First, herring
Black herring is one of the four major fish in China, also known as Qing Wu, Luosiqing, Qinggu, Blackfish, Blackfish, Blackfish, Blackfish, Bronze Blue, Qingbang, Wuhouqing and so on. It is a large fish in CYPRINIDAE and Yarrow subfamily. It is distributed in the Yangtze River, Pearl River and its tributaries, Yellow River, Heilongjiang and other northern water systems in China, and its population is small. In rivers, the largest individual can reach 70 kg, common individuals can reach 15-25 kg, and in ponds, it can grow to 10- 15 kg.
Black herring lives in the lower layer of water, grows fast and tastes delicious, so it is a kind of fish with high economic value. The food of herring is mainly snails in mollusks (including lake snails, vertebral snails, etc.), but also clams, freshwater shellfish, flat snails and so on. Black herring sometimes eats benthic dragonfly larvae, chironomid larvae and mosses, etc. In the fry stage, it mainly eats zooplankton. Because herring is a carnivorous fish, its intestine is not long, which is about 1.2- 1.4 times of its body length. Because mollusks live in underwater sludge, herring has gradually become a benthic fish. In recent years, the snail resources in rivers and lakes have decreased greatly. In order to develop herring culture, many units are mainly feeding artificial compound feed at present.
The natural spawning grounds of herring are widely distributed. The spawning period in the Yangtze River, Xijiang River and Pearl River is from April to June, and it is a little later in Northeast China. Natural spawning is most prosperous in the Yangtze River and Xijiang River. At present, herring fry mainly rely on artificial propagation. Choosing mature parent fish to induce spawning in time is the key to artificial propagation of herring. The spawning period of herring is generally from early June to late June, with the water temperature of 22-30℃ and the optimum temperature of 25-28℃. The brooding amount of herring is 13 kg, and the parent fish can reach10,000,000 eggs; 18kg is1570,000 capsules; 34 kilograms can reach 3.36 million capsules.
Black herring grows rapidly, and 1 year fish can reach 0.4-0.5 kg; 2 nd instar fish can reach 1.5-2.5 kg; The 3 rd instar fish can reach 3-4 kg or even more than 5 kg. Due to the lack of feed, herring is gradually not used as the main fish culture. Except in Jiangsu and Zhejiang, there are not many in the north and south, and even less in the north. As the main fish culture, 60-80 fish are stocked per mu. As a fish culture, 10-20 fish per mu should be stocked, and only 3-5 fish or 5- 10 fish should be stocked when the feed is insufficient.
Second, grass carp
Grass carp is one of the four major fish in China, also known as bighead carp, grass green, grass root (northeast), fat, white bighead carp, mixed seed, and glutinous rice (Compendium of Materia Medica). It belongs to CYPRINIDAE and CYPRINIDAE. It is widely distributed, and it is produced from the northeast plain in the north and Hainan Island in the south. Grass carp grows fast, tastes delicious and has few fine spines, so it is loved by the masses. Grass carp is named after its herbivore, which has a wide source of feed, convenient feeding and very common breeding.
The feeding habits of grass carp vary with different developmental stages. In the larval stage, the larvae live on animal food, and the fry with a body length of 1 cm take small zooplankton as the main food. At that time, the intestine also grows correspondingly, and gradually turns to eat rotifers, cladocera, chironomid larvae and other planktonic crustaceans. Young fish over 5 cm gradually turn into typical herbivorous fish, but in the early stage (fingerling stage), they mainly eat turnip, duckweed and other tender aquatic plants or artificially chopped dry vegetables. Grass carp adult fish mainly feed on higher aquatic plants, and they eat a wide variety, which varies with the water environment. In general, grass carp like to eat bitter grass, hydrilla verticillata, POTAMOGETON POTAMOGETON, duckweed and tender wormwood. In fact, most aquatic plants can be ingested as food, but some aquatic plants (such as water hyacinth, water hyacinth, peanut, etc.) are not eaten by grass carp, and can only be fed to grass carp after fermentation, saccharification or chopping. Grass carp likes to eat all kinds of dry grass, such as Pennisetum, Setaria viridis, barnyard grass and so on. Grass carp also likes to eat all kinds of artificially cultivated high-yield grasses, such as perennial ryegrass, Ixeris sonchifolia, Sudan grass, goose food and so on. Grass carp also eats all kinds of commercial feeds, such as bran, grains and dregs.
The spawning grounds of grass carp are widely distributed, with the exception of the Yangtze River, Huaihe River, Pearl River and Qiantang River, as far north as Heilongjiang in the northeast. The spawning season of grass carp in the main stream of the Yangtze River is from late April to late May, and the fecundity of grass carp in the Yangtze River area is: 6 kg with a weight of 300,000; 10 kg weighs about1100,000 capsules. The artificial propagation of grass carp has been popularized all over the country. As long as the parent fish is well cultivated, the artificial aphrodisiac effect of grass carp is better, and the rate of inducing spawning, hatching and going to the pond can reach 70%-90%.
Grass carp is the main fish culture species in many areas. One of the reasons is to use grass carp feces to fertilize water and promote the growth of mixed silver carp and bighead carp. As the main fish culture, 80- 100 fish per mu are stocked; As a companion fish culture, 20-30 fish are stocked per mu, and the most suitable stocking specification is 2-year-old fish (0.25-0.5 kg per fish). Such fish can grow to 1.5-2.5 kg in the current year, and can reach 3-4 kg or even exceed 4 kg after being reared 1 year (3-year-old fish). In the process of feeding grass carp, special attention should be paid to feeding management. In order to reduce gill rot, enteritis and other diseases of grass carp, we must adhere to the "four fixed" (timing, quantitative, qualitative and positioning) feeding, and prevent diseases and treat diseases in time. Grass carp likes clear water, so in recent years, grass carp has also been used as the main breed of industrialized fish culture and cage fish culture.
Third, silver carp
Silver carp is one of the four major fish in China, also known as silver carp, silver carp and silver carp. It belongs to CYPRINIDAE and HYPOPHTHYS molitrix. Widely distributed, China can grow from south to north.
Silver carp inhabits the middle and upper layers of water. In natural rivers and lakes, the largest individual can reach more than 20 kg, and in ponds, the largest individual is 10- 15 kg. Silver carp has the characteristics of fast growth, few diseases and no need for special artificial feeding. Therefore, although the meat taste is not as good as herring and grass carp, it is still the main fish in pond culture, especially in suburban fish culture, and its output ranks first, especially in ponds in Jiangsu and Zhejiang, which accounts for 40%-60% of the total aquaculture output.
Silver carp mainly eats phytoplankton (including bacteria attached to algae). In the fry stage (body length 15 mm or so), they eat zooplankton and artificially fed soybean milk. The feeding method of silver carp is a special type, and its gill rakes are different from those of bighead carp. There is a small bone bridge between each gill rake and its neighbors, and the outside is covered with spongy sieve membrane. Therefore, tiny phytoplankton (algae) cannot be filtered out of the body with water and become food. Silver carp is a typical fish that ingests algae. The main components it swallows are various diatoms, dinoflagellates, golden algae, yellow algae, etc. There are also rotifers, small crustaceans and protozoa in the intestine. Larger cladocera and copepods are rarely eaten. In recent years, there have been some new discoveries about the feeding habits of silver carp, that is, sawdust and bacteria are very important in the food of silver carp. According to relevant reports, in some ponds with poor phytoplankton, the second-instar silver carp mainly consists of cyanobacteria detritus at the bottom of the pond in the whole summer, and the detritus accounts for 90%-99% of its food weight. When the phytoplankton in the water is low, or cyanobacteria such as Schizosaccharomyces planus are dominant, silver carp stops filtering in the water layer and turns to benthic algae.
Silver carp have natural spawning grounds in the Yangtze River, Xijiang River, Pearl River and Heilongjiang, and the breeding season is from April to May, which is earlier in the south and later in the north. At present, silver carp fry mainly come from artificial propagation. The mature age of silver carp parent fish is 3 years old, and in recent years, some degraded silver carp have matured at 2 years old. The best age for inducing labor is over 3 years old and weighs 3-6 kg. The fecundity of silver carp is: 4.8kg is 200,000 eggs; 10 kg can reach1700,000 capsules.
Adult culture of silver carp is common, especially in areas lacking forage and snails, where silver carp is the main fish. Although grass carp is the main fish in some areas, the actual stocking quantity of silver carp is still larger than grass carp. Generally, the stocking number as the main fish culture is 200-300 fish per mu, and up to 500 fish can be stocked; As a fish culture, put 100- 150 or 80- 100 fish per mu. The general growth rate of silver carp is: the fish can grow to about 13.2 cm (about 8000 fish per mu); The second-year-old fish grows to about 0.5 kg (if the second-year-old silver carp is cultivated, it can only grow to about 0.25 kg); The 3rd instar fish can grow to 1.5-2.5 kg. Under the condition of sparse culture and intensive culture, the fish can grow to the commodity specification of about 0.5 kg in that year. The feeding of silver carp is usually based on manure, grass manure and compost, but some concentrate such as bran, bran and distiller's grains can also be properly added to accelerate the growth.
Fourth, bighead carp
Bighead carp is one of the four major fishes in China. Aristichthys mobilis belongs to CYPRINIDAE, CYPRINIDAE, HYMENOPHYS, and CYPRINIDAE. Commonly known as: silver carp, chubby fish, black carp, yellow carp, pine fish, silver carp, bighead fish. English name: Bighead, Bighead crap.
Bighead carp has a flat side and a very large head. The mouth is big, end-position, and the jaw is slightly inclined upward. The gill rakes are fine and page-shaped, but they are not United. There is a spiral suprabranchial organ in the upper part of oropharyngeal cavity, with small eyes and low position, which is unnecessary. The swallowing teeth are spoon-shaped and smooth. The scale is small, and the ventral surface only has pelvic fins and even anus with cortical abdominal edges. The pectoral fin is long, and the end far exceeds the base of the ventral fin. The upper part of the body is gray-black, the abdomen is gray, and there are many irregular spots of light yellow and black on both sides.