Net cleaning technology has evolved dramatically over the past two decades, but the choice between manual and automated systems still depends on farm scale, site conditions, and budget. The anti-fouling methods comparison rates the main approaches side by side.
Manual cleaning covers everything from diver-operated pressure washers to nets hauled onto service vessels and cleaned on deck. It is labour-intensive but flexible. Divers can inspect and target specific fouled areas, repair net damage during the cleaning operation, and adapt to unusual conditions. For small-scale farms with a handful of cages, or for shellfish operations where cage nets are not involved, manual methods often remain the most practical option. The downsides are speed (a diver team might spend an entire day on one large cage), safety risks in cold or rough water, and inconsistent results depending on operator skill.
Automated in-situ cleaning machines changed the economics for larger farms. These devices — typically disc cleaners or high-pressure washer heads mounted on a frame — are lowered onto the net panel and guided around the cage perimeter while fish remain inside. Cleaning time drops to 2-4 hours per cage. Results are more consistent because the machine maintains constant pressure and coverage. The major suppliers (companies in Norway, Scotland, and Australia lead this market) offer models suitable for cages from 80m to 200m circumference.
ROV-based cleaning represents the latest generation. Remotely operated vehicles fitted with cleaning heads can reach depths of 30 metres or more, operate in strong currents that would be unsafe for divers, and provide real-time camera footage of the cleaning process. The capital investment is substantial — a purpose-built cleaning ROV with control system and support equipment can exceed one million euros — but for offshore and exposed sites, ROVs may be the only viable cleaning option.
How this breaks down by farm type: small farms and shellfish operations lean toward manual methods. Medium-scale coastal salmon farms typically invest in in-situ disc cleaners, either purchasing their own or hiring specialist cleaning contractors. Large and offshore operations are moving toward ROV systems that can handle deeper nets and harsher conditions.
Regardless of which method you use, when you clean matters as much as how. Norwegian farm data consistently shows that hitting fouling at the hydroid and early mussel stage — before heavy barnacle encrustation sets in — cuts net damage, shortens cleaning time, and dumps less debris into the water. Our fouling season calendar helps you plan the timing. Clean early, clean often.