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       To withstand the high energy offshore environment, farms must be built to be more robust than those inshore. However, the design of the offshore technology is developing rapidly, aimed at reducing cost and maintenance.

While the ranching systems currently used for tuna use open net cages at the surface of the sea (as is done also in salmon farming), the offshore technology usually uses submersible cagesThese large rigid cages – each one able to hold many thousands of fish – are anchored on the sea floor, but can move up and down the water column. They are attached to buoys on the surface which frequently contain a mechanism for feeding and storage for equipment Similar technology is being used in waters near the Bahamas, China, the Philippines, Portugal, Puerto Rico, and Spain.By submerging cages or shellfish culture systems, wave effects are minimized and interference with boating and shipping is reduced Offshore farms can be made more efficient and safer if remote control is used,and technologies such as an 18-tonne buoy that feeds and monitors fish automatically over long periods are being developed.

Existing offshore structures

       Multi-functional use of offshore waters can lead to more sustainable aquaculture "in areas that can be simultaneously used for other activities such as energy production".Operations for finfish and shellfish are being developed. For example the Hubb-Sea World Research Institutes’ project to convert a retired oil platform 10 nm off the southern California coast to an experimental offshore aquaculture facility. The institute plans to grow mussels and red abalone on the actual platform, as well as white seabass, striped bass, bluefin tuna, California halibut and California yellowtail in floating cages.

Integrated multi-trophic aquaculture

       Integrated multi-trophic aquaculture (IMTA), or polyculture, occurs when species which must be fed, such as finfish, are cultured alongside species which can feed on dissolved nutrients, such as seaweeds, or organic wastes, such as suspension feeders and deposit feeders.This sustainable method could solve several problems with offshore aquaculture.The method is being pioneered in Spain, Canada, and elsewhere.

Roaming cages

      Roaming cages have been envisioned as the "next generation technology" for offshore aquaculture.These are large mobile cages powered by thrusters and able to take advantage of ocean currents.One idea is that juvenile tuna, starting out in mobile cages in Mexico, could reach Japan after a few months, matured and ready for the market.^[1] However, implementing such ideas will have regulatory and legal implications.