What pond conditions are needed for pond farming of adult rainbow trout?

Adult fish farming is the rearing of fingerlings into market-size fish. Generally, adult fish are raised by starting with fish that are a full year old as fingerlings, and in some cases the fish of the current year are raised all the way until market-size fish are harvested from the pond. But no matter which farming method is used, to achieve high yield and high efficiency, a sufficient quantity of fingerlings must be stocked; usually, during the one-year growing period, the annual production is 3.5 to 5 times the stocking quantity.

Pond condition requirements for pond farming of adult rainbow trout

For adult fish farming, the pond is required to have an area between 60 and 600 sq m. Both round and square ponds are acceptable, and the design can also be adapted to local conditions, but the pond depth must reach 0.8 to 1.2 m, the water depth 60 to 80 cm, and the pond bottom slope 0.8%.  

The water depth requirement is that the pond water depth can be adjusted as the fish grow. Generally, adult fish ponds and broodstock ponds have a water depth of 60 to 90 cm. The pond wall height must exceed the water depth by 30 cm. The water depth is often controlled by adding or removing drain gate plates.  

Under special circumstances such as excessive floating mud or poor water retention, the pond is required to have a bottom made entirely of concrete, and the pond bottom slope is generally required to be above 1/100.  

Concrete walls give a better effect and are durable. The structure of the inlet and outlet is very important and should meet the requirements of water passage, escape prevention, waste discharge and easy replacement of grating plates. The mesh size of the grating plates should be determined by the size of the fish, and the grating plates can be installed at an incline, which both enlarges the water passage area and makes it easier to remove debris.  

When designing fish ponds, generally the fingerling ponds are placed upstream and the adult fish ponds downstream. They can be arranged in two forms: longitudinal rows or horizontal rows. When water volume is insufficient, longitudinal rows are better. The number of ponds is calculated on the basis of 1 million eyed eggs producing 800,000 fingerlings and 500,000 adult fish, requiring 3000 to 3500 sq m of water surface. The yield target per unit water surface is generally calculated at 20 to 40 kg per sq m of water surface.  

Adult fish farming in practice also includes broodstock farming. Broodstock ponds are used for cultivating rainbow trout broodstock or reserve broodstock. The area, shape and requirements of broodstock ponds are the same as those of adult fish ponds, and the pond depth, water depth, pond bottom slope and so on are also the same as those required for adult fish ponds. However, in severe cold seasons, if conditions permit, overwintering indoors should be considered, and the designed area can then be relatively smaller. For example, a broodstock pond area between 50 and 200 sq m, pond length 20 to 30 m, pond width 4 to 5 m, pond depth 0.8 to 1.2 m, water depth 60 to 80 cm, and pond bottom slope 0.8%.  

In actual production, because flowing-water ponds are very limited, adult fish ponds can also be used to cultivate fingerlings. If built inside a greenhouse, to save area, long strip-shaped ponds are better. If built outdoors, and if water volume is sufficient, and considering that the water flow should not leave dead corners, round ponds can also be built where conditions permit, with the outlet designed in the center and the slope inclined toward the center point, so that during drainage water can be discharged from the bottom center, which helps with the discharge of waste.  

In order to use water sources efficiently, adult fish farming ponds generally maintain a relatively high farming density. Since the water supply is mainly a supply of oxygen, and oxygen is related to temperature, water volume, temperature and oxygen are the three major factors affecting farming density.  

If it is an old pond being renovated, both flow-through earthen ponds and flow-through cement ponds suitable for flowing-water farming can serve as adult fish farming ponds, and cement ponds used for farming fish such as sturgeon can also serve as rainbow trout adult fish farming ponds. The area and shape can be square or round, and during renovation the design should be adapted to local conditions; it is best to create a water level difference among the ponds, and the water depth of each pond must reach 60 to 100 cm. There should be a certain slope from the water inlet to the drain of the pond bottom. The water supply method is best arranged in parallel; if a series arrangement is used, then no more than 3 ponds should be connected in series, to prevent water quality and water flow from being affected.  

Generally, two inlet gates are installed: the first controls the inflow, and the second is a fish-blocking screen. The drain gate is generally designed as a gate with the functions of blocking fish, draining water and controlling water level. Under normal circumstances, a water source with a flow of 1 liter per second can produce 50 to 200 kg of adult fish, and the water body in the pond must have an appropriate flow speed, guaranteed to be between 1.2 and 1.8 m/min. Fish ponds should be built with a waste discharge system to ensure regular waste discharge and control water quality. The outlet generally has the functions of drainage and waste discharge. Generally, both the inlet and outlet should enlarge the water passage cross-section as much as possible. In particular, the inlet is generally trumpet-shaped; when water enters the fish pond through the inlet gate it appears fan-shaped, and there must be a certain drop, letting the water fall into the fish pond to obtain an aeration effect.

Nutritional value of rainbow trout  

1. Protein  

Rainbow trout skin and flesh are rich in protein, and part of this protein consists of components essential to the human body; after being eaten, it can play a role in beautifying the skin and strengthening the bones.  

2. Vitamins  

Rainbow trout is relatively rich in vitamins, especially vitamin D, whose content is relatively higher than in other foods. As we know, vitamin D plays an important role in human bone growth, and people lacking vitamin D are prone to diseases such as rickets.  

3. Unsaturated fat  

Rainbow trout roe contains highly unsaturated fatty acids and ovoprotein, and is a nutritional product with relatively high nutritional value.  

4. Trace elements  

Among the mineral elements in rainbow trout, iron is the most prominent, and iron is closely related to human blood production and plays an important role in maintaining the normal activity of human internal organs.   

Effects and functions of rainbow trout  

1. Rainbow trout is sweet in taste and warm in nature, and has the effects of warming the stomach and harmonizing the middle, and stopping diarrhea.  

2. Beautifying the skin  

Rainbow trout is relatively rich in components such as protein, ovoprotein and unsaturated fatty acids, and women who eat it consistently can achieve a very good skin-beautifying effect.  

3. Protecting the heart and cerebrovascular system  

Fish oil extracted from rainbow trout is rich in unsaturated fatty acids, whose main function is to protect the heart and cerebrovascular system and prevent cardiovascular and cerebrovascular diseases. At the same time, the unsaturated fatty acid content in rainbow trout is far higher than in other freshwater fish, which makes rainbow trout all the more valuable.  

4. Promoting brain development  

Rainbow trout contains phosphoprotein, which can promote brain development and is especially suitable for people who frequently use their brains.

Speaking of rainbow trout, I think everyone probably does not know it particularly well. This fish is relatively uncommon in daily life, so its price is also relatively more expensive, and therefore the investment cost of farming rainbow trout is also much higher.