The most primitive marine fish. There is no maxilla, so it is also called jawless. The body surface is bare and scaleless, the body is slender and eel-shaped, and the bones are completely cartilage. There are no lateral fins, no shoulder straps and belts, the spinal cord exists for life, and there is no vertebral body. It has a single unpaired nostril, and the gills formed by endoderm are located in the muscle sac and open to the outside. This class is some small or medium-sized fish-shaped animals. There are more than 60 species in the world, belonging to 2 orders, 3 families 14 genera. In China, only lamprey of Japan and lamprey of Brucella are seafood.
Cartilaginous fish (
Cartilaginous fish)
Endoskeleton is cartilage, but it is often strengthened by calcification, and there is no real bone tissue. The body surface is covered with shield scales. Spiny or naked without scales. There is no seam in the skull, and there is a gill cover on each side of the head, which is open to the outside. The intestine is short, with spiral valve inside and no swim bladder. Males have a special mating organ, called flipper, which is formed from the inside of the ventral fin. In vivo fertilization, viviparous, viviparous or viviparous are all crooked tails. There are more than 650 species of cartilaginous fishes 12 orders, 40 families and 130 genera in the world. Widely distributed in all sea areas of the world, but mainly concentrated in low latitude sea areas; It is distributed from the coast to the deep sea of 3000 meters. There are 10 orders, 35 families, 73 genera and 166 species of cartilaginous fishes in China, which can be clearly divided into two fauna: standard northern species and standard southern species. The "standard northern species" often live in the Yellow Sea, Bohai Sea and the northern part of the East China Sea. The "standard southern species" usually live in the South China Sea, and some species can live in the Taiwan Province Strait and southeast waters with the warm current.
osteichthyes
Wolf fin fish (bony fish)
The most advanced and prosperous class of marine fish. The endoskeleton is ossified, and the head is often covered with membranous bone, and the bone has seams. The body surface is covered with hard scales or bone scales, or bare without scales. External gill holes 1 pair, gill spacing degenerated, and gill filaments were supported by double rows of gill strips. Usually the swim bladder has segmented fins and no spiral valve in the intestine. Some fish have dorsal ribs and abdominal ribs, and their otoliths are very strong. Usually in vitro fertilization, no cloaca. There are 420 families, more than 3,800 genera,18,000 species of bony fishes in the world, among which there are about12,000 species of marine fishes. There are 780 genera and 1825 species of marine teleost in China.
Edit the body structure of this paragraph.
Body types can generally be divided into:
Torpedo type
This kind of fish lives in the middle waters and is the best swimmer, such as mackerel, mullet and tuna.
Arrow shape
Similar to torpedo type, but long, odd fins move backward, inhabit surface water and swim well, such as barracuda and jaw needle fish.
Transverse flat type
The back axis height of this kind of fish increases, and the left and right sides are extremely flat, which can be divided into three kinds: grouper, sunfish and flounder, which inhabit the bottom and near the bottom respectively. Fish structure
snakelike
This kind of fish has a slender body and a round cross section, and generally inhabits marine benthos, such as eels and sea dragons.
Belt type
The body height is extended to a lateral flat type, and it is not good at swimming, such as hairtail and yellow hairtail.
pelletized
Fish of this size have almost spherical bodies and generally underdeveloped caudal fins, such as box bream and some round fin fish.
Longitudinal flat type
The height of the dorsal abdominal axis of this fish is reduced, and its body shape is flat, such as various rays, rays, rays, rays, etc. ? ? Wait a minute.
fin
The main movement and balance organs of marine fish are divided into two categories: paired lateral fins, including pectoral fins and ventral fins; Pairs of odd fins, including dorsal fin, anal fin and caudal fin. The caudal fin is attached to the tail end and has the function of steering and pushing. It can be divided into three types: prototype tail with equal upper and lower leaves, such as mackerel and tuna; Curved tail, the upper leaf is more developed than the lower leaf, which is helpful for upward movement, such as sharks; Orthomorphic tail, the lower leaf is more developed than the upper leaf, which is helpful for downward movement, such as flying fish.
1, red clown fish
The body colors of red clown fish are bright red, purple red, purple black and so on. And there is a silvery white belt behind the eyes, like a luminous collar.
They often hide in coral bushes or anemones and are the first choice for marine invertebrates to create landscapes. They are also one of the few species that can be artificially propagated and are deeply loved by people.
& lta href="/i？ tn = baiduimage & ampct=20 1326592。 lm=- 1。 cl = 2 & ampword = % BA % EC % D0 % a 1% B3 % F3 % D3 % E3 " target = " _ blank " & gt； /me? tn = baiduimage & ampct=20 1326592。 lm=- 1。 cl = 2 & ampword = % BA % EC % D0 % a 1% B3 % F3 % D3 % E3 & lt； /a & gt；
2. Radar fish
The radar fish is 7-9 cm long and cylindrical. Eyes close to the front of the body, dorsal fin in two. The spines of the first dorsal fin are tall and straight, standing on the back of the fish like an antenna. The second dorsal fin and gluteal fin are symmetrical up and down. The first half of the fish is silvery white, the second half is pink, and the tail fin is purple.
The petite radar fish, no more than an inch long, looks like a small leaffish in a pond, but it shines like a firefly, making people realize its difference.
& lta href="/i？ tn = baiduimage & ampct=20 1326592。 lm=- 1。 cl = 2 & ampword = % C0 % D7 % B4 % EF % D3 % E3 " target = " _ blank " & gt； /me? tn = baiduimage & ampct=20 1326592。 lm=- 1。 cl = 2 & ampword = % C0 % D7 % B4 % EF % D3 % E3 & lt； /a & gt；
3. Batfish
Batfish is like a pancake. Its body is white with brown stripes.
He has many thorns and a small mouth. The fishing rod on his head is very short, above his mouth. Batfish living in the deep sea have luminous organs at the top of the fishing rod.
Walk with pectoral fins and ventral fins, and jump like a frog in case of danger or fright.
& lta href="/i？ tn = baiduimage & ampct=20 1326592。 lm=- 1。 cl = 2 & ampword = % F2 % F9 % F2 % F0 % D3 % E3 " target = " _ blank " & gt； /me? tn = baiduimage & ampct=20 1326592。 lm=- 1。 cl = 2 & ampword = % F2 % F9 % F2 % F0 % D3 % E3 & lt； /a & gt；
Coral reef fish
Colorful butterfly fish, fox upside down fish, four-line turtle
Tropical ornamental fish "golden battleship"
Reef cod
White fin shark
Angel fish
Snail fish
Xiaozhuyu
Nurse sharks, leopard sharks, fish, turtles.
"New Year Fish"
Arowana
The ocean is the main habitat of fish, and there are traces of marine fish from the poles to the equatorial waters, from the coast to the ocean, from the surface to the abyss of thousands of meters. The diversity of living environment leads to the diversity of marine fish, but due to the similarity in organization, structure and function, a series of similarities are produced. According to the similarities and differences between fish, people define fish as a marine vertebrate, which breathes with gills and moves with fins. Most of its body is covered with scales, usually with swim bladder, which can change the temperature. From this definition, any marine life with spine movement that breathes with gills, swims with fins and lives in water all its life, whether it is like a fish or not, is definitely a fish. For example, there is nothing about the seahorse that makes people think it looks like a fish, but in fact, the Shanghai horse has the characteristics of the above fish and belongs to the real fish; Other marine organisms, such as squid and abalone, are called fish and belong to mollusks or mammals. Although they are used to being called fish, it has nothing to do with it.
The history of human research on marine fish can be traced back to a long time ago. In the 4th century BC, the Greek scholar Aristotle recorded 1 15 species of fish living in the Aegean Sea in his book Fauna, and systematically described the structure, reproduction and migration of fish. China is one of the earliest countries in the world to develop, utilize and study marine fish. 1975 The ancient tomb excavated in JIAOZHOU Bay, Shandong Province, proves that China was able to catch many kinds of marine fish as early as the Neolithic Age, such as giant salamander, barracuda, black snapper and blue spotted snapper. In ancient writings, there are not only detailed descriptions of fish habits and fishing periods, but also understanding of the growth, reproduction and ecology of marine fish.
It is said that the study of modern marine fish began with the Natural History of Fish published by French scholars G.B. Ju Ye Wei and A. Valencia. Since then, scholars from all over the world have made a lot of investigations and studies on the migration, reproduction, growth, distribution and development of marine fish resources, among which the achievements of marine research vessels such as Challenger, Albatross and Dana are the most remarkable. Since 1950s, high-tech technologies such as electron microscope and satellite remote sensing have been widely used, and a great deal of research has been done on the organization, physiology and ecology of marine fish. In 1950s, China conducted a large-scale survey of marine fish, published a series of monographs on fish for the first time, and studied and developed the physiology, ecology and heredity of fish.
According to the survey. At present, there are 265,438+0,723 species of fish, including about 6,543,380+0.2 million species of marine fish. There are 3 187 species of marine fish in China. These fish are generally classified into three categories.
1. Cyclostomata is the most primitive fish. It has no mandible, so it is also called jaw. The body surface is bare and scaleless, the body is slender and eel-shaped, and the bones are completely cartilage. No lateral fins, no shoulder straps and belts, lifelong spinal cord, meta-vertebral body. It has a single unpaired nostril, and the gills formed by endoderm are in the muscle sac and open to the outside.
The second is cartilaginous fishes. Endoskeleton is completely osteogenic, but it is often strengthened by calcification, which is any real bone tissue: the body surface is covered with peltate scales, spines or bare scales. There are no seams on the skull. There is a branchial fissure on each side of the head, which opens outward. The intestine is very short, and there is a spiral valve inside. No fat. Males have a special device for mating with the inside of the ventral fin, which is called flipper foot. In vivo fertilization. Ovoviparous, viviparous or viviparous, with curved tail, cartilaginous fish are widely distributed in the ocean, but mainly in low latitude waters.
The third category is bony fish. It is an advanced fish and the most prosperous class at present. The endoskeleton ossifies, the head floats and there are often membranous bones, and there are bone seams between the bones. The body surface is covered with hard scales or bone scales, or bare without scales. The outer branchial foramen 1 pair, the branchial septum degenerates, the branchial filaments are supported by double rows of branchial strips, usually with fatty multi-segmental fins, and there is no spiral flap in the intestine. Some fish have dorsal ribs and abdominal ribs, and their otoliths are very strong. Usually in vitro fertilization, no cloaca. There are about 18 000 species of teleost in the world.
The body types of marine fish can be generally divided into: ① Torpedo-type, which lives in middle waters and is best at swimming, such as mackerel, mullet and tuna. ② Arrow shape. Similar to torpedo type, but long, strange fins move backwards, inhabit surface water, and are good at swimming, such as pike and jaw needle fish. ③ lateral flat type. The back axis height of this kind of fish increases, and the left and right sides are extremely flat, which can be divided into three kinds: grouper, sunfish and flounder, which inhabit the bottom and near the bottom respectively. ④ Snake type. This kind of fish has a slender body and a round cross section, and generally inhabits marine benthos, such as eels and sea dragons. ⑤ Belt type. The body height is extended to a lateral flat type, and it is not good at swimming, such as hairtail and yellow hairtail. ⑥ spherical. The body of this kind of fish is almost spherical, and the tail fin is generally underdeveloped, such as box bream and some round fin fish. ⑦ vertical and flat. The height of the dorsal abdominal axis of this fish is reduced, and its body shape is flat, such as various rays, rays, rays, rays, etc. ? ? Wait a minute.
Fin is the main movement and balance organ of fish. Pairs are called lateral fins, including pectoral fins and ventral fins; The unpaired ones are called odd fins, including dorsal fin, anal fin and caudal fin. Tail fin is born in the tail of fish and has the function of turning and pushing. Generally, it can be divided into round tail (the upper and lower leaves are equal in size, such as mackerel and tuna), curved tail (the upper leaves are more developed than the lower leaves, which is helpful for upward movement, such as sharks) and straight tail (the lower leaves are more developed than the upper leaves, which is helpful for downward movement, such as flying fish).
There are three ways of fish reproduction, namely oviparous, ovoviviparous and viviparous. Most fish are oviparous. Egg-laying fish usually discharge mature eggs directly into water for in vitro fertilization to complete the whole development process, but a few fish (such as some sharks) are fertilized in vivo and fertilized eggs are still developing in vitro. Oviposition fish are generally fertilized by eggs, and fertilized eggs develop in the body, but the nutrition of embryos depends on their own yolk supply, which has nothing to do with the mother, such as white-spotted star shark, white-spotted horn shark, Japanese partial shark, Xu-pressure plough ray, sea crucian carp and black (fish king). Viviparous fish are generally fertilized by eggs in the mother, and the embryos formed by fertilized eggs have blood circulation contact with the mother. Its nutrition comes not only from the yolk of the body, but also from the supply of the mother, such as the gray star shark. The spawning amount of fish is much higher than that of terrestrial vertebrates, which varies greatly, from several large eggs (such as many sharks) to 300 million floating eggs (such as molas). Generally speaking, fish that don't protect their eggs after laying eggs have a large amount of eggs, such as red snapper, which produces about 6.5438+0.5 million, and eel produces 700-65438+0.5 million. After spawning, the fish that protect the eggs lay less eggs, such as dozens to hundreds of eggs in the hippocampus.
The growth rate and individual size of fish vary greatly at each stage. The research shows that the smallest individual fish is goby, with a body length of only 7.5- 1 1.5 mm; The largest can reach 20 meters, such as whale sharks. The fastest growth period of fish is usually before sexual maturity. After that, most of the bait eaten by fish is used for the maturation of sexual products and the storage of fat, and only a small part is used for the growth of body length, so the growth slows down and the growth of body length almost stops during aging. The growth rate of each species is also very different. Some fish can grow to be as big as their parents within one year after hatching, while others need several years to grow to be as big as their parents. The life span of fish also varies from species to species. Some species of Tigeraceae and Carnivora live less than 1 year, while some sturgeons can live to1year. The highest age of Pseudosciaena crocea found in Zhejiang coastal area of China is 29 years old, and the longest life span of Atlantic fish is 23 years old. Some fish, such as salmon and European eel, all die after their first sexual maturity.
Due to different species, fish also show great differences in feeding. According to the nature of food, fish can be divided into three types: phytophagous fish, carnivorous fish and omnivorous fish. Phytophagous fish, the bait is mainly phytoplankton, such as blind fish, barracuda, lanyu and so on; Carnivorous fish generally feed on animals, and most of the fish in the ocean belong to carnivorous fish, such as hairtail, grouper, large yellow croaker, whale shark and basking shark. Omnivorous fish refers to eating more than two kinds of foods with different properties, including animals and plants, and also eating bottom humus, such as grouper and leaffish. The different eating habits of fish directly affect their exercise intensity. Generally, carnivorous fish have strong exercise intensity and fierce temperament, while herbivorous fish have weak exercise intensity and mild temperament. Different eating habits and the intensity of exercise also directly affect the meat quality of fish.
Marine fish is human's friend and favorite food. Humans should provide opportunities for fish to recuperate, protect the marine ecological environment and create a good natural living environment for fish. I hope I can help you agree.