CARIE

Over 800 fish species produce vocalizations, many of which are species-specific, though some remain poorly understudied. The westslope cutthroat trout (Oncorhynchus lewisi), an understudied species, has limited literature documenting its sound production. This study utilized hydrophone technology to investigate whether westslope cutthroat trout produce vocalizations and, if so, whether these vocalizations are species-specific compared to other species. Using passive acoustic monitoring (PAM), three primary methods were utilized: visual observation, video recordings, and audio data collection. During the trout's spawning window, two devices were installed in a tributary in southwestern Alberta: a hydrophone for audio recordings and a waterproof camera, positioned upstream of redd-digging activity to avoid disturbance, while yet close enough to collect video footage with auditory data. A total of 16.7 hours of audio recordings were captured, resulting in 1,913 audio files. From these, 100 high-quality recordings were selected for analysis. Across this subset, 1,671 unique sounds were detected. Comparative analysis revealed that the characteristics of these sounds are distinct, supporting the hypothesis that they are species-specific. This research highlights the versatility of hydrophone technology in studying freshwater species among other species. The use of non-invasive and cost-effective methodologies, such as passive acoustic monitoring paired with hydrophones offers novel opportunities to enhance conservation efforts and deepen our understanding of aquatic species.