Comprehensive Utilization Techniques for Fish Fingerling Ponds During the Winter Fallow Period

Using Winter-Fallow Fingerling Ponds to Raise Marketable Fish Raising a crop of marketable fish in winter-fallow fingerling ponds can both increase production and help regulate the "summer shortage" in the aquatic product market. Because the rearing period is relatively short and temperatures are low, the following techniques should be adopted: 1. Stock early, that is, stock immediately after the fingerlings are concentrated in ponds, so as to make full use of the growing period. Based on a maximum water depth of 2 m, the usual stocking rate is 125-150 kg per mu. The usual stocking ratio is about 40% silver carp, about 10% bighead carp, about 30% grass carp and bream, and about 20% black carp and common carp. Stock@#@233@#@ed fish should be large in size; generally, silver carp and bighead carp should be 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 fish are stocked, fertilizer should be applied promptly. Organic fertilizer should be the main type 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 level. 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 commercially caught crabs from large water bodies, temporary holding in idle fingerling ponds can be used to wait for@#@136@#@ or stagger the market peak and 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 marketable 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 2-3 days. In winter, the water depth should be more than 1.5 m to prevent death from suffocation due to lack of oxygen after freezing. When the water temperature is relatively high, some animal-based feed (small fish, small shrimp) and plant-based feed (pumpkin, sweet potato, etc.) may be appropriately fed to ensure that the river crabs are plump and strong for market.

Planting Forage Grass In winter-fallow fingerling ponds, ryegrass can also be planted on the pond bottom, which can both provide feed for marketable fish and serve as base fertilizer for raising fingerlings again in the original fish pond. 1. Dig ditches to filter water and sow at the right time. Drain the water from the vacated fingerling pond. Dig a perimeter ditch around the pond and then dig a field ditch every 2 m to facilitate draining the pond water. Sow when the silt is semi-dry and semi-wet, using 1.5 kg of seed per mu. Complete sowing before the end of November; early sowing sprouts quickly and gives a high emergence rate. 2. Strengthen management and prevent waterlogging. Seedlings emerge 5-7 days after sowing. When the air temperature rises to 15°C, the forage grass grows rapidly, and some chemical fertilizer should be applied as a 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 and add water to stock 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 marketable fish in spring. After that, cut green forage once about every 20 days. About 20 days before stocking summer-fry fingerlings, add water to submerge the green forage, fertilize the water quality, and put in some duckweed. After the summer-fry fingerlings are stocked in the pond, there will be sufficient and suitable feed in the pond.