Paralichthys lethostigma is a kind of high-quality aquaculture species, which is naturally distributed on the north coast of Florida and Gulf of Mexico and in the Gulf of Mexico. coastal. Its meat is delicious, delicate and smooth, contains a large amount of unsaturated fatty acids and DHA, has a high economic value and nutritional value, as the current domestic farming is very small, the market price is expensive, is a valuable fish, the prospect of freshwater farming is very broad. The variety has a wide salt range, strong disease resistance, high temperature resistance, strong adaptability to the environment, resistance to hypoxia, and high growth rate. Because there is no foreign spotted gingiva breeding industry, it is favored by consumers in the United States, Japan, South Korea and other international markets and has a very good foreign market. Since 2001, our country has introduced and domesticated one after another for artificial breeding. Its breeding history is not long. The Seedling breeding technology of desert spotted gingiva in China has been broken, laying the foundation for breeding and promotion of desert spotted gingiva.
First, biological characteristics
1. Morphological characteristics The desert gingival shape is similar to that of China's brown gingiva. Its shape is flat and oval. Both eyes are on the left side of the head. There are many irregular spots on the body. The body has light brown eyes. The abdomen is light in color and can change with the surrounding environment in order to hide the body and avoid predators. Females grow faster than males and sexual maturity occurs at age 2 (male is generally between 20.3 cm and 25.4 cm, and females are generally between 30.5 cm and 35.6 cm).
2, the temperature requirements Desert spot gums have a wide temperature, tolerance water temperature is 2 °C ~ 36 °C, the normal growth temperature of 17 °C ~ 30 °C, the optimum growth temperature 21 °C ~ 26 °C. In seawater, the spotted gingiva have an appropriate temperature performance from 4°C to 30°C. In freshwater, its temperature can be from 6°C to 32°C. Therefore, the desert gingiva can be found in the southern region, the northern region and the coastal regions. Inland areas are widely farmed.
3. Requirements for salinity Desert spotting gums are broad-salinity fishes, which can be cultured in seawater, brackish water and freshwater. Their ability to adapt to salinity is extremely strong. Their salinity ranges from 0 to 60 ‰. The best salinity is 5‰ to 35‰.
4. The requirements for light intensity require that the culture light intensity should be <2000 Lux, the suitable surface light intensity should be around 700 Lux, the most suitable is 500 Lux, and the bottom light intensity should be >40 Lux.
5, the requirement of dissolved oxygen is suitable dissolved oxygen is 4mg/L ~ 12mg/L, but the best in the saturated state, the most suitable 7mg/L ~ 9mg/L, when the dissolved oxygen can still be eaten at 3mg/L, in 2.5 Feeding will stop at mg/L, and when the dissolved oxygen is below 1.5 mg/L, floating head begins to appear.
6, the requirements of the PH value
The suitable pH range is from 5.5 to 9.5, most preferably from 7.0 to 8.2.
7, the requirements for food The desert spot is a carnivorous fish, mostly in the natural world for small fish to eat, followed by crustaceans, cephalopods, etc., during the day to eat more than at night. The artificial breeding uses chilled fresh fish and shrimps, or special compound feeds for butterflies.
8. The largest individuals of the desert spotted gingiva captured in nature, with a total length of more than 90 cm, a weight of 11 kg or more, a maximum individual life of more than 10 years, and a growth rate of desert gingiva in nature, the fastest in June. From November to November, the growth rate was closely related to the conditions (water temperature, feed) and other conditions. Artificial breeding Under the suitable environmental conditions, fry 6cm ~ 10cm after 6 months to 8 months of culture, weight can reach 500g or more, its growth rate is very good.
Second, pond culture due to desert spot gums strong resistance, strong adaptability to the environment, very suitable for pond culture, farming methods can be monoculture or polyculture.
1. The selection of ponds can be carried out by using existing ponds for dredging and reconstructing. The depth of water is required to be about 1.8m to 2.0m. The water supply and drainage systems are fully equipped, and the water is fresh and pollution-free. The pond area is preferably 2 mu to 5 mu. It is necessary to remove silt from the bottom of the pond, loosen the bottom, and repair the pond. Before clearing the seedlings, it is necessary to thoroughly disinfect the ponds, and it is best to use quicklime (or bleaching powder) to disinfect them. Generally, the dosage per acre can be about 200kg. The whole pool is sprinkled over and over, leaving no dead ends.
2, the choice of seedlings to choose physical health, normal activities, individual uniform seed for the breeding object, the body length is generally about 5cm ~ 10cm, specifications in the best 10cm or more. The selected seed should be desalted, and the salinity should be equal to the salinity of the culture pond. When desalinating, the salinity can be reduced every other day to gradually reduce the salinity.
3. Stocking Density and Time of Seedling Emergence The stocking density of pond culture is generally about 800 per acre. Under the conditions of pond substratum loosening and oxygenation, the stocking density can reach 1,000 to 1,500 per acre. When the water temperature reaches 15°C or more, the water can be put in when the water temperature exceeds 18°C.
4. Feeding pond management ponds can feed fresh wild fish and shrimps, or feed special artificial feed for alfalfa, feeding 2 times to 3 times a day, and the daily amount of fresh wet bait is the weight of fish. From 7% to 10%, the daily feed rate of artificial compound feed is 3% to 5% of the fish's body weight. The specific feeding amount should be based on the fish's activity, food intake, weather conditions, and water quality.
5, water quality regulation of pond water can not be a large row of large aquaculture, adequate water, it is best to change the water once every 15 days, each time the amount of water exchange for the pool of water 1/4 to 1/3, to maintain the pond The water quality and color of the water are refreshing, and the transparency is about 30cm. The dissolved oxygen is sufficient. During the entire cultivation process, the water temperature, dissolved oxygen, and pH should be measured at regular intervals. During the high temperature season, the water level should be raised to increase the exchange of water.
6, daily management of desert spotted gingiva breeding process, should adhere to the daily tour pool, observe the fish activity, feeding conditions, pay attention to whether the fish body abnormal changes, to grasp a reasonable amount of feeding, reduce residual bait, regular Biopharmaceutical disinfection and bait feeding prevent diseases.
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