Comprehensive Utilization Methods of Fish Fingerling Ponds During the Winter Fallow Period

Raising market-size fish: Using winter-fallow fingerling ponds to raise one season of market-size fish can both increase production and help ease the "summer shortage" in the aquatic product market. Because the rearing period is relatively short and temperatures are relatively low, the following techniques should be adopted: 1. Stock early, that is, stock immediately after the fingerlings are combined into ponds, so as to make full use of the growing period. Stocking rate is calculated at a maximum water depth of 2 m, generally 125-150 kg per mu. The stocking ratio is generally about 40% silver carp, about 10% bighead carp, about 30% grass carp and bream, and about 20% black carp and common carp. The stocked @#@233@#@ fingerlings should be large-sized, generally silver carp and bighead carp over 250 g, grass carp over 500 g, bream over 100 g, black carp over 1 kg, and common carp over 250 g. 2. Strengthen management. After the fingerlings are stocked, fertilizer should be applied in time. Fertilization should mainly use organic fertilizer to ensure that the pond water has a certain fertility. In winter, choose clear and warm weather and feed once every 2-3 days, with the feeding amount at about 20% of the usual amount. In spring, as water temperature rises, increase the feeding amount and maintain good water quality, so that the fish school maintains a relatively high growth rate and reaches market size on schedule.

Temporary holding of river crabs: For market-size crabs caught from large-water aquaculture, in order to wait @#@136@#@ or stagger the peak marketing period, idle fingerling ponds can be used for temporary holding to earn the seasonal price difference. Before temporary holding, the pond should be cleared and disinfected with quicklime or bleaching powder, and escape-prevention walls should be built with materials such as asbestos tiles and calcium-plastic boards. Generally, 200-300 kg of market-size crabs are held per mu. It is best to hold them separately by size and by sex. During temporary holding, keep the water quality fresh and control the water depth at about 1 m. When the water temperature is above 10°C, change the water once every 2-3 days. In winter, the water depth should be above 1.5 m to prevent death from hypoxia and suffocation after freezing. When the water temperature is relatively high, appropriately feed some animal-based feed (small fish, small shrimp) and plant-based feed (pumpkin, sweet potato, etc.) to ensure the river crabs are plump and strong for market.

Planting forage grass: In winter-fallow fingerling ponds, Italian ryegrass can also be planted on the pond bottom, which can both provide feed for market-size fish and serve as base fertilizer for raising fingerlings again in the original pond. 1. Open ditches to drain water and sow at the right time. Drain the idle fingerling pond. Dig a surrounding ditch along the pond perimeter, and then dig a field ditch every 2 m to facilitate draining the pond water. When the silt is semi-dry and semi-moist, sowing can begin, using 1.5 kg of seed per mu. Complete sowing before the end of November; early sowing sprouts quickly and has a high emergence rate. 2. Strengthen management and prevent waterlogging. Seedlings emerge 5-7 days after sowing. When the temperature rises back to 15°C, the forage grass grows rapidly, and some chemical fertilizer should be applied as topdressing. Before the rainy season the following year, clear the drainage ditches in advance and prepare for waterlogging prevention. 3. Cut green forage at the right time, then add water and stock fish. Carry out the first green forage cutting in April of the following year to make up for the shortage of green feed for market-size fish in spring. After that, cut green forage once about every 20 days. About 20 days before stocking summer fry, release water to flood the green forage, fertilize the water quality, and put in some duckweed. After the summer fry are stocked in the pond, there will be sufficient and suitable feed in the pond.