Biotelemetry is the preferred monitoring tool for studying the movement ecology of species and understanding how animals migrate. Biotelemetry is a constantly evolving technology that allows us to remotely measure the behaviour of animals and the environment in which they live by measuring abiotic variables, and how this environment affects their physiological and energetic status by measuring biotic variables such as heart rate or muscle activity.

XPO is equipped to study the behaviour and mobility traits of fish in aquatic environments (obstacle passability, habitat reconnection, diel or seasonal migratory patterns, home ranges, spatial niches or habitat preferenda) by mobilising multiple telemetry tools using radio, acoustic (or ultrasonic) transmission and radio frequency identification (RFID).

VHF radio telemetry instruments are used in shallow (<10-15 m) or turbulent inland waters, allowing for fish movement monitoring using mobile or stationary receivers for periods ranging from weeks to months with a fine spatial range. Acoustic telemetry instruments are mainly used in marine and estuarine environments as well as in deep continental waters (>15 m), allowing the tracking of fish movements using anchored or towed hydrophones for periods ranging from weeks to months with a range of a few hundred metres. LF-RFID systems (mainly HDX technology) can more recently be used as telemetry tools in any aquatic environment for unlimited time periods thanks to small passive integrated transponders (12, 23 or 32-mm HDX pit-tags) easily inserted in fish or injected transcutaneously, and sending transmission signals to mobile or stationary antenna receivers with a limited spatial range (a few metres). Each method is used alternatively or in combination depending on the objectives of the study, the species and life stages targeted and the types of environment in which the fish move, and biotelemetry may or may not be associated with bio-logging (e.g. Data Storage Tags, Pop-up Satellite Archival Tags to trace trajectories retrospectively).

To track fish, telemetry is organized

Because of those crucial potentialities in aquatic biodiversity studies, the community of biotelemetry users is growing. Therefore a national French symposium on fish telemetry has been organised by EABX¹ (XPO) every two years since 2011. These francophone meetings, which combine scientific presentations and equipment demonstrations over two days, are aimed at scientific and technical actors from different research institutes and R&D centres², NGO for the protection of diadromous fish, fishing federations, environmental engineering offices and companies designing telemetry equipment. Through these common tools, such thematic symposiums encourage exchanges and promoted links between fundamental and applied research, R&D and management for the preservation of the quality of aquatic systems and ecological restoration. Some private companies were also invited to present their innovations and improvement in materials development that are ever better adapted to our needs, which are expressed here. Experiences are shared and about 20 scientific presentations provided support to discussions around the expertise, in particular with our Belgian, Swiss and Canadian colleagues. The last Telemetry Meetings were held on 10 and 11 October 2018 with 70 participants.

¹ Under the aegis of the GRISAM (Scientific Interest Group on diadromous fish)

² Universities, CNRS, IUT, MNHN, Irstea, Inra, Ifremer, Onema R&D, EDF R&D, EDF CIH, CNR, INRS (Quebec)