Guangdong advances marine ranching with new cage systems

China's push to build a modern "blue granary" is gaining fresh momentum in Guangdong province, where two advanced marine ranching cage systems have completed commissioning, underscoring the province's efforts to expand deep-sea aquaculture and strengthen its marine economy.

The systems, Ganghang 2001 and Ganghang 2002, are China's first pair of hexagonal pile-supported, liftable truss cage systems and are ready for delivery and operation in the waters of Jieshi Bay in Shanwei, Guangdong province, according to Guangzhou Dredging Co Ltd, a subsidiary of China Communications Construction Company Ltd and the project's developer and builder.

Built for Guangdong Provincial Port and Shipping Group Co Ltd, the two systems are part of Guangdong's efforts to advance its "New Maritime Guangdong" initiative, as modern marine ranching has been identified as a key driver of high-quality marine economic growth.

Each cage is designed as a regular hexagon, with a side length of 24.5 meters, a height of 17 meters and a weight of about 900 metric tons. Each unit can provide nearly 20,000 cubic meters of aquaculture water volume, said Xu Yanqing, technical head of the project.

"This is the first truss cage system in China to adopt a hexagonal streamlined structure," Xu said. "It can effectively disperse the impact of wind, waves and currents, reducing vortex formation and wear on the netting."

The cages are equipped with an intelligent lifting system, allowing their operating depth to be adjusted along the pile legs in response to changing sea conditions, according to the company.

The equipment also includes a chilled fresh-feed pelleting and feeding system, which integrates loading, crushing, pelleting, pneumatic conveying and broadcast feeding. The system is expected to improve feed utilization and reduce pollution from feed residue, the company said.

Guangzhou Dredging said it has participated in more than 10 marine ranching projects in recent years, completing six pile-supported cage systems, one semi-submersible cage system and more than 230 reinforced gravity cage systems.

The company is also moving from equipment construction toward full-chain marine ranching services, covering solution design, equipment manufacturing, offshore installation, delivery, operation and maintenance.

"We will not only safeguard this patch of blue, but also move farther into the deep blue," the company said.