Nanomaterial-enabled hydrodynamic and infrastructure monitoring in marine aquaculture

As the scale and complexity of the RAS (Recirculatory Aquaculture System) on land is increasing, aquaculture is expanding into the more energetic offshore environments. This shifting trend increases the requirement of continuous monitoring of wave, current, cage depth, structural load, flow, pressure and mesh level in cages, tanks and pipes. Use of conventional instruments is constrained to the reliance on cables, high power, limited space coverage and losses of performance due to biofouling and corrosion. As a result, they often cannot provide the continuous data input required for modern operational control. This review aims to highlight the recent progress in hydrodynamic and infrastructure sensing by various types of nanomaterials in marine aquaculture. Nanostructured coatings and functionalized optical fibers from nanomaterials have increased anti-fouling resistance and have allowed distributed measurements surrounding cages, tanks and reservoirs. Two-dimensional materials, such as graphene, MXenes and laser-induced graphene support conformal strains and pressure sensing devices that follow the geometry of the structural components while monitoring isolated point devices. Triboelectric nanogenerators (TENGs) allow self-sensing of wave energy, currents, flows and levels by converting mechanical motion into electrical signals. Altogether, these approaches point to a future of self-powered surveillance on infrastructure surfaces and networks. We discuss the remaining gaps in validating these nanomaterial-based devices on long-term uses, the robustness of packaging and adhesion under immersion, and the selection of calibration and standardized performance indicators on real farm operating conditions.