How should debris be removed from a crawfish pond?
When farming crayfish in ponds, once wild fish such as wild silver carp, snakehead, and crucian carp get mixed in, these trash fish will compete with the crayfish for food, greatly interfering with the crayfish's normal feeding and growth, and even preventing the crayfish from reaching marketable size within a certain period, thereby affecting farming profits. Based on practice, taking the following three measures not only does not affect the normal growth of the crayfish, but can also increase the pond's farming profits.
Biological removal method
This makes use of the fact that mandarin fish only eat live feed, turning the small trash fish in the crawfish pond into mandarin fish with relatively high economic value, thereby increasing the pond's farming profits. Without adding feeder fish, 3 to 5 mandarin fish fry can be stocked per mu of water surface; if feeder fish are appropriately added later, 10 to 15 mandarin fish fry can be polycultured per mu of water surface. Generally, each mu of water surface can produce 150 kg of mandarin fish and 160 kg of crayfish, with a net profit of 4000 yuan.
Biological lectin removal method
If mandarin fish are not polycultured in the crawfish pond, some hemoglobin-type lectins can be used directly to kill the small trash fish. For example, use “Shayubaoxia'an”, dilute it 2000 times with water, and splash it over the whole pond, using 60 to 80 milliliters per mu of water surface at a depth of 1 meter. It can remove various wild trash fish, snails, mussels, and leeches from the pond, but it is harmless to shrimp and crabs.
Tea seed cake removal method
Tea seed cake contains 12% to 18% tea saponin, which can cause the red blood cells of aquatic animals to break down, so it can kill wild trash fish, spiral shells, river mussels, frog eggs, tadpoles, and some aquatic insects, but it has almost no effect on shrimp and crabs. In intensive culture of freshwater crayfish in ponds, if a large amount of wild trash fish is found, 8 to 10 kg of tea seed cake can be used per mu of water surface, soaked in water, and then splashed over the whole pond. On one hand, it removes the wild trash fish from the pond; on the other hand, it can promote molting in crayfish.