Cage culture technique of golden Pomfret

Golden Pomfret, also known as Pomfret ovum, Pomfret, etc., is one of the valuable marine economic fishes along the southern coast of the family Pomfret. China's Taiwan and Hainan have successfully raised seedlings, and a considerable number of them have been sold back to Guangdong and Fujian for cage feeding. There are mainly two modes of cage culture and pond culture. Let's take a look at the cage culture technology of Pomfret.

Sea area selection

The cage of Pomfret should be selected in the sea area where there is a certain wind barrier or the wind and waves are relatively small, the flow is smooth, the water exchange is sufficient, it is not affected by the inner harbor fresh water and pollution sources, the water quality is fresh and the water quality environment is relatively stable. The water depth is generally required to be 10-15 meters (after ebb tide). If it is a deep-water cage, it can be set in a sea area with a water depth of more than 20 meters. Generally, at the lowest tide, the distance between the bottom of the cage and the bottom of the sea should be at least 2 meters. In order to ensure the success of aquaculture, the water quality of the aquaculture area should meet the following conditions: salinity 20 ~ 30 ‰, water temperature 1832 ℃, pH 7.9, transparency 815m, dissolved oxygen more than 5mg / L.

Cage preparation

The cage for raising Pomfret is generally made of wire made of polyethylene material. The mesh is 2.5cm to 3.0cm. The size of the cage can be adjusted according to the size and actual situation of the fry, ranging from 3 × 3 × 4 m to 4 × 4 × 4 m. With the popularization and application of deep-sea cage, it has been proved that Pomfret is also suitable for this kind of cage culture. Therefore, in deep-sea areas, deep-water cages made of high-strength polyethylene (PE) with a diameter of more than 20 meters can be used for farming. According to the size of the cage and the different conditions of the tidal current and waves, a single cage can be fixed at a single point, or multiple cages can form a net row, and the net row composed of multiple cages should maintain a suitable distance, which is generally required to be more than 3 meters, in order to ensure the smooth flow of water.

Fish stocking

The release time of Pomfret is from April to May every year, and the stocking specification is 2cm. When the water temperature rises and stabilizes above 18 ℃, it is the suitable release time for fish species. The stocking density of Pomfret should be flexibly controlled according to the water quality and environmental conditions in the sea area, the level of culture technology and daily management, the source of bait and the requirements of yield and specifications. Generally speaking, if you want to harvest as soon as possible, fish fry with a body length of about 10 cm can be put into 40-50 fish per cubic meter of water. If you are not in a hurry to harvest, you can appropriately increase the culture density. Fish fry should be disinfected before stocking to kill pathogens and parasites. after stocking, the early nutrition, strong fry and anti-stress ability should be strengthened.

Feeding management

1. Feed selection: Golden Pomfret is a carnivorous fish. In the past, minced fresh mixed fish was mainly used for feeding, but it can also be fed with formula feed throughout the process and have a better culture effect. The expanded formula feed of high-grade marine fish is widely used in the cage culture of Pomfret.

2. Feed feeding: the golden Pomfret has a large amount of food and fast digestion. Under the condition of artificial feeding, if you stay for a short time after feeding, if you re-feed its favorite food, it will still compete fiercely. Therefore, the daily feeding amount can be controlled at more than 20% of the fish body weight in June, July and August, when the water temperature is suitable for its growth, and can be appropriately reduced in other months when the water temperature is low. There are also some breeders who, in order to make them grow rapidly and compress their growth cycle, increase their daily feed intake to 40% of their body weight by increasing the feeding times in the high temperature season.

3. Daily management: the daily management of cage culture should be "five diligence and one detail", that is, diligent observation, diligent inspection, diligent inspection, diligent washing and disease prevention, patient and meticulous bait, and prevention of accidents such as strong wind, pollution, man-made and so on. The farmed golden Pomfret should be inspected frequently, and attention should be paid to observing the activity of fish schools, water color, water quality and so on. Generally, water temperature and air temperature should be measured every morning, middle and evening, PH value should be measured once a week, and transparency should be measured twice a week. The body length and weight of Pomfret were measured every 15 to 20 days or so to grasp its growth rate and regularity, to determine the amount of feed, and to check whether there were diseases in Pomfret.

4. Cage management: the cleaning and replacement of cages in cage culture is a very important work. When the cage system is soaked in sea water for a certain period of time, shellfish such as barnacles, oysters and all kinds of algae will be attached more or less. This hinders the smooth flow of water and the exchange of water to a certain extent, thus affecting the growth of Pomfret and aggravating the sinking force of the cage system. Therefore, in the daily management work, it is necessary to change the net and clean according to the biomass attached to the cage and the situation of fish culture. Generally change the net every 3 to 6 months, when changing the net, you must prevent farmed fish from getting involved in the net corner to cause bruising and death, and the operation should be meticulous. Cage cleaning can be carried out by means of high-pressure water gun spray washing, fresh water soaking, exposure and so on.

5. Safety in production: the safety of the cage should be checked frequently in the process of cultivating Pomfret in marine cages. The method of surface and underwater (diving) observation should be used to often check the attachment of the cage system, whether the cage is damaged, whether all kinds of cable bones are worn, whether the fixed facilities of the cage system are firm and hard, etc., and take corresponding measures to deal with the problems in time to prevent them from happening. Before the occurrence of disastrous weather, measures should be taken to cover the net, check and adjust the tension of anchors and piles, strengthen the pulling and fixing ropes of cages, check the firmness of frames, anchors and piles, and take precautions such as the migration of aquaculture personnel and ships to safe havens.

6. timely fishing: the artificially hatched golden Pomfret fry in that year are generally put in about 10 centimeters, and the commercial specifications of more than 400 grams can be reached in 4 or 5 months. Generally speaking, the market price of golden Pomfret is better when the market price is more than 600g / tail, so it is recommended to harvest at this time. In addition, breeders can determine the starting time or release specifications according to the growth of golden Pomfret and market forecasts, in order to maximize profits.