A steel tube runs around its perimeter, which is 80 feet wide. The shape of the cage is two wide cones connected at their flat ends. Researchers call it biconical. Last April the Oceanic Institute pumped 70,000 moi fingerlings into the cage. The fish are fed daily through a tube that divers snag and bring to the surface.
Divers are able to enter the cage through a zipper in the mesh.
A crew is on hand about eight hours a day. One of the duties of the divers is to scrub marine growth off the mesh. Hawaii Sea Grant Program director Charles Helsley said that while there are challenges, such as maintaining the structure, there are also benefits. On land, aquaculture can have a fair amount of pumping cost, and wastewater disposal problems. One issue is whether a confined school of fish create a plume of waste down-current from the cage.