How environmental acoustics enhance offshore wind projects
By using underwater acoustic monitoring to capture the sounds of marine life over time and across different locations, researchers can assess the ecological impacts of offshore wind development at every stage, from planning through to decommissioning.
What is environmental acoustics?
Environmental acoustics includes two closely related fields that investigate animal sounds and their relationship with the environment. Both fields are interdisciplinary, merging principles from biology, ecology, physics, and acoustics to understand animal communication and environmental changes. The first field, bioacoustics, explores how living organisms produce, transmit, and receive sound in their environment. The second, ecoacoustics, investigates natural and anthropogenic sounds and their relationships with the environment.
Both fields rely on collecting and analysing underwater sounds using hydrophones (underwater microphones), a method known as passive acoustics monitoring (PAM). These devices capture the underwater soundscape (like a landscape but made with sound) over a wide range of frequencies. Further analysis helps identify different species and manmade sound sources.
Environmental acoustics offers several advantages over traditional survey methods. Unlike surveys that take physical samples, environmental acoustic monitoring is non-invasive and can operate continuously. It provides long term data on marine life presence, behaviour, diversity and ecosystem dynamics without disturbing populations and natural habitats. This continuous monitoring is particularly valuable for studying nocturnal and elusive species that are hard to directly observe.
When combined with measurements across a wide area, such as digital aerial surveys for marine mammals or echosounders for fish, acoustic measurements across time can give a deeper understanding of marine life. Traditionally, acoustic monitoring had to be scoped and deployed separately from metocean campaigns used for wind resource assessments. Now, we’ve integrated acoustic analysis directly into our market-leading SEAWATCH® services, enabling acoustic monitoring to run as part of standard metocean deployments for offshore wind development. This allows projects to gain early insights into marine ecology without the need for separate surveys. We’re also incorporating sea ambient noise characterisation, including acoustic levels and spectral distribution, alongside bioacoustics analysis across a wide spectrum of marine species. By revealing how marine animals use an area and how this changes over time, this integrated approach supports legislative compliance and provides essential insight into how acoustic energy varies across development phases.
Applying environmental acoustics in offshore wind
The offshore wind sector faces a double challenge when it comes to underwater noise. First, the sector has seen remarkable growth over the past decade; according to the Global Wind Energy Council, 8 GW of new offshore wind capacity was installed in 2024, bringing the global total to 83 GW. With a projected compound annual growth rate of 25 % to 2030. This growth is driven by the need to reduce carbon emissions and further diversify the energy mix. Second, these projects also generate underwater noise in an already noisy ocean.
Noise levels in the ocean have increased significantly over the last seventy years, largely due to increased international shipping and other human activities. Many creatures in our oceans rely on sound to find food, mates, and their families, so this rise in noise has consequences for them.
At the same time, the cost of underwater recording devices has dropped, the frequency range that can be recorded has expanded, and the ability to analyse and understand the sounds of the oceans is growing dramatically. This has led to the application of environmental acoustics in marine and offshore wind sectors, to better understand how marine species use sound and how sound affects them.
In the same campaign, we can combine environmental acoustics with video analysis of bird life, from our partners at Spoor. This also supports the long-term viability of offshore wind projects, paving the way for a harmonious coexistence between renewable energy development and marine conservation.
More than marine mammals
We’re expanding the application of environmental acoustics beyond marine mammals, using our integrated metocean platforms and collaborating with leading researchers to advance biodiversity monitoring.
While marine mammals have been a primary focus, environmental acoustics is increasingly being applied to other species as well. Marine biologists have used PAM for several decades to study vocalising species of marine mammals such as whales and dolphins. But fish, and even invertebrates, can also be recorded and monitored.
One of the largest efforts to apply PAM to fish biodiversity monitoring was conducted by independent researchers and involved 27 sampling sites covering nearly 2,000 km of coastline over three years. In this study, Di Iorio and colleagues assessed the relationship between fish acoustic biodiversity, habitat parameters, and environmental status (Di Iorio et al., 2021). Their work shows how ecoacoustics can help identify the drivers of large-scale patterns in species distribution and ecosystem dynamics across both space and time. We have supported similar large-scale biodiversity monitoring efforts through our deployment of PAM systems in metocean campaigns, contributing to datasets that inform habitat assessments and ecosystem modelling.
Ecoacoustics analysis has proven to provide valuable insights into fish biodiversity and community dynamics in several environments, ranging from coastal areas to deepsea canyons, over different spatial scales (Bolgan et al., 2020; Bolgan et al., 2022) and in the context of marine energy production (Bolgan et al. 2025). Our work has helped shape the application of ecoacoustics in offshore wind, particularly in understanding fish community dynamics and acoustic biodiversity.
The evolution of fish bioacoustics and ecoacoustics has recently been reviewed, with particular attention to their applications and limitations (Bolgan, 2025). This review shows how research in fish bioacoustics has evolved significantly, from single-species studies to comprehensive biodiversity monitoring. While early work focused on species-specific acoustic behaviour, morphology, and evolution, ecoacoustics now supports conservation and population-level acoustic ecology. Over time, studies have shifted from foundational bioacoustics and species-specific investigations to computational approaches for broader ecological and biodiversity monitoring (Bolgan et al. 2025).
Commercially important species are particularly interesting to monitor using environmental acoustics. These insights can provide valuable information on the location, timing, and duration of spawning aggregations. This is crucial for effective fisheries management and potential impacts from underwater noise. One example of such a species is the Atlantic cod. In this species, both sexes produce a low-frequency grunt during agonistic interactions throughout the year, but males vocalise most during spawning. PAM has been used to monitor Atlantic cod spawning grounds in the Massachusetts Bay for decades (Caiger, P. E et al., 2020). This approach is particularly effective because cod are vocally active during the breeding season, making PAM a long-term, continuous, and non-invasive method for identifying when and where spawning aggregations occur.
Environmental acoustics offers a powerful, non-invasive way to monitor marine life, especially in hard-to-access areas or for elusive species. By integrating PAM into our SEAWATCH® campaigns, we help you gain deeper insights into marine behaviour and temporal patterns, enabling more informed decisions, stronger stakeholder relationships, and reduced environmental impact. While this approach offers many advantages, interpreting acoustic data can be complex and requires specialised expertise. It is also limited to species that produce sound and typically provides relative rather than absolute abundance. That’s why working with experienced professionals is essential to ensure your measurement campaigns deliver meaningful, actionable insights.
Future developments in environmental acoustics
The future of environmental acoustics looks very promising. Advances in machine learning for sound analysis are speeding up species identification, while improvements in communication technologies are enabling more real time monitoring. On-edge analytics are also playing a role by reducing the amount of data that needs to be transmitted. This allows for lower power transmitters and longer battery life. At the same time, more sensitive and durable hydrophones are increasing the reliability and reach of monitoring systems. Together, these developments are helping to reduce the cost per data point of environmental acoustic insights.
There’s also growing potential for wider ecosystem monitoring and acoustic enrichment. Research from Woods Hole Oceanographic Institute (WHOI) and other institutions have identified that reef forming species such as corals and oysters produce measurable sound, and the richness of this sound correlates with the health of the reef (Kaplan, M et al., 2015). WHOI and others have gone a step further, demonstrating that playing the sound of a healthy reef improves the likelihood of larvae settling on degraded reefs during restoration efforts (Lillis, A, et al., 2015) (McAfee, D, et al., 2023). Since reefs form the foundation of many ecosystems, acoustic enrichment offers an exciting new way to support ocean health.
Environmental acoustics are also being integrated with other marine monitoring techniques. Professor Beth Scott at the University of Aberdeen is leading the PELAgIO-ECOWind project, using seabed frames fitted with three sensor types. These include acoustic doppler current profilers to track current movement, upward facing echosounders to detect shoaling fish and diving birds, and PAM to monitor marine mammal predator behaviour. This combination of data provides deeper insights into the biological and non-biological drivers of ecosystems and the influence that marine structures are having on them.
Using these types of active (producing sound) and passive (listening to sound) acoustic techniques over long periods and wide areas could significantly improve scientists’ understanding of marine ecosystems. PAM can provide a more comprehensive and multidimensional view of marine biodiversity and behaviour when combined with other remote sensing methods such as environmental DNA sampling, video analysis, and active acoustics. This integrated approach aims to reduce some of the planning bottlenecks that offshore wind developers currently experience by providing richer, more actionable insights for environmental assessment and consultation.
Conclusion
Both bioacoustics and ecoacoustics offer powerful tools to enhance the understanding of marine ecosystems around offshore wind projects. Environmental acoustics provides long-term insights into marine life presence, behaviour, diversity, and ecosystem dynamics. These insights help developers understand how marine animals use an area, how this changes over time, and how offshore wind turbines may influence those patterns. As technology continues to advance, environmental acoustics is set to play an increasingly vital role in supporting both sustainable energy development and marine conservation.