Laser device can slay sea lice on farmed salmon noninvasively

Knowing that sea lice are a threat to salmon farms and surrounding sea life, Stingray Marine Solutions AS (Oslo, Norway) has developed a submersible device that they call Optical Delousing, which employs a green laser to help eradicate the parasites noninvasively. Sea lice—which are planktonic and therefore abundant in coastal areas—are destructive, 8–12 mm demons that attach themselves to healthy host salmon and feed off their mucus and skin, with the potential to lower the salmon's immune system and make them susceptible to diseases. Worse still, sea lice can transfer from farmed salmon to wild salmon and threaten the health of wild stocks.

A current method to rid sea lice from farmed salmon involves adding a pesticide branded SLICE (emamectin benzoate) to salmon feed; once consumed, the drug is absorbed into the salmon's tissue and transmitted to the sea lice to kill them off. Unfortunately, however, sea lice are forming a resistance to the drug. Recognizing this, Stingray developed a barrel-shaped, 1.50-m-high, 220-lb device that submerges directly into a salmon farm's net pens and uses an onboard camera vision system with real-time image recognition software to capture images of the lice as salmon swim past the device. Whenever the outer shape of the sea lice is recognized on the salmon's skin, the system's green laser (Jenoptik's JenLas D2.8 532 nm diode-pumped disk laser, which is also used in ophthalmology, laser endoscopy, and dermatology) releases a continuous-wave beam that destroys the tissue of the parasite without damaging the fish.

The company is working on developing additional utilities for the Optical Delousing device, which could enable fewer installations of different types of equipment in salmon farm pens. For more information, please visit http://en.stingray.no.