Ultrasonic Anti-Fouling

Ultrasonic anti-fouling systems use piezoelectric transducers bolted to cage frames or net support structures to emit high-frequency sound pulses — typically in the 20-200 kHz range — into the surrounding water. These pulses create microscopic cavitation bubbles and pressure waves at the net surface that disrupt the formation of bacterial biofilms and diatom slime layers. Since biofilm is the essential first stage of the fouling colonisation sequence, preventing it delays or reduces the settlement of macrofouling organisms that follow.

The technology shows genuine promise against soft foulers and early-stage biofilm. Field trials on Norwegian salmon cages have measured 30-50% reductions in slime accumulation on net panels within transducer range. Against hard foulers like acorn barnacles, however, effectiveness drops significantly — cyprid larvae appear less sensitive to ultrasonic disturbance once they commit to settlement. Coverage is another practical challenge: each transducer has an effective radius of only a few metres, so a full cage installation requires multiple units, driving up both capital cost and power consumption.

Fish welfare is an active area of research. Certain ultrasonic frequencies overlap with hearing ranges of salmonids and sea bass, potentially causing stress or avoidance behaviour. Responsible deployment requires frequency selection that balances fouling efficacy with minimal fish disturbance — consult the FAQ section for current guidance on frequency-species interactions. Ultrasonic systems work best as part of a layered approach: suppressing biofilm formation while mechanical or chemical methods handle breakthrough macrofouling. The cost calculator can model transducer installation and energy costs against reduced cleaning frequency for your specific farm site.