Cage cultivation techniques of Pseudosciaena Crocea fingerling

I. the setting of cages

1. The flow velocity of the selected sea area is generally less than 1 m / s, and the flow direction is straight and stable, avoiding being set in the sea area with migratory cyclone. At low tide, the bottom of the box should be more than 1.5 meters from the bottom of the sea. The surface water temperature of the sea area is 7: 30 ℃, the salinity is 12: 32, and the transparency is between 0.2 and 3.0 meters.

two。 Selection of cage specifications at present, the cages for cultivating Pseudosciaena Crocea fingerlings are all floating cages, that is, they are suspended on 10 wooden frames of 5 m × 5 m. Fish species with a size of 4cm and 5cm generally use a nodular mesh with an eye length of 5mm and 8mm, while those with an eye length of more than 5cm use a nodular mesh with an eye length of 10mm.

3. The cage frame is fixed by piles in the direction of tidal current with 3000mm 5000 wire polyethylene cable. There are two ways to hang the cage on the frame: one is in the slow current sea area, the cage is hung directly in the frame, and then the four corners of the box are hung with sand bags, known as the "soft box"; the other is in the rapids sea area, the four corners of the cage are hung on the hexahedral frame welded with galvanized pipe, called "hard box", this kind of cage can not only block the current, but also maintain the shape of the cage, in order to prevent the fish from being scratched by the net coat.

2. Stocking of fish species

1. At present, there are three main ways to transport large yellow croaker species: first, oxygen transport in plastic bags, which requires the size of fish species to be less than 2.5 cm, and to maintain a low temperature; second, live water ship transport, fish species specifications are required to be more than 3 cm; third, continuous inflatable transportation is carried out in ordinary cabins. Stop feeding before transportation, and require neat specifications, strong physique and good vitality.

two。 The time to put the fish species into the cage should be during the neap tide, preferably when the flat tide slows down. When it is low in winter and spring, it is necessary to choose a sunny afternoon, and in the hot season, it is appropriate to choose the morning and evening when the weather is cool. Fish species of different sizes should choose cages of different sizes, and neat fish species should be kept in the same cage so as not to kill each other. Generally speaking, the stocking density of fish with a size of 3 cm is about 1000 pieces / cubic meter.

III. Breeding of fish species

1. The feed species of Pseudosciaena Crocea is carnivorous fish. the fish that have just entered the box can be fed with seashells minced meat and artificial formula feed. More than 25 grams of fish can be fed directly to chopped pieces of fish.

two。 Because the feeding time interval of Pseudosciaena Crocea is slow and small, it is necessary to adhere to the method of feeding slowly in the process of breeding. Fish species of less than 30 mm are fed 6-8 times a day when they first enter the box, and the number of times is gradually reduced according to their growth. As the fish feed better in the morning and evening, the feeding interval can be appropriately shortened. When the sun is strong at noon, the fish generally do not float and feed, so the feeding time can be lengthened appropriately.

3. In the method of baiting, the bait should be fixed at a fixed point and paddle with hands first, so that the fish can form the habit of floating and feeding in the cluster. first, cast quickly in the cluster, and then continue to feed a small amount around when a large number of fish are full and scattered or sinking, so that weak fish can also eat bait. Sometimes, due to environmental and climate change, fish species only feed in the middle layer. The feeding amount should be controlled according to the previous feeding situation and the "cackle" sound issued during the fish feeding. If the current is too fast, it should not be fed.

IV. Daily management

1. Due to the small mesh in the fish breeding stage, the cage will attach attachments after a period of time, resulting in mesh blockage, especially in the high temperature season, if you use a screen mesh of less than 40 mesh, it is easy to be blocked by attachments, resulting in the anoxic death of fish species in the box, so it is necessary to often check the mesh blockage and change the net clothes in time. In general, the net clothing below 5mm mesh in the high temperature season should be changed every neap tide, and the specifications of fish fry should be checked and screened. In order to prevent fish injury and eliminate pathogens, formalin can be used for fish disinfection in the box change. if it is found that the vitality of the fish is declining, full or the current is fast, it is not suitable to change the box.

two。 When the current is fast, we should pay attention to observe the reduction of cage capacity and the growth dynamics of fish species, and check whether the cage rope is broken and whether the sunken son is displaced. If the fish species do not float and feed in groups when no special reasons are found, and the unique "gurgling" sound of Pseudosciaena Crocea is not heard, we should consider whether the cage is damaged or disease occurs, and timely measures should be taken. If there are many seabirds in the sea area, put a net cover on the cage.

3. Environmental factors such as water temperature, specific gravity, transparency and flow should be observed regularly every day, and the cluster, feeding, disease and death of fish species should be observed, and detailed production records and medication logs should be made. summarize the causes of seasonal disease and take corresponding measures.