A Detailed Explanation of the Key Points of Australian Redclaw Crayfish Farming Technology

SummaryPond conditions: The pond water quality must be fresh and rich in dissolved oxygen. Shrimp fry stocking: Before stocking, the pond must be dried and disinfected, and pests such as catfish and snakes must be thoroughly removed from the pond. Feed feeding: Feed small trash fish, river snails, shrimp compound feed, and so on. Daily management: Change the water frequently, and inspect the pond diligently at ordinary times. Disease prevention and control: Pay attention to diseases such as brown spot disease and black gill disease. If disease occurs, isolate and treat it promptly.

1. Pond Conditions

1. Freshwater crayfish prefer a water environment with fresh water quality and rich dissolved oxygen, so the pond should be chosen in a place with sufficient water sources, no pollution sources, and convenient water intake and drainage.

2. The most suitable pond area is 2000-3300 sq m. The pond bottom is best made of sandy or hard soil, there must not be too much silt, and the pond bottom must have submerged plants covering no less than one-fifth of the area.

3. In addition, the pond must be equipped with good water inlet and drainage facilities, and the water inlet and drainage outlets must be fitted with mesh covers. Aquatic plants such as water grass, water hyacinth, and water lettuce are planted around the pond.

2. Shrimp Fry Stocking

1. Before stocking shrimp fry, the pond must be dried and disinfected. In addition to sprinkling quicklime, pests in the pond, such as catfish and snakes, must also be thoroughly cleared out.

2. The most suitable stocking time for shrimp fry is from March to May, and stocking should be carried out on a clear morning or evening. The size of the shrimp fry is 2 cm to 4 cm. The density is 800-1000 individuals per mu.

3. Bait Feeding

1. Australian redclaw crayfish has a wide diet and likes feed such as small trash fish and river snails, and also likes shrimp compound feed.

2. Generally, within 3 days of releasing the fry, feed mainly minced small trash fish and minced meat; over the following month, feed small trash fish.

3. When the shrimp fry grow to 6-7 cm, they can be entirely fed crushed river snails, river mussels, and an appropriate amount of plant-based bait.

4. The feed should be given once each morning and evening every day, and the amount of feed put in should account for about 4%-7% of the body weight of the Australian redclaw crayfish. The specific amount of feed to put in should be adjusted according to the feeding situation of the Australian redclaw crayfish.

5. Most of the feeding by Australian redclaw crayfish takes place at dusk and at night, and the amount of feed put in at night should account for more than 70% of the whole day's feed amount.

4. Daily Management

1. The pond water quality for Australian redclaw crayfish must always be kept fresh. Generally, 15-20 cm of water needs to be changed each week, and there must be sufficient dissolved oxygen.

2. At ordinary times, inspect frequently, patrol the pond frequently, promptly clean out the moss in the pond, and also pay attention to observing the various activities and feeding conditions of the Australian redclaw crayfish, and pay attention to preventing and removing pests.

5. Disease Prevention and Control

Since the Australian redclaw crayfish was introduced into China, no explosive or epidemic diseases have been found, but when the farming density is relatively high, attention must also be paid to disease prevention and control.

1. Brown spot disease

(1) The main manifestation of brown spot disease is speckled dark brown ulcers on the body surface shell of diseased shrimp, which often lie at the pond edge in a dying state. (2) The prevention and control method is mainly to keep the shrimp pond water quality good, regularly change the water or apply quicklime, and carry out pond dredging every year; during the processes of harvesting, transportation, and stocking, operate carefully to prevent damaging the shrimp shell; if Australian redclaw crayfish are found to be sick, 1 mg/kg furacilin can be sprinkled for treatment, and at the same time, 10—15 mg/kg tea seed cake liquid can be sprinkled to promote the shrimp body to molt and repair the damaged shell.

2. Black gill disease

(1) This disease is mainly caused by water pollution and mold infection. Its symptom is that the gills change from red to brown or light brown, until they completely turn black, causing gill shrinkage.

(2) The prevention and control method is to use 2—3 mg/kg furazolidone or bleaching powder to kill the pathogen, or use malachite green or methylene blue at 2 mg/kg for whole-pond sprinkling. The third is ciliate disease. This disease is mainly caused by ciliates such as Epistylis and Vorticella attaching to the body surface, appendages, eyes, and gills of the shrimp. When relatively severe, it can make the crayfish restless and swim frequently at the pond edge, hindering feeding, molting, and growth. It can even cause the crayfish to suffocate and die from lack of oxygen. Generally, injecting new water and keeping the pond water clean can be adopted for prevention. For treatment, a 0.40 mg/kg copper sulfate solution can be used to soak the diseased crayfish for 5—6 hours, with each treatment course lasting 3—5 consecutive days.