Abstract:
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.
