Ultrasonic anti-fouling for aquaculture

One of the biggest challenges in the Norwegian fish farming industry is the control of biofouling, which is the accumulation and growth of marine organisms on submerged surfaces. Not only cage nets, but also any other submerged surface, such as the feed barge and cage structures, need to be cleaned regularly. Biofouling can lead to reduced fish health, affect the cage stability, and worsen biofouling rates. Non-chemical cleaning technologies that are currently used for biofouling maintenance of nets and other submerged structures, such as high-pressure cleaning, are costly and heavily time-consuming tasks. Currently, different companies develop large offshore fish farming facilities. These companies would considerably benefit from an environmentally friendly ultrasonically based antifouling technology that reduces maintenance and operational costs. Ultrasonic antifouling is a relatively new technique that started its commercialization in the field of boating. This technique directly excites the submerged surface (e.g., the hull of a boat) with ultrasonic vibrations to prevent sea organisms to attach. Unfortunately, there exists very little documentation on the effect of ultrasonic antifouling. To our knowledge, there are no scientific publications that describe biofouling prevention by direct ultrasonic excitation. However, experimental investigation is considered essential for increased understanding and optimal use of ultrasonic antifouling. This project proposes to experimentally investigate the effect of ultrasound on biofouling by direct ultrasonic excitation of submerged surfaces. The aim is to develop new scientific knowledge and competence about the efficiency and optimal ultrasonic antifouling treatment through pilot and full-scale trials on (new) submerged structures of large fish-farming facilities. Resulting knowledge can subsequently serve as a basis for new or improved antifouling technologies to reduce costs in the fish farming industry.

One of the biggest challenges in the Norwegian aquaculture is the control of biofouling, which is the accumulation and growth of marine organisms on submerged surfaces. Not only cage nets, but also any other submerged surface, such as the feed barge and cage structures, need to be cleaned regularly. Among the reasons for biofouling maintenance are the potential negative impacts of biofouling on fish health, cage stability and the exacerbation of biofouling rates. Non-chemical cleaning technologies that are currently used for biofouling maintenance of nets and other submerged structures, such as high-pressure cleaning, are costly and heavy time-consuming tasks and may necessitate removal from the water. Ocean Farming, a desired project partner and subsidiary of the SalMar Group, is currently developing a large offshore fish farming facility and implementing new technologies. This company is interested in an antifouling concept based on ultrasonic technology that would reduce maintenance and operational costs. This project proposes to develop a scientific knowledge about optimal ultrasonic anti-fouling treatment, and how efficient it is, of fish farming facilities through pilot and full-scale trials on new planned large facilities. This knowledge is currently not available in the scientific literature and would represent a break-through for the understanding of the potential of ultrasound as an anti- fouling technology.