Fishing for sound: Monitoring reef communities with passive acousticsNovel Approaches

Maryann Watson¹

¹University of Groningen, Netherlands

Monitoring coastal marine habitats presents many challenges. Using multiple methods to capture different aspects of ecosystems can strengthen the information gained regarding habitat status and provide additional insights. Passive acoustic monitoring presents a low impact and innovative method to provide metrics for long-term monitoring of habitats through descriptions of acoustic patterns, or soundscapes, of biological communities. In the Wadden Sea, a highly degraded coastal ecosystem, two artificial reef experiments were deployed in 2021 and 2022 with similar goals of testing the effects of reintroducing habitat complexity for reef communities. Fish sampling at these two experimental sites show that the reef community is developing over time. Soundscape recordings at these sites reveal patterns of biological sounds across trophic levels (including fish and seals) with higher sound abundances and diversity on the reefs compared to adjacent bare sand, giving us an enhanced picture of habitat use over traditional monitoring methods such as fishing. Collecting bioacoustic signals over multi-week periods, fish presence and abundance is represented holistically versus single point surveys or sampling. By improving our knowledge of artificial reef community development due to novel monitoring techniques, we can better understand how these habitats are used. This is particularly important in high-priority restoration areas, where comprehensive monitoring is essential to larger-scale and longer-term restoration projects.