Advances in telemetry approaches and technologies applied to fish ecology and management

Abstract

Telemetry and biologging have been key tools in fish ecology for several decades (Hussey et al., 2015; Matley et al., 2022; Watanabe & Papastamatiou, 2023) and helped uncover several mysteries within this realm, including migrations, behaviour, activity and space use, intra- and interspecific interactions or human impacts. The technology has remarkably improved since its first application, allowing us to monitor smaller-sized fish for longer periods. Sensors on board tags add additional capacity to measure internal and external properties of the tagged fish, such as their temperature, depth and acceleration. In addition, the analytical tools and approaches to infer fish movement and behaviour derived from telemetry data have considerably advanced to allow complex and high-dimensional spatial and temporal analyses.

There is a global community of fish-tracking scientists who use animal tracking tools to address applied and fundamental questions about fish populations in every ocean of the world and scores of inland waters. The Sixth International Conference on Fish Telemetry gathered many of these scientists in Sète, France, from 11 to 16 June 2023, providing the opportunity to share the latest advances in telemetry approaches and technologies for studying movement ecology of fish and for fisheries management. The present collection of papers is representative of the current trends in fish ecology studied through the prism of biologging and telemetry, with 11 (41%) papers focused on marine systems, 7 (26%) on freshwater systems and 9 (33%) addressing both systems (i.e., estuary or transitions between rivers and sea).

This special issue offers readers a wide range of approaches and tagging methods applied to dive deeper into a fish's movement ecology. Although the more common tagging methods provided new insights into fish ecology with acoustic telemetry determining the large-scale migrations of rays in a regional network of receivers (Elston et al., 2025) and pop-up archival satellite tags providing the first long-term migration route of sunfish (Mola mola L.) in the Mediterranean Sea (Rouyer et al., 2025a), other developing tools were also applied. For example, data-storage tags were used in combination with acoustic telemetry to study connectivity of pollack (Pollachius pollachius) in the French-English Channel (Gonse et al., 2025). In addition, several approaches were proposed to study predation in fish, including acoustic tags with acceleration sensors to map the dynamics of shark activity and its associated predation pressure on prey (Laurioux et al., 2025) or the test and use of predation tags in several case studies: brown trout (Salmo trutta L.; Kennedy et al., 2025), largemouth bass (Micropterus nigricans; Shorgan et al., 2025) and salmon (Salmo salar; Waters et al., 2025). More well-established sensors, such as depth and temperature sensors, integrated into acoustic tags were also used to investigate environmental preferences and niche partitioning of fish (Nickel et al., 2025). Depth sensors integrated into positioning systems allow the incorporation of the vertical dimension of fish activity by building more accurate three-dimensional habitat use models (Richter et al., 2025). Finally, heart-rate sensor tags were implanted in the musculature associated with the cleithrum of Atlantic bluefin tuna (Thunnus thynnus) using an atraumatic trocar to investigate their field physiological rates for the first time (Rouyer et al., 2025b).

Acoustic telemetry is now an accessible tool for fish ecologists, but there are limitations to what tracking fish can tell us, which was discussed by Jacoby and Piper (2025). One of the most effective ways that acoustic telemetry is used is for improved understanding of behavioural mechanisms in fish, such as homing (Mitamura et al., 2025) or elusive spawning migrations (Abecasis et al., 2025). Acoustic telemetry can also offer the opportunity to investigate research questions at the metacommunity level, for example, studying coexistence, resource partitioning and management of multiple species (Orrell et al., 2025). Applying random forest models to environmental data associated with telemetry-based presence–absence in several species can help improve our ability to infer fish habitat suitability, which can be used for fish management and restoration (Larocque et al., 2025). Acoustic telemetry data can provide critical estimates of fish vital rates, such as survival, when associated with mark-recapture Cormack-Jolly-Seber models, which can be applied for fisheries management (Rodger, Guthrie, et al., 2025) or infer multispecies tagging mortality (Martínez-Ramírez et al., 2025). Acoustic telemetry can also be used in restoration ecology, for example, to monitor how fish use dam passage in fragmented rivers (Dodd et al., 2025; Shry et al., 2025) or by monitoring the behaviour and survival of hatchery-fish reared to stimulate recovery of a population afflicted by low survival of wild fish (Sortland et al., 2025). The development of regional and national scale acoustic telemetry networks also allows one to monitor the migrations of multiple species at larger scales (Livernois et al., 2025) or migrations at the interface of freshwater and marine systems (Pearson et al., 2025; Rodger, Lilly, et al., 2025). Although many acoustic telemetry studies assess connectivity of tagged individuals among and between habitats, the term ‘connectivity’ has never been consistently used. Welch et al. (2025) provide a framework of connectivity definitions to assist future studies on connectivity. Among the limitations of acoustic telemetry is the variability in the detection range, which can be highly reduced in shallow and structurally complex environment. Kanno et al. (2025) challenged the use of acoustic telemetry in mangrove habitats, characterized by very shallow depths and dynamic seascapes, to study shark and ray movement, demonstrating that fish can be successfully tracked in these understudied habitats. Tag attachment innovations are constantly pushing the limits in tag retention and track durations, improving the quality and quantity of data collected from animals (Junge et al., 2024).

This research collection provides the reader with a broad overview of the latest developments and application of acoustic telemetry in the field of fish ecology and management. Biologging and telemetry represent a rapidly evolving field, and the biennial International Conference on Fish Telemetry is a key venue for conversations about new developments and novel applications of fish tracking to address the most complex questions confronted by aquatic scientists and managers. This collection of articles provides the readers with inspired new developments in the field and will be useful to support future research for the study of fish movement ecology.