Australia SeaFisher fish cage system consists of 12 cubic cages anchored to the seabed, which can sink to a depth of 20 m to keep them safe during storms.
The SeaFisher system consists of 12 fish cages that float near the surface when waves are not too high. Photo: University of Queensland
A team led by Professor Chien Ming Wang of the University of Queensland and Professor Joerg Baumeister of Griffith University developed SeaFisher, a storm-resistant offshore fish cage system, New Atlas reported on March 7. The project was commissioned by Australia's Blue Economy Cooperative Research Centre. The new study was published in the journal Marine Science and Engineering.
Each SeaFisher system is 120 m long and consists of 12 polyester mesh cubes, spaced evenly in two rows. The cages are made from lightweight, high-density polyethylene tubes that are linked together. The entire system is held in place by a suction anchor at the front of the system. This is the only connection point to the seabed. This allows the SeaFisher to continuously rotate around the anchor to stay in the direction of the waves. A fender at the front helps deflect incoming debris.
If the waves aren’t too big, SeaFisher will still float near the surface. But when the weather starts to get worse, water is pumped into the system’s polyethylene tubes. This allows SeaFisher to sink to a maximum depth of 20 meters and stay there to ride out the storm safely. The cages have a mesh cover over them, so the fish remain inside as SeaFisher sinks. When the storm passes, water is pumped out of the tubes, helping the system to float again.
The team is testing small prototypes, and will eventually build full-size ones. Each SeaFisher system is estimated to cost about $6 million, less than many current offshore fish farms. The team hopes the system will have a relatively short payback period.
“We estimate that each cubic cage can hold about 24,000 adult fish weighing 5 kg. The system can be used to grow multiple fish species side by side, or even adapted to grow seaweed, using waste from fish cages to provide nutrients for plants,” said Wang.
Thu Thao (According to New Atlas )
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