In recent years, the demand for sea bream in commercial fishing has increased significantly, and so has the need for pod flowers. Although alfalfa blossoms naturally reproduce in both flowing and still water, their reproduction is often limited due to environmental factors. Many fish eggs and fry are consumed by predators, leading to a low survival rate. To address this, artificial breeding methods have been developed. These techniques help concentrate spawning, improve fertilization and hatching rates, and ultimately increase the survival of fry, enabling more controlled and efficient production.
Artificial breeding involves several key steps:
First, selecting broodstock is crucial. The broodstock must be purebred, healthy, and free from disease. They should be plump and strong, with a balanced ratio of males to females—typically 1:1. Female broodstock should be at least three to four years old and weigh around 1.5 kg, while males should be two to three years old and weigh at least 1 kg. It's also recommended to keep broodstock for a year before spawning rather than collecting them just before the breeding season. This allows for better preparation and ensures optimal conditions for successful breeding.
Next, broodstock feeding plays a vital role in their development. A varied diet that includes both plant-based and animal-based foods helps meet their nutritional needs. Feeding only one type of food over a long period can lead to nutrient deficiencies. Additionally, maintaining good water quality is essential throughout the breeding process. Oxygen levels must be monitored closely, especially during autumn when water tends to become stagnant. Regular water changes and the presence of plankton are important for keeping the environment suitable for broodstock.
Broodstock cultivation should also consider the previous year’s growth. If they were properly nurtured, they will be more likely to produce high-quality eggs. If not, their gonads may remain underdeveloped, resulting in poor breeding outcomes.
Spawning takes place in carefully prepared ponds. The area should range from 0.2 to 1 mu, with a depth of about 1 meter. The pond should be clean, well-drained, and located in a quiet, sunny area. Before use, the pond must be disinfected, and the water should be filtered to prevent contamination. Fish nests made from materials like palm leaves, aquatic plants, or synthetic fibers are used. These nests should be placed in shallow water, about 1 meter from the shore, and arranged in a way that mimics natural spawning conditions. They should be sterilized before use and replaced regularly after spawning.
To enhance spawning success, some breeders use oxytocin injections. The dosage varies depending on the sex and weight of the fish, with females receiving 0.5 ml per kilogram and males receiving 1/3 to 1/4 of that amount.
Incubation can take place in either earthen or concrete ponds. The density of eggs is usually between 3,000 and 5,000 per cubic meter. Alternatively, drenching water incubation involves placing the eggs in a controlled indoor environment, where moisture and temperature are carefully managed. The ideal temperature is between 20°C and 25°C, and the eggs must stay moist without drying out.
Another method, detacking water incubation, involves removing the sticky coating from fertilized eggs before placing them in running water. This helps prevent clumping and improves hatching success.
Once the fry emerge, they should be fed immediately once their yolk sacs disappear. Water quality must be maintained by regularly changing the water, ensuring the temperature difference does not exceed 3°C. Avoid adding water while feeding to prevent fry from eating the surface. During hot weather, bubble disease can occur, so frequent water changes are necessary. Also, it's important to remove frogs, dragonflies, and other aquatic pests that could harm the fry.
Dried chilli slices
Sichuan Liuhang Agriculture Co.Ltd , https://www.lhagriculture.com