Structured biogenic habitats are biodiversity hotspots that host a wide range of soniferous species. Glass Sponge Reefs (GSRs) are rare and sensitive systems that have only been documented in shelf habitats in the Northeast Pacific from Portland Canal to the Strait of Georgia, British Columbia, Canada. Galiano Reef is a GSR located in the Salish Sea, in the Outer Gulf Islands Sponge Reef fishing closure, British Columbia, Canada. Little is known about the soundscapes of these deep-water systems and the potential impacts of anthropogenic noise on them. Here we describe the biophony and the anthropophony on and outside of Galiano reef. In September of 2016 we deployed three underwater acoustic recorders that captured sound continuously for approximately four days. The two recordings from the reef (within and at the margin of the reef footprint) were significantly louder in the mid- and high-frequency bands (100-1000 Hz and 1-10 kHz respectively) than the recordings made in soft-bottom habitat away from the reef. These frequency bands are known to correlate with aspects of the biological community as well as benthic cover in shallow-water systems; visual surveys conducted in the area confirmed the presence of several known soniferous species. More fish sounds were recorded on the reef compared to the off-reef site. There was a significant difference in the influence of vessel traffic on Sound Pressure Levels at the three locations across all frequency bands, with the greatest influence in the low frequency band at the reef-margin location. Our results suggest that GSRs have a distinct soundscape, which warrants the use of passive acoustics as a tool to monitor the ecosystem
