How to Build Effective Escape Prevention Facilities for Crab Ponds
To prevent river crabs from escaping, escape prevention facilities are built 0.3-0.5 m from the pond edge in crab ponds. Escape prevention facilities for crab ponds include:
1. Agricultural plastic film fencing
The escape prevention wall of the crab pond is 0.5-0.7 m high (it can be slightly lower for ponds with 1-year-old crabs), buried 0.15 m in the soil. The escape prevention wall leans slightly toward the inside of the pond at a 60 degree angle, and its inner side is smooth with no supports. The corners of the escape prevention wall are rounded. Installation method: first use wooden stakes as supports and galvanized wire or plastic rope as the framework, fold double-layer film in half, press the two lower ends together into the mud 0.1-0.15 m, and rest the upper end on the galvanized wire or plastic rope; the film must be taut and straight. This method is low in cost, easy to install, does not withstand strong winds, and requires timely repair and replacement. This type of escape prevention facility is mainly used for crab seed or rice-field crab culture water bodies.
2. Calcium plastic board or aluminum sheet fencing
On the pond ridge, use 0.8 m high calcium plastic board or aluminum sheet, bury it 20 cm in the soil and compact it, use steel bars or wooden posts with drilled holes as stakes, punch holes in the boards and fix them to the stakes. This method has the advantages of light weight, convenient transportation and installation, low cost and good escape prevention effect, and generally has a service life of 3-4 years. This type of escape prevention facility is mainly used for adult crab culture.
In addition, to prevent frogs, ducks and other harmful organisms from jumping into the crab pond, polyethylene mesh (4 mesh/cm2) should be used to enclose the pond all around, with the bottom of the net buried 10 cm in the soil and the net height 1 m, forming a frog prevention net; the frog prevention net and the escape prevention wall are spaced 0.5-1 m apart.