Habitat-specific performance of high-frequency acoustic telemetry tags in a tropical marine environment

High-frequency (>175 kHz) acoustic telemetry transmitters are increasingly being used to track the movements of small fishes and other aquatic organisms. These transmitters, which are often smaller than conventional types, have primarily been used in freshwater, yet limited information is available on their efficacy in estuarine or marine environments. This study quantified detection ranges (DR) of 180-kHz tags and potential environmental factors influencing detection probability in three different habitats within a large embayment in Costa Rica. Mangrove (DR at 50% detection efficiency; DR50 = 121.0 m ± 8.1 s.e.) and transitional estuarine (DR50 = 145.6 m ± 12.2) habitats had relatively high detection ranges, albeit smaller than similar studies in freshwater, highlighting the effectiveness of using this frequency in tropical marine environments. By contrast, performance within rocky reef habitat was poor (DR50 consistently <0 m), which may have been caused by the heterogeneous bottom structure or close proximity detection interference (CPDI) due to ambient noise. This study provides novel information on the performance of high-frequency acoustic tags in a tropical marine environment serving as an important case study as investigations of the spatial ecology of small fishes in both marine and freshwater become more common.