This 4,000-tonne Atlantic salmon operation in Hordaland, western Norway, had relied on standard nylon nets with fortnightly in-situ disc cleaning throughout its production history. Despite consistent cleaning schedules, the farm experienced persistent fouling-related problems: dissolved oxygen levels inside cages dropped below 6 mg/L during peak fouling months (July-September), feed conversion ratios worsened by approximately 12 percent during late summer, and net replacement costs averaged 180,000 euros annually due to fouling-accelerated wear on nylon mesh.
In 2018, the operation trialled a hybrid approach on four of its twelve cages, replacing nylon nets with copper-alloy mesh panels on the lower two-thirds of each cage while retaining nylon on the upper section (which is easier to access for cleaning). Weekly in-situ cleaning was maintained on the nylon portions only. Over two full 18-month production cycles, the copper-hybrid cages showed 85 percent less total fouling biomass than all-nylon control cages. Net cleaning costs for the hybrid cages fell by 40 percent, and dissolved oxygen remained above 7 mg/L throughout the fouling season. The copper panels showed no measurable degradation after 36 months of continuous deployment.
This site is marked on the aquaculture farm map with regional fouling intensity data. For a detailed cost-benefit analysis of copper alloy nets, see copper nets versus silicone coatings. The biofouling cost calculator can model savings from similar hybrid configurations, and the solutions comparison tool evaluates all available anti-fouling methods side by side.
Outcomes
Implemented integrated management combining copper-alloy net panels with weekly in-situ cleaning. Reduced biofouling mass by 85% compared to untreated nylon nets. Net cleaning costs decreased by 40% over a 2-year production cycle.