Plasticity in fish acoustic behavior
Plasticity in fish acoustic behavior lead image
Many fish species communicate with sounds. Anthropogenic noises, such as those caused by boats, can mute these acoustic cues important for spawning, courtship, communication, and navigation. In the presence of elevated noise, some animal species have been shown to change their calls, by increasing the amplitude or changing their timing and frequency. These changes improve signal reception by listeners and are described by the Lombard effect, which has infrequently been documented in fish.
To investigate the effect of boat noises on fish soniferous behavior, Somogyi and Rountree used passive acoustic monitoring (PAM) to measure the sound patterns of freshwater drum, a potential indicator species in North American freshwater food webs.
“PAM is an important tool for understanding fish biology,” said author Nicholas Somogyi. “While this technique has been used extensively in marine environments, it is used much less in freshwater. However, freshwater environments bear a large portion of global losses in biodiversity, and there is growing evidence that anthropogenic noise reduces fitness across taxa.”
The authors analyzed the occurrence and characteristics of drum calls and found evidence of the Lombard effect. The presence of boat noise led to adjustments in drum acoustic behavior, indicated by an increasing number of knocks, higher frequencies, and significant shifts in the timing of drum spawning-choruses.
“We hope to see additional studies confirming the behavioral implications of fish acoustical behavior, as well as the continuing application of spatial statistics and machine learning in this space,” said Somogyi. “Models that predict presence or abundance based on passive acoustical data would be an intriguing next project.”
Source: “The sound production of Aplodinotus grunniens in the presence of boat sounds,” by Nicholas A. Somogyi and Rodney A. Rountree, Journal of the Acoustical Society of America (2023). The article can be accessed at https://doi.org/10.1121/10.0020542 .
