Underwater Robots · Part of The Humanoid Group

Drones for Fish Farms

Fish farms were quick to adopt compact underwater drones, using them to check nets and moorings between diver visits. This guide covers the jobs they do, how farmed salmon react to a vehicle and where autonomy research is heading.

By Kenji Nakamura · Updated October 2026

Inspection duties behind the dives

Standard Norge notes that Norway's Regulation on requirements for technical standards for aquaculture farms for fish in the ocean, lakes and watercourses (NYTEK22) refers to NS 9415 for site surveys, farms and their main components. The standard calls for a user handbook covering inspection and maintenance, which is where a drone earns its keep. Routine dives let staff look along net walls for holes and wear, check where ropes and chains meet the cage, and spot growth building on the netting. Treat each dive as an entry in that handbook regime: note the cage, the depths covered, what was found and what action followed, so the footage supports the farm's formal duties.

How salmon react to a vehicle

Fish behaviour affects both welfare and footage. A study in Aquaculture by SINTEF Ocean and NTNU tested six object designs in sea cages and found that farmed Atlantic salmon kept greater distances from larger objects, and from yellow objects than from white ones, with an average avoidance distance of 3.8 body lengths once fish size was taken into account. For a farm, that suggests a smaller, paler vehicle may disturb the shoal less and get closer views. Enter a cage slowly, avoid switching lights on abruptly in front of the fish, and ask the maker whether hull colour or light intensity can be changed before you equip several sites.

Autonomy research for cage inspection

Most farm drones today are piloted, but research is pushing towards vehicles that plan their own dives. CageReporter, a project led by SINTEF Ocean with funding from the Research Council of Norway, aims to develop autonomous functions for adaptive mission planning so that a vehicle can gather high-quality data from the cage space. Its targets include detecting abnormal fish behaviour, inspecting nets and mapping water quality, and it aims to cut the cost of such systems by a factor of 5 to 10 compared with conventional technology. Treat these as research goals, and ask any supplier which autonomous features have been proven on working farms.

Fitting dives into the working day

A drone is one more piece of equipment on a busy site, so plan where it fits. Schedule inspection dives away from feeding, lice treatments, crowding and well-boat visits, when currents, cranes and moving nets make close work risky and footage less useful. Agree with the site manager who may launch, from which walkway or boat, and how the pilot will talk to anyone working on the cage above. Keep the tether clear of mooring lines and lift it out before any vessel manoeuvres nearby. On sites with many cages, vary the order of inspections so the same pen is not always checked at the end of a tiring shift.

Sources and further reading

Farmed Atlantic salmon (Salmo salar L.) avoid intrusive objects in cages: the influence of object shape, size and colour, and fish length — Aquaculture (SINTEF Ocean and NTNU), via SINTEF.
Sea-cage trial showing how far farmed salmon keep from objects of different size, shape and colour.
CageReporter — SINTEF Ocean.
Research project on autonomous underwater vehicles that inspect nets, watch fish behaviour and map water quality in cages.
NS 9415 Floating aquaculture farms: site survey, design, execution and use — Standard Norge.
Norwegian standard for fish farm structures, including inspection and maintenance duties set out in user handbooks.

Common questions

Can an underwater drone find holes in a fish farm net?

Yes, a camera-equipped drone can show holes, tears and worn patches on net walls, though visibility, current and fish density limit what you see. Pair regular drone checks with diver inspections or net-cleaning visits for areas that are hard to reach.

Do fish farms need permission to use underwater drones?

Rules differ by country, so check your site licence conditions, biosecurity plan and local maritime rules, and tell your insurer. Take extra care when a vehicle has been used at another farm, because equipment moving between sites can carry disease.

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