Is Radio Telemetry Getting Washed Downstream? The Changing Role of Radio Telemetry in Studies of Freshwater Fish Relative to Other Tagging and Telemetry Technology
Steven J. Cooke and Eva B. Thorstad
Abstract.—Radio telemetry is now considered a standard tool for fisheries professionals studying fish in freshwater systems. However, interest in radio telemetry technology may be waning in popularity relative to other technologies such as acoustic telemetry and passive integrated transponders, which have recently become popular for tracking studies in freshwater. The purpose of this paper is to identify the unique characteristics of radio telemetry that continue to make it an extremely powerful tool for elucidating the fundamental biology of aquatic organisms, particularly those living in shallow, fluvial habitats, and in providing information to enable effective management and conservation of aquatic resources. By evaluating the peer-reviewed literature on radio telemetry in aquatic systems over a ten year period, we summarized the advances in fisheries science owing to radio telemetry and identified trends related to study design, tagging techniques, and tracking strategies. We also identified research questions and management needs that cannot be effectively addressed using technologies other than radio telemetry, with main emphasis on hydropower development, microhabitat use and movements, mortality, predation, winter biology, natural history studies of imperiled fish in developing countries, and studies in habitats where physical characteristics restrict the usefulness of other techniques. We emphasize that it is important for radio telemetry practitioners to not dismiss simple manual tracking studies where individual tagged fish are discriminated by using discrete frequencies. Indeed, such an approach can yield insight that is not possible with fixed stations alone, and is particularly useful for developing countries where capacity and finances may not exist for deployment of fixed stations. By characterizing and clarifying the actual and potential role for radio telemetry within the broader landscape of tagging and telemetry technologies, we hope to enable telemetry practitioners to make informed decisions regarding the optimal choice of tagging technology when designing and executing telemetry studies in freshwater systems. We submit that radio telemetry is not getting washed downstream, but there are now simply more technological options for researchers interested in the study of freshwater fish.