Detailed Explanation of Key Points on Sleeper Fry Breeding Technology

Sleeper, commonly known as "puyu," has a high meat content, delicious flesh, and rich nutrition, with market demand exceeding supply, and fry supply has become the main factor affecting sleeper aquaculture.

1. Broodstock selection

Broodstock can be purchased from the market or selected from naturally caught broodstock, choosing robust, disease-free, and injury-free individuals of 2 to 3 winter ages, requiring females above 100 g and males above 150 g.

2. Broodstock cultivation

The pond used for breeding requires a flat bottom, an area of 1 to 3 mu (1 mu = 667 sq m, the same below), and a water depth of 1.2 to 1.5 m. Remove excess mud, disinfect with quicklime, then fill with filtered water. Apply 500 kg of fermented manure per mu. Soak the collected broodstock in 3% salt water for 10 to 15 minutes, and stock 1000 to 1500 fish per mu of water surface. When the water temperature reaches above 14°C, start feeding, mainly with small fish, small shrimp, and minced river mussel meat. Starting from April, flush with water once every 2 to 3 days to promote gonadal development.

3. Induced spawning and hatching

When the water temperature stabilizes above 20°C, set up one "three-piece tile" as an artificial spawning nest for every 2 to 3 female fish. Generally after 12 hours, the female and male fish pair up to spawn and fertilize; checking the tiles will reveal the male fish guarding the eggs. When the water temperature is 18 to 25°C, it takes about 15 to 25 days for all to hatch and break the membrane into fry. After the fry hatch, the spawning nests can be removed, and the broodstock can be removed by methods such as seine netting, dip netting, and ground cage trapping.

4. Fry cultivation

Place an appropriate amount of aquatic plants in the pond to provide habitat for the larvae. For larval food, use compost such as chicken manure to cultivate small zooplankton, and supplement with egg yolk, etc.; as the fry grow, add soybean milk, minced fish, etc. During the cultivation process, maintain fresh water quality and sufficient dissolved oxygen, and regularly splash quicklime and bleaching powder, etc. After 1 month of feeding, when the fry grow to 2 to 3 cm, switch to feeding minced small trash fish, crushed river snails, mussel meat, and soybean cake paste, with a daily feeding amount of 1% to 3% of the total fish body weight in the pond.

6. Fingerling harvesting

Sleeper fingerlings have the habit of burrowing in mud and attaching to grass, making harvesting relatively difficult. The following methods can be adopted: (1) Use a dip net to catch under the aquatic plants; (2) Lower the water level and use ground cages to trap; (3) Use a fingerling net to seine; (4) Drain the pond to catch them.