Can You Dig Trenches for Crayfish Farming in Rural Fish Ponds? A Detailed Guide to the Precautions

More and more people are getting into crayfish farming, and due to various factors and constraints, some fish ponds have been converted into crayfish ponds. Because the farmed species differ and their biological habits vary, the corresponding technical requirements also differ. So what precautions should be taken when farming crayfish in rural fish ponds? Can you dig trenches?

1. Can you dig trenches when farming crayfish in fish ponds?

If you are considering long-term farming, it is best to dig trenches; if you are farming short-term, you can skip the trenches. Crayfish monoculture places certain requirements on the pond, and after many years of farming and pond renovation, a fixed method of pond excavation has gradually been worked out. Mastering the excavation method helps save on engineering costs, and later also helps with crayfish farming management and increases yield. The purpose of digging trenches: to create a large range of depth, increase the range of activity, prevent escape, and allow overwintering in winter.

2. How should a crayfish pond be dug?

1. East at the top, west at the bottom, length-to-width ratio

The orientation of the crayfish pond should suit local conditions, and it is best to choose an east-west orientation, which helps with sunlight exposure and shelter from wind and waves in the crayfish pond. The pond width should be kept at 28-32 m, the length-to-width ratio at about 5:1, and the area at 5-6 mu. This width is a relatively suitable width for crayfish farming, convenient for daily feeding management and spraying of medications. In engineering terms, it is also the suitable length of a conventional excavator arm, so the pond banks can be built by digging to the left and right without a second excavation, wasting no labor.

2. Narrow banks, flat slopes, suitable depth

The width of the central bank surface in the pond should be kept at 0.8-1.0 m, the slope ratio at 1:2-2.5, and the pond depth at 1.5-1.6 m. A narrow bank surface helps save land, and for thirteen-spice crayfish ponds the wind and waves are small and damage to the pond banks is minor. The slope ratio should not be too large; when summer water temperatures are high, if the pond edge is too shallow, the high water temperature affects crayfish feeding. The suitable standard for pond banks effectively saves on development costs.

3. Curved bottom, central trench, concave head

The pond bottom is arc-shaped, deep in the middle and shallow on both sides. When excavating, the excavator digs soil to pile up the banks, and only the soil in the middle 5-8 m of the pond needs to be dug, so the arc of the pond bottom can form naturally. A 2×1×0.5 m collection trough is designed at the drainage end of the pond, which helps control the water at the bottom of the pond when the pond is dried in spring.

4. Inlet and outlet, leave some margin

When excavating the pond, consider the inlet and drainage locations well, and leave margin for the access roads; do not economize excessively on land and fail to leave enough distance for the access roads, causing rework after the project is finished.

3. What are the precautions for farming crayfish in rural fish ponds?

1. Silt removal: especially in fish ponds with a long farming history, the pond bottom silt can become thick due to accumulated farming years, residual feed, dead fish and other factors, and crayfish farming ponds must not have too much bottom silt, which must be controlled below 10 cm. Therefore, for these ponds the pond water needs to be drained for silt removal work.

2. Pond drying, sterilization, pond clearing: thoroughly dry the fish pond after silt removal is completed or the pond water is drained, until the bottom soil opens into cracks; then a small amount of water can be introduced (about 5 cm), and quicklime can be spread over the whole pond for disinfection, sterilization and pond clearing, with quicklime used at 150-200 jin per mu. Fish ponds must undergo pond clearing treatment to kill residual fish eggs and other organisms and natural enemies that affect crayfish farming.

3. Bank reinforcement, building escape-prevention facilities: raise and widen the fish pond banks, keeping the height at 1.5 m and the width at 3-4 m; it is best to redesign and renovate the inlet and drainage system and introduce new inlet and drainage pipelines. Install escape-prevention netting around the fish pond to prevent the farmed crayfish from escaping.

4. Planting aquatic plants: crayfish farming must involve planting aquatic plants. About one week after the sterilization and pond clearing work in the farming pond is completed, reintroduce water, keep the water level at about 15 cm, and plant aquatic plants. The aquatic plants should mainly be Elodea, Hydrilla verticillata, Vallisneria and others, supplemented by alligator weed, water hyacinth and others, with the planting area controlled at about 30% of the farming area.

5. Water quality adjustment, seedling stocking: after the aquatic plants have taken root, gradually deepen the water level, make necessary adjustments to the water body according to water color, fertility and other factors, and carry out seedling stocking after the water body is normal. Generally, brood crayfish are stocked in June-August, and shrimp fry are stocked in September-October and March-April, with brood crayfish at about 40 jin per mu and shrimp fry at about 80 jin per mu.

After seedling stocking is completed, promptly carry out feed feeding, water quality adjustment, water level management and daily management work, do a good job of daily crayfish disease prevention, and harvest and sell promptly once the crayfish reach the required size.