How to safely get abalone through the summer when farmed in the south
It is understood that abalone has very high requirements for the water temperature of the farming sea area, and its suitable growth water temperature is around 20°C. Once summer arrives, northern varieties such as black abalone and Pacific abalone introduced to the south will die in large numbers because the water temperature is too high, while at this time the water temperature in northern sea areas such as Qingdao is relatively suitable for abalone growth. In recent years, whenever summer comes, many farmers in Fujian send abalone seedlings and nearly finished abalone to Shandong and other places for farming, and then bring the abalone back in November of that year.
Abalone transport uses two methods, dry transport and wet transport. Generally, short-distance and short-duration transport uses the dry method, while long-distance and long-duration transport uses the wet method; plastic boards are usually used as the attachment substrate for abalone during transport, placed in washed and disinfected hard containers, and the abalone to be transported must be selected and held in temporary culture to increase the transport survival rate.
Abalone transport plans and arrangements must be thorough. In the dry transport method, the abalone density must be reasonable, without squeezing each other, ensuring high humidity and low temperature, watering at regular intervals, preventing direct sunlight and rain, placing them in a ventilated and shady place, and delivering them to the destination on schedule. In the wet transport method, the pump must be guaranteed to operate normally, there must be sufficient seawater, the density should be sparse, without overlapping, the water flow should be large, the temperature difference should be small, and feces and debris should be removed in a timely manner; if the transport time is too long, a small amount of feed should be given.
After transport, when the abalone reach the destination, they must go through a period of temporary culture to restore their vitality before being detached and divided for separate farming. For injured abalone, methods such as lowering the water temperature, ultraviolet sterilization, or medication can be used.
Farming juvenile abalone must involve feeding, and the quality of the feed directly affects the growth rate of the abalone. Generally, abalone around 3 mm cannot yet feed on large algae and mainly rely on attached diatoms as food, so no feeding is needed at this time; after growing to 5-6 mm, they begin to also eat tender algae such as Enteromorpha. As the individual grows, they shift to mainly large seaweeds.
The number and amount of feedings in natural sea areas and farming depend on the season. In summer, the water temperature is high, seaweed is prone to rot, the thalli decay and sink to the bottom, ammonia nitrogen in the water increases, and dissolved oxygen decreases, which easily causes deterioration of the culture environment and affects the normal activity of abalone. Therefore, at this time feed once every 2-3 days, and the amount fed should be smaller, with finishing it as the standard. Autumn is the season when abalone grows relatively fast, so sufficient fresh feed needs to be given, once every 4-5 days. In winter, the water temperature is low and the abalone's food intake is small. Fresh algae soaked in water for 7-8 days will not rot, so in winter it is enough to feed once every 8-10 days. Note that each feeding should be carried out after clearing residual feed and abalone excrement and replacing with fresh seawater.
Abalone likes to eat tender algae, and when there is no fresh seaweed, dried algae can be soaked and used as feed. Feeding with a mixture of algae gives better results. Among the algae, wakame, sea intestine weed, kelp, and Sargassum are seaweeds that abalone relatively prefers to eat, with good feed results and fast growth speed. The locally relatively abundant nori, test results show, is not ideal and has a great impact on abalone digestion.
Abalone farming can also involve feeding artificial compound feed. When using it, consideration should be given to the fact that it contains animal protein and is prone to rot when soaked in water, so the timing of feeding should be correspondingly shortened.
In factory-based abalone farming or tunnel abalone farming, the feeding is basically the same as above. The difference is that in factory-based farming or tunnel farming, the water temperature and room temperature are relatively constant, so the feeding times differ somewhat.