Standards and management of freshwater lobster culture in Australia

Australian freshwater lobster is one of the most precious shrimp in the world. It grows mainly in Australia, so it is not as simple as raising crayfish. Australian freshwater lobster is much more expensive because it is expensive, so the cost of breeding is much higher.

What is Australian freshwater lobster?

Australian freshwater lobster (Cherax quadricarinatus), the scientific name of the four-ridged smooth-shelled Nan'ao shrimp, also known as red crayfish, native to Australia, looks like sea lobster, is one of the most valuable freshwater economic shrimp species in the world. The body color of the shrimp is brown and green, and there is a bright red band on the outside of the mature male shrimp, which is beautiful and good-looking, so it is also known as red crayfish.

Australian freshwater lobster, also known as red crayfish, belongs to the family Eriocheir sinensis. It is a large freshwater crayfish native to Australia. The shrimp has been introduced and cultured in Guangdong Province in recent years and has achieved success in artificial breeding and adult shrimp culture. at present, it is being popularized and cultured inside and outside the province. Australian freshwater lobster is called freshwater lobster because it is larger, resembles sea lobster and lives only in fresh water. The individual usually weighs 100g to 200g, and the largest individual in Australia can weigh up to 500g. According to research, Australian freshwater lobster is one of the most valuable economic shrimp species in the world.

Management techniques of culturing Australian freshwater lobster

First, the suitable growth rate. Australian lobsters are naturally distributed in subtropics and tropics. A better growth rate can be obtained between 18 ℃ and 32 ℃. The time when the water temperature in Yangzhou is higher than 18 ℃ from May to November is six and a half months. When the water temperature reaches more than 16 ℃, it can begin to grow normally. In order to make full use of local thermal energy resources, the release time of Australian lobster in Yangzhou should be arranged in early May and the starting time is late November.

Second, water quality requirements.

① water source mainly takes the surface water of unpolluted rivers, lakes, reservoirs and other large water bodies as the water source. Groundwater can also be used, which has the following advantages: a fixed and independent source of water; wild fish without pathogens. No pollution. The temperature is relatively stable throughout the year.

In the process of culture, the pH value of ② water had a lowest value of 6.10 and a maximum value of 9.33, but 6.5 Mel 9.0 was better, and it was better to be neutral.

③ water dissolved oxygen, Australian lobster can survive for a short time, although it is resistant to hypoxia and dissolved oxygen is less than 1 mg / L, but if it is in a state of low dissolved oxygen for a long time, it will affect its growth and survival rate. Therefore, if necessary, the pond should be equipped with aerator or other oxygenating equipment to keep the dissolved oxygen above 4 mg / L, so as to avoid the pollution of heavy metals, pesticides, herbicides, oil, chlorine, methane, argon sulfide, high iron content and so on.

④ cultured in micro-running water or adding new water regularly can promote the growth of lobster.

Third, pond conditions.

The ① pond should be rectangular and unlimited in area, but it is better to use 2mi 5 mu, with a water depth of 0.9 mi 1.5 m, and the direction of the pond's long axis should be the same as that of the summer wind.

② pool bottom hard soil, no silt, pool wall must have a slope, and the slope should be greater than 3 ∶ 1.

③ ponds should have a good drainage and irrigation system, with water entering the upper part of the pond and drainage at the bottom of the pond at the other end, and the inlet and outlet should be protected against enemy and escape nets.

The bottom of the ④ pond should have a submerged plant area with an area of about 1pm and 5 bottoms, and there should be sufficient artificial concealment, such as waste tires, nets, PVC pipes, waste tile tanks, bamboo rafts and so on.

⑤ conditional ponds can be equipped with aerator.

Fourth, stocking technology and daily management.

① density: 600 young prawns of 3cm per mu can be properly mixed with 100 silver carp, 50 flower silver carp and 50 grass carp.

② microaquaculture or adding 2 Mel fresh water three times a week.

③ feeding should be fixed-point, fixed-time, qualitative and quantitative, and the types of feeding should be diversified as far as possible, such as water hyacinth, water lotus, parsley and other aquatic plants, cow dung, pig manure, artificial pellet feed. It can also be fed properly with animal erbium materials such as snails, earthworms, mussels, etc. Feed mellow cow dung once a week, 100 kg per mu, in the four corners of the pond, all submerged into the water, feed pellet feed once a day, and 20% of shrimp body weight at 6 pm.

During the high temperature period of ④ in summer, attention should be paid to increasing the amount of water flow or water injection, and the times of water injection, and the aerator can be turned on at night.

The growing environment of Australian freshwater lobster

1. Water temperature: Australian freshwater lobster has the habit of adapting to the tropics and can withstand high temperature. the suitable temperature range for growth is 24 ℃ 42 ℃, which is lower than 21 mol. Below 10 ℃, the adult shrimp stopped growing. Adult shrimps will also die if they grow up below 9 ℃, so overwintering management should be carried out in areas with lower winter temperatures.

2. Dissolved oxygen: Australian freshwater lobster can withstand not only high temperature but also low oxygen. Under normal circumstances, the dissolved oxygen in the pool is kept between 4-5mg/L and grows normally. Adult shrimp can even tolerate the dissolved oxygen content of 1mg/L and can climb out of the water for a short time to breathe in the air. Young shrimp are relatively sensitive to low dissolved oxygen, and shrimp seedlings can not survive in 1.2mg/L water.

3. Ph value: the suitable pH value is 6.5 Mel 9. The incubation period should be more than 7, because the acidic water quality is not conducive to shelling growth, which will increase shelling death or prolong shelling time.

4. Salinity: Australian freshwater lobster does not require high salinity, so it can grow smoothly in freshwater ponds. At the same time, the larvae can adapt to the salinity 3g/L, and the adult shrimp can still adapt to the 5g/L concentration. Therefore, 1% of juvenile shrimp and 3% of adult shrimp can be soaked in salt water for a short time to kill the body surface parasite.

Breeding habits of Australian freshwater lobster

Australian freshwater lobster is native to the tropics of Australia and has a rapid growth rate, reaching 50ml 80g in 6 months. Australian freshwater lobsters generally reach sexual maturity at the age of 6-12 months. The large claw extension of sexually mature male shrimp has a distinct red or orange stripe, and there are a pair of papillary reproductive spines at the base of the fifth pair of footsteps. The female shrimp has a pair of reproductive pores at the base of the third pair of feet, and the claw of the male shrimp is blue and the length is less than the body length. Sexually mature Australian freshwater lobsters reproduce naturally in ponds when the water temperature is above 21 ℃.

Australian freshwater lobster breeds for a long time, starting in April and ending in October. The optimum temperature for reproduction is 22 ℃, and the optimum water temperature is 28 ℃. Mature female shrimp must be shelled before mating. Generally, the female shrimp ovulates within 24 hours after mating, then combines with sperm and fertilizes, and the fertilized egg is orange. After spawning and fertilization, the eggs are hatched by the mother with eggs, and the incubation period is 30 / 32 days when the water temperature is 28 / 29 / ℃. Australian freshwater lobsters can lay eggs 2mur3 times a year.

With people's continuous pursuit of the quality of life, many years ago, what we pursued was to solve the problem of food and clothing, but now most people pursue taste, and a small number of people pursue things that are usually difficult to eat and rare. Australian freshwater lobster is absolutely recommended for this kind of people to eat shrimp.