Abalone Cage Farming: Methods and Characteristics
Abalone is a valuable marine delicacy. In recent years, artificial abalone farming in China has developed rapidly, with the main farming models including factory farming, floating raft suspension farming, and bottom sowing farming. The sunken cage farming model is a new type of abalone farming model that has recently emerged.
Sunken Cage Design
The sunken cage is a reinforced concrete structure. Its external height is 60 cm, the outer circumference diameter is 105 cm, and the inner diameter is 100 cm. The entire sunken cage consists of five parts: (1) The cage body, which is the main part of the sunken cage. The bottom has 7 round holes with a diameter of 16 cm, and the bottom of the side of the cage body also has 8 round holes with a diameter of 4 cm, to facilitate water flow. (2) The cage lid, also a concrete structure, which makes the sunken cage a closed environment. The center of the lid has a feeding port with a diameter of 30 cm. (3) The net sleeve, made of polyethylene net with a mesh size of 0.3 cm to 0.5 cm, is installed on the inner wall of the sunken cage to prevent abalone from escaping. (4) The iron wire support, composed of 8# iron wire, supports the net sleeve. (5) The abalone habitat platform, a concrete structure, is installed inside the net sleeve of the sunken cage for abalone to inhabit. Each sunken cage can hold 600 abalone.
Sunken Cage Placement
The sunken cages are placed in the sea 1 month before seedling release. In addition to meeting the ecological requirements of abalone, the placement site must also meet the following conditions: smooth tidal currents, gravel substrate; small wind and waves; after low tide, the cage body must be exposed 20 cm to 30 cm for farming management.
Seedling Selection and Transportation
The size of abalone seedlings must be above 2 cm. They are required to be uniform in size, without gaps, bright in color, and with fresh and obvious growth marks on the edges of the shell. Such seedlings have good vitality and are suitable for farming.
The best time to purchase seedlings is generally March to April, and August to October is also acceptable. Abalone has strong tolerance to transportation. If the transportation time is less than 2 hours, they can be transported exposed to air; if longer than 2 hours, they can be transported in live water vehicles.
Daily Management
Abalone can be fed bait on the second day after being placed in the cage, entering the normal management stage. During this stage, Sargassum or Gracilaria must be fed once every 12 to 15 days. The amount of bait per sunken cage per feeding is 5 kg to 6 kg. During the peak growth period, 8 kg to 9 kg of bait must be fed each time.
The cages must be thoroughly cleaned once a month, mainly to remove accumulated sand, leftover bait, small shrimp, small crabs, etc. During cleaning, avoid keeping abalone exposed to air for too long, or bumping and injuring or killing them.
Throughout the entire farming period, abalone activity, seawater salinity, pH value, water temperature, etc. must be recorded daily.
Characteristics of Abalone Farming in Sunken Cages
Low investment. The farming scale can be large or small. Small-scale farming can operate with an investment of 10,000 yuan to 20,000 yuan, suitable for ordinary farmers.
Low cost. Compared with factory abalone farming, etc., abalone farming in sunken cages is very low in cost.
Short cycle. From seedling release to harvest takes only 5 months to 6 months.
Strong wind and wave resistance. Cement sunken cages are very sturdy, and when placed on tidal flats they can withstand strong winds and waves.
Low risk. From practice, as long as the survival rate reaches 40%, even if the price drops to 80 yuan to 100 yuan per kg, the cost can still be recovered.