How to prevent and treat gas bubble disease in abalone? Farmers need to master these methods
[Clinical symptoms] In diseased abalone, the suction ability decreases or they even lose the ability to attach completely, and food intake drops sharply or they even stop feeding. The abalone body floats on the water surface, the pigment at the mouth area degenerates, and the radula becomes abnormally dilated. Dissection shows bubbles in the epithelial tissue, throughout the body muscles and connective tissues, and gas embolism also occurs in the blood vessels, the vacuoles in blood cells enlarge, and the internal organs become swollen.
[Etiology and epidemic situation] There is still no relatively consistent view on the cause of this disease to date. Some researchers believe it is caused by juvenile and young abalone not yet being fully adapted to artificial compound feed, which disrupts the original microbial system in the digestive tract; other researchers believe that under strong light and poor water flow, the fresh seaweed fed to them produces excessive dissolved oxygen through photosynthesis, causing the disease in abalone; still other researchers believe it is pathogenic and caused by infection with certain pathogenic bacteria. Since the late 1980s, this disease has occurred from time to time in seedling production units in China, and it is one of the common diseases of juvenile and young abalone during the 1 to 2 months after stripping; abalone seedlings in the intermediate rearing stage may also sometimes develop the disease. This disease mainly occurs in high-temperature seasons, and the incidence is relatively low in low-temperature seasons. After onset, it spreads relatively quickly, affects a wide area, and causes a relatively large number of deaths, and may cause extremely serious consequences for seedling production units.
[Prevention and control measures] In daily feeding, strictly follow the “four fixed” principles, and also note: (1) When feeding large amounts of fresh seaweed, avoid strong light exposure and increase the water flow rate. (2) If abalone indigestion caused by feeding artificial compound feed leads to fermentation and then the production of bubbles, as long as the bubbles are punctured to release the gas, the diseased abalone can slowly recover on their own. In addition, suitable palatable bait can be chosen as a replacement. (3) After the disease is discovered, promptly transfer the diseased abalone to fresh seawater for temporary rearing and increase the flowing water volume.