Whales, wind, and whale watching—Uncovering the secret soundscape of Geographe Bay

Abstract

Quantifying the acoustic soundscape of an area is an important precursor to understanding the significance of that area from an environmental perspective, as well as providing useful environmental context to inform environmental management. Underwater soundscapes provide important contextual information about the use of that habitat by marine fauna species as well as some of the anthropogenic stressors that may be present. Multi-year acoustic data collected from an underwater acoustic recorder near Cape Naturalist in Geographe Bay was used to characterize the underwater soundscape and complete an initial assessment of cetacean presence. Ambient noise conditions within the Bay were characterized, providing an interim baseline of the ambient noise conditions within the Bay, identifying the biological and anthropogenic contributors to the soundscape. This characterization provided a better understanding of species presence within the Bay and general trends in occurrence, and has also been used to investigate the scale and extent of existing anthropogenic pressures. The information from the monitoring program has been applied to better understand the value of the Geographe Bay area to different species, while at the same time setting a benchmark for ongoing monitoring efforts and providing inputs into detection range modeling to assist in enhancing program design.