Fish sing louder in conjunction with a wind-forced coastal upwelling system off south-east Australia

Fish choruses are a significant biological component of Australian underwater soundscapes. Due to the links between fish chorus production and the life functions of the fishes producing them, passive acoustic monitoring of fish choruses can provide important ecological data that can be applied to the management of fish populations and their respective habitats. However, little is known regarding the distribution, behaviour, drivers, and functions of fish choruses produced in offshore environments. This study utilised long-term passive acoustic monitoring data to investigate the environmental drivers of a fish chorus recorded along the southern Australian continental shelf, off Portland, Victoria. Generalised Additive Mixed Models were applied to acoustic recordings alongside a range of environmental remote sensing data which captured local conditions such as primary productivity, water temperature, current, sea surface height, nutrient availability, salinity, moonlight levels, and wind speed. This study revealed a significant relationship between the Portland fish chorus and periods of high local primary productivity resulting from the Bonney Coast upwelling system. This upwelling system is predicted to be significantly impacted by climate change in the future. As the Portland fish chorus may be produced as a function of feeding or reproduction, this study has provided a baseline for tracking the response of the chorus source species to future environmental and anthropogenic change.