The World Intellectual Property Organisation has published a patent application and search report for a submersible rotatable cage for fish farming. The application was submitted by Canadian company Open Ocean Systems Inc.
The cage comprises a central axle, a buoyant structure positioned about the central axle, and a netting attached to the buoyant structure.
The buoyant structure rotates about the central axle while the cage is in a submerged position. The cage can form part of a system, which includes a net cleaning apparatus, a tethering mechanism and sweep net, that forms the basis for underwater fish farming.
The patent application and search report may be reviewed via the free WIPO patent search capability.
In the most common setup for fish farming plants, a number of floating net cages are anchored close to shore using buoys and weights to stabilize the cages in the water.
An optimal installation for fish farms of this sort is in sheltered waters such as bays and fjords and these setups often comprise support frames with gangways for operational purposes, such as maintenance and feeding.
Surface cages, however, are sensitive to severe weather conditions, such as high winds, waves and ice, which can be a serious threat in northern areas.
Submersible cages have been suggested and tested. However, these types of cages have not become commercially feasible due to problems with stability, handling and cost. The present invention claims to overcome these limitations.