Black cockroaches belong to the submarine water-bottom fish, mainly distributed in the western North Pacific. In the Yellow Sea and Bohai Sea in China and the East China Sea, the northern coast has been seen all year round. North Korea, Japan and southern Okhotsk are also distributed.
I. Introduction
1. Biological characteristics 1 Morphological characteristics and distribution. Black crickets are elongated and flat. The body length is generally 20 cm to 30 cm and the weight is 100 g to 300 g. The kiss is more pointed, the mandible is longer than the maxilla, and the two jaws, the vomer and the cheekbone are finely toothed. There is a black line on the outside of the maxilla, the back of the head is low, and the back is pointed. Big eyes high. The interval between the eyes is approximately equal to the eye's eye, and there is a pure spine at the lower edge of the orbital bone. There are missing kkkk in the middle of the dorsal fin, with 13 fin spines and 12 soft strips. Caudal fins rounded. Wearing a fine round scales. Gray and brown on the back and sides, with irregular black markings. Chest and belly gray. The dorsal fins are dark yellow and the rest of the fins are grayish black.
2 living habits. Black cockroaches are more resistant to low temperatures, their optimum temperature range is 8°C to 25°C, and they grow faster at 14°C to 22°C. When the water temperature is 5 °C ~ 6 °C then stop feeding. The lethal temperature is 1 °C.
Black storks like to inhabit shallow sea rock reefs or seaweed groves, do not like light. Before 2nd age, they inhabited the rocky sea area with a water depth of less than 20 meters. The older fishes move along with their growth to the deep sea, and when they reach the bbbb phase, they swim back to the shores with a water depth of 20 to 30 meters. Black storks do not travel long distances. However, in the spring and autumn, with the change of the water temperature, the group can make short-distance travel. Is a carnivorous fish, miscellaneous fish, shrimp, shellfish, cephalopods, etc. can eat. The black sea bream in the Yellow Sea and Bohai Sea mainly eats small fish such as squid, yellow peony, fangshiyun, yujin fish, sardine, and grouper, as well as ridge-tailed brown shrimp, eagle claw shrimp, and cephalopods. Black quail is very bulimia, high stomach fullness, food intake is large, the daily food intake of younger fish can reach 7.5% of body weight, satiety amounted to about 11%.
3 grow. The black storks grow faster. From the offshore cage culture experiment in Shandong, the species of 7 cm to 18 cm in length and 40 gram to 150 gram in weight were placed on July 30 and the average weight was measured on November 15. It measures 25.5 centimeters in length and weighs 485 grams. Continue wintering in the local sea area and continue growing in the following year. Before the 5th instar, the black storks grew fast, declined after the 5th instar, and decreased significantly after the 8th instar. 1 cm to 2 cm seedlings breed up to 250 grams in the second year and 600 grams to 800 grams in the third year. The breeding black quail seedlings reached 400 grams in the second year and 900 grams to 1,000 grams in the third year.
4 breeding habits. Black quail eggs raw fish. The males were between 2nd and 3rd instar. The females were mature from 3rd to 4th in age. The breeding population consisted of 3rd instar to 14th instar. The males were 3rd in 4th instar and 5th in 7th instar. Male and female broodstock were copulated before and after November, after which the eggs were fertilized in the female body and developed into sub-fish. The initial water temperature is about 11°C, the water temperature during the peak period is 13°C～16°C, and the litter of Shandong coastal nearshore is from April to May, and the peak period is mid-May.
The birthplace usually has a smooth flow of water and fresh water in the reef sea area near the shore and inner bay. Sub-fish can swim freely from the mother's output. Initial production of sub-fish is 6.2 mm to 7.2 mm in length. The resulting fish has been actively feeding. Juveniles were all 10.25 mm to 15.00 mm in size, all fins disappeared, hard fins began to appear, and the external appearance was completely similar to adult fish. Juveniles are very active, prey on the initiative and have mutual food. From june to april, young juveniles 30 mm to 50 mm in length can be caught along the coast.
2. Economic traits Black wolfberry, its fresh meat, white, less fat, soft and hard palatability, especially steamed and soup, for everyone's pro-Lai. Due to fast growth and strong adaptability, it is a species for cage culture and factory culture.
3. Status of aquaculture At present, the breeding of black seabream is mainly cage culture, because it can naturally overwinter in the northern sea area, thus reducing the overwintering links, saving part of the cost, and is welcomed by the majority of farmers. In recent years, the scale of breeding has been developed from a few to a few. At the end of 100,000, its prices are between 40 and 50 yuan/kg in the Tianjin and Beijing markets.
4. Analysis of Economic Benefits According to the current situation of breeding on the coast of Shandong, the net cage investment is about 1,000 yuan/ton, the seed is 2 yuan/tail, the breeding cycle is 3 years, and the feed coefficient is 8:
1 Net cage input: 1,000 yuan/only 10 = 10,000 yuan (10 in each group, one person cares)
2 seed input: 2 yuan / tail 500 / cage 10 = 10000 yuan 3 bait cost: 500 / net 10 net 70% 1 kg 80.5 = 14000 yuan 4 staff salary: 10,000 yuan / year 3 years = 30000 yuan 5 Output value: 50070% 1kg 1040 yuan/kg = 140,000 yuan 6 Benefits: 140,000 yuan, 1 million yuan, 1 million yuan, 14,000 yuan, 3 million yuan, 76,000 yuan This shows that the economic benefits are quite substantial The main problem is that the production cycle is long and it takes only 3 years to see the benefits. The capital turnover cycle is slightly longer.
Second, nursery technology
1. broodstock. Artificially cultivated seedlings and naturally-occurring seeds can be used as nursery broodstock. It is also possible to collect wild fish that are about to give birth directly into the production pool, and do not give baits for a short time without giving birth. However, in such cases, the survival rate of the child is sometimes low.
6 to 7 days, the total length of the fish is 6.6 mm or more, and 0.5 to 1/ml of Artemia nauplii is added. From 10th to 12th day, the total length is about 7.5 mm. ～2/ml, from the 25th day to the 26th day, the total length of more than 17 mm began to use the chopped squid and squid with the bait.
During the feeding process, a certain amount of live bait in the pool water must be maintained, and excessive surplus of bait should be controlled at the bottom of the pool by suction. In the early stage of cultivation, 500,000 seedlings of 24 millimeters or so were produced. The requirements for biological feed were approximately 30 billion rotifers, 5.1 billion Artemia nauplii, and 1.7 billion breeding larvae.
Rotifers, Artemia nauplii, and cultivated Artemia need to be fortified prior to feeding (refer to true larvae).
When Japan was reared in the early stage of black seabream, the number of unit water bodies (cubic meters) was 5700 to 10420, and the survival rate was 53%. Practice has proved that the main factor influencing the survival rate of black cockroach nursery is the quality of the first-born fish. The use of young broodstock has a strong vigor and a high survival rate.
2 post-cultivation. When the juveniles were 75 mm to 30 mm in total length, the early breeding was completed. If high-density breeding is continued, the resulting mutual disability will result in massive deaths. Out-of-pool method: Use a compound feed to trap the juvenile fish to one place and suck it out with a siphon tube. The remaining can lower the water level, and the fish can be fished out with a net. The juveniles were transferred to a secondary culture pool or transferred to a sea cage for 2 cultures. Develop 5 cm to 12 cm large size fish species. Breeding ponds and sea boxes can refer to real breeding.
The rearing stocking densities were: full length 30 mm, 5000/m3; total length 40 mm, 2500/m3; full length 50 mm, 1000/m3. Exceeding the above densities can cause significant growth differences due to unbalanced ingestion among individuals, resulting in mutual disability and susceptibility to disease. The bait is mainly fish and shrimp meat with complex vitamins and bait. There are two kinds of bait and they are used alone. The compound feed should gradually increase the particle size of the feed according to the size of the fish in different stages of growth, and use palatability as a principle. The amount of feeding depends on the feeding conditions, which is about 2.5% to 3.0% of the fish's body weight. The ground pool feeding can be fed 4 times a day, sea cage feeding can be fed 2 times to 3 times a day. In the rearing period, sorting should be repeated to avoid individual size differences. Adjusting the amount of stocking to maintain the appropriate density and changing water, the survival rate can be as high as more than 90%.
3 earthen pond nursery. Utilizing the numerous advantageous conditions of coastal ponds in China and combining with the biological characteristics of black sea bream, carrying out seedling cultivation in earthen ponds is a low cost and quick shortcut. Muping District, Yantai City, Shandong Province has accumulated rich experience in breeding seedlings of black earthworms. Specific operations can refer to soil pond nursery.
Third, to develop black locust fast growth, a wide range of temperature resistance, strong adaptability, less fish disease, bait conversion rate, aquaculture technology is simple, and the high price of commercial fish, is the sea cage and earth pond breeding of fine varieties. According to the actual situation in China, the development of earth pond culture should be the mainstay. The small earthen ponds can be used as a rear breeding pond or an intermediate cultivation pond. The large-sized fish species bred can be stocked in large and medium-sized earth ponds after indoor wintering, and the commercial fish weighing 400-500 g can be cultivated in that year. Due to its low resistance to low temperatures (lowest tolerable 0.5°C) and low growth temperature, it is particularly suitable for coastal farming in northern China.
The Japanese sea bream mainly uses sea cages (similar to other sea fish breeding net cages) and stocks about 10 cm in length. The growth of farmed fish is much faster than that of natural fish, and it is generally reached in June the following year. It measures 20 centimeters in length, weighs 160 grams, and has a commercial fish size of 400 grams to 500 grams in the autumn.
Management during the cultivation mainly includes the following aspects:
1. Stocking density. In the case of sea cage culture, the weight 25 g is 150 to 300/m3, 100 g to 45 to 50/m3, 200 g to 23 to 25/m3, 400 g. It is between 14 and 16/m3, and 1000 to 6 to 7/m3.
2. Feed the bait. The bait is mainly low-grade fishes, shrimps, and scraps such as small scads, shrimps, and scallops. Since the optimum temperature range of black cockroaches is 8°C to 25°C, the optimal growth temperature is 14°C to 22°C, so a small amount of feeding is started from 6°C to 7°C, and the feeding is performed 2 times a day at 14°C to 22°C. The daily feeding amount was controlled at 4% to 8% of the body weight. During the wintering period, it gradually decreased and stopped feeding.
3. Water quality adjustment and sorting change network. When the earthen ponds are farmed, the management can refer to the black sea turtles and try their best to maintain good water quality.
When cages are cultured, new nets are replaced in time for contamination and fish growth, and the necessary size sorting is performed in conjunction with network changes. This is the key to improving the survival rate.
IV. Disease Prevention and Control Black quail breeding is in its infancy. The diseases found are the same as those of true crickets and black locusts. There is nothing special about it. The prevention and treatment methods are the same as those of true maggots and black lice. The key is to strictly control the stocking density according to the regulations. Try to feed live bait.
Pesticides-Plant Growth Regulator
Pesticides-Plant Growth Regulator,Hydrogen Cyanamide 50% Solution,Hydrogen Cyanamide 50% Solution 420-04-2,High Effect Hydrogen Cyanamide 50% Solution
Ningxia Darong Chemicals & Metallurgy Co., Ltd. , https://www.darong-cyanamide.com