Culture technology of "fine scaled fish" in high latitudes

Culture technology of [fine scaled fish] in high latitudes

Daxing'anling is the western part of the Xing'an Mountains, located in the northeast of the Inner Mongolia Autonomous Region, northwest of Heilongjiang Province, the geographical coordinates are between 43° N and 53° 30′ N, between 117° 20′ and 126° E, with a total length of more than 1400 km, an average width of about 200 km, and an altitude of 1100 ~ 1400 m. Daxing'anling has a water system dominated by Heilongjiang and Nenjiang, with Ilhuri Mountain as the watershed, Lingbei as the Heilongjiang river system, and Lingnan as the Nenjiang river system. The main rivers are Dogu River, Huma River, Ta River, Dobukur River and Gan River, with a basin area of 154 rivers with a basin area of 50km2 or more, and 28 rivers with a basin area of 1000km or more. Lakes are dotted with lakes. The average annual temperature is -1.2 °C. With the implementation of the natural forest protection project in Daxing'anling in recent years, it is imperative to close the mountains and cultivate forests and open up new industries. In the natural waters of Daxing'anling Mountains, there are fine scaled fish, the flesh and taste of fine scale fish are very delicate, it is necessary to explore the breeding technology of fine scale fish, which will play a positive role in increasing the production of fine scale fish and promoting local economic development.

First, external features

The body is long spindle-shaped and slightly flattened. The head is blunt, the back of the head is broad and flat, and the center is slightly convex. The kiss is not prominent or slightly protruding. At the end of the mouth, the lower jaw is slightly shorter than the upper jaw, the posterior end of the maxilla reaches below the center of the eye, and there is a row of sharp teeth on the upper and lower jaws, the plough bone, and the palate bone. The tongue is thick and free. The gill hole is large, lateral, reaching forward below the center of the eye. The body is scaled and the head is scaleless. The lateral lines are complete and relatively straight. The dorsal fin is short and slightly concave on the outer margin; the adipose fin is opposite to the fin; the ventral fin begins below the middle of the base of the dorsal fin, does not extend posteriorly to reach the anus, and has a long axillary scale at the base; the caudal fin is forked. There are 65 to 75 pyloric blind sacs. During life, the back is dark brown, the side of the body to the abdomen is gradually white, the back and sides of the body are scattered with oblong oval black spots, the spot margin is a pale red ring, along the dorsal fin base and the fat fin each have 4 to 5 round black spots.

Second, the living environment

It is a cold water type of foothill fish. Living in the sea 900 ~ 2300m mountain stream, the water flow is turbulent, the water quality is clear, the bottom of the water is mostly large gravel, rich in dissolved oxygen, the perennial water temperature does not exceed 20 °C. In late autumn, wintering in deep pools or deep troughs of river channels. Except during flood periods, it is rarely seen in the main stream of the plain.

Active feeding throughout the year. It mainly feeds on invertebrates, small fish, etc., but also preys on frogs and small rodents. Extremely bulivorous, the food in the stomach can account for about 10% of its own body weight, and it is more likely to prey on fish that grow 1/2 of the size of its own body. The most appetizing times of the day are morning and evening, and other times lurk in the shaded bottom of the stream on both sides of the stream. The appetite after spawning is particularly strong. It generally winters in the deep water areas of rivers.

3. Reproduction and development

Females mature at 4 to 6 years, while males mature earlier. Eggs are laid once a year. When the early spring thaws, it migrates upstream to spawning. Spawning grounds are generally located in rapids with a water depth of 1 to 1.2 m and a gravel substrate. The spawning period is late spring and early summer, and the water temperature is 8 to 12 °C. The fecundity of the fine scale fish is 1629 to 7420 grains. Broodstock build spawning beds during spawning, and die in large numbers after breeding, especially males. Egg sedimentation, light yellow, egg diameter about 4 mm. Under the condition of lower water temperature, the development of embryos takes 50 days at water temperature of 3.5 °C, 45 days at 5 °C, 20.5 days at 11 °C, and 12 to 15 days after hatching. Juvenile fish prefer to lurk between gravel gaps, swim less often, and usually feed on small fish, aquatic insects, small animals living on the shore, and plants.

Fourth, the breeding technology at all stages

1. Breeding of fine scaled fish

The reservoir is glass steel flat groove (40cm×30cm×20cm), flowing water aquaculture, inlet water flow 18 ~ 20L / min, 60cm above the water surface set 100 watt fluorescent lamp illumination. The stocking density is 10,000 tails per tank. The total length of the newly hatched fine-scaled fish is 14 to 16 mm. During this period, the juvenile fish lie on the bottom of the water, and its development depends entirely on the nutrition of the yolk sac. Baby fish are prone to suffocation and death due to excessive accumulation or poor water flow and lack of oxygen, and the amount of water injection should be appropriately increased to maintain more than 20L/min per 100,000 fish.

2. Breeding of juvenile fish

The size of the pond is 10m long, 2m wide and 30cm deep. As the yolk sac absorbs 2/3, it gradually floats up and swims in the water. The stocking density of juvenile fish in the flat row trough is 6000 fish/m2, and the stocking density of juvenile fish in the juvenile pond is 3000 fish/m2.

When the floating rate of juvenile fish reaches more than 50%, it is advisable to feed the open feed, and the open feed is artificial compound feed. Artificial compound feed for juvenile fish with a crude protein content of 45% can be selected, but the fat content should be above 12%. Feed particle size 0.3~0.5 mm.

The density of the bait required for the first feeding of the slender-scaled juvenile fish is one of the key factors for its survival. After the yolk sac is absorbed, the juvenile fish transfers from endogenous to exogenous nutrition period, the physique is still relatively weak, the active feeding ability is weak, so it is necessary to feed the appropriate and sufficient bait in time, otherwise the juvenile fish will enter the hunger period. In the breeding stage of juvenile fish, hunger is often one of the most important causes of the death of juvenile fish, and the feeding of rotifers and water silk worm powder are animal bait, their particle size is very suitable for the caliber of fine scale fish, and they can also be evenly distributed in the water body, water silk worm powder can also float on the surface of the water body, which can make it easier for the open fish to obtain open food, thereby providing a material basis for its survival, therefore, in the breeding process of the fishlet, Providing an adequate supply of bait is a key measure to improve the survival rate of juvenile fish.

3. Breeding of fine-scaled fish fingerlings

Adopt flow pond cultivation, flow pool using cement pool, single pool area 30 ~ 90m2, pool depth 60 ~ 80cm, water depth of 50 ~ 60cm. The width of the pool is 1.2 to 2.5m. The slope at the bottom of the pool is 2:1000 to 5:1000. The water flow of the flow pool is 100~300L/min, and the water depth is 50~60cm. Adjust the stocking density according to the growth specifications of the fine scaled fish. Fish fingerlings with a size of 5g, the stocking density is generally 1000 fish /m2; the stocking density of 10g fish fingerlings is generally 800 fish/m2; the stocking density of fish fingerlings with a size of 20g is generally 600 fish/m2; the stocking density of fish fingerlings with a size of 30g is generally 500 fish/m2.

4. Grow-out culture of fine scaled fish

Flow pond culture: cement tank is used. The cement pond is rectangular in size and has an area of 200 m2, a pond depth of 100 cm and a water depth of 80 cm. The width of the pool is 6.67m, the length of the pool is 30m, and the slope ratio of the bottom of the pool is 12:1000. Ponds are arranged in parallel. The water source is groundwater with a lower water temperature. The water temperature of the fine scale fish is suitable for growing at 13 to 20 °C, the most suitable growth water temperature is 13 to 16 °C, and the maximum water temperature shall not exceed 20 °C. The pool water exchange rate should be more than 2 times /hour, and the flow rate should be maintained at 0.02~0.16m/s. The dissolved oxygen in the water is more than 6mg/L, and the ammonia nitrogen should be controlled below 0.0075mg/L. Fish fingerlings with a size of 20 to 50g generally have a stocking density of 150 to 300 fish/m2; fish fingerlings with a size of 100g generally have a stocking density of 150 fish/m2; fish fingerlings with a size of 150g are generally stocked at 100 fish/m2; fish fingerlings with a size of 200g are generally stocked with a stocking density of 75 fish/m2; fish species with a size of 300g are generally stocked at a density of 50 fish/m2.

Lake breeding: It is appropriate to choose waters with dense aquatic grass in lakes (the coverage rate is preferably more than 90%), the water body is clear and transparent, pollution-free, the maximum water temperature in summer is not more than 20 ° C, the dissolved oxygen of the water body is not less than 5mg/L, and the total amount of suspended solids in the water is not higher than 15mg/L for release and proliferation, and there should also be abundant benthic animals, aquatic insects, small fish and shrimp and other bait organisms in the water body. Stocking of juvenile fish and 1-year-old fish species is available. Juvenile fish are 3 to 5 cm in size. The stocking density is 10 to 30 fish/mu. 1-year-old fish species size to about 25g is appropriate, stocking density to 5 to 10 fish / mu is appropriate, fine scale fish have the habit of migrating to the depths of the river in late autumn and early winter, generally in late September to early October to fish, otherwise the fine scale fish will dive into the depths of the lake to prepare for wintering, it is difficult to catch.