Glass sponge reef soundscapes

Abstract

Many structured biogenic habitats are biodiversity hotspots and thus possess unique soundscapes largely driven by the biophony. To date, the vast majority of research has focused on shallow-water biogenic habitats such as coral or oyster reefs. Glass sponge reefs are a deep-water habitat analogous in many ways to shallow-water coral reefs. These reefs are built by three species of hexactinellid sponges which form complex 3-dimensional habitats that support diverse communities of animals. Many soniferous animals, including rockfish, are strongly associated with patches of live-sponge dominated habitat within the reef foot-print. Consequently, we hypothesized that glass sponge reefs and the communities they support would generate unique soundscapes. Beginning in September of 2016, we deployed a series of underwater acoustic recorders on sponge reefs throughout Canada’s Pacific continental shelf. Initial results show that recorders located on sponge reefs were significantly louder in the mid- and high-frequency bands (100–1000 Hz and 1–10 kHz, respectively). Additionally, many fish calls were detected in recordings from within sponge reefs, while few fish calls were observed at similar depths in off-reef habitats. We will discuss our understanding of the link between soundscapes and biodiversity in glass sponge reef habitats and the potential application of ecosystem-level monitoring.