Methods and Technical Key Points for Polyculture of Yellow Catfish in Ponds

Polyculture of yellow catfish in ponds is also called pond supplementary culture or pond mixed culture of yellow catfish, which can be yellow catfish (Pelteobagrus fulvidraco) or darkbarbel catfish (Pelteobagrus vachelli). Because yellow catfish has strong environmental adaptability, the aquaculture technology for polyculture of yellow catfish is relatively simple.

(I) Pond condition requirements

According to the environmental requirements for pollution-free aquatic product aquaculture, the water source in the aquaculture environment should be pollution-free, and the various chemical components in the substrate and water quality should not exceed standards; however, there are no strict requirements regarding pond area and other aspects. Nevertheless, ponds for culturing yellow catfish still require sufficient water source, convenient water intake and drainage, and relatively abundant various types of bait organisms in the water body (small shrimp, small snails, small fish, etc.).

(II) Several models for polyculture of yellow catfish

Because there are many models of pond fish farming in China, carrying out different quantities of yellow catfish supplementary stocking according to different models mainly based on different cultured fish is an important guarantee for improving benefits. It should be noted that in stocking models with fish of the same feeding habits, factors such as whether these fish have a stronger ability to compete for food than yellow catfish should be considered.

1. Polyculture of yellow catfish in a model mainly based on filter-feeding fish The main filter-feeding cultured fish mainly include silver carp and bighead carp; as the main cultured fish, they live in the upper or upper-middle layers of the water body. The supplementary cultured fish in this model include grass carp, bream, blunt snout bream, common carp, crucian carp, and tilapia, etc. From the perspective of feeding habits, silver carp and bighead carp feed by filtering plankton, grass carp, bream, and blunt snout bream mainly feed on grasses, while common carp, crucian carp, and tilapia are mainly omnivorous fish. From the feeding habits, it can be seen that in this model, the main cultured fish silver carp and bighead carp, and the main supporting fish grass carp, bream, and blunt snout bream, have no conflict with yellow catfish in terms of living water layer and feeding habits. Only the secondary supporting fish common carp, crucian carp, and tilapia have a certain feeding-habit conflict with yellow catfish. Therefore, in the stocking of fingerlings in this model, omnivorous fish such as common carp, crucian carp, and tilapia should be reduced.

Generally speaking, polyculture of yellow catfish does not require feeding them separately, but the stocking quantity is determined according to the quantity of small miscellaneous fish, small shrimp, small snails, and other bait organisms in the pond; at the same time, the stocking quantity should be determined by considering the quantity of fish with similar feeding habits such as common carp, crucian carp, and tilapia; it should also be determined according to the designed yield of the culture model mainly based on silver carp and bighead carp. This model has a designed yield of 400-600 kg. Therefore, in stocking yellow catfish, the quantities of summer fry (about 2-6 cm) and winter fingerlings (about 8-15 cm) are different. Usually, when there are some common carp and crucian carp, stock 200-400 summer fry of 2-3 cm yellow catfish per mu, and about 150-200 fingerlings of 5-6 cm; when there are no omnivorous fingerlings such as common carp and crucian carp, the stocking quantity of yellow catfish can be increased to 0.5-1 times the above. When stocking winter fingerlings of yellow catfish, stock 50-150 per mu.

2. Polyculture of yellow catfish in a model mainly based on herbivorous fish The feeding habits of grass carp, bream, and blunt snout bream are aquatic grasses and some terrestrial grasses, and they also consume artificial compound feed, so they are usually called herbivorous fish. Generally speaking, in a culture model mainly based on herbivorous fish, the supplementary stocked fish include filter-feeding fish silver carp and bighead carp living in the upper water layer, omnivorous fish common carp and crucian carp living in the bottom layer, and a small number of carnivorous fish such as mandarin fish, snakehead, and black carp stocked as secondary species. The characteristic of a stocking model mainly based on herbivorous fish is that the fish in the pond are mainly herbivorous, there is more leftover bait and residual feed in the pond, and at the same time there are large amounts of undigested nutrients in the feces of the feeding fish, which can provide abundant feed for yellow catfish. In addition, when the designed production goal is high yield and high efficiency, aerators and other fishery machinery and equipment must be present, creating a good atmosphere for the living environment of yellow catfish.  In a model mainly based on herbivorous fish, the quantity of polycultured yellow catfish can be somewhat larger than in a filter-feeding main culture model. Generally, stock 350-450 summer fry of 2-3 cm yellow catfish per mu, and about 100 winter fingerlings, referring here to when there are a small number of omnivorous fish. Strictly speaking, when designing polyculture of yellow catfish, the stocking of common carp, crucian carp, and tilapia fingerlings should not be considered, or only a small number should be stocked; in that case, the stocking of yellow catfish fingerlings can be appropriately considered for increase.

3. Polyculture of yellow catfish in a model mainly based on carnivorous fish Black carp, snakehead, mandarin fish, and bass mainly feed on relatively large aquatic animals (such as fish, shrimp, snails, etc.) and are called carnivorous fish. This culture model is currently not carried out very extensively, and its regions are also relatively limited. Its supplementary cultured fish include silver carp, bighead carp, grass carp, bream, and blunt snout bream, etc. Considering that snakehead, mandarin fish, etc. live in the middle or middle-lower layers of the water body and have no conflict with yellow catfish in feeding habits, yellow catfish can be polycultured to utilize leftover bait and residual feed in the water and small fish and shrimp that the main cultured fish cannot use. However, considering the possibility that the main cultured fish may mistakenly eat yellow catfish, the stocking of yellow catfish should mainly be winter fingerlings, so that they can protect themselves relying on their hard 3 spines (2 pectoral spines, 1 dorsal spine). The stocking density is about 150 winter fingerlings per mu. Some people have proposed that summer fry can be stocked at 500-600 per mu, and the stocking time should be after the main cultured fish have grown to 10-12 cm, that is, after the main cultured fish have become dependent on artificial compound feed, then stocking yellow catfish. How effective this is remains to be further explored.

4. Polyculture of yellow catfish in a model mainly based on omnivorous fish Common carp, crucian carp, and tilapia have a wide feeding range and mixed feeding habits, and are called omnivorous fish. These fish are similar to yellow catfish in feeding habits and have a certain conflict. Only when various types of feed in the pond are sufficient can summer fry of yellow catfish be stocked. Of course, from a theoretical point of view, polyculture of yellow catfish winter fingerlings will not pose much of a problem, because at this time the fingerlings are large and have hard 3 spines to protect themselves. Generally speaking, polyculture of 2-3 cm yellow catfish summer fry is about 300 per mu, and the stocking quantity of winter yellow catfish is 50-80 per mu.

5. Polyculture of yellow catfish in a model mainly based on pearl cultivation The feeding habit of freshwater pearl mussels is also filter feeding. In the mussel-fish model of polyculture, silver carp and bighead carp living in the upper water layer are stocked only in small numbers because of similar feeding habits, while herbivorous fish can serve as the main polycultured fish in this model, as their feeding habits do not conflict with pearl mussels. Yellow catfish can obtain relatively good benefits in this model. Generally speaking, when stocking yellow catfish in this model, consideration can be given to stocking few or no other omnivorous fish. The stocking density of yellow catfish is the same as in “polyculture of yellow catfish in a model mainly based on filter-feeding fish”.

6. Polyculture of yellow catfish in a model mainly based on river crab The feeding habit of river crab is omnivorous with animal food as the main food, and its living water layer is the bottom layer, which conflicts with yellow catfish. However, practice has initially proved that polyculture of yellow catfish in river crab ponds can obtain relatively good benefits. This is mainly because river crabs mainly feed on snails and clams in the pond and can also make good use of artificial compound feed. In addition, river crabs are relatively timid and easily frightened, and under the threat of the pectoral spines and dorsal spine of yellow catfish, river crabs generally will not eat yellow catfish. This has been fully proved in many years of stomach content dissection of river crabs.