World-first biosensor taking cues from oysters to monitor local environments

Oysters are arguably Australian’s favourite seafood, with an estimated 16 million of the molluscs farmed each year, creating an industry value of roughly $100 million  

Unlike land-farmed foods, such as lamb or pork, a significant challenge for oyster farmers is tracking the conditions of the water their stock is farmed in and the effects it has on the animal’s health and growth.  

To improve oyster farming processes, and get the best oysters to your plate, CSIRO’s Data61 and the University of Tasmania have developed a world–first biosensor capable of detecting responses to environmental changes in sentinel animals in commercial environments.  

“Traditional methods of checking growth and condition involve physically visiting the oysters at each growing location, grabbing a few and opening them to visually inspect the animals,” explains project lead and senior researcher at Data61, Mr John McCulloch. 

Deployed in the D’Entrecasteaux Channel south of Hobart, oysters are outfitted with a credit-card–sized sensor glued to the bottom of their shell to record the animal’s heart rate and act as a communications device. 

This sensor also monitors the water temperature, depth of the animal, and the amount of sunlight reaching the animal. A small magnet is placed on the top shell to monitor the mollusc’s gaping (opening or closing position of the shell) or feeding.  

The automated telemetry system within the sensor electronically transmits the collected data to Data61’s Senaps ‘Sensor Cloud’, an advanced data analysis and spatio-temporal platform that enables farmers to understand how their stock is reacting to the environment in real-time.  

“This project provides an as-it-happens rundown of the behaviour, health and welfare of the oysters,” says Mr McCulloch. 

“By applying this methodology, farmers can better understand the impacts of environmental and management practices, equipping them with the power to make better data-driven decisions for the short- and medium-term management of their stock.” 

The biosensors will allow farmers to make informed decisions on feeding, moving and harvesting their animals, as well as acting as an early warning signal for seasonal challenges such a Pacific Oyster Mortality Syndrome (POMS).  

The sensors, which can last up to 12 months without maintenance, measure the heart rate of the oysters by detecting changes in the level of reflectance from infrared beams on the surface of the mollusc’s body. As the heart beats, it changes shape, affecting how much light is reflected.  

Changes in the magnetic field strength generated from the magnet situated on the top of the animal’s shell measure whether the shell is closed or open and how widely. Gape opening and closing patterns change in response to environmental variations such as salinity and water quality.  

A machine learning mapping model is used to establish relationships between data points, with the team discovering links between temperature and heart rate and gape pattern, and salinity and heart rate. 

“As more data becomes available, more insights to the subtleties and variations in production across sites and around the state will be found contributing to minimisation of production risks and growth of the industry,” explains Mr McCulloch.  

Local high school students from the area surrounding the D’Entrecasteaux Channel have discovered the benefits of these biosensors first–hand with an aquaculture farming program run by the Marine Discovery Centre (MDC) and Data61.  

Over 1,500 students have attended the two-hour classes in the last year, with sessions providing students with hands-on learning. The centre’s two interactive biosensor hardware and software systems allow students to holistically understand how the technology gathers and displays data and what it means in relation to animal physiology and the environment they’re being farmed in.  

“The MDC provides a unique opportunity for school students from around the state to access learning resources and opportunities that would be impossible for individual schools to maintain,” says Mr McCulloch. 

“The engagement with the MDC has highlighted the enthusiasm and passion our educators have for inspiring the next generation of marine scientists.” 

According to Oysters Tasmania, the peak body representing oyster and mussel growers and hatcheries in the state, Tassie’s oyster and mussel industry currently provides direct employment for over 300 people, who produce roughly 3 million dozen oysters and over 730 tonne of mussels each year, with an estimated ‘farm gate’ value of $24 million. With Australia and the world’s penchant for these molluscs, it’s crucial that aqua farmers are able to produce the best quality product and ensure animal health and wellbeing while doing so, with the Tasmanian oyster industry to play a leading role.