First report of sound production in rock bass ( Ambloplites rupestris )

There is a knowledge gap in descriptions of sound production in freshwater fishes. Here, we provide the first description of sound production in rock bass ( Ambloplites rupestris ) in their natural habitat. We used an action camera to record six calls from a rock bass in Stoney Lake, Ontario, and two calls from a rock bass in the Otonabee River, Ontario. Calls were associated with opening the mouth, flaring the opercula, and moving the pectoral and median fins erratically while the fish approached a novel object (our camera anchor). Rock bass calls ranged from 0.3 to 28.6 (mean = 9.32) s in duration and consisted of 2–62 sound pulses (mean = 22.7). Individual sound pulses had a mean duration of 0.065 s and a mean interval of 0.43 s. Pulse frequency was bimodal with a mean lower peak at 158 Hz and a mean upper peak at 362 Hz. We compared the calls of rock bass to those of other centrarchids from the literature and found that the sounds were structurally similar. Future studies should investigate rock bass sound production in captivity, the mechanisms of sound production in rock bass, the role of acoustics in rock bass ecology, and systematically describe sounds so they may be used in passive acoustic monitoring.