Mixed culture of soft-shelled turtle and fish

The mixed culture of soft-shelled turtle and fish is a way of raising soft-shelled turtle and fish. The experiment shows that the benefit of mixed culture of soft-shelled turtle and fish is 1 or even several times higher than that of other mixed culture methods. The following is a brief description of its animal learning and breeding methods as follows.

1 the zoological principle of mixed culture

The mixed culture of soft-shelled turtle and fish refers to the mixed culture of soft-shelled turtle and fish in the same pond. From the point of view of zoology, the mixed culture of soft-shelled turtle and fish can not only make full use of the biological cycle of water body, but also maintain the dynamic balance of water ecosystem. Soft-shelled turtle and fish can not only coexist, but also promote each other, and because of less investment and fast capital turnover, it can be accepted by the majority of farmers, it is a new way of high-benefit culture technology, and has a good development prospect.

1.1 mixed culture of soft-shelled turtle and fish can increase production

Soft-shelled turtles are reptiles that breathe with their lungs and do not absorb dissolved oxygen in the water. They must often float to the surface to absorb oxygen in the air, while fish breathe through their gills in the water. Therefore, there is no contradiction between soft-shelled turtle and fish in the main living environment factor-dissolved oxygen, and because the soft-shelled turtle regularly "ventilates", it can balance the dissolved oxygen between surface water and bottom water. it can not only prevent the oversaturated oxygen produced by the exuberant photosynthesis of phytoplankton in the water from escaping into the air, but also make up for the "oxygen debt" in the deep water layer. It is not only beneficial to the metabolism of fish, but also can promote the reproduction of plankton. At the same time, due to the activity of the soft-shelled turtle at the bottom of the pond, the organic matter precipitated on the bottom of the pond can be decomposed regularly, even if the pond water is anoxic, the danger of "flooding pool" of fish can be reduced or avoided. The water body of the mixed culture pond of soft-shelled turtle and fish can often maintain a high dissolved oxygen content, and its monthly average value is 35% higher than that of the control adult fish pond.

In the mixed culture pond of soft-shelled turtle and fish, when the ammonia produced by the metabolism of soft-shelled turtle reaches a certain concentration, it is not conducive to the growth and development of soft-shelled turtle. However, due to the extensive use of ammonia by phytoplankton, it can play a role in purifying water quality, so it is not easy to cause serious water pollution and affect the growth of soft-shelled turtles and fish.

Soft-shelled turtles do not harm healthy fish, but they can eat sick and dead fish that are slow to move. Therefore, the mixed culture of soft-shelled turtle and fish can also prevent the spread of pathogens and reduce the occurrence of fish disease. Under the same feeding conditions, the survival rate of fish in soft-shelled turtle and fish mixed culture pond was higher than that in simple fish culture pond. In addition, soft-shelled turtles can also prey on zoobenthos such as clams and snail lions in the pond to reduce ineffective consumption in the pond.

(2) mixed culture method

Mixed culture of commercial soft-shelled turtle, commercial fish; juvenile soft-shelled turtle, fish fry; backup parent soft-shelled turtle, commercial fish; mature parent soft-shelled turtle spawning, fish fry and other methods, the following introduces the mixed culture model of commercial soft-shelled turtle and commercial fish.

2.1 mixed culture ponds

The area should not be too large, preferably 2 million mu (667 square meters), pool depth 1.5 square meters, pool slope 3 ∶ 1, pool bottom silt should not be too thick, pool bottom flat. The escape prevention facilities are complete. The fish bait table and the soft-shelled turtle feed table should be as far away as possible to avoid the competition between turtles and fish. The sun back platform is located in the water 2m away from the dike to the sun, to the leeward and to the south.

2.2 stocking and collocation proportion of soft-shelled turtle and fish

2.2.1 stocking time varies due to different climates. The time of releasing fish in East China is about March, and the release of soft-shelled turtles can be in mid-May; in South China, fish and soft-shelled turtles are released in February and late April respectively; in Central China, they can be released at the same time; and in Northeast and Northwest China, it is appropriate to be later.

2.2.2 the species of soft-shelled turtle should be artificially cultured, and the specification 200g/ is only about. The stocking density should be considered comprehensively according to the individual size and feeding area, the individual size can be properly sparse, and the density of the small individual can be higher; the density of the large water surface can be smaller, and the density of the small water surface can be higher. The stocking density is 1 / 2 / m2.

2.2.3 the stocking of fish species should not only consider the collocation of fish species, but also pay attention to the reasonable stocking density. As far as species are concerned, silver carp, bighead carp and other plankton-eating fish are the main species, properly matched with herbivorous and omnivorous fish, and the stocking density is 900 per mu.

2.3 feeding and management of mixed culture

The soft-shelled turtle can be fed with artificial bait, which can be fed at the beginning according to 1%-2% of the body weight of the soft-shelled turtle at the time, and then increase or decrease appropriately according to the situation of the bait at that time; the bait of the fish should be fed according to the feeding habits of the fish (mainly commercial bait and artificially planted Sudan grass). The feeding time of soft-shelled turtle and fish bait should be staggered appropriately, and it is best to feed soft-shelled turtle bait about 30 minutes after feeding fish bait (mainly snail, fresh miscellaneous fish and a small amount of compound feed, which is fed on the saddle-shaped eating platform, about 9 ∶ 00 a day) to ensure turtle feeding; in case of abnormal climate, water should be injected in time to prevent the death of soft-shelled turtle and fish caused by the decrease of oxygen dissolved in pond water. Add water once every 10 days, 20~30cm each time, add water once in 2-3 days in summer and autumn, and sprinkle with quicklime 20~30mg/kg in the whole pool once in 20-30 days. Aerators should be opened frequently to prevent fish from being attacked by soft-shelled turtles after floating heads. The tolerance of soft-shelled turtle and fish should be considered when sprinkling quicklime and bleaching powder. Quicklime should not exceed 30mg/kg and bleaching powder should not exceed 15mg/kg. In addition, it is necessary to have special personnel on duty, inspect the ponds in the morning and evening, check the water quality, check the bait of soft-shelled turtles and fish, check whether the escape prevention facilities are damaged, check whether there is any illness, and do a good job in flood control, wind prevention, and theft prevention. In addition to inspection in the morning and evening, you should walk around the pond as little as possible, especially when the turtle basks its back at noon on a sunny day.