How to Improve the Utilization Rate of Winter-Idle Fish Fry Ponds

After the winter pond consolidation until the release of summer fry the following year, most fish fry ponds have an idle period of about half a year. If they are comprehensively utilized, the utilization rate and economic benefits of the fish fry ponds can be greatly improved. Four methods of utilizing winter-idle fish fry ponds are introduced below.

Raising market-size fish: Using winter-idle fish fry ponds to raise one season of market-size fish can both increase output and help regulate the "summer shortage" aquatic product market. Because the rearing period is relatively short and the temperature is relatively low, the following techniques should be adopted: 1. Stock early, that is, stock immediately after the fish fry are consolidated into ponds, so as to make full use of the growing period. The stocking amount is calculated at a maximum water depth of about 2 m, generally 125 kg to 150 kg per mu. For the stocking ratio, generally silver carp account for about 40%, bighead carp about 10%, grass carp and bream about 30%, and black carp and common carp about 20%. Release @#@233@#@ large-size fingerlings, generally silver carp and bighead carp above 250 g, grass carp above 500 g, bream above 100 g, black carp above 1000 g, and common carp above 250 g. 2. Strengthen management. Fertilize promptly after the fish are stocked. 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 to 3 days, with the feeding amount at about 20% of the usual amount. In spring, as the 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 the market size on schedule.

Temporary holding of river crab: For commercially caught crabs taken from large water bodies, in order to wait for @#@136@#@ or stagger the peak marketing period and for other reasons, idle fish fry ponds can be used for temporary holding to earn the seasonal price difference. Before temporary holding, disinfect the pond with quicklime or bleaching powder, and build an escape-prevention wall with materials such as asbestos tiles and calcium-plastic boards. Generally, 200 kg to 300 kg of market-size crabs are temporarily 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 to 3 days. In winter, increase the water depth to above 1.5 m, and prevent death from suffocation due to ice cover and oxygen deficiency. 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 they are plump and strong for market.

Temporary holding of freshwater shrimp: Around November each year, freshwater shrimp are caught intensively for market, and prices are relatively low at this time. Idle fish fry ponds can be used to purchase smaller-size shrimp and hold them together temporarily, to be marketed around the Spring Festival or in spring. Temporary holding ponds should be selected in places with convenient transportation, abundant shrimp sources, and easy marketing. Each mu of water surface can temporarily hold 100 kg to 200 kg of freshwater shrimp, and they should be held separately by size. During temporary holding, pay attention to water quality regulation, keep the pond water transparency between 30 cm and 40 cm, insist on feeding every day, and when the water temperature is above 7°C appropriately increase the feeding amount and feeding frequency. Do a good job in management work such as preventing escape, preventing oxygen deficiency, and preventing theft.

Planting forage grass: Winter-idle fish fry ponds can also use the pond bottom to plant ryegrass, which can both provide feed for market-size fish and serve as base fertilizer for raising fish fry again in the original pond. 1. Dig ditches to filter water and sow at the right time. Drain the empty fish fry pond, dig a surrounding ditch along the pond perimeter, and dig another field ditch every 2 m to facilitate draining the pond water. When the silt is semi-dry and semi-wet, sowing can begin, using 1.5 kg of seed per mu. The sowing time should be no later than the end of November. Early sowing germinates quickly and has a high seedling emergence rate. 2. Strengthen management and prevent waterlogging. Seedlings emerge 5 to 7 days after sowing. When the temperature rises back above 15°C, growth is rapid, and some chemical fertilizer should be applied as topdressing. Before the rainy season the following year, clean the drainage ditches in advance and prepare for waterlogging prevention. 3. Cut green forage at the right time, then fill with water and release fish. In April of the following year, carry out the first cutting of green forage 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, fill with water to submerge the green forage, fertilize the water quality, and put in some duckweed. After the summer fry are put into the pond, there will be sufficient and suitable feed in the pond.