1, the water surface should not be too small, but more than 6000m2. The area is too small, the water quality environment changes greatly and is unstable, which affects the growth of mussels.
2. Beads can be cultured on the water surface with the water depth of 1.5-4.0m, preferably 2-3m. Beads below 1m and above 5m are not suitable for cultivation.
3, sufficient water, no pollution, toxic substances content shall not exceed the fishery water quality standards.
4. A certain speed of running water (the flow rate is not more than 0. 1m each time) is beneficial to the growth of mussels and pearls. Production practice has proved that mussels can produce 5-8 grams of pearls a year in rivers and lakes with flowing water and good conditions, while they can only produce 5-8 grams of pearls in still water for three years.
5. Sufficient sunlight can directly produce thermal effects, thus providing energy for pearl mussels and their predators. Light also has a direct influence on the color of pearls. It can not only increase dissolved oxygen in water, but also promote water movement and heat transfer.
6. Clay is the best soil quality, followed by river soil, and loess and sandy soil are the worst. There should be proper silt at the bottom of the pool.
The PH value of 7.7-8 is the most suitable for the growth of pearl mussels and the secretion of nacre.
8. Generally, the dissolved oxygen is greater than 5mg/L in summer and 3mg/L in winter.
9. The transparency of mussel water is 30cm.
10, and the optimum water temperature range of mussels is 18-28℃.
1 1, the content of inorganic salts in water is the most important, because calcium is the main component of pearls and mussels. Generally, the calcium content in water is required to be above10 mg/L. When the calcium content in water is low, it can be solved by applying quicklime.
12. Nitrogen is an essential nutrient for the growth of all algae. The high content of ammonia nitrogen indicates that the water body is relatively fat, exceeding 2 mg/L, indicating that the water body is seriously polluted and has an impact on the growth and survival of mussels; When the content of ammonia nitrogen is lower than 0. 1 mg/L, it shows that the water quality is too thin to meet the needs of natural bait proliferation.
13, the nitrite content should be between 0.01-0. 1 mg/L. When the content exceeds 0.1mg/L, mussel beads will grow slowly or die.
14. There should be no aquatic vascular plants in aquaculture waters to prevent them from competing with the feeding organisms of pearl mussels for nutrition. Some enemy creatures, such as shrimp and crabs, should also be removed in time.
Second, the choice of water areas.
Whether it is ponds, ditches, harbors, lakes, reservoirs or rivers, mussels and pearls can be cultivated in pearl breeding waters as long as the environmental conditions meet the above requirements.
Thirdly, the cultivation of mussels.
1. At present, mussels are mostly cultured by hanging and cage. There are two hanging methods: single hanging and string hanging on a line to raise more than two mussels. The number of cages depends on the size of cages (cages, net clips), and it is generally appropriate that each clam can touch the bottom of the cage.
2. There are 800- 1200 mussels per mu; There is a 600-800 swing. Reproductive density depends on body weight and fatness. Physical, chemical and biological factors such as water flow and water depth increase or decrease with the size of mussels.
3. Mytilus culture has become the main production content of fishery comprehensive development and utilization in our city. Grass carp, bream, crucian carp, Siniperca chuatsi and Pelteobagrus fulvidraco can be properly stocked in ponds with pearl culture as the main culture, and a small amount of silver carp and bighead carp can be stocked to fully tap the production potential of water bodies.
Fourthly, the management of mussels.
1. Management of temporary culture period after operation: After operation, mussels are temporarily cultured in water with slight running water and fresh water quality, and rest for 15-30 days. During this period, it is generally not allowed to turn over at will after hanging, and it is not allowed to leave the water, and it is not allowed to open the shell for inspection, so as not to affect its physical recovery and the formation of beads. If the water is too fat and the transparency is less than 30 cm, measures should be taken to reduce the fatness. A month later, the mussels in the temporary culture waters were inspected, and it was found that the dead mussels were removed in time and then hoisted to the pearl culture waters again.
2. Strengthen water injection, water change and oxygenation: Mussels are raised in closed still water without running water, and will die of hypoxia when they encounter high temperature, shallow water and low pressure. Therefore, it is necessary to replenish water in time, change water or keep the water fresh and oxygen-enriched, so as to avoid the slow growth of mussels and pearls under hypoxia.
3. Adjust the lifting depth in time: adjust the lifting depth of pearl mussels in time according to the water level, water temperature and seasonal changes. It should be hoisted deep in winter and summer (40-60 cm below the water surface) and shallow in spring and autumn (below the water surface 15-20 cm).
4. Feed water and fertilize well: If the water quality of the pearl pond is thin, fertilize it in time. Fertilizer can be organic fertilizer, chemical fertilizer or both. Organic fertilizer for pheasants, ducks and poultry is better. Before use, add 1 quicklime, and use it after fermentation and decomposition. The fertilizers are mainly urea and calcium superphosphate (dosage ratio is 1:2 or 1:3). After adding water, the two fertilizers are mixed and sprayed, so as to achieve multiple times, less dosage, less application and diligent application. General urea per mu 1 kg. You can also splash soybean milk (feed and fertilizer). At the same time, calcium fertilizer (quicklime) is applied, and the PH value is low. High PH value, less application. Keep the transparency of the pool water at about 300 meters.
5. Removal of attachments: after cultured pearl mussels are hung for a period of time, a large number of attached sludge and organisms (such as algae, freshwater sponges, collembola, etc.) are attached. ) often attached to cages, net bags and mussels, affecting the growth of cultured pearl mussels and must be cleaned regularly. Rinse every other month during April-10.
6. Maintenance of breeding facilities: In the process of breeding, the damaged breeding facilities should be repaired in time to avoid economic losses.