Design of a novel biosensor implant for farmed Atlantic salmon (Salmo salar)

Accessing the welfare status of animals in salmon farming is a challenge due to the large production scale and limited diversity of technologies available to quantify individuals’ behavioural and physiological parameters. To increase technology diversity and facilitate rapid testing of future biosensing implants for farmed fish, we have designed and implemented a reusable and retoolable implant. The implant (9.4g, 13mm diameter × 47mm length) consists of a primary module with a basic sensor suite measuring linear accelerations, rotational rates, compass heading, temperature and magnetic field strength, and a user-defined secondary module featuring a biosensor measuring heart rate and changes in tissue perfusion (photoplethysmography) enabling estimation of blood oxygen saturation (SpO 2 ). In this study, we describe the hardware (HW) and software (SW) of this sensor device and outline how it can be used to collect different data types from free-swimming farm fish in research and production settings. Finally, we discuss how this platform could be used as a tool for realising precision farming methods to improve animal welfare in aquaculture.