What are the common diseases in crayfish culture? How to prevent and cure?

Crayfish, also known as crayfish, red crayfish and freshwater crayfish, are freshwater economic shrimp and are popular because of their delicious meat. Because of its omnivorous, fast growth and strong adaptability, it forms an absolute competitive advantage in the local ecological environment. The range of food intake includes aquatic plants, algae, aquatic insects, animal carcasses, etc., and kill each other when food is scarce. Crayfish has become an important economically farmed species in China in recent years. What are the common diseases in crayfish culture? How to prevent and cure?

Common diseases in crayfish culture

1. Soft shell disease

Etiology: insufficient calcium intake, or lack of light reduces calcium transformation, low pH value for a long time, and thick mud at the bottom of the pond may cause soft shell disease of lobster. Excessive density of shrimp seedlings and long-term feeding of single bait can also lead to this disease.

Symptoms: the shrimp shell is soft and thin, the body color is not red, the vitality is insufficient, the exercise ability is poor, foraging is not prosperous, refuses to eat, the growth is slow, the coordination ability is poor, the shrimp shell is thin and soft as a whole.

2. Hemorrhagic disease

Etiology: caused by Aeromonas aerogenes.

Symptoms: the body surface of the diseased shrimp was covered with bleeding spots of different sizes, especially the appendages and abdomen were more obvious, the anus was red and swollen, and soon died.

3. Rotten shell disease

Etiology: caused by Pseudomonas aeruginosa myxobacteria Vibrio or Flavobacterium infection.

Symptoms: there are obvious festering spots on the diseased shrimp shell, the spots are grayish white, when severe fester is black, the spots are sunken, there are holes, and finally lead to internal infection and even death.

4. Black Gill disease

Pathogen: a semi-known fungus of the genus fungal pathogen. The disease is caused by the deterioration and pollution of the water quality of the pond, which causes Fusarium to multiply and parasitize on the Gill filaments, body walls, appendages or eyeballs of crayfish.

Symptoms: Gill from flesh color to brown or dark brown, until completely black, causing Gill atrophy, diseased shrimp often stay motionless on the shore, and finally die because of difficulty in breathing.

Second, how to prevent and control common diseases in crayfish culture?

1. Prevention and treatment of soft shell disease.

Dredging in winter.

Clear the pond with quicklime and sprinkle with 25 mg / liter quicklime every 20 days after seedling release.

To control the stocking density, the average amount of shrimp in the pond should be 200 to 300 jin per mu, and the density should not be too high.

The area of aquatic plants in the pond shall not exceed 30% of the pond area.

Bait diversification, appropriate increase in calcium bait, feed feeding, increase the content of calcium, such as can add "Wangsheng calcium, quick supplement 100" and so on.

The suitable PH value of lobster is between 6 and 8. Try to keep the PH value of the water within this range. If the PH value is low, it can be conditioned with quicklime.

2. Prevention and treatment of hemorrhagic disease.

Keep the water color, do a good job of changing the bottom of the water, usually pay attention to the use of Huijin iodine, aquaculture Ann disinfection.

Red body Kang is added to the feed regularly.

The diseased shrimps were isolated in time, and the feed was added to the feed for 3-5 days.

3. Prevention and treatment of rotten shell disease.

When transporting and throwing seedlings, the operation should be meticulous, the disabled should not enter the pond, and the seedlings can be disinfected with 3% salt water for 5 minutes before entering the pond.

Operate carefully at ordinary times and try not to hurt seedlings.

Keep the pool clean.

There's plenty of bait.

Sprinkle the whole pool with 25 g / m3 of raw limed water every 15 to 20 days.

4. Prevention and treatment of black mumps.

First use Huidian 150~250g/ mu. Rice + aquaculture an 0.1g / m3 water body 0.15g to change the bottom, water gold 0.3mu 0.5L per mu to detoxify. After that, Huijin iodine was given at 45mg / m ~ 3 water body + 10~15mg per kg body weight.