Validation of an open-source hardware for cardio-physiological studies in fish: A statistical equivalence study with...

Monitoring heart rate (fH) accurately is fundamental for fish eco-physiological studies. However, these measurements rely heavily on expensive experimental tools. Here, we aimed to validate BITalino, an inexpensive, open-hardware biosignal acquisition system for measuring fH that could help to democratize research in fish physiology. BITalino is a modular electrophysiological system with a dedicated electrocardiogram (ECG) module that records ECG signals through electrodes connected to the module via lead wires and attached directly to the subject. We compared BITalino with a widely used research-grade physiological recording system (BIOPAC) by measuring fH in fish using both devices simultaneously. Heart-rate measurements did not differ significantly between devices, and there was no significant Device×Time interaction, indicating that both systems tracked temporal variation similarly. The intra-class correlation coefficient (ICC) showed that 85.9% of the variance was due to biological differences between fish, with less than 5% from device-related variance. These results confirm that BITalino can be effectively used for fH monitoring in fish physiology studies. Beyond its low cost, its portability, modular design, open-hardware architecture and compatibility with third-party analysis software make it easily adaptable for different experimental applications, and may facilitate its use in resource-limited research settings.