When is the right time to stock crayfish fry? An introduction to fry breeding methods
In our daily lives, shrimp is a fairly common and frequently eaten aquatic product, and it has many varieties. As everyone knows, shrimp has extremely high nutritional value, and eating it regularly can supplement the nutrients the human body needs; moreover, its flesh is tender and delicious, making it deeply loved by everyone. As demand for shrimp keeps rising, wild shrimp can no longer meet our needs, and farmed shrimp has become one of the most popular farming projects today. So do you know how shrimp fry should be stocked?
How to raise shrimp fry
1. Fry stocking: stock 50,000 to 100,000 fry per mu, with a size of more than 1.5 cm, preferably in June to July.
2. Shrimp seed stocking: stock 20 to 25 kg of shrimp seed per mu, with a size of 1,000 to 1,600 individuals/kg, preferably in October to December.
3. Stocking precautions: fry and seed stocking should be carried out on cloudy days or rainy days; if it is a sunny day, it should be done in the early morning or evening to avoid direct sunlight and prevent it from affecting the survival rate of stocking. The fry and seed should be stocked all at once in sufficient quantity.
4. Adding silver carp and bighead carp fingerlings: add 80 to 100 silver carp and bighead carp fingerlings per mu of shrimp pond, with a size of about 30 individuals/kg; summer fry of silver carp and bighead carp can also be added, 200 per mu. Silver carp and bighead carp fingerlings must be stocked 10 to 15 days after the shrimp fry and seed are stocked, to ensure the freshwater shrimp's demand for food organisms. Adding silver carp and bighead carp can first regulate water quality, and second make full use of the water body to bring in extra income from fish.
When is it more suitable to raise crayfish fry
The conventional stocking time is generally in November each year or the end of March the following year. In the process of crayfish farming, under suitable temperatures and sufficient feed, juvenile shrimp can generally grow to commercial size in 60-90 days. Stock fry in March, start selective harvesting around June, selling the large and keeping the small. Because of harvesting the large and keeping the small, and harvesting and restocking in turns, the recapture rate can be increased, a good price can be obtained, and the goal of high yield and high efficiency can be achieved.
The reproduction process of red swamp crayfish
Red swamp crayfish reproduce once a year, with May to September as the peak period. The reproduction of red swamp crayfish is rather special; most of the reproductive process is completed in burrows, so egg-bearing shrimp are rarely seen in ordinary production. After mating, the ovary needs 2 to 5 months to finally mature, and then ovulation and fertilization occur. The fertilized eggs are purple-maroon in color and adhere to the setae of the swimmerets on the abdomen; egg-bearing shrimp often keep their abdomen close to the accumulated water in the burrow to keep the eggs moist. The fecundity of red swamp crayfish is relatively small, generally 100 to 700 eggs, with an average of 300 eggs. The incubation time of the eggs is 14 to 24 days. During development, the larvae of red swamp crayfish do not need any external nutrient supply; newly hatched fry need to stay on the abdomen of the parent shrimp for about 10 days before leaving the mother.
If conditions are unsuitable, they can survive in the burrow for several weeks without eating or drinking. After the pond is filled with water, the fry and parent shrimp crawl out of the burrows one after another and naturally distribute themselves in the pond; sometimes the parent shrimp carry the larvae into the water body and then release the larvae. Although red swamp crayfish carry relatively few eggs, the survival rate of hatched larvae is very high. The scattered reproductive habit of red swamp crayfish limits the large-scale production of seed stock and brings adverse effects to intensive production.
Precautions for farming red swamp crayfish
1. Red swamp crayfish varieties
At present, there is only one variety of red swamp crayfish in our country, which is the one we usually see, whose scientific name is Procambarus clarkii. Anyone asking for a high price under the banner of a new red swamp crayfish variety is definitely running a scam.
2. Purchasing shrimp fry
The purchase of shrimp fry should follow the principle of nearby sourcing. Generally, the transport time should not exceed two hours. It is best to buy directly door-to-door from farmer to farmer, and try not to go through intermediaries. During transport, load at low density, spread aquatic plants on the bottom, and handle gently.
3. Releasing shrimp fry
When releasing shrimp fry, the size of the fry should not be too uniform. Otherwise, it may sometimes lead to the phenomenon that when prices are high, the fry have not grown yet, and just as they have grown, prices begin to fall again. Moreover, once uniformly sized fry grow up at the same time, it will cause excessive pond load and ecological collapse. Also, the phenomenon of red swamp crayfish killing each other has little to do with the factor of size differences.
4. Increase hiding places
Red swamp crayfish are naturally aggressive and have a strong habit of occupying territory. If there is no space or cover for them to hide, it will lead to a very serious phenomenon of mutual killing. When farming red swamp crayfish, some aquatic plants such as water hyacinth can be placed and planted in the water body. While providing them with hiding places, the aquatic plants can also serve as food for the red swamp crayfish.
Through the above content, I believe everyone has gained a certain understanding of shrimp fry breeding techniques. When it comes to shrimp farming, red swamp crayfish is now a famous freshwater economic shrimp, with delicious flesh, fast growth and strong adaptability, and its farming prospects and benefits are especially good!