How to stock fry in cage culture of yellow catfish

I) Preparation before stocking fry

1. Preparation of cages of different specifications Cages of corresponding specifications should be prepared according to the size of the fry to be stocked. If the stocking size is 2 cm, second- or third-stage fry cages and second-stage grow-out cages should be prepared; for fry of 5 cm, second-stage fingerling and second-stage grow-out cages should be prepared; for those over 10 cm, first-stage cages should be prepared.

2. Feed must be ready Artificial feed is the material basis for cage culture of yellow catfish, and feeding is required within 1 to 2 days after the yellow catfish are stocked. Therefore, the feed must be prepared in advance. The feed should be prepared according to the size of the yellow catfish stocked. If the stocked fry are small and have not been trained to accept feed or have been poorly trained, fresh animal feed should be prepared; conversely, if the stocked size is large and they have already been trained to accept feed, artificial pellet feed of the corresponding size should be prepared.

3. Cage safety inspection must be thorough Before and after the cage is placed in the water, the net body should be strictly inspected. If any damage or holes are found, they should be repaired on the spot immediately to ensure the safety of the cage. This is the key to the success or failure of the culture, and one must never be careless or negligent.

II) Stocking density of fry

1. Raising market-size fish from summer fry In cage culture of yellow catfish, at present four-stage cage stocking is generally adopted; when the stocked fry are too small, five-stage cage culture should be considered. The first-stage cage raises fish from 2 cm to about 4 cm; the second-stage cage raises them from 4 cm to 5-6 cm; the third-stage cage raises them from about 6 cm to 8-10 cm; the fourth-stage cage raises them from 8-10 cm to market-size fish. The stocking density in the first-stage cage is 2000-3000 fish per sq m; the density in the second-stage cage is 1500-2000 fish per sq m; the density in the third-stage cage is 500-600 fish per sq m; the density in the fourth-stage cage is 350-450 fish per sq m.

2. Raising market-size fish from winter fingerlings Stocking winter fingerlings to culture yellow catfish is a good way to bring market-size fish to market in a balanced manner. The multi-stage cage culture introduced above refers to the form of raising the current year's summer fry to market size in the same year, and is currently a relatively popular intensive yellow catfish culture model. Raising market-size fish from winter fingerlings involves winter fingerlings cultivated in ponds being stocked into cages from January to March each year; if the overwintering conditions of the fingerling pond are poor, the fingerlings can also be stocked into cages in November-December to overwinter in deeper water (of course, the density must not be high). There is also another situation, namely that part of the fry in the cages in the current year that have not grown to market size can only be used as fingerlings for culture in the second year, which is also the form of cultivating fingerlings in the first year and raising market-size fish in the second year. This form is also one of the ways for yellow catfish to break through seasonal restrictions, achieve balanced marketing year-round and improve benefits. The stocking density of winter fingerlings is 300-500 fish per sq m, and can also be 500-1000 fish per sq m.