High-Pressure Water Washing

High-pressure water washing uses jets at 100-200 bar to strip fouling organisms from nets, cage frames, longlines, and shellfish growing equipment. The technique works on everything from slippery biofilm to cemented acorn barnacles, making it one of the most versatile mechanical cleaning options available. Equipment ranges from handheld lance systems costing a few thousand euros to truck-mounted units with heated water capability for larger shore-based operations.

In practice, pressure washing is most commonly applied to nets and trays that have been lifted out of the water for servicing. Salmon farms typically rotate net panels on a scheduled cycle — one set in the water, another ashore being cleaned and repaired. Shellfish growers in France and Ireland use pressure washers between growing cycles to strip fouled bags and trestles before restocking. The method leaves zero chemical residue and the removed material can be collected and disposed of properly, unlike in-situ methods that release debris into the marine environment.

The main drawback is labour. Large-scale operations with dozens of nets find pressure washing time-consuming and physically demanding, which is why many have shifted toward in-situ robotic cleaners for routine maintenance while reserving pressure washing for periodic deep cleans ashore. Excessive pressure also damages net coatings and weakens fibre integrity over repeated treatments. The methods comparison charts cleaning speed against cost and effectiveness across all mechanical approaches. For farms balancing manual labour costs against equipment investment, the cost calculator provides side-by-side projections. See also the glossary for technical terms used in fouling management.