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1 Natural Conditions at the Fence The Zaobaoshan Reservoir is a plain medium-sized reservoir with a water storage capacity of 43.5 million m3. The aquaculture water area is 1000 ha. The annual water level during the breeding period is 2 to 4 m, the average water depth is 4.3 m, the fence area is 0.4 ha, and the maximum water depth is 5.4 m. The average water depth is 2.8m. The water and grass in the enclosure are rich, the coverage rate is nearly 100%, and the water transparency during the cultivation is 0.8-2.0m. There is a small amount of farmland and rural domestic water influx in the south of the fenced site, and there is no industrial pollution.
2 Materials and Methods
2.1 The fence material block consists of inner and outer double-layer meshes. The height of the mesh is 6m. The inner layer mesh is woven with 22 polythene wires. The mesh size is 2a=3cm. The outer layer mesh is braided with 34 polyethylene threads. The size of the frame is 2a=8cm; the frame of the supporting net is water fir and bamboo, and the length is not shorter than 7.5m; the sinker is a gabion and is made of 34 vinyl wires and woven into 2a=6cm. Mesh bag, made of pebbles, mesh bag diameter 8cm, pebble diameter not less than 4cm.
2.2 Fish source and stocking experiments The selected carp seedlings were all Cockroach crucian carp. The fish fingerlings were purchased from the Dongting Lake fishermen and were all robust and non-injured fish caught by net foil and bamboo cages. It was transported three times in succession on December 27th, 30th and January 8th, 1996. The total weight was 332.8kg, the specification was between 50 and 120g/tail, a total of 4035 tails, and the average tail weight was 80g. Each time the fish species were returned, they were soaked with 3% salt solution for 5 to 10 minutes and then put into the fence water.
2.3 Feeding and Management
2.3.1 Bait Fish Source: Bait fish are obtained in two ways. The first is to use ponds to culture fish species such as cockroaches, cockroaches, and clams The second is the use of dense-eye cages to trap small wild fish such as cockroaches, cockroaches, and kisses from the reservoir. The body length of the pupa, pupa, and bream that are fed is about 50% of the body length of the bream, while other baitfish are regulated to control their mouth height that is lower than that of the bream. The live fish with a full selection of bait fish are sterilized with 3% salt water and fed. In addition, there is a certain amount of buckwheat cakes and wheat bran in the fenced waters all year round to feed the bait fish.
2.3.2 Feeding of bait fish: After the catfish species are released, feed bait fish at the same time. Feeding amount and feeding time of bait fish depend on water temperature and weather. Feeding amount in high temperature season is 15 to 20% of carp weight, feeding once every 7 days; feeding in low temperature season is 5~ 15%, feeding once every 10-15 days. Each time a new bait fish is fed, there is a certain amount of remaining bait fish that was last fed in the fenced waters.
2.3.3 Daily management: First, sample weighing. At the end of each month, the net was cast (afterwards, the carp was used to trap "flower baskets"). Samples of carp were caught and their growth was observed and weighed to determine the feed amount of the bait fish in the next stage. The second is to prevent and treat disease. Every half month, copper sulphate and ferrous sulphate mixture (5:2) and bleaching powder are used to change bags to control common diseases of carp. The third is to insist on daily morning and evening patrols, often picking up debris on the side of the net, cleaning, checking nets, and fixing loopholes in time. The fourth is to make a diary and record the growth, activity and management measures of the eel every day.
2.4 adult fishing
On December 20th and 24th, 1997, HGL-1 pulsed electric smasher, fish catcher and trawl net were used for fishing to try to ensure that the captured goods were fresh and live. The amount of capture on the second day accounted for about 70% of the total output. On December 27, it switched to trawling. Through a total of three days and eight times of net fishing, the catch rate of carp in the fenced area reached over 97%. On December 31st, the waters in the fence were observed and only a small amount of carp was found in individual mud in the deep water.
3 Results Through a year of fencing raise trials, a total of 3946 fish tails were caught, 2183.4kg, the average size of 553.3g/tail, the survival rate was 86.46%, the population gain multiple was 6.77 times, and the feed coefficient was 5.8. The output value reached 127947 yuan and net profit was 72,208.4 yuan.
4 Discussion
4.1 The library has good water quality, and the water body is rich in dissolved oxygen. As long as the rich fence area of ​​aquatic plants is selected, good natural environment conditions can be created for the habitat, predation, and growth of carp. The experiment shows that the farmed carp in the Kuqin Fence is, in the case of adequate feed and palatable food, a kind of commercial carp farming method with less investment, high efficiency, quick response and practical and feasible technical route.
4.2 The weight of the commercial carp caught in the test is between 0.48 and 1.2kg, which is generally larger than the standard. The selling price of the carp is higher than that of the standard carcass (customer's specifications in the market: 0.45-0.75kg per tail). It is much lower, which increases both costs and benefits. Therefore, it is necessary to grasp the specifications for catching and catching of adult fish by controlling seed size, breeding cycle, etc. In addition, the experiment tried to use a “flower basket†to trap the squid, and this method can also be used to trap and catch the squid that has “reached the standard†in order to improve the breeding efficiency.
4.3 The stocking density of this experiment is 10,500 tails/ha, which is determined by reference to the stocking density of the single-tailed sturgeon in the pond. The result of the test is that the population gain multiple of carp is 6.77, and the individual size of commercial carp is generally larger, indicating that the stocking density of the carp is relatively small. Therefore, in the case of a suitable environment and a sufficient amount of bait fish, the stocking densities of the larvae in the pond can be increased. In the experiment, the feed coefficient reached 5.8, which was higher than the fish feed ratio of about 4.5 for the cage-raised cod fishing group. This may be related to the increase of energy consumption due to the increase of the activity space and the feeding intensity of the cod. It may also be related to the fact that the size of some bait fish in the initial stage of cultivation is too small to escape from the blockage. Therefore, it is advisable to raise the fish of the same size in the fence raising and the area of ​​the fence can be reduced, or artificially use the mesh to divide the area within the fence to limit the space for fish activities and increase the utilization rate of the food.
Catfish farming technology series of literature appreciation (3)
---- Cultured squid test in squid fencing The squid (Siniperca chuatsi) is a precious carnivorous economic fish that has been favored by consumers because of its delicate meat and delicious taste. From December 1996 to December 1998, the author conducted a trial of commercial fish farming in the reservoir of the Heyeba of the Lubaoshan Reservoir in Minjiang, Hunan Province, and achieved good results.