The Noise Reference Station (NRS) Network is a flagship project of the NOAA Ocean Noise Strategy, established to document baseline ocean ambient sound conditions, inform noise management, and support research, national security, and public engagement with ocean acoustic environments. This unique network of hydrophones is a collaborative effort between OAR’s Pacific Marine Environmental Laboratory (PMEL), the NMFS Ocean Acoustics Program (OST), all NMFS Science Centers, the NOS National Marine Sanctuary System, and the National Park Service to establish and collect consistent and comparable long-term acoustic data sets covering all major regions of the U.S.

Background

Passive acoustic monitoring of the ocean ambient sound field is a critical aspect of NOAA’s mandate for ocean and coastal stewardship. This includes detecting and characterizing: (1) sounds produced and used by living marine resources (e.g., endangered marine mammals); (2) natural sources of noise from physical oceanographic processes; and (3) anthropogenic noise sources that contribute to the overall ocean noise environment. Noise generated by anthropogenic activities (especially commercial shipping and seismic oil & gas exploration) is increasingly being recognized as a potential threat to marine mammals which are protected in the U.S. by the Marine Mammal Protection Act and the Endangered Species Act. Current scientific data suggest that increased ambient noise levels impact marine mammals by hindering communication, altering communication behavior, altering locomotive behavior, and inducing stress. Additional concerns associated with the degraded acoustic quality of diverse habitats broaden these concerns to include possible repercussions for fish and invertebrate species, many of which NOAA manages as commercially-harvested, protects as resources within sanctuaries, or studies as key elements to sustaining healthy ecosystems. For these reasons it is important for science-based regulatory agencies including NOAA to monitor long-term trends and changes in the ambient sound field.

The NRS is internationally recognized and engages U.S. and international partner scientists across universities, research institutes, federal laboratories, and private industry.  The NRS is also DOD-supported in the Coast Guard 2023 National Defense Authorization Act (Section 315). NRS data have been utilized to directly influence management decisions. For example, Haver et al (2020) provided new information about whale presence near the NRS offshore of Central California, resulting in an extension of a seasonal vessel slow down to reduce interactions between large vessels and cetaceans. These data have also provided important information for the NOAA Office of National Marine Sanctuaries condition reports. The NRS project encompasses a successful partnership with the National Parks Service to document conditions in marine national parks. The NRS is a cross-NOAA collaboration with PMEL (OAR) providing critical instrumentation that was designed and customized specifically for long-term continuous monitoring of deep-water environments.

Research Objective

The objective of the project is to establish a network of ocean noise reference stations in U.S. waters to monitor long-term changes and trends in the underwater ambient sound field (Haver et al. 2018, 2025). The identical autonomous acoustic recording systems were developed and built in-house at PMEL to ensure proper calibration and consistency of the collected data sets. The hydrophone moorings are currently deployed in the following areas:

Deployments

Over 63 cumulative years of audio data are publicly available for download at the National Centers for Environmental Information Passive Acoustic Archive.

It is of critical importance to continue these baseline measurements to gauge the changes in the marine ambient sound environment.. We investigate the spatio-temporal variability in low-frequency deep ocean ambient sound levels (10 - 2,000 Hz) at these 13 ocean regions within the U.S. EEZ. View standardized time-series metrics of sound levels, detection products, and other ocean indicators from these sites and other NOAA-led monitoring projects at the U.S. Ocean Sound Monitoring and Condition Reporting website. Our ongoing goal is to maintain the array, building on the multi-year record of ambient sound levels in these regions.

Listening to the Sea - NOAA story map of the Ocean Noise Reference Network

Selected Publications

Dziak, R.P., Haver, S.M., Roche, L., Mellinger, D.K., Gedamke, J. (2025). North Pacific Ocean sound levels 2018–2022: COVID-19 pandemic impacts on anthropogenic noise. Npj Acoust., 1, 15. https://doi.org/10.1038/s44384-025-00017-6

Haver, S.M., Adams, J.D., Hatch, L.T., Van Parijs, S.M., Dziak, R.P., Haxel, J., Heppell, S., McKenna, M., Mellinger, D.K., Gedamke, J. (2021). Large vessel activity and low-frequency underwater sound benchmarks in United States waters. Frontiers in Marine Science, 8, 669528, 1-13. https://doi.org/10.3389/fmars.2021.669528

Haver, S.M., Dziak, R.P., Hatch, L.T., Haxel, J., Kavanagh, C., Matsumoto, H., McKenna, M.F., Roche, L., Parijs, S.M.V., Wall, C.C., Gedamke, J. (2025). Retrospective on decadal progress of the NOAA/NPS ocean noise reference station network. PeerJ, 13, e20382. https://doi.org/10.7717/peerj.20382

Haver, S., Gedamke, J., Hatch, L.T., Dziak, R.P., Van Parijs, S., McKenna, M., Barlow, J., Berchok, C., DiDonato, E., Hanson, B., Haxel, J., Holt, M., Lipski, D., Matsumoto, H., Meinig, C., Mellinger, D.K., Moore, S., Oleson, E., Soldevilla, M., Klinck, H. (2018). Monitoring Long-Term Ambient Noise Trends in U.S. Waters: The NOAA/NPS Ocean Noise Reference Station Network. Marine Policy, 90C, 6-13. https://doi.org/10.1016/j.marpol.2018.01.023

Haver, S., Fournet, M.E.H., Dziak, R.P., Gabriele, C., Gedamke, J., Hatch, L.T., Haxel, J., Heppell, S.A.,McKenna, M., Mellinger, D.K., Van Parijs, S.M. (2019). Comparing the Underwater Soundscapes of Four U.S. National Parks and Marine Sanctuaries. Frontiers in Marine Science, 6, 500, 1-14. https://doi.org/10.3389/fmars.2019.00500

Haver, S.M., Rand, Z., Hatch, L.T., Lipski, D., Dziak, R.P., Gedamke, J., Haxel, J., Heppell, S., Jahncke, J., McKenna, M., Mellinger, D.K., Oestreich, W., Roche, L., Ryan, J., Van Parijs, S.M. (2020). Seasonal trends and primary contributors to the low frequency soundscape of the Cordell Bank National Marine Sanctuary. Journal of the Acoustical Society of America, 148 (2), 1-14. https://doi.org/10.1121/10.0001726

Munger, J.E., Herrera, D.P., Haver, S.M., Waterhouse, L., McKenna, M.F., Dziak, R.P., Gedamke, J.,Heppell, S.A., Haxel, J. (2022). Machine learning analysis reveals relationship between pomacentrid calls and environmental cues. Marine Ecology Progress Series, 681, 197-210. https://doi.org/10.3354/meps13912

Pearson, E.J., Oestreich, W.K., Ryan, J.P., Haver, S.M., Gedamke, J., Dziak, R.P., Wall, C.C. (2023). Widespread passive acoustic monitoring reveals spatio-temporal patterns of blue and fin whale song vocalizations in the Northeast Pacific Ocean. Front. Remote Sens., 4. https://doi.org/10.3389/frsen.2023.994518

Wall, C.C., Haver, S.M., Hatch, L.T., Miksis-Olds, J., Bochenek, R., Dziak, R.P., Gedamke, J. (2021). The next wave of passive acoustic data management: How centralized access can enhance science. Frontiers in Marine Science, 8, 703682, 1-15. https://doi.org/10.3389/fmars.2021.703682

Wall, C.C., McKenna, M.F., Hatch, L.T., Van Parijs, S.M., Bochenek, R., Dugan, P., Parcerisas, C., Ryan, J., Anderson, C.D., Becker, K., Berchok, C., Biddle, M., Boebel, O., Canino, A., Canonico, G., Cline, D., Davis, G.E., Frasier, K., Gedamke, J., Haver, S.M., Khazmutdinova, K., Kinneging, N., Kumar, A., Marian, A., Miksis-Olds, J.L., Montie, E.W., Ponirakis, D., Rice, A.N., Rowell, T.J., Rueda, C., Shumchenia, E., Shyka, T., Staaterman, E., Thomisch, K. (2025). Big data, sound science, lasting impact: A framework for passive acoustic monitoring. Big Earth Data, 0, 1–35. https://doi.org/10.1080/20964471.2025.2583505

Investigators

Robert P. Dziak, Samara Haver, Lauren Roche, Jay Turnbull, David K. Mellinger
NOAA/PMEL Acoustics/CIMERS
2115 SE OSU Drive
Newport, OR 97365
Robert.P.Dziak@noaa.gov
Samara.M.Haver@noaa.gov
Lauren.K.Roche@noaa.gov
James.Turnbull@noaa.gov
David.K.Mellinger@noaa.gov