Carp breeding in our country typically occurs during the winter season, and for successful reproduction, the water temperature must be above 20°C. The salinity should be higher than 18‰, ideally around 30‰. Therefore, the selection of a suitable breeding site is crucial. It should have high salinity, good water quality, a reliable freshwater source, convenient transportation, and sufficient power supply. To maintain the required temperature throughout the breeding process, geothermal or factory waste hot water is ideal, as it helps save energy. Existing off-season equipment used for prawn seedlings along the coast can also be adapted for squid artificial breeding.
The seedling facility should include several key areas: broodstock holding and wintering ponds (10–20 m² each, with a depth of 1.2–1.5 m), spawning ponds (10–30 m²), hatching tanks and cylinders, nursery ponds (each at least 5 m², with a depth of 1.2–1.5 m), and live bait cultivation ponds for Artemia eggs and cockle pods. These can also be used for nursery purposes. Additional facilities such as water supply, gas supply, heating systems, and emergency power stations are essential to ensure smooth operations.
For broodstock collection and rearing, wild salmon or pond-raised carp that are 3–4 years old can be selected as broodstock. Healthy individuals weighing over 1 kg, free from disease, are preferred. They should be kept in dedicated pools at a stocking density of 100–150 kg per mu, with feed containing at least 30% crude protein. Daily feeding should be 5–8% of their body weight. Water transparency should be maintained at around 35 cm, and dissolved oxygen levels should not drop below 3 mg/L. Freshwater flushing is important—once every two weeks initially, then once a week after September, with each flush deepening the water by about 30 cm. Salinity should be reduced below 10‰ before August and gradually increased to 20‰ afterward.
Indoor breeding begins in late November when outdoor temperatures fall below 15°C. Broodstock are moved into controlled temperature pools, where the water is kept around 17°C to promote gonad development. By late November, females usually reach advanced oocyte stages, with oocyte diameters exceeding 450 microns. Males, whose sperm are ready, are placed in temperature-controlled pools. Each cubic meter of water holds one brood fish. To prevent infections, nitrofurazone (at a concentration of 110-6) is added, and an inflatable filter stone ensures continuous aeration. Salinity should be above 18‰, and natural light cycles should be maintained with illumination of at least 200 Lx. During this period, non-disintegrating pellet feeds are provided, and water is regularly replaced with care taken to avoid large temperature fluctuations.
Artificial induced spawning starts in late November for broodstock with oocytes larger than 630 microns. Common hormones used are LRH-A and salmon pituitary, either alone or in combination. When used separately, the dose per kilogram of fish is 300–400 μg LRH-A or 15–20 mg salmon pituitary. For combined use, it's 150 μg LRH-A plus 10 mg salmon pituitary. Females receive two intramuscular injections 24 hours apart, with 1/3 and 2/3 of the total dose respectively. Mature males may receive a single injection at the time of the second female injection, at half the female dose.
After hormone treatment, broodstock are placed in the spawning pool. Water conditions should match those of the holding pool, with continuous water flow and temperature maintained between 20–23°C. A male-to-female ratio of 1:1.5 is recommended. The hormone effect typically lasts 15–20 hours. If oocyte development is delayed, a third injection may be given at the same dosage. Artificial insemination is performed in a 1 m³ container with aeration. Signs of readiness include a swollen abdomen, protruding anus, increased respiration (over 140 breaths/min), and white calcium-rich feces. At this point, spawning and dry insemination are carried out. Mature eggs contain about 3,000 eggs per milliliter.
Fertilized eggs are hatched in water with salinity between 20‰ and 28‰, with approximately 1,500 eggs per liter. The temperature should be maintained between 17°C and 23°C, avoiding sudden changes. Continuous aeration is needed to keep dissolved oxygen above 4.5 mg/L. Fresh water is changed as needed based on water quality. Incubation takes about 40–60 hours, and fry are kept in the hatching container for four days before being transferred to nursery ponds.
Waist massager
Waist massager
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