hatched from the fertilized eggs prefer to lurk in the dark places between the gravel, growing to about 50 mm, and then begin to descend into the river and go to the sea, feeding on small plankton or dead mothers along the way; when they reach the mouth of the sea, they stay for a period of time, that is, migrate to the far shore; when they reach sexual maturity, they return to the freshwater river to complete the task of reproduction.
Salmon is a ferocious carnivorous fish that eats benthic creatures and aquatic insects when young, and feeds mainly on small fish such as jade tendon fish and herring in the ocean. The life habits of salmon are very interesting, just like the Heilongjiang fishermen said: "Born in the sea, dead in the river". Salmon is a migratory fish species that grows in the North Pacific Ocean. When it reaches sexual maturity, in order to reproduce offspring, it must go through all kinds of hardships, enter the river, and trace it back to the spawning field to reproduce. The salmon that spawns in China's rivers, every autumn (September to October), flocks cross the Sea of Okhotsk, bypass Sakhalin Island, trace the Heilongjiang River, day and night, tirelessly, trek, keep advancing, 30 to 35 kilometers every day and night, whether it encounters shoal canyons or rapids waterfalls, it never retreats, rushes through many obstacles and crosses layers of obstacles, until it swims to the destination and finds a suitable spawning place. Salmon on the way in order to cross the waterfall
Or obstacles, with its tail to hit the water, by high-speed swimming and forward obliquely jump out of the water, jump into the air as high as 2 to 2.5 meters. Because it is good at jumping, the Old Latin name takes sale, which means jump, and is derived from the English salmon.
Sixth, the production and real estate season
Salmon is found on the eastern and western shores of the North Pacific. In China, the Ussuri River, Heilongjiang River and Songhua River are the most numerous, and the Tumen River, Hunchun River, Mijiang River, Suifen River, NenJiang River, Mudanjiang River and Dajia Creek in Taiwan Province are also distributed. The fishing season is from September to October, the length of the fish population is generally 53 to 81 cm, the weight is 1 to 5 kg, and the largest individual can reach about 10 kg. There are three species of salmon in Chinese rivers: ordinary salmon (O.keta), masu salmon (O.masou) and humpback salmon (O.gorbuscha).
Migrating into China's Heilongjiang, Tumen River and other water systems, ussuri river more, September to November for the peak production season. The Ussuri River is rich in salmon, carp, silver carp, mandarin fish, crucian carp and other fish, which is the largest salmon producing area in China.
7. Spawning secrets
Secret One
After growing in the ocean for about 4 years, the salmon will migrate thousands or even miles to spawn in the freshwater rivers where it was born, regardless of the long distance. Due to the large number of salmon, and their trip is one-way (generally after spawning, they all die in the river), so the migration will bring a large amount of material and energy they absorb in the ocean back inland, feeding many inland creatures, such as the North American grizzly bear is a very dependent on salmon animals, north American salmon migration area there are more than 200 species of salmon as food for survival, 80% of the nitrogen in the forest in this area is brought in from the ocean by salmon. Therefore, the great migration realizes the circulation of matter and energy within nature.
Secret two
The reason why salmon migrate is because the eggs of salmon can only survive in fresh water. Of course, there should be other reasons.
Secret Three
How salmon crossed the vast ocean to return to their place of birth is still a mystery. The latest research shows that salmon have an iron particle in their brain that, like a compass, can help them find their way forward accurately on Earth.
Secret Four
Salmon migrate to rivers, and due to sudden exposure to fresh water, their kidneys and other organs have to adapt to a sudden lack of salt, which is a life-and-death test for them. Under normal circumstances, after entering the river, they will stop eating, or even stop drinking water, and they will struggle to run upstream, relying on the energy stored in the body.
Secret Five
When salmon are ready to spawn, their body color changes significantly and becomes very bright, such as the North American salmon turning red (see the picture under the directory of morphological characteristics). Of course, this discoloration process is not completed at once, but begins from the time of migration to the large secretion of river sex hormones. After spawning, salmon die due to lack of physical strength.
Secret Six
The roe of salmon is bright red and has a diameter of 7 mm, which is very large compared to the general roe, so it is a superior raw material for making caviar.
Secret Seven
Salmon swim upstream in rivers and often encounter many high-drop currents, such as waterfalls
Salmon jumping small waterfalls
Bu, at this time, the salmon will jump over, which is the ability of the salmon to evolve over six million years. They jump, sometimes equivalent to a person jumping over 4 floors. Because it is good at jumping, the Old Latin name takes sale, which means jump, and is derived from the English salmon.
Secret Eight
In general, Pacific salmon die after spawning, but this is not the case with Atlantic salmon, which spawn year after year. But the corroded carcasses of Pacific salmon nourish the rivers and provide plenty of food for their growing children.
(The content under this table of contents is based on the BBC documentary "The Salmon Migration of Cannabis Salmon from Major Events in Nature")
VIII. Classification
There are three species of salmon in China's rivers: ordinary salmon (O.keta), masu salmon (O.masou) and humpback salmon (O.gorbuscha).
There are five species of salmon in North America: Pink salmon, Chum, Silver Salmon, Sockeye, and Chinook salmon.
9. Economic value
Salmon is a valuable large economic fish. The body is large and fat, the meat tastes delicious, can be eaten fresh, can also be glued, smoked, processed canned, all have a special flavor. Salted fish eggs are known as "red seeds", which have high nutritional value and enjoy a high reputation in the international market.
In China, salmon is an export species, its English name is Chuum salmon, from Liaoning, Heilongjiang to Japan.
Salmon is not only a large and precious specialty fish in Heilongjiang Province, but also one of the precious freshwater fish in China. Its flesh is delicate, red, delicious, extremely rich in fat, and its nutritional value is quite high. It contains 14.9 to 17.5% protein, 8.7 to 17.8% fat, 61.4% water, 1384 calories per 100 grams, 50 mg of calcium, 153 mg of phosphorus, and 1.9 mg of iron. It also contains sugars and multivitamins. Its eggs are crystal clear, grains like pearls, rich in phosphate, calcium and vitamins A and D, and are recognized as feasts. Salting it into "hemp salmon roe" is the "red fish roe" that is famous in the international market and is very popular with the public in Europe and the United States. The Hezhe people living in Heilongjiang Province also use salmon skins to make leather, making leather clothes, pull-up boots, cigarette packs and wallets. The meat, liver, sperm nest and head of salmon have medicinal value. Its flesh has the effect of tonifying fatigue, strengthening the spleen and stomach, warming the stomach and medium, and can treat edema, weight loss, indigestion, swelling and fullness, vomiting acid, convulsions, swelling and sores. Cod liver can be prepared with cod liver oil. Sperm nest can be prepared protamine and formulated into a variety of protamine preparations, adapted to the treatment of reactions caused by excessive injection of heparin; it also has a significant hemostatic effect on certain hemorrhages (such as acute bleeding of the upper gastrointestinal tract, lung coughing, etc.).
Artificial hatching of salmon
High profits and broad prospects have promoted the development of artificial breeding technology for salmon! For the first time, Huairou District, Beijing, has successfully hatched salmon artificially, and it is expected that 2500 seedlings will be successfully hatched. The artificial culture technology of salmon has been further improved, catching up with the United Kingdom and the United States. Many consumers have doubts about how long it will take for artificial hatching technology to be put into production, promote the economic development of salmon, and allow more people to eat this precious fish species.
It is understood that salmon fry have been able to breed artificially in Beijing, Tianjin, Heilongjiang and other places, which will further promote the breeding gap of precious economic fish species in China, optimize the structure of marine aquaculture, and promote the healthy and sustainable development of salmon farming. [1]
X. Etymology of the word salmon
The Latin literary name keta comes from the Russian language, while the Russian кета is derived from the Orenchun language keta, in addition, the northern languages of the Mantungus language family such as Evenki (Evenk), Evan, and Nekidhar, the word keta means "big salmon".
Chinese scientific name salmon, comes from the Hezhe language. In Tongjiang City, under the jurisdiction of Jiamusi City, Heilongjiang Province, in the lower reaches of the Heilongjiang River under the jurisdiction of Qindeli Town, the Hezhe people who call themselves "Hezhen" are called dawa imaha. The upper reaches of the Heilongjiang River above the town of Sindli, and the self-proclaimed "Qileng" Hezhe people who live along the Ussuri River, call it daw imaha. Republic of China scholar Ling Chunsheng's "Hezhe People in the Lower Reaches of the Songhua River" is recorded as dau imaha under the entry "Salmon". In the Hezhe language, imaha means "fish", so dawa imaha, daw imaha or dau imaha is "dawa fish", "daw fish" or "dau fish". In Russia, the languages of Nanai, Oroch, Ude, Ulich, Ocro and other languages belonging to the Mantungus language family in Russia are called dawa, and the dawa does not need to be said after the imaha already means this fish, so the original meaning of dawa-daw-dau is "salmon", and the name of this fish is dawa-daw-dau. Chinese transliterated dawa-daw-dau as "big", and imaha transliterated as "maha", and in order to show that "da maha" is a fish, a "fish" was added after it, so the word Chinese salmon is derived from the Hezhe language of Heilongjiang Province.
In addition, some local common names call it "Dafa salmon", "Dafa salmon", is from the Manchu dafaha, Manchu dafaha is "salmon".
(Excerpt from "Chinese Chinese", 1999)
11. Sea lice infection
Sea lice, a parasitic crustacean that afflicts salmon. However, when their hosts are eaten by other big fish, these parasites will "abandon the boat" and "camp" on the carnivorous fish. The researchers report in the online edition of Biology Letters that this previously unrecognized escape strategy is definitely bad news for the entire food chain.
Due to large-scale fish farming, the spread of sea lice has become out of control in the waters of British Columbia, Canada. Tight and crowded fish cages are breeding grounds for this parasite, eating off the skin, muscles and blood of their hosts and frequently spreading between schools of juvenile wild salmon. It is for this reason that the rate at which wild salmon are infected with sea lice is skyrocketing, even leading to the imminent extinction of some salmon populations.
A team of researchers led by BrendanConnors, a behavioral ecologist at Simon Fraser University in Burnaby, Canada, has now found that sea lice's spreading skills are more powerful than people thought. The researchers asked carnivorous fish that had not been infected with sea lice — silver salmon and mountain trout — to stay with two juvenile salmon, one of which was infected by sea lice and the other uninfected. When the carnivorous fish ate one of the salmon, the researchers examined whether the former was infected with sea lice. It turned out that carnivorous fish were safe if they ate uninfected salmon, and if they ate infected salmon, the carnivorous fish had a 70% chance of being infected — a process that sea lice would run to their new host, a process that can be observed with the naked eye. Connors said: "This is amazing! "These sea lice will accurately 'jump' from the body of the salmon to the predator's eye." ”
The discovery that more male sea lice would flee their hosts than female sea lice puzzled Frédéric Thomas, a parasitic biologist at the French National Institute in Montpellier. He said that the situation, in which males are able to escape death while females die in large numbers, has evolved to be only one way to die.
Alan Pike, a fisheries biologist at the University of Aberdeen in the United Kingdom, stresses that these sea lice can only survive on salmon, which includes salmon and trout. If a fleeing sea lice falls on the wrong predator, it will not survive. What Pike wanted to know was how sea lice could survive in such a harsh environment.
Connors believes that the life-saving jump of sea lice shows that fish farms can not only be infected by juvenile wild salmon, but even by predatory fish that eventually eat them. "We haven't considered the spread of these sea lice in the food chain," he said. ”
Third Exhibition Hall
【Nutrition and Efficacy of Fish】
Kanji: fish yú
Evolution of fish bone inscriptions:
Quoted from Ding Zaixian and Ding Lei, "Dongyi Culture and Shandong Bone Inscription Interpretation", Chapter 19, Section 2, China Literature and History Publishing House, February 2012. Fish belong to the vertebrate subphylum of the chordate phylum, and the average person divides the vertebrates into five categories: fish (53%), birds (18%), reptiles (12%), mammals (9%), and amphibians (8%). According to the late Canadian scholar Nelson (1994), there were 24,618 known species of fish worldwide at that time, accounting for more than half of the named vertebrates, and new species of fish were constantly being discovered. About 32,100 species have been named worldwide.
1. Animal characteristics
Fish is the oldest vertebrate. They inhabit almost all of the planet's aquatic environments – freshwater lakes, rivers to saltwater seas and oceans.
There are about 26,000 species of fish that have been found in the world, and the fish live in the water, distributed in the ocean and freshwater, two-thirds of the ocean lives in the ocean, and the rest live in fresh water. There are 2,500 species in China, of which there are more than 100 kinds of medicinal animals, and the common medicinal animals are seahorse, sea dragon, yellow eel, carp, crucian carp, sturgeon (maw is maw glue), giant yellow croaker (otolith is fish brain stone) liver oil (vitamin A and vitamin D) are the main raw materials. Hydrolyzed proteins, cytochrome C, lecithin, cerebrophospholipids, etc. can be extracted from various fish meats, and the liver and ovaries of puffer fish contain a large amount of tetrodotoxin, which can be extracted to treat neuropathy, spasms, tumors and other diseases. The bile of large fish can be used to make "biliary pigment calcium salts", which are used as raw materials for artificially making bovine yolk. The differences between the various orders of fish are as great as between the classes of terrestrial vertebrates. Fish are generally considered to be spiky and spindle-shaped, streamlined, finned, gill-breathing aquatic animals, but many more species do not meet this definition. Some fish are extremely long, some are extremely short; some are flattened, some are flattened; some have large fins or complex shapes, some are degenerate and even digested; the shape of the mouth, eyes, nostrils, and gill openings varies greatly; some fish breathe air and will drown when immersed in water. Fish is an important food for humans. Overfishing, pollution and environmental change can all destroy fish stocks, which prey on and help control mosquito-borne diseases such as malaria. Fish are important laboratory animals in behavior, physiology, ecology and medicine.
The fish is an aquatic cold-blooded vertebrate that breathes with gills and has jaws and fins. Extant fish can be divided into two main populations: cartilaginous fish (such as sharks) and teleost fish (linear fin and wavy fin fish). Both groups of fish first appeared in the early Devonian period. The more advanced group of linear finfish, called teleost fish, began to evolve during the Jurassic period and today has become the fish with the largest number of individuals. There are also several species of fish that have become extinct.
Fish, accompanied by human beings through more than 5,000 years of history, and human beings have formed an indissoluble relationship, becoming a very important food and ornamental pet in human daily life, but what animals are "fish" for people? How to define fish, but few people know. With the development of science, people's definition of fish has also changed a lot.
Nearly half a billion years ago, a major leap took place in the course of life on Earth, with the emergence of the earliest fish-shaped animals, which opened the prelude to the history of vertebrates, which led to the development of the animal kingdom and entered a new historical stage. Real fish first appeared more than 300 million years ago, in the entire long history process, once survived a large number of fish, has long been with the passage of time and extinction, today's living on the earth fish, only a small part of the later emergence, evolution of a very small part of the species.
Humans have long been able to identify species and give names, usually referred to as "fish" includes all animals in the water, so many animals living in the water are named fish, and whales, seals, giant salamanders (baby fish), squid, squid, octopus, starfish, jellyfish, sponges, Wenchang fish, etc. are confused with fish.
Twenty thousand years ago, the ancient Greek philosopher Plato defined fish as follows: "This class [of fish] is created by something completely ignorant and unconscious." The Lord of Transformation thought that it was no longer worth it to give pure breath in this category, because they were the offspring of all kinds of evil and there were unclean hearts. The Lord of Transformation threw them into the water, causing them to breathe through the deep sludge of the divine and pure air. This is how fish and oysters, as well as all other aquatic animals, have been separated far away as punishment for the great sin of ignorance." Plato's views are full of creationism. Due to the development of modern science, this view has long been completely rejected.
At the beginning of the Han Dynasty in China, "Erya" divided animals into four categories: insects, fish, birds and beasts, of which fish included fish, amphibians, reptiles and other low vertebrates, as well as whales and shrimp, crabs, shellfish and so on.
In the 18th century, the Swedish naturalist Linnaeus founded modern taxonomy, and in his book Natural Systems, he divided the animal kingdom into six classes: mammals, birds, amphibians, fish, insects, and worms. In 1859, the British biologist Darwin published the book On the Origin of Species, which gave birth to systematic taxonomy. Since then, the definition and scope of fish have been determined.
Which animals are "fish"? Modern taxonomists define a "fish" as a vertebrate that lives in water all its life, breathes with its gills, and swims with its fins. Fish include three major groups of gardeners, cartilaginous fish and teleost fish, there are about 26,000 kinds of known fish in the world, which is the largest variety of vertebrates, accounting for about 48.1% of the total number of vertebrates.
Second, the shape of the animal
1. Spindle shaped
Also known as the basic type, it is the body shape of a general fish, suitable for swimming in the water, and the whole body is spindle-shaped and slightly flattened. Among the three body axes, the head and tail axis is the longest, the dorsal and ventral axis is the second, and the left and right axes are the shortest, so that the entire body is streamlined or slightly flattened, which is conducive to reducing the resistance when moving forward in the water, so this type of fish is good at swimming. It often inhabits the middle and upper layers of water. Long-distance migrations are possible. Examples: carp, crucian carp, shark.
2. Side flat type
Among the three body axes of this type of fish, the left and right axes are the shortest, and the proportion of the head and tail axes and the dorsal and ventral axes is not too much, forming a symmetrical flat shape on the left and right sides, so that the entire body shape is flat and wide, so the ability to swim is worse than the spindle type, living in the middle and lower layers of the water. Long-distance migrations are rare. Such as pomfret, butterfly fish, bream, rouge, swallow fish and so on.
3. Flat type
Among the three body axes of this type of fish, the left and right axes are particularly long, and the dorsal and ventral axes are very short, so that the body size is flattened up and down, and the movement is slow, which is not as flexible as the first two types, and the multi-camp benthic life. For example, stingrays, rays, trout and catfish.
4. Stick type
Also known as eel type. The head-tail shaft of this type of fish is particularly long, and the left and right axes and the ventral axis are almost equal, both are very short, so that the whole body shape is stick-shaped. Its swimming ability is stronger than that of the lateral flat type and the flat flat type. Suitable for burrowing in underwater mud and living in underwater sand and gravel. Such as yellow eels, eels and a variety of moray eels.
In addition, some fish take on special sizes due to their adaptation to special living environments and lifestyles, such as sea dragons, sunfish, river rays, flounders, box fish, etc. Regardless of the size of the fish, it can be divided into three parts: head, trunk and tail. Neckless is characterized by the fact that the head and torso are interconnected and fixed, which is one of the differences between fish and terrestrial vertebrates, and the dividing line between the head and torso is the posterior edge of the gill cap (teleost fish) or the last pair of gill fissures (cartilaginous fish). The trunk and tail are generally demarcated by the posterior margin or the starting point of the fin, or, to be precise, at the end of the body cavity or the first caudal vertebral.
Third, athletic ability
1. Overview
The appendages of fish are fins, which are motor organs that swim and maintain balance in the body. The fins are composed of supporting fin bones and fins, and the fins are divided into two types, one is an angled fin that is not segmented or branched, and is produced by the epidermis and is found in cartilaginous fish; the other is a squamous fin or bony fin, derived from the scales, with, branched or unbranched, found in teleost fish, and the fins are connected with thin fins. Bone fins are divided into two types, fin spines and soft stripes, which are formed by the deformation of a fin strip, which is a hard spine that neither branches nor segments, and is possessed by higher fish. The soft strips are soft and knotted, and their distal branches (called branched fins) or non-branched (called non-branching fins) are formed by merging the left and right halves. The fins are divided into two categories: odd fins and even fins. The even fins are pairs of fins, including 1 pair of pectoral and ventral fins, equivalent to the front and back limbs of terrestrial vertebrates; odd fins are unpaired fins, including dorsal fins, caudal fins, and fins (anal fins). The basic function of the dorsal and fins is to maintain body balance, prevent tilting and rocking, help swim, and the tail fins act like a rudder, controlling direction and propelling the fish body forward. Common fish generally have the above five kinds of fins, such as chest, abdomen, back, buttocks and tail. However, there are a few exceptions, such as yellow eels without even fins, odd fins are also degenerated; eels have no abdominal fins; electric eels have no dorsal fins, and so on.
2. Caudal fin
Determines the direction of movement, provides the impetus to move forward, and if lost, the fish will not turn. Depending on the shape and position of the end of the tail vertebrae, the caudal fin can be divided into four types:
Round caudal fin: the caudal fin is a leaf, the tail vertebrae extend all the way to the posterior end of the caudal fin, dividing the fin into dorsal-ventral symmetry, and the tail fin is pointed at the end, which is mostly found in the embryonic stage and the juvenile stage of fish.
Crooked caudal fin: The caudal fin is divided into two lobes, and the end of the caudal vertebrae is slightly curved upwards into the upper lobe of the caudal fin. The upper lobe is longer, and the lower lobe is small and slightly prominent, forming a crooked caudal fin that is asymmetrical both inside and outside. Common in modern cartilaginous fish and a few teleost fish. Such as sharks, sturgeon and so on.
Orthogonal caudal fin: divided into two lobes symmetrical up and down, the end of the caudal vertebrae only reaches the base of the caudal fin, and slightly upturned, retaining traces of crooked caudal vertebrae, the tail fin is completely symmetrical in shape, and the lower lobe is supported by increased subcoccine bone fragments. The orthogonal caudal fin is one of the characteristics of higher fish. According to the change of fin shape, there are a variety of fin shapes.
Prototype caudal fin: The end of the caudal vertebrae stretches straight to the end of the tail and is rounded, not as pointed as the rounded tail, and the upper and lower lobes of the tail fin are roughly equal, which is a primitive tail type, found in the round mouth, and the fish are only found in juvenile fish.
3. Pectoral fins
Keep the fish body balanced, if lost, the fish body will sway from side to side. Equivalent to the forelimbs of a terrestrial animal, it is born on the thorax of the posterior edge of the gill cap. It has the function of moving, balancing and mastering the direction of movement of fish. When the fish stops advancing, the pectoral fin is used to control the balance of the fish body; when swimming slowly, the pectoral fin plays the role of a boat oar; when traveling at high speed, the pectoral fin is close to the fish body, when it is lifted, it can slow down and brake; when the pectoral fin is close to the fish body on one side and lifted on the other side, the fish body turns towards the lifted side to assist the tail fin to play the role of rudder.
4. Ventral fins
Keep the fish body balanced, if lost, the fish body will sway from side to side. Equivalent to the hind limbs of terrestrial animals, it has the ability to assist the dorsal fin and fin to maintain the balance of the fish body and assist the fish body to rise and fall. The location of the ventral fin varies from fish to fish, and the ventral fin of cartilaginous fish is generally located on both sides of the cloaca. The shape is similar to the pectoral fin and slightly smaller. The ventral fin of the teleost fish is located on the ventral side of the trunk called the ventral fin ventral position. This is a more primitive type of species, such as carp, salmon, catfish, herring, etc.; located in front of the pectoral fin, the chest after the gill cover is called the ventral fin chest position, such as sea bass, yellow fish and seabream; the throat located between the two gill lids is called the ventral fin larynx, such as catfish and stingrays. The ventral fin thoracic and laryngeal positions are advanced features that emerge after the evolution of fish. These well-positioned ventral fins are an important marker in the evolutionary history of fish and are of great significance in animal taxonomy.
5. Dorsal fin
Keeping the fish body upright plays a key role in the balance of the fish body, and if it is lost, it will lose its balance and roll over. But there are also some long fish, with dorsal and fins that assist in body movement and propel the body forward. For example, the dorsal fin of the fish, the fin of the electric eel, the dorsal fin and the fin of the moray eel can all push the body forward. Another example is the special shape of the seahorse, which also relies on the small dorsal fin movement to push the body forward. The fin type is a recorded form that indicates the composition of the fin and the number of fin strips. The first letter of each fin in Latin represents the category name of the fin, such as D for the dorsal fin, A for the fin (anal fin), V for the ventral fin, P for the pectoral fin, and C for the caudal fin. The uppercase Roman numerals represent the number of spines. Arabic numerals represent the number of soft bars, and the range of thorns or soft bars is represented by "one", which is represented by "one" when the spines are connected to the soft bar, and separated by ", " when separated. For example, the fin type of carp: D.. III.I. IV.17~22;P. I. 15 to 16;VII.1819;A... III.1.5~6;C.20~22.
The above indicates that carp has a dorsal fin, 3 to 4 hard spines and 17 to 22 soft strips; 1 hard spine and 15 to 16 soft strips in the pectoral fin; 2 hard spines and 8 to 9 soft strips in the ventral fin; 3 hard spines and 5 to 6 soft strips in the fin; and 20 to 22 soft strips in the caudal fin. The fin type of the perch is D. XII.I.-13;A.. III.1.7~8;P.15~18;V.I.15.15. It means that the perch has two dorsal fins, the first dorsal fin consists of 12 hard spines without soft stripes; the second dorsal fin includes 1 hard spine and 13 soft strips; the fin has 3 hard spines and 7 to 8 soft strips; the pectoral fin has 15 to 18 soft stripes; and the ventral fin has 1 hard spine and 5 soft strips. The movement of fish is very closely related to changes in body shape and fins, and its swimming power mainly depends on the following three ways:
Use the muscles of the trunk and tail to contract in waves.
Paddling movements that rely on the swing of the fins.
The reaction force caused by the gill hole to spray water backwards is used to advance the fish body. In addition to swimming, a few fish also have a special form of movement, that is, jumping or flying, such as silver carp can jump obliquely out of the water very high, and then fall vertically into the water. After jumping hard and obliquely out of the water, the flying fish can also open its wide pectoral fin and soar up to about 300 meters in the air. Salmon can repeatedly jump over a variety of obstacles in the river and migrate from the sea to the middle and upper reaches of the river to spawn. In addition, there are very few fish that can crawl, such as trout and bouncing mud.
6. fin
Coordinates the other fins to balance the other fins, and if lost, the body shakes slightly.
4. Animal skin
The skin of fish is composed of epidermis and dermis, the epidermis is very thin, composed of several layers of epithelial cells and germination layers, the epidermis is rich in single-celled mucus glands, which can continuously secrete a slimy liquid, so that the body surface forms a mucus layer, lubricating and protecting the fish body, such as reducing the frictional resistance of the skin; improving the ability to exercise; removing bacteria and dirt attached to the fish body. At the same time, it makes the body surface slippery and easy to escape the enemy. Therefore, the epidermis is of great significance to the life and survival of fish. Subpidermal is the dermis layer, which is rich in blood vessels, nerves, skin receptors, and connective tissue, as well as pigment cells, brilliance cells, and fat cells in the deep layers of the dermis and scales. Pigment cells have black, yellow, red three kinds, melanocytes and yellow pigment cells are present in the skin of common fish, red pigment cells are mostly found in the local skin of tropical exotic fish, brilliance cells do not contain pigment and guano containing crystals, there is a strong reflectivity, so that fish can show silver-white flashes, some fish live in the depths of the ocean or dim water layer, with another skin derivative - luminescent glandular cells, can secrete phosphorus-rich substances, fluorescence after oxidation, in order to trap phototropic organisms, Or as a signal of contact between the same species and the opposite sex, such as some species in the deep-sea snake mullet, the dragon head fish and the horned trout.
Between the epidermis and the dermis, or there are many scales in the dermis, fish scales are unique skin derivatives of fish, composed of calcium, covered in the whole body or part (a certain part) of the fish body surface, can protect the fish body from mechanical damage and external adverse factors of stimulation, so it is called "exoskeleton". It is also one of the main characteristics of fish. The scales of extant fish can be divided into three types according to their appearance, structure and occurrence characteristics.
The scales are formed by the combination of the dermis and epidermis, including the substrate of the dermis evolution and the dental parts of the plate, i.e. the round or diamond-shaped substrate of the hard bone buried in the dermis and the conical spines (dendonts) protruding from the outer edge of the epidermis towards the body and the central bulge. The surface of the dentium is covered with enamel evolved from the epidermis, the center of the dentized part is the medullary cavity, the entire medullary cavity is opened at the bottom of the substrate, and there are blood vessels and nerves passing into the cavity. The occurrence and structure of the shark's body surface and the same occurrence and structure of the teeth should belong to the homologous organs, so the shark's teeth are also called skin teeth. The structure of the scales is more primitive and is found in cartilaginous fish scales.
The obagonal bony plate scales evolved from the dermis have a layer of calcified hard scales with special brightness on the surface, called glitter. Hard scales are the most primitive scales in bony fish, such as those of finches and sturgeon.
Bone scales are a bony structure evolved from the dermis, rounded, with anterior end inserted into the scales, and the posterior end exposed to the skin in a free state, arranged in a compound tile shape. According to the shape of the free trailing edge, it is divided into round scales and ctenophores. The free posterior margin of the round scales is smooth and blunt, and is commonly found in lower-level teleost fish such as cyprinids and herring orders. Ctenophores have serrated protrusions on the posterior margin, which are most common in higher fish such as perch. Regardless of the round scales or ctenophores, there are concentric circles on the surface, called annual rings. As with the annual rings of plant stems, it is possible to speculate on the age, growth rate, reproductive season, etc. of fish.
Fifth, the role of scales
As an external skeleton, the scales can not only maintain a certain shape of the fish body, but also reduce friction with water.
It provides a protective barrier for the fish body to isolate it from the countless microorganisms around it, effectively avoiding infection and fighting disease.
The scales in the belly of the fish can reflect and refract bright light, like a mirror, so that the fierce aquatic animals underneath are dazzling, producing a color of heaven and water, not distinguishing objects, and becoming a natural camouflage.
In addition, biologists determine the age of fish based on the rings of the rings on the scales (each round indicates a winter), and can also more correctly grasp their growth, mortality and health.
Most of the sides of the fish body have one or more lines that evolve from a single nest to a tubular line, called lateral line scales, and each side line scale has a lateral line hole, which can feel the low-frequency vibration of water. The scales of the bony fish are usually identified according to their number, size, and shape, and the arrangement of the number of scales is recorded, which is often expressed with a fractional formula, called the scale type: for example, the scale form of crucian carp is 28 to 30, the lateral scales of crucian carp are 28 to 30 pieces, the lateral line scales are 5 to 6 pieces, and the lateral lower scales are 5 to 7 pieces.
6. Fish bones
1. Overview
The bones of fish are divided into two categories according to their nature: cartilage and hard bone. Cartilaginous fish retain cartilage throughout life, and there is a calcareous precipitate in the cartilage, also known as calcified cartilage. The bones of the bonefish are mainly hard bones, which are divided into two kinds of softened hard bone and periosteum according to different forms: the hard bone formed by ossification on the original basis of cartilage is softened hard bone, such as vertebrae, ear bone, occipital bone, etc.; the hard bone formed by direct ossification of dermis and connective tissue is called membrane bone, such as frontal bone, parietal bone, gill cap, etc. The bones of fish are divided into two parts, the central axis bone and the appendage bone, according to the part.
2. Appendage bones
Appendage bones are divided into odd fin bones and even fin bones. The dorsal, and caudal fin bones in the odd fin are supported by the fin bones (spoke bones) inserted into the muscle, and the fin bones of the teleost fish are also called fin bones. The even-fin skeleton consists of two parts: the band bone (shoulder strap and lumbar bone) and the fin bone (the fin bone and the fin strip). In fish, except for the shoulder strap of the teleost fish, all the appendage bones are not directly related to the spine, which is also one of the characteristics of fish, which is determined by the way the fish moves by swimming.
3. Divide the skull and spine
(1) The largest number of skulls: The skull of a teleost fish is composed of about 130 pieces of bone (referring to existing fish, and the skulls of primitive fish in ancient times can be as many as 180 pieces), which is the animal with the largest number of brain bones in vertebrates. The skull of a fish is divided into two parts: the cranial skull and the pharyngeal skull.
(1) The skull of the cartilaginous fish is a cartilage cavity to protect the brain, the structure is simple, there is no demarcation and suture, only the back of the brain is covered by a membrane, such a skull is called a soft skull. There are several pieces of occipital bone, ear bone, sphenoid bone, and sieve bone ossified from the soft skull of cartilaginous fish, as well as the nasal bone, frontal bone, parietal bone, plough bone and other membranous cranial parts derived from the membrane bone, so the structure is very complex. The skull of a teleost fish is synthesized from many pieces of bone to form the main part of the skull.
(2) Vertebrates start from fish, pharyngeal arch differentiation into upper and lower jaws, wells form pharyngeal cranium, fish pharyngeal cranium is the most developed, formed by 7 pairs of ">" shaped pharyngeal arch, the first pair is enlarged into a jaw arch, the dorsal section of the jaw arch is called palatal cartilage, and the abdominal segment is called Michael's cartilage. The two constitute the upper and lower jaws of cartilaginous fish. The appearance of the upper and lower jaws is more advanced than that of the round mouth, and it can actively consume food. The durodete fish evolved into the membranous premaxilla and maxilla, replacing the cartilage maxilla (palatine cartilage), Mychonnes cartilage evolved into the joint bone, tooth bone and corner bone of the cartilage, etc. The second pair of tongue arches is composed of both sides of the tongue and jaw cartilage, tongue cartilage and central, basal tongue cartilage, mainly for the support of the tongue, but also to help support the upper and lower jaws, the 3rd to 7th pairs for the gill arch, supporting the gill and gill septum, so that the gills are separated from each other, which is conducive to breathing.
(2) Spine replaces the spine: The spine of fish is composed of many vertebrae connected to each other to form a columnar bone to replace part or all of the backsteord, which has the function of supporting the body and protecting the spinal cord and major blood vessels, which is more advanced than that of round mouths. The vertebrae of fish have the characteristics of inward depression on both sides of the front and back, called two concave vertebral bodies or double concave vertebral bodies, which are unique to fish, and the remaining spinal cord can be seen in the adjacent two vertebral space and the small tubes that run through the vertebral body. Vertebrates start with fish, and the basic structure of the vertebrae has been formed. The vertebrae of both cartilaginous and teleost fish are divided into vertebral bodies, myelin arches, myelin spines, chalcedonial arches, and pulsal spines. Among them, the vertebral body is the main part, the ribs are connected to the transverse process of the vertebrae, and the ribs of the teleost fish are mostly more developed.
Seven, the digestive system
The digestive system of fish consists of the digestive tract and the digestive glands, which already have gastrointestinal differentiation and a pronounced pancreas. Because fish live in water all their lives, their digestive organs and feeding habits are adapted to living in the water. The mouth is located between the upper and lower jaws, there are no salivary glands in the mouth, and the oropharyngeal cavity of fish has real teeth, which can actively ingest and prey on, which is more advanced than the round mouth. The teeth on the jaws of plate gills are transformed from shield scales, and the teeth of the teleost fish are divided into oral and throat teeth depending on the site of birth. Fish that generally feed on plankton have thin, fluffy teeth arranged in bands;
Viii. The evolutionary process
Among the 5 major categories of vertebrates, fish are the lowest, and they appeared earliest on Earth. We are familiar with living fish, but we are more unfamiliar with the early fish in geological history and how they evolved into living fish. Let's go back in time.
The earliest known fish fossils, found in the late Cambrian strata about 500 million years ago, are only scattered scales that do not give us a silhouette of the fish's body. It was not until the Late Silurian and Devonian periods, between 400 million and 350 million years ago, that a large number of fish fossils were found. Some of these fish fossils are very different from each other in terms of tectonic characteristics, indicating that there were already many types of fish at that time. It is likely that, before the fossil record was available, they had parted ways and gone a long way in their respective evolutionary paths.
The earliest fish to appear were jawless fish. As the name suggests, they do not have an upper or lower jaw, only a funnel-like mouth at the front of the body. This kind of mouth can not take the initiative to eat, only rely on the flow of water to bring the tiny creatures into the mouth. In addition, they do not have ventral fins, but have membranous exoskeletons that wrap around the outside of the body. Therefore, jawless fish are also known as armored fish. Because of the existence of this exoskeleton, it has caused some controversy among relevant scholars: is cartilage first or hard bone first? In the process of vertebrate embryogenesis, cartilage always appears first, and then from the cartilage forms hard bone. It is generally believed that individual occurrence reflects systematic occurrence. According to this, in the process of biological evolution, it should be cartilage first, hard bone later, but the earliest vertebrates appeared first but hard bone, how to explain this? Some people say that cartilage still comes first, but cartilage cannot be preserved as fossils. Exactly, there is no conclusion.
Jawless fish include two very different classes: cephalic and finnal carapace, each of which has its own branches, with different types of representatives, and has also flourished. By the middle of the Devonian Period (about 350 million years ago), most of them were extinct. Only because some of the characteristics of the living lamprey and hagfish are consistent with the cephalic class, scholars speculate that the former may be the living representative of the latter. According to this, the head A class should not be finally extinct. However, no intermediate link was found between the cephalopods to the lamprey and hagfish, from the Devonian to the modern 300 million years (Figure 14). How these parasitic modern jawless fish evolved from their armor-clad ancestors is still a mystery. Finned acess are not represented and are considered extinct. However, due to the similarity of certain features of heteroceros in finned carapace to later jawed fish, it has been said that heteroaceous may be a distant ancestor of jawed fish. Whether this is the case or not, more arguments are needed.
The earliest jawed fish were shield fish, which not only had upper and lower jaws, but also even fins. In this way, it is possible to actively feed. Shieldfish are usually divided into carapaceous and carapace, both of which are clad in armor and most flourished in the late Devonian period. The former can be represented by coccyx fish, and the latter can be represented by grooved scale fish. Some believe that shieldfish may be related to modern sharks, but others believe that they may be more closely related to teleost fish.
Plate gills, also known as cartilaginous fish, include sharks and whole-headed species. Sharks are often considered primitive fish because of their cartilaginous skeleton. Cartilage comes first, hard bone comes later. But there are also those who believe that the cartilage of sharks is secondary, "degenerated" by hard bone, with hard bone first and cartilage later. Aren't both armored and shield fish rigid? The earliest hard bones are truly primitive.
The earliest cartilaginous fish appeared in the early Devonian period (380 million years ago), and the slit shark is often regarded as one of the most primitive representatives and is likely the ancestor of all sharks. It is a shark that is nearly 1 meter long and has a typical shark body type , spindle-shaped , with large eyes and near the end of the snout. Two dorsal fins, the first with a thick dorsal spine in front of it. The pectoral fins are particularly large and the ventral fins are small. The upper and lower lobes of the caudal fin are symmetrical in appearance, but the internal structure of the upper spine extends all the way to the end of the upper lobe of the caudal fin, so it is still a crooked tail. The even fin has a broad base and a pointed end, which is a primitive type of fin. The teeth are "pen holder" shaped, with the tip of the tooth in the center high and the side low. From the central trunk of the slit shark, which is an approximate cartilaginous fish, various sharks evolved in the later period, including typical sharks and rays with flattened bodies. These sharks have lived in the ocean since the Mesozoic Era and have neither been particularly prosperous nor eliminated.
Bony fish are the most progressive fish and the "masters" of the world's waters today. It is generally believed that teleost fish evolved from spiny fish. Echinoss are early jawed fish that appeared in the early Chlorene (400 million years ago) and continued into the Permian (250 million years ago). This is a small fish that was once thought to be related to shield fish, to cartilaginous fish, and through the study of new materials, it was determined that it was related to teleost fish.
There are two major branches of bony fish, one called rayfin fish and the other called meat fin fish. The former first appeared in the middle Devonian period, about 380 million years ago, and reached modern fish through three evolutionary stages of cartilaginous hard scales (partial cartilage, orthopedic scales, and pronounced crooked tails), whole bone fish (partial cartilage, orthopedic scales, and light crooked tails) and eukeletal fish (hard bones, round scales, orthopedic tails). Meat fin fish include total finfish and lungfish, while total finfish are divided into spiny fish and fanfin fish. The Latima is the only living representative of the empty spiny fish, while the fanfin fish is all fossil species. The latter was once considered to be the ancestor of terrestrial tetrapods, but was denied by Chinese scholars. Lungfish began to appear in the Devonian Period (360 million years ago) and are still represented by The Australian Lungfish, the African Lungfish and the South American Lungfish. As the name suggests, lungfish can breathe with their lungs, which is a basic requirement for terrestrial vertebrates, and with other characteristics, lungfish have been thought to have been the ancestors of terrestrial tetrapods. Later this "ancestral" status was replaced by fanfin fish with "inner nostrils". In the 1980s, with the denial of the nostrils inside the fanfin fish, the ancestral theory of the fanfin fish wavered. So the relevant scholars returned to the lungfish to find the ancestors of terrestrial tetrapods.
9. Specific functions
1. Flying fish
The body of the birdfish is long, flattened and round, and slightly fusiform. Generally, the body length is 20 to 30 cm, and the weight is 400 to 1500 grams. The dorsal area is quite wide, the sides are flatter to the tail and the tail is thinner, and the ventral surface is very narrow. The head is short, the snout is short, the eyes are large, and the mouth is small. The teeth are thin and the upper and lower jaws are narrowly banded. The dorsal fin is opposite the fin at the back of the body. The pectoral fin is long and wide, reaching the end of the fin, and the ventral fin is large and posterior, reaching the end of the fin. The two fins stretch like dragonfly wings.
2. Fish that can make sounds
The carp "barks"; the electric catfish bark like a cat's fury; the box bream can make a canine call; the bream sometimes barks like a pig, sometimes like a groan, sometimes like a snoring; and the seahorse makes a monotone like a drum. Totoaba is known for its good barking, with sounds such as rolling, drumming, bee-finches flying, cat calls and whistles, and their calls are particularly common during reproduction for the purpose of flocking.
3. Fish that generate electricity
Some fish can generate electricity, and the voltage they emit is several times larger than the voltage of electricity we use. There are about 500 species of fish with power generation capacity, such as electric eel, electric catfish, electric eel, electric ray and so on.
All kinds of power generation fish, the intensity of the current they emit and the level of voltage are different. The body of the electric ray is flat and gardeny, with a long tail, living like a ball fan. The electric catfish living in the Nile River in Africa is only 1 meter long, but it can emit 350 volts of high-voltage electricity.
4. Glowing fish
Some fish emit light, such as the striped fish and the dragon head fish on the southeast coast of China, which are emitted by the luminous bacteria attached to the body, while more fish emit light emitted by the luminous organs of the fish itself.
Candlelight fish has multiple rows of light emitters on its abdomen and ventral side, like rows of candles, so the bald head of the candlelight fish in the deep sea is flattened on the back and covered by a pair of large light emitters, which may play a visual role.
5. Fish that can walk
The turtle shell perch inhabits static, slow-flowing, silt-heavy bodies of water. When the water body dries up or the environment is unwell, it often relies on swinging the gill cover, pectoral fin, turning over and other methods to climb over the embankment, slope, move to new waters, or lurk in the silt. The gill upper vessel of the turtle shell climbing perch is very developed, can breathe air, so it is away from the water for a long time without dying, when the water body is deprived of oxygen, away from the water, or can live for a long time in the slightly moist soil. The turtle shell perch feeds on small fish, shrimp, zooplankton, insects and their larvae.
6. Fish drowning in the water
Fish have gills, can breathe in the water, and can float freely in the water. However, it is true that fish living in the water can also drown?
While this sounds ridiculous, it is true. The swim bladder is the "lifebuoy" of the fish when swimming, which can adjust the specific gravity of the fish body by inflating and deflating. In this way, the fish needs only minimal muscle activity when swimming, and can maintain a stable state of non-sinking and floating in the water. However, when the fish sinks to a certain depth (i.e. "critical depth"), the huge pressure on the outside world will make it unable to adjust the volume of the swim bladder. At this time, it is subjected to less buoyancy than its own gravity, so it involuntarily sinks to the bottom of the water, can no longer float, and eventually drowns because it cannot breathe. Although fish can also float up by swinging their fins and tails, if they sink too deeply, this will not help.
10. Reasons for migration
There are many reasons for fish migration, first of all, due to the influence of external conditions. Fish live in the water, and their activity is affected by factors such as temperature, water flow, and salinity. But migration is mostly caused by changes in water temperature. When the water temperature changes, the fish have to look for a suitable environment for life, thus creating migration. Because the lateral line receptors on either side of their bodies are particularly sensitive to the stimulation of water flow, they can help fish determine the speed of the water flow and identify the direction.