Photo credit: Magd Al-Bawaab (Egypt)
Technical review: Abdel Rahman El Gamal (Founder of the website)
There are several species of scallop in China; two of which are widely farmed (Bay scallop, Argopecten irradians and Japanese scallop, Patinopecten yessoensis). Both species enjoy high growth rate in addition to their tolerance and performance under different environmental conditions especially in regard to temperature and salinity. Because scallops are filter feeders, the chosen culture sites should ensure an abundance of natural food, adequate of water velocity, and minimum to no silt or pollution.
The photos show the grow-out of scallop whereas the juvenile scallops (shell height 5 mm) are reared to marketable size.
As shown in the photos, lantern cages are used in the grow-out of scallop. These cages have been found to be the most economical, durable and easier to handle. The cages are net tube woven with 6–12 ply polyethylene thread, separated into 7–8 chambers by plastic discs of 30 cm diameter with some round holes on them. There is a space of 15 cm between every two discs. The cage has two layers of netting, the inner of 2–3 cm mesh and the outer of 1–3 cm mesh. The number of chambers depends on the depth of the water. The cage is generally about 1.4–1.5 m in height. An attached photo show the making of lantern cages as required by the culture of scallop.
About 25–30 juveniles are usually stocked in each chamber of the cage. When the scallops grow to 2–5 cm in shell length, the outer layer is removed. The removal of the outer layer also helps in getting rid of the fouling organisms.
During the grow-out season that takes 6-9 months, the fouling organisms should be continuously removed. Similarly, with the growth of the scallops, the flotation capability of the main raft lines must be increased and the hang links should be checked regularly to prevent the cages from touching the sea bottom.
References: An overview of China’s aquaculture – 2010, FAO, 1991, Training manual on breeding and culture of scallop and sea cucumber in China, WIKIPEDIA