Key Techniques and Methods for Wuchang Bream Farming Explained

Wuchang bream, commonly known as tuan tou bian (blunt-snout bream) or suo xiang bian, mainly lives in rivers and lakes. It usually inhabits the middle and lower layers of the water. Its main foods are Vallisneria, Hydrilla verticillata, mollusks, and debris from lake-bottom plants, filamentous green algae, freshwater sponges, and so on. The spawning period is from May to June, when pearl organs appear on the bodies of both males and females. It is distributed in rivers such as the Heilongjiang, Yangtze, Pearl, Qiantang, and Min rivers, as well as in lakes such as Dongting Lake, Poyang Lake, and Liangzi Lake.

Living Habits of Wuchang Bream

1. Overview: It is distributed in medium-sized affiliated lakes in the middle and lower reaches of the Yangtze River. It is relatively suited to still-water life. It usually inhabits the middle and lower layers of open-water areas where the bottom is muddy and submerged plants grow. Juveniles mainly feed on cladocerans and crustaceans; adults feed on aquatic plants, mainly Vallisneria and Hydrilla verticillata, and also eat a small amount of zooplankton.

2. Feeding habits: Wuchang bream is a herbivorous fish, and its feeding capacity and intensity are lower than those of grass carp. Fingerlings and adult fish mainly feed on aquatic vascular plants such as Vallisneria, Hydrilla verticillata, and Potamogeton, and also like to eat terrestrial gramineous plants and vegetable leaves. They can also consume some lake-bottom plant debris and a small amount of zooplankton, so their feeding range is relatively broad. They generally begin feeding in April and continue until November, with the largest intake from June to October.

3. Growth: Wuchang bream is a medium-sized fish with relatively fast growth, growing fastest at 1 to 2 years of age. Under conditions with abundant aquatic plants, generally the fish of the current year can reach 100 to 200 grams in body weight; two-year-old fish can reach 300 to 500 grams, after which the growth rate gradually slows. The largest individual can reach 3 to 5 kilograms.

Farming Conditions for Wuchang Bream

1. Pond conditions: The pond area is 3000 sq m to 10000 sq m, with a water depth of more than 2 m. It is better if it is rectangular and does not leak. The pond bottom should be flat, with a silt thickness of about 20 cm, and it should be equipped with machinery for drainage and irrigation, feed processing, transport, and aeration. The fishery machinery power per mu of pond should be above 0.5 kilowatts. The ponds are required to be relatively concentrated and contiguous for easy management.

2. Water quality conditions: The water source should be sufficient, the water quality fresh, and there should be no pollution. The pond water transparency should be 30 cm to 35 cm, the dissolved oxygen content about 5 mg/L and not lower than 2 mg/L, and the pH value between 7 and 8. During the farming period, regular water addition is required. From July to September, add water once every half month, with each addition of 20 cm to 30 cm.

Fry Breeding of Wuchang Bream

Wuchang bream can reach sexual maturity at 2 to 3 years of age. Its breeding season is slightly later than that of carp and crucian carp, and slightly earlier than that of Chinese carps. In the middle and lower reaches of the Yangtze River, the spawning period is mostly from late April to early June, that is, when the water temperature is 20 to 29°C. In lakes, they spawn in places where aquatic plants flourish. The fertilized eggs are adhesive and develop attached to aquatic plants or other objects. For parent fish of Wuchang bream cultivated in ponds, during the breeding season, if there is slight flowing water or other conditional stimulation, non-concentrated natural spawning can occur. Therefore, after the beginning of spring each year, female and male parent fish should be cultivated separately, and at the proper time artificial oxytocin should be used for concentrated batch reproduction to produce fry.

For artificial fry breeding, natural spawning or artificial induced spawning methods can be used. The parent fish used for breeding are best cultivated in ponds for one year, or they can be selected directly from natural water bodies after being caught. Sex identification of Wuchang bream is relatively easy. Starting from the fingerling stage, the first fin ray of the pectoral fin of the female fish is thin and straight, while that of the male fish is thick and curved in a “wave” shape. After sexual maturity, the backs of the first several fin rays of the male fish's pectoral fin, as well as the dorsal and ventral margins of the caudal peduncle, have dense “pearl organs,” which feel rough to the touch; the abdomen is relatively small, and after gently pressing the rear abdomen, milky white semen flows out. The female fish has only a small amount of “pearl organs” on the orbital bones and back, and the abdomen is enlarged and soft. During reproduction, well-matured parent fish can be selected, paired and grouped according to plan, and put into the spawning pond, or first subjected to artificial induced spawning with hormones so that they spawn and fertilize naturally. Because the eggs of Wuchang bream are adhesive, the eggs can be made to attach to artificially arranged spawning nests and then hatched in still water. Artificial egg collection and fertilization can also be used, after which the fertilized eggs are de-adhered and then subjected to flowing-water artificial hatching. Its breeding process and operation methods are basically the same as those for carp.

Seedling Cultivation of Wuchang Bream

Wuchang bream fry are small and delicate, so care should be taken during handling. When the fry are stocked into the pond, the water quality should not be too fertile, and when counting before pond removal, they should not be too densely crowded. To rear fry into spring fingerlings, the graded rearing method is often used.

Only 2 to 3 days after hatching do the fry gradually leave the spawning nest to move freely and begin feeding on small zooplankton. Therefore, after the fry are stocked into the pond, an appropriate amount of fertilizer should be applied every day. For de-adhered hatched fry, it is suitable to stock 120,000 to 150,000 per mu. When the fry begin to feed, it is best to first feed cooked egg yolk 1 to 2 times, then feed soybean milk for a few days, and afterward determine the amount of fertilizer according to the fertility of the water and the growth of the fry. After 15 to 20 days of rearing, the fry can grow to 2 to 3 cm, and at this time they are divided into ponds for further rearing.

For the second pond division and thinning, stock 40,000 to 50,000 fire-fry fingerlings per mu. Cultivation mainly relies on fertilizing to grow plankton, and at the same time soybean cake slurry can be fed every other day. Some plant feed such as duckweed and small duckweed should also be added. After about one month, they can be reared into summer fingerlings of 4 to 5 cm, and the survival rate can reach about 80%.

Rearing summer fingerlings into winter fingerlings is the third stage of rearing. Its method is basically the same as that for cultivating grass carp. The transparency of the pond water is generally kept at about 30 cm. The stocking density is generally 5000 to 7000 per mu, with an additional 10 to 20% summer fingerlings of silver carp, bighead carp, and black carp. It is also possible to stock 10 to 20% Wuchang bream in ponds mainly used for rearing silver carp and bighead carp fingerlings. In the early stage after stocking, feed duckweed, small duckweed, and soybean cake slurry, and later feed Spirodela polyrhiza, Hydrilla verticillata, or chopped fresh terrestrial grass. By the time winter begins, they can generally grow to 12 to 15 cm, and the survival rate can reach more than 90%. In the second year, they are reared into market-size fish.