Smart System for the Prevention of Biofouling on Aquaculture NETs by Ultrasonic Wave Technology

The NETWAVE project evaluates use of ultrasound technology to reduce biofouling of mariculture cages and the potential effects of this technology on the welfare of cultured fish.

As soon as any object is submerged into water, a bacterial biofilm starts to form and if not prevented or removed, the biofilm creates a healthy environment for the initial development of smaller algae (microfouling), followed by larger algae and larger molluscs (macrofouling). These biofilms often serve as a refuge for potential pathogens and parasites increasing disease outbreak and death risks. Biofouling on mariculture infrastructures restricts water exchange leading to reduced oxygen levels in water, affecting fish growth and increasing the weight of cages causing deformation / breakdown and unintentional fish escapes with detrimental impact for wild fish populations.

Biofouling develops extremely quickly and has major operational and financial impacts on marine industries. Current anti-biofouling strategies present significant economic, healthcare, logistical and environmental limitations. Antifouling coatings (thin, toxic layer of heavy metals or organic biocides such as copper), momentarily prevent the onset of biofouling but have detrimental effects on shellfish/fish growth and survival.

The aim of the NetWave project is to evaluate a world first class anti-fouling system, NetWave, based on ultrasonic waves, to finally commercialize a novel cost-effective and easy-to-use system enabling 95% prevention of micro-fouling layers occurring on nets. The system is chemical-free, requires no human intervention and it has been already successfully tested for algae control. However, there has been little research about effects on fish health. Therapeutic ultrasound (high power and high frequencies (1 W/cm2, 1MHz), is known to damage to the outermost epithelial layers of fish. Therefore the task of AWI is to study the animal health and welfare aspects of this technology. We will analyse its influence on the primary, secondary and tertiary stress response of the fish as well as potential negative impact on different tissues affecting the morphology and functionality of important organs such as skin, liver and gills.