Integration of Automated Anomaly Detection with Real-Time Fish Stress Monitoring Using QR Code-Enabled Biosensors in Diverse Aquatic Environments
Authors: WU Haiyun , Ideta Kazuki , Horiguchi Yusuke , Matsumoto Haruto , Murata Masataka , Ohnuki Hitoshi , Shibata Takayuki , Endo Hideaki 
Published: December 2024

Background and Objectives:
In our laboratory, we have developed a biosensor capable of monitoring fish blood glucose levels as an indicator of stress response in real time. Previous studies faced challenges with traditional communication systems using radio waves or visible light, which were susceptible to interference from water mediums and ambient light. Therefore, this research aimed to develop a stress response monitoring system that could transmit information even in seawater and freshwater environments, utilizing QR code technology with error correction capabilities and automatically detecting abrupt anomaly changes in sensor response values.
Materials and Methods:
The glucose biosensor was constructed using a needle-type electrode with a Pt/Ir wire (φ: 0.178 mm) as the working electrode and Ag/AgCl as the reference electrode, with glucose oxidase immobilized on the working electrode surface for glucose oxidation. A microcontroller development kit (M5Stack Core2) was employed to convert sensor response values into QR codes, allowing for voltage application to the sensor and QR code display based on sensor response values. An iOS application was developed as a reading module to enable communication via QR codes. Stress response was monitored using freshwater fish (Nile tilapia, Oreochromis niloticus) and saltwater fish (Largescale Blackfish, Girella punctata). Additionally, a model capable of detecting abnormal sensor data using a One-Class Support Vector Machine was created utilizing baseline glucose concentration data. This model was integrated into a webcam control program to attempt real-time and automatically detect abnormal data.
Results and Discussion:
The QR code display system using M5Stack Core2 proved effective in applying voltage to the glucose biosensor, converting sensor response values to QR codes, and displaying them on the LCD screen. Stress response monitoring of freshwater and saltwater fish resulted in data retrieval rates of 100% and 84.6%, respectively, demonstrating the feasibility of wireless monitoring via QR codes regardless of water type. Furthermore, the stress response monitoring system incorporating abnormal data detection capabilities successfully identified communication issues and variations in response values due to stress induction, providing user feedback. These results highlight the capability of the system to monitor fluctuations in fish blood glucose levels in real time, potentially contributing to addressing issues such as the spread of fish diseases and mortality caused by stress. Future efforts will incorporate cloud storage and remote access features to enable real-time data monitoring and analysis from any location.
Conclusion:
Developing a real-time wireless monitoring system using QR code technology significantly advances understanding and addressing fish stress responses. By enabling continuous monitoring of glucose levels in fish, the system has the potential to mitigate the adverse effects of stress-related diseases and mortality. Further enhancements, including cloud integration and remote access, aim to enhance the system's usability and accessibility for researchers and aquaculture professionals, ultimately contributing to improved fish welfare and management practices.

Figure 1