Parent fish selection of trout parent fish includes female fish and male fish, which must come from two culture areas and cannot have close relatives. Trout that is planned to be raised as parent fish should be cultured separately, and the best fish should be discarded and cultured qualitatively. The group that intends to choose female fish must not keep male fish, and the group that intends to choose male fish must not keep female fish.

It is necessary to establish a file of parents' pairing relationship on their own farm to ensure the excellent characters of future generations. Trout farms that produce eye-catching fish eggs should select and keep their parent fish every year. In the production process, it is necessary to eliminate the parent fish with poor fecundity and add new parent fish. Ensure the number of parent groups as needed.

The newly selected parent fish and the newly bred parent fish cannot be mixed for the time being, and the newly bred parent fish is weak in physique and poor in feeding ability. Therefore, the artificially propagated parent trout should be raised separately, and then put into the artificially propagated parent fish pond for cultivation next year after the physical fitness is completely restored.

In the early stage of trout parent fish cultivation, male and female individuals are mixed in the same pond, and one month before artificial breeding, male and female individuals are raised in separate ponds respectively. When male and female individuals are mixed, the stocking density of parent trout is 3 ~ 5 per square meter of water surface, and when male and female individuals are raised separately, the stocking density is halved.

Recovery of parent fish after breeding The parent fish of trout consumes a lot after artificial breeding, and its physique is weak. In actual production, special attention should be paid to ensuring the survival rate of parent fish after breeding. Because the parent fish that has just been artificially propagated has been out of the water for a long time, it should be gently put into the pool when it is released, and the position should be chosen in the relatively gentle upstream of the pool. If the parent fish lies flat on the bottom of the pool, it should move gently and let it swim slowly.

Feed is more nutritious than usual. It is best to feed some feed that is easy to digest and absorb, and add antibiotics to increase the vitamin content in the feed. Be more careful than usual when feeding, feed slowly for a long time, and try to ensure that the postpartum parent fish eat as soon as possible.

The water in and out of the parent fish pond after delivery should be as gentle as possible to avoid the formation of rapids and reduce the energy consumption of fish. If we pay attention to the recovery of parent fish after delivery, we can greatly improve its survival rate and ensure the number of parent fish produced next year.

2, feed and feeding

The selection and preparation of feed trout culture ponds are basically cement ponds. There is almost no natural feed in the pond, and the nutrition depends entirely on artificial feeding. Therefore, the selection and preparation of high-quality complete feed is the key to trout culture.

Commercial feed can be directly selected for parent fish feed of trout. The commercial parent fish feed has comprehensive nutrition and stable quality, and the labor intensity in the breeding process is low, but the price is high and the storage time is long, which is easy to cause nutrient loss. If you make your own feed, you must strictly control the quality of raw materials, and every raw material can't go bad. The feed protein should be above 42%, animal protein should be above 80%, and the fat content should be above 6%.

Rich in minerals and vitamins, it is best to prepare, process and feed now. Specific formula: imported fish meal 50%, meat and bone meal 10%, protein meal 20%, blood meal 5%, alfalfa meal 5%, secondary meal 5% and soybean oil 5%. Additives are added according to the amount of parent fish of pre-mixed trout, and if the pre-mixed fish does not contain carotenoids, 40-60 ppm carotenoids are added.

Conditional can feed fresh wild fish, animal offal and other animal bait. Feeding fresh animal bait must be clean and hygienic, and the quality must be strictly controlled. You must never feed those who have the source of the disease.

Feeding trout parent fish with feed is relatively large in size, slow in movement and low in stocking density. The actual feeding needs patience and care. Mansha should ensure that every fish can eat the feed every time.

When using finished feed or self-made feed, if antibiotics, vitamins, carotene, etc. Everything needs to be added. First, calculate the amount of substances to be added, dissolve them in warm water, spread the feed to be added, spray it evenly on the feed with a sprayer, and dry it indoors before feeding.

The feeding amount of parent fish is 0.5% of the fish weight, which can be flexibly controlled when feeding. If the feeding amount of parent trout is reduced, the feeding amount can be reduced. But it should be analyzed in time to find out the reasons for the decrease. In general, the feeding amount will be reduced during the breeding season, or factors such as changes in water quality and feed will also lead to a decrease.

The feed cultivated by parent trout can be fed for a long time if there is animal bait such as fresh wild fish, but at least 0.2% of the finished feed should be fed every day. Otherwise, when the freshness of animal feed is not guaranteed, feeding finished feed will easily lead to changes in eating habits and induce diseases. Every 100 kg of fresh animal feed is calculated as 30 kg of finished feed.

For example, parent fish 1000 kg culture, the daily feeding amount is 0.5%, all finished products are fed, and the daily feeding amount is 5 kg. If you want to feed fresh animal feed, the finished feed should not be less than 0.2%, that is, 2 kg of finished feed and 10 kg of fresh animal feed should be fed every day.

Feed twice a day at 9: 00 and 17: 00. Feeding fresh animal feed can improve the reproduction rate, fertilization rate and hairy eye rate of trout, and finally improve the survival rate of fry culture. Therefore, when breeding parent trout, try to feed more fresh animal feed.

3. Breeding species

There are about 16 species of salmon and trout that can be completely cultured in seawater and fresh water areas in the world. The marine culture of trout in China has achieved initial results, but it has not been popularized, and almost all of them are freshwater culture. There are mainly four kinds, which have formed a complete artificial breeding technology and have been cultivated in a large area or are being expanded.

Rainbow trout: 2-year sexual maturity, life-long multiple reproduction. The annual average water temperature is below 1 ~ 2℃, and the body weight of the second instar can reach 1 kg. The largest individual in pond culture is 7 kg. The yield per square meter of running water pond culture can reach more than 25 kilograms. The diseases that affect survival are mainly viral diseases and vibriosis.

Golden trout: Biological characteristics, growth rate and yield per unit area are similar to rainbow trout. It has both edible, fishing and ornamental values. Its golden yellow color is a dominant genetic trait, which has important germplasm value for breeding and scientific research. Because of its golden color, richness and elegance, the market price is higher than that of rainbow trout.

Mountain trout: Suitable for fishing in ponds and streams. 2 years of sexual maturity, only once in a lifetime. The second-instar fish weighs 400-700g, and the largest individual is 900- 1000g. Strong disease resistance, generally not infected with viral diseases. At the water temperature of 22 ~ 25℃, the viability and feeding intensity are better than rainbow trout.

Sun spotted salmon: sexually mature at the age of 2, and it is suitable for fishing for many times in its life. Under the condition of annual average water temperature 12℃, the weight of two-month-old fish is10 ~130g, and that of two-year-old fish is 500 ~1000g. The largest individual is over 2000 grams. The survival activity and feeding intensity in 0 ~ 4℃ environment are better than rainbow trout. I like to eat artificial bait in sinking, and I also like to eat submerged bait. Strong disease resistance, basically not infected with viral diseases.

In addition, there are native species of salmon, Taiwan Province hucho and spotted trout, as well as imported species of river trout, Arctic spotted trout, silver trout, Atlantic trout and brown trout. Experimental breeding is under way.

4. Breeding environment

water temperature

Both fresh water and mariculture need a low-temperature water environment. In summer, the water temperature does not exceed 22℃, and the highest temperature does not exceed 24℃. Sea water and fresh water that do not freeze in winter or in a short time can be used to breed salmon and trout. Water temperature is an important factor affecting the effect of aquaculture. In a suitable temperature range, the higher the water temperature, the faster the growth.

The higher the water temperature, the lower the dissolved oxygen. When the water temperature reaches 22℃, the dissolved oxygen in the water will drop to 5 ~ 6 mg/L. At this time, there are two unfavorable factors in the water environment: high water temperature and low oxygen content. The metabolic intensity and feed efficiency of fish will be reduced, which will seriously affect growth and even lead to death. When the water temperature is lower than 65438 08℃, the growth is generally unaffected by water temperature and dissolved oxygen.

dissolved oxygen

Salmon and trout like to live in waters with high dissolved oxygen. In general, the safe critical value of dissolved oxygen for rainbow trout is 3.15mg/L. The safe critical value of fish raised in low oxygen environment for a long time is reduced to about 2.45 mg/L. When the dissolved oxygen is lower than 5 mg/L, the respiratory frequency of rainbow trout is accelerated, and when it is lower than 4mg/L, the swimming is slow.

When the fish group appears floating at the water inlet, the dissolved oxygen in the water has dropped below 3 mg/L, and the life of the fish has been threatened. In a quiet environment, the oxygen consumption of fish will decrease. Stimulating factors such as temperature, light and vibration will increase oxygen consumption and reduce the safety of dissolved oxygen environment.

Stimulation of water temperature changes can increase oxygen consumption by 30% ~ 70%, while illumination and vibration stimulation can increase oxygen consumption by 20% ~ 30% and 40% ~ 50% respectively. The compound stimulation composed of many factors will increase the oxygen consumption by more than 1 times compared with the static state. When feeding salmon and trout in the running pond, the dissolved oxygen in the drain should be kept above 4 mg/L.

water quality

The water quality factors affecting the growth of salmon and trout are very complicated, mainly the pH value of water and the concentration of ammonia nitrogen. The tolerance range of rainbow trout to pH is 5.5 ~ 9.2, and the suitable range is 6.5 ~ 7.5. Acidity, especially strong acidity, will inhibit the growth of rainbow trout.

Uncomposed nitrogen, especially ammonia nitrogen and nitrite, comes from residual organic matter such as bait and feces, and is toxic to salmon and trout. The tolerance concentration of rainbow trout to ammonia nitrogen is 0.01.25mg/L. If the ph is around 7 in running water pond, the tolerance concentration can reach 0.05 ~ 0.6mg/L. In near-neutral water, ammonia nitrogen generally does not cause great harm. The higher the water temperature and ph value, the stronger the toxicity of ammonia nitrogen.

The higher the dissolved oxygen content in water, the stronger the tolerance to ammonia nitrogen. When dissolved oxygen is above 7 mg/L and ammonia nitrogen reaches 0.8 ~ 1.0 mg/L, rainbow trout will not be harmed within 6 weeks. When the dissolved oxygen content is below 5 mg/L and the ammonia nitrogen content is above 0.5 mg/L, the growth of rainbow trout will slow down, the gills will be easily damaged, and even the kidney and liver tissues will be dysfunctional.

Turbidity of water quality is also an important factor affecting the growth of salmon and trout. Turbid water quality will hinder the vision of fish and affect their feeding and growth. When building salmon and trout farms, it is possible to fully understand the environmental situation of water sources.

Farmers can judge the water quality according to whether there are wild animals in the water when they build small farms. If small fish, aquatic insects and other creatures live in the water source, then this water source can generally be used to cultivate salmon and trout.

Rainbow trout and whitebait, which are suitable for mariculture, spend their infancy in fresh water environment. With the growth of individuals, salt tolerance is gradually enhanced. The salinity tolerance of juvenile, current, first-year-old and adult rainbow trout is 0.5% ~ 0.8%, 1.2% ~ 1.4%, 2% ~ 2.5% and 3.5% respectively. After about 10 days of brackish water transition, young fish over 35 grams can adapt to seawater life.

5. Feeding management

Water quality management trout generally breed in running water, and the water quality is relatively fresh. The main thing is to control the running water, increase the flow three months before artificial breeding, and the water exchange capacity of the pool can reach 10 times a day. In the recovery stage of artificial breeding parent fish, the flow should be small and the water flow should be gentle, usually 5 times a day and 7 times a day.

In daily management, check the fish fence at the inlet and outlet regularly, repair it in time if it is damaged, remove the sediment in time to ensure the smooth flow of water, carefully observe the feeding situation of fish when feeding, and analyze and solve the abnormal phenomenon as soon as possible. In rainy season and late autumn, it is necessary to increase the number of pond inspections, clean up the dirt and fallen leaves washed by rain in time, and prevent siltation and blockage of fish pens.

Dredge the trout brooding pond, and regularly remove the excrement and other sundries deposited at the bottom of the pond. When cleaning, first use fishing nets to drive all the fish to the water inlet, increase the water flow in the pool, and use shovels and other tools to clean the sediment at the bottom of the pool.

You can also use a sewage suction pump to pump out the accumulated sewage. Generally, it needs to be cleaned once a month, and the cleaning time is generally selected at 14: 00. At this time, the weather is warm, five hours have passed since the feeding time in the morning, and there are still five hours before the feeding time in the afternoon, so the normal feeding of fish cannot be affected.

The prevention and control of fish diseases requires high water for trout culture, and there are few general diseases, mainly protozoan parasitic diseases. Adding some anti-insect drugs and feeding regularly can completely solve this problem. Trout farming is all artificial feeding, and there is almost no natural bait in the pond.

Therefore, the feed must be comprehensive in nutrition and fresh in raw materials, otherwise it is easy to produce nutritional diseases, and the feed requirements for trout parent fish are even stricter, especially the minerals and vitamins must be comprehensive, and the vitamins that are easy to lose should be increased. Try to feed some fresh animal bait regularly, or add some fresh plant juice to the feed.

In order to cultivate parent fish well, it is necessary to select parent fish with high-quality genetic genes, feed them with comprehensive nutrition bait, and pay special attention to every small link in the breeding process. Only by grasping the key link of trout parent fish cultivation can we produce high-quality trout eggs, ensure a solid material foundation for trout cultivation and develop trout industry healthily, continuously and rapidly.

Extended data

They usually live in the middle and upper reaches with clear water and bottom sand. The suitable living temperature is 12 ~ 18℃, and the optimum growth temperature is 16 ~ 18℃. The suitable growth temperature for young fish is 65438 00℃. Below 7℃ or above 20℃, appetite decreases and growth is slow. If you don't eat above 24℃, your body will weaken or even die. Rainbow trout like countercurrent and oxygen.

When the dissolved oxygen in water is less than 3 mg/l, a large number of deaths will occur; When it is lower than 5 mg/L, the respiratory rate is accelerated and you feel uncomfortable. Above 6 mg/L, it grows well. Rainbow trout live in water with pH value of 5.5 ~ 9.2, and the optimum pH value is 6.5 ~ 6.8.

With the growth of individuals, the adaptability to salinity is gradually enhanced. The suitable salinity of floating juvenile fish is 5 ‰ ~ 8 ‰, 1 year-old fish is 20 ‰ ~ 25 ‰, and adult fish is 35‰. When the weight reaches more than 35 grams, you can adapt to seawater life as long as you transit through brackish water.

Baidu encyclopedia-rainbow trout

Baidu encyclopedia-trout