Automated Water Quality Monitoring in Aquaculture Facilities

Salmon aquaculture pens. (Credit: Tristan Schmurr via Flickr CC BY 2.0)

Aquaculture as an alternative to commercial fishing has seen a boom over the last decade as the global demand for seafood grows. Seen as an alternative to aggressive fishing practices, well-managed aquaculture facilities consistently produce seafood without disturbing the native ecosystem.

Due to the volume of fish present in these facilities, water quality monitoring is critical to ensuring that the farmed fish stay healthy. Drops in dissolved oxygen can lead to fish kills, and sometimes the death of entire pens. Temperature fluctuations can also be hazardous to fish health, leading to illness or death.

Traditionally, water quality monitoring is conducted manually from a boat in each pond/net. This process is repeated several times a day, including overnight as dissolved oxygen drops during the nighttime due to the lack of photosynthesis. Unfortunately, this process can be quite time-consuming and costly, making automated solutions an alternative that helps save on labor and time.

How Data Buoys Transform and Automate Aquaculture Monitoring Practices

One possible solution is the use of data buoys in aquaculture ponds. These buoys are instrumented with dissolved oxygen and temperature sensors (and other relevant parameters), which continuously monitor water quality. Furthermore, these buoys are typically solar-powered, making them self-powered and efficient, limiting maintenance and eliminating any charging costs.

Instead of simply instrumenting the buoy cage, which would only gather surface data, the addition of a thermistor string and daisy-chained dissolved oxygen sensors provide a profile for each parameter, allowing staff to view water quality throughout the water column.

If equipped with a telemetric data logger, operators can view data in real-time. Datacenters like WQData LIVE offer the ability to set up alerts that will notify a list of contacts when dissolved oxygen levels or temperatures have reached unsafe thresholds. The real-time viewing option and threshold alerts allow managers to act quickly and hopefully prevent fish losses.

Large Aquaculture facility in Martin Bord, West Bosnia. (Credit: Julian Nyča via Wikimedia Commons CC BY-SA 3.0)

Without a telemetric logger, operators will have to go out to the site and retrieve data frequently. This setup also does not allow facilities to make adjustments at the moment, possibly missing hypoxic events or spikes in temperature. Such a system is less ideal as regular site visits are still necessary and, therefore, less automated.

Since each pen may have varying water quality conditions, a buoy would need to be deployed in each pond, making data buoys a more realistic solution for smaller operations. Additionally, because the buoys stay in the same place, the sensors may experience biofouling, though preventative treatments can help mitigate such issues.

Still, the real-time alert capabilities and real-time access to data allow operators to react quickly and automate water quality data collection. Continuous data collection and the ability to view all of the data collected over time simplify trend spotting, helping to inform better management strategies.

Monitoring Water Quality in Aquaculture Facilities Using Drones

For larger operations, an emerging technology known as Hybrid Aerial Underwater Robotic Systems (HAUCS) may be the ideal solution. A 2023 study published in Applied Sciences describes HAUCS as an IoT framework that “employs a swarm of unmanned aerial vehicles (UAVs) or drones integrated with underwater measurement devices to collect the in-situ water quality data from aquaculture ponds.”

The benefits of HAUCS is that the drones are automated and follow a set path plan that monitor entire facilities or set ponds. Because of the hybrid design, the drones can monitor multiple depths and locations in one pond and then repeat the process in another. Once completing its path, the drones automatically return to their charging ports.

An additional benefit to the drones is that they will not accumulate biofouling at the same rate as a stationary system due to the vehicles constantly moving through the water. While some maintenance will always be required, HAUCS limits the amount of intervention necessary.

In order to make HAUCS fully automated, the 2023 study stresses the need to implement real-time telemetry options into the drones. Otherwise, operators will have to travel to the charging station to manually retrieve data.

Conclusion

Ultimately, automating the water quality monitoring process will help save on costs and make data acquisition easier. As HAUCS is still under development, the use of data buoys or other real-time sensor arrays can be an effective means of automating monitoring.

While in-situ monitoring techniques provide immediate data, they rely on operators sampling when an event occurs, possibly missing a sudden drop in dissolved oxygen or a spike in temperature between sampling visits.

For this reason, the implementation of real-time technology in any automated water quality monitoring solution is essential to ensuring operators can make changes quickly and minimize fish losses.

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