The pristine pike is a small individual, generally about 200 millimeters in length, distributed in the Indian Ocean and the western coast of the Pacific Ocean, China is only produced in the South China Sea and the East China Sea. The barracuda and mullet are larger, generally 200-500 millimeters in length and 600-800 millimeters in size. The barracuda is the main harbor fish species in the Yellow Sea and Bohai Sea, and the mullet is the main harbor fish species in the East China Sea and the South China Sea. The barracuda is distributed in the western part of the North Pacific Ocean, while the mullet is widely distributed in the Atlantic, Indian and Pacific Oceans. The barracuda and mullet are produced in the four major seas of China: South, East, Yellow and Bohai.
Breeding mode of barracuda. The breeding season of the barracuda varies from place to place, from the end of April to the beginning of June in Bohai Bay, and from the beginning of April to the beginning of May in Zhejiang. The age of sexual maturity is 2 to 3 years old for males and 3 to 4 years old for females. Juvenile fish feed on zooplankton, while adult fish feed on diatoms and small organisms. Artificial feeding can be fed rice bran, soybean cake and wine lees and other feeds. Every year, they regularly form groups to spawn at the mouths of harbors and estuaries.
Natural reproduction
The barracuda, also known as "meat stick" and "red-eyed mullet", is a valuable new species of freshwater and saltwater aquaculture along the coast of China. In recent years, Shandong, Jiangsu, Zhejiang, Shanghai and other provinces and cities using shoals, harbors and inland ponds and other waters, artificial culture of barracuda has reached an area of more than 2,000 hectares, an average of 0.067 hectares of fish production of more than 750 kilograms. The ecological habits of the barracuda and artificial breeding technology is described as follows:
The breeding season of the barracuda, Bohai Bay, China, usually for the end of April to the beginning of June each year, Jiangsu, Zhejiang coast for the beginning of April to mid-May. The age of sexual maturity is generally 2-3 years old for males and 3-4 years old for females. Generally, females carry between 1.5-6 million eggs. Wild pike can weigh more than 10 kilograms. Every year in April, the barracuda will be in the estuary area spawning, only a short distance back to swim, to the depths of the sea in December to overwinter.
The barracuda spawns regularly every year in groups in harbors, estuaries, mudflats, and other places. In early June to the end of July, the Yellow Sea, Bohai Sea coast barracuda juveniles are very rich, and into the entrance of the river into the group feeding, this is the best time to catch wild fish species artificially.
Artificial reproduction
Artificial reproduction with the parent fish to the male fish more than 3 years of age, the female fish more than 4 years of age is good. Appropriately, more individuals weighing 0.5 to 1 kilogram are selected, and the parents are required to be robust and free of injuries and diseases. Parent fish should be selected and retained in the fall when adult fish are caught. Before stocking, the pond bottom should be cleared of excessive silt and wild fish. Each mu stocking parental fish 50 ~ 80.
The cultivation pool should be properly fertilized with organic fertilizers to maintain a certain degree of water quality and transparency of about 25 cm, and at the same time need to feed a variety of concentrate feed to ensure that the parents have adequate nutrition. Parent fish cultivation pool salinity is generally about 10 ‰ appropriate. In the freshwater or 3 ‰ below the low salinity of the water raised barracuda, spawning before must go through the "salt water transition". During the spring intensive cultivation period, the pool must be regularly filled with fresh seawater, which is conducive to the gonadal development of the parent fish.
The males should be selected so that there is a thick, milky white semen coming out of the abdomen near the genital pore when pressed gently. The female fish should be chosen to have an enlarged, soft and elastic abdomen, and a slightly protruding reddish genital pore. And use the egg collector inserted into the genital pore from the ovary to take eggs for visual and microscopic observation, such as eggs were beige, full and glossy and surrounded by a semi-transparent circle, the egg diameter of 0.60 mm or more, the adhesion between the egg particles is loose, put into the water can be dispersed by stirring, can be selected as a catalytic parental fish. The female to male ratio of the spawning parent fish is generally 1:1.5, if the male fish is less mature, the ratio can be increased appropriately.
Pike artificial fertilization, first of all, to choose the male fish with thick milky semen at the genital pore, while the female fish to the abdomen is expanded and soft and rich in strong sense of elasticity, the genital pore is red and slightly protruding the most ideal. Insert the ovipositor into the female's genital pore to take eggs from the ovary for visual and microscopic observation. If the eggs are beige, full and glossy, surrounded by a semi-transparent circle, with a diameter of 0.6 millimeters or more, and the adhesion between the egg grains is loose, and the eggs can be dispersed by stirring them in the water, then they can be chosen as the parents for catalyzing the spawning.
The ratio of male to female spawning parents is generally 1:1.5, and the water temperature should be between 15-22 degrees Celsius.
The hormone used for pike oxytocics is mainly the pituitary gland of Roubaix or pike, with a dose of 15-30 mg per kilogram of body weight; or chorionic gonadotropin 3000-3500 international units; luteinizing hormone-releasing hormone analogs of 100-300 micrograms can also be used. The above oxytocics can be used alone or in combination. Usually 1-2 injections are sufficient.
The mature egg used for artificial insemination is observed under the microscope to be round, full, crystal clear, with an oil globule.
Put a bit of seawater on the mature semen and observe it under the microscope, the spermatozoa that swim sharply are of the highest quality.
Static water incubation salinity should be more than 15 ‰, streaming water incubation salinity in 7 ‰ -13 ‰, pH 7-9, water temperature 14-24 ℃. The water used for incubation should be filtered to prevent debris and hostile organisms from entering. Generally, static water hatching, running water hatching and aerated hatching are used. Pike at 14-24 ℃, the incubation time is generally 35-56 hours.
Species cultivation
First hatchlings, after 4-5 days, the yolk sac has shrunk, the fish can swim, and can open the mouth to feed, at this time you can move the fry into the nursery pond to cultivate. Every 0.067 hectares can put 70,000-80,000 fish fry. At the beginning, fertilizer and splashing soybean paste is the main, later with soybean cake paste direct feeding, feeding twice a day, feed splashing in the shallow water around the pool. After 1 month of feeding, barracuda fry up to 3-3.5 centimeters, you can pull the net exercise, and in time to divide the pond for fish breeding.
Species cultivation, generally per 0.067 hectares can be put into the fish fry 6000-7000, caught natural barracuda fry that year can be cultivated into 12-18 cm of fish species. Barracuda can be mixed with shrimp, basal shrimp, shrimp and other crustaceans, low salinity seawater or freshwater pools can be mixed with freshwater fish, but do not mix with snakeheads and other ferocious carnivorous fish.
Pike feed, can be fed according to local conditions, rice bran, wheat bran, soybean cake, peanut cake, cotton kernel cake, as well as vegetable cake or chicken manure, etc., conditions can also be fed with feed. Feeding feed requirements to do "four": one is positioning, to be built in the breeding pond and stocking density of feed table, feed table area of 50 square meters or so, or select the hard bottom of the positioning of the put; two is timed, generally in the morning 8-9 am, 3-5 pm feeding, chaff and cake mixing put the first coarse material; three is the Quantitative, put the amount of feed based on the number of fish, water temperature, dissolved oxygen and other factors, usually the amount of concentrate for the fish body weight of 1%-1.5%, 10% of the roughage, the most do not exceed 15%; four is the quality of feed, feed to high-quality, fresh, non-polluting.
The daily management of the pike is very important, we should always keep the exchange of water and the safety of the inlet and outlet, to prevent rats from biting the barrage. Pay attention to the inspection of pond facilities before and after the flood tide and high winds.
The barracuda is very resistant to disease, and large-scale breeding is rarely found to be sick. In order to prevent the occurrence of disease, usually mainly focus on prevention. Disinfection and strengthening of early water management should be carried out to control the occurrence of other freshwater fish diseases when putting in fish species. April-October each year, 20 kg of quicklime per month, splashing 1 time near the fish foraging platform, can effectively prevent surface fish disease; early July to early August, respectively, per 100 kilograms of fish with hygromycin 1 grams or sulfadiazine 10 grams, mixed in the feed fed to the fish, once a day for 5 days, can effectively prevent the body of the fish disease.