Sensor deployments for Hydrodynamic and infrastructure in marine aquaculture environments must withstand the biofouling-prone waters and demanding maintenance conditions (Hopkins et al., 2021). Nanostructured metals, ceramics, and polymer coatings help address this durability barrier by reducing biofouling and surface degradation (Liang et al., 2024). This can enhance both the stability and lifespans of the sensors used. The same can be applied to both offshore cages and land-based RAS (Recirculating Aquaculture System) infrastructure, where conventional equipment often fails due to fouling, corrosion, and mechanical stress.

Nanomaterial decorated optical fiber sensors extend this platform into distributed surveillance applications. Bare optical fibers are highly resistant to electromagnetic interference and support long-distance multiplexing as well (Wang et al., 2021). Nanoscale coatings and structured films can expand sensing coverage, and multi-parameter capability around the deployed cages. Nanomaterial coatings, including metallic and semiconductor nanoparticles and other nanostructured films, can be applied to the selected fiber regions (Ielo et al., 2021). By amplifying the evanescent field and localized surface plasmon resonance effects, particularly from noble metal nanostructures, these coatings can enhance the sensitivity to refractive index, and, depending on the configuration, strain, and temperature (Li et al., 2022; Urrutia et al., 2015). As a result, nanocoated fiber loops attached to cage rings and anchors can record a number of physical parameters, such as, distributed strain, vibration, and pressure; thereby complementing point measurements from wave and current sensors.

Similar strategies can also be applied to tanks and reservoirs. Optical fiber level sensors benefit from nanomaterial integration. Coatings containing noble metal nanoparticles, or ITO (Indium Tin Oxide), enhance plasmonic resonances and the evanescent field, making spectral signals more sensitive to changes in the immersion state (Urrutia et al., 2015; Lopez et al., 2021). Distributed Rayleigh-backscattering approaches have demonstrated continuous level detection along fibers in cryogenic systems (Chi et al., 2022; Jauregui-Vazquez et al., 2021). The same design logic could enable spatially resolved level profiles in aquaculture with no moving parts. It could also provide a multiplexed backbone for broader infrastructure monitoring.

Depth and pressure measurements are important as they can help operators keep cages at targeted depths which can limit exposure to hypoxic or thermally stratified layers (Sievers et al., 2022). Graphene, MXenes, and LIG can offer higher sensitivity, and can be packaged for better signal stability, compared with traditional rigid pressure elements (Sun et al., 2025; Wang et al., 2022a). Graphene-based pressure sensors typically use atomically thin, highly conductive films whose resistance or capacitance changes under small deformations (Deshmukh et al., 2023). Multilayer graphene foams, textiles, and patterned films can detect pressures from a few pascals to hundreds of kilopascals, while maintaining fast response and mechanical flexibility (Tian et al., 2015; Guo et al., 2024).

Laser-induced graphene (LIG) pressure sensors can be patterned directly onto polymer substrates. This, in turn, can create flexible and corrosion-tolerant devices. These sensors have been tested as depth probes in seawater. Protective polymer composite coatings can further improve the resistance to chemical degradation and biofouling, thereby helping maintain long-term stable performance (Volkenburg et al., 2023; Kaidarova et al., 2020). When laminated onto cage frames, mooring lines, or submersible collars, LIG sensors could provide information on spatially resolved depth and pressure.

MXenes, two-dimensional transition-metal carbides and nitrides, also support flexible pressure and strain sensing (Huang et al., 2018). Their conductivity, tunable surface terminations, and lamellar structure enable sensitive piezoresistive responses across wide ranges of pressure often along with good cycling stability (Lu et al., 2020). Pressure-sensitive underwater fabrics coated with nanocomposites have been reported to maintain stable performance during submersion (Fan et al., 2022). This suggests that MXene or MXene-hybrid sensors could be designed to conform to nets, bags, or tank walls. In offshore cages, these approaches could enable whole-cage, multi-point monitoring and finer control of submergence during harmful algal blooms, surface warming, or extreme wave events.

Nanomaterial-based pressure and strain sensors can allow the decorated structure itself to act as a distributed sensing surface. MXene- and graphene-based strain gauges can be printed onto or mounted on mooring chains, brackets, or composite beams. These gauges can detect small deformations created by changes in drag forces (Grabowski et al., 2022; Khalid et al., 2025). These signals can be combined with the measurements from waves and currents by TENG buoys or optical fiber arrays. This allows operators to estimate the hydraulic resistance and drag buildup. This supports predictive cleaning and properly timed schedules in changing the net.

Process and infrastructure sensors in RAS were primarily designed for rigid, bulk, cabled and single-point measurements. Conventional flow meters and diaphragm pressure gauges with wetted interfaces are vulnerable to fouling and scaling. Equally, they are costly and complex to deploy at high densities (Delgado et al., 2021). Two-dimensional materials offer an alternative path toward conformal and distributed sensing surfaces.

Nanomaterials enable electrodes monitoring chemistry and hydraulics within the same flow environment. Graphene and related 2D materials can be patterned onto flow cell surfaces to detect trace pollutants or disinfectant residues. As such, scalable graphene-based sensor arrays for the detection of toxins in running water streams have been reported, along with an emphasis on robust fabrication suitable for real-world deployment purposes (Maity et al., 2023). The same could be extended to RAS by employing flow-through cells measuring flow rates while enabling graphene-based detection of core water-quality.

Nanomaterial-based pressure sensors provide alternatives to rigid and diaphragm-based counterparts. A textile-based pressure sensor made from multilayered graphene coated on polyester has been reported (Lou et al., 2017). This could operate over a broad range up to ~800 kPa while maintaining sub-kilopascal sensitivity. Laser-scribed graphene foams and films also show high sensitivity across wide pressure ranges (Gao et al., 2025; Tian et al., 2015). When wrapped around filter housings or attached to structural pipe sections, these devices could detect early pressure increases linked to fouling or scaling.

MXenes extend pressure and strain sensing by combining physical properties, such as metal-like conductivity along with hydrophilic surfaces. Polymer-MXene and MXene-nanocarbon composites show large signal changes under small loads as well as fast response and often stable cycling (Yang et al., 2022; Qin et al., 2024). When printed as conformal coatings on curved components, they could turn filter lids, pipe elbows, or pump casings into active sensing surfaces. This could help localize early signs of fouling or cavitation.

Nanomaterials also support structural health monitoring of aquaculture infrastructure. MXene-based strain sensors can be embedded into composite laminates, beams, and shells (Yao et al., 2025; Khadem et al., 2025). Self-sensing polymer composites containing carbon nanotubes, graphene, or related fillers can convert mechanical strain into measurable electrical changes, thereby enabling distributed monitoring along structural elements (Tao et al., 2025). Graphene-based strain and vibration sensors can also be applied as thin conformal layers. Laser-patterned graphene devices offer a wide dynamic range and can provide stable signal, supporting their potential deployment on critical joints, flanges or brackets in pump skids and tank stands (Miao et al., 2019; Kaidarova et al., 2020).

A major development in wave sensing is the triboelectric nanogenerator (TENG). TENGs use nano- and microstructured polymer and electrode surfaces to convert mechanical motion into electrical signals and usable power. A self-powered triboelectric ocean-wave spectrum sensor (TOSS) uses a tubular TENG housed in a hollow-ball buoy. It measures wave height and frequency from multi-directional motion while generating its own power, reducing reliance on external batteries or cables (Zhang et al., 2020). Coral-like and stackable TENG wave sensors use this concept through modular and biomimetic designs supporting larger arrays. This can improve their performance in more complex wave conditions. Nanostructured triboelectric interfaces increase surface charge density and strengthen the electrical output. This feature can improve sensitivity to tiny variations in wave intensity that help define safe operating limits and calibrate hydrodynamic models near farms (Wang et al., 2022a, b). Disk-type TENG buoys and stackable TENG modules also show that the harvested wave energy can power sensors to monitor salinity, temperature, and other basic parameters (e.g., pH), alongside motion sensing. These designs create compact, self-powered sensor units and could support sustained, high-density wave surveillance around marine aquaculture sites (Jung et al., 2024, 2025).

The triboelectric approach has also been extended to act as current sensors. TENG-based current meters make use of the fluid motion around a rotor or vibrating element, which can generate electrical signals reporting flow speed and variability. A self-powered, speed-adjustable TENG-based ocean-current sensor has been developed for abyssal operation, where battery replacement is nearly impossible (Pan et al., 2024). Tailored triboelectric films and flexible electrodes can further improve sensitivity to changes in current speed while harvesting energy from the flow.

In marine aquaculture, current meters could be deployed around and beneath cages to provide continuous information on the strength and direction of flow without extensive power lines (Zhang et al., 2023a). This would support cage-deformation analysis, waste-plume dispersion modelling, and feed-plume tracking. At present, many farms rely on a small number of fixed-site Doppler Current Profilers/sensors or rotor current meters, which require external power for signal transduction. In contrast, networks of smaller, self-powered nodes could deliver denser and more resilient coverage, including at the relatively low current velocities typical of farm sites.

In RAS, maintaining spatially distributed flow measurements accurately across multiple loops and side streams remains a core challenge. Conventional approaches can require extensive wiring and multiple power supplies, which creates complex and costly infrastructure that is difficult to maintain and prone to failure. TENGs based on nano-microstructured polymers allow flow to serve as both energy source and a sensing signal (Choi et al., 2023). In single-electrode and tubular TENG flow sensors, the inner wall of a pipe is lined or coated with nanostructured triboelectric materials such as PTFE (Polytetrafluoroethylene) or related fluoropolymers. As water moves through the pipe, contact electrification generates voltage or current pulses whose amplitude and/or frequency correlate with flow rate. Micro- and nanoscale interface engineering can increase surface charge density, while surface texturing, hydrophobic coatings, and layered dielectrics help improve signal stability (Tang et al., 2021; Jiang et al., 2019; Cui et al., 2022). Hybrid triboelectric–electromagnetic devices can extend the measurable range in large pipelines. The triboelectric component supports sensitivity at low flow speeds, while the electromagnetic unit broadens the upper range. Both elements can be powered by the motion of the fluid.

Level sensing in tanks and sumps can also benefit from self-powered approaches. In a liquid-solid tubular TENG, a PTFE tube with distributed copper electrodes converts water-column motion into position-dependent electrical signals. Bubble-driven variants offer a similar route to self-powered level detection (Li et al., 2022). Some TENG architectures integrate energy harvesting and level sensing in the same structures and can maintain measurable output across a wide range of immersion conditions (Cui et al., 2022; Xu et al., 2022). When mounted inside wells, these sensors can continue generating level signals during brief power outages.

Across cages and RAS infrastructure, TENG-based devices enable sensing that can be partially powered by the same physical processes that are being measured. This can overcome some shortcomings in reliance on cables and frequent battery replacement. When combined with conformal 2D sensing layers and durability-focused nanocoatings, these systems can enable denser and more resilient monitoring networks for both hydrodynamic and infrastructure conditions.