The research, published in Frontiers in Mammal Science, presents the first passive acoustic monitoring survey of beluga habitat use in the Churchill River estuary. Because the monitoring took place in summer 2020, during COVID-19 travel restrictions and the early stages of the Port of Churchill’s reopening, maritime activity was unusually low. Whale-watching was limited to a handful of motorboats, and commercial traffic consisted of a single vessel. That quiet window gave scientists a rare chance to record beluga vocal behavior under near-natural conditions, establishing an acoustic benchmark before planned port expansion increases vessel traffic and underwater noise.

The technical setup was ambitious. Two single-channel Porpoise hydrophones, mounted on custom moorings designed to eliminate any moving parts that could generate noise, were deployed roughly two kilometers apart in the estuary. One recorder sat in deeper water in front of the Port of Churchill; the other lay upstream, away from the main navigational channel. The hydrophones sampled at 192 kilohertz, fast enough to capture both beluga tonal sounds and echolocation clicks, whose energy is concentrated between 30 and 50 kilohertz. Over 33 days, the recorders logged 1,315 hours of audio across 2,720 files, running on a duty cycle of 29 minutes on and 1 minute off.

Automated detectors developed by JASCO Applied Sciences identified beluga vocalizations in two categories: tonal sounds, including whistles and buzzes, and clicks. Six contour detectors followed the time-frequency traces of tonal calls, while a click detector based on the Teager-Kaiser energy method processed high-pass-filtered data. To verify performance, the team manually analyzed a random 5 percent subset of recordings, comparing hand annotations with algorithm output. The detectors proved reliable, achieving precision of 0.85 and recall of 0.91 for clicks, and precision of 0.79 and recall of 0.91 for tonal sounds, with manual and automated counts strongly correlated.

Statistical models then linked the vocalization counts to environmental variables. Generalized linear mixed models with a negative binomial distribution tested vocal activity against tide phase and light level, with hydrophone location as a random effect and an autoregressive structure to handle temporal autocorrelation. Light level and tide phase both emerged as significant predictors. Vocal activity was substantially higher during daytime than nighttime, and flood tide produced more vocalizations than high tide for both clicks and tonal sounds. Tonal sounds were also more frequent during flood tide than ebb tide.

The spatial patterns were just as revealing. The deeper downstream recorder, near the river mouth, consistently logged more vocalizations than the shallower upstream site, regardless of time of day or tide. At the downstream site, tonal sounds peaked during flood tide, declined during high and ebb tides, and rose again at low tide, a sequence consistent with belugas entering the estuary on rising water, moving upstream, and returning downstream. The upstream site showed maximum tonal sound detections during flood and high tides, when water levels were highest, and minimum detections at low tide. Belugas appear to use high tides to access shallow upstream areas that would strand them at lower water, a pattern matching earlier visual studies of the estuary.

Because tonal sounds in belugas are typically associated with social interactions, while clicks are linked to echolocation for navigation and prey detection, the acoustic geography hints at behavioral functions. Upstream shallow areas, busy with tonal sounds during high water, may serve primarily as social grounds, possibly including molting. The high click counts at the deeper downstream site during low tide suggest increased echolocation, potentially for navigation or opportunistic foraging, since tidal currents can aggregate prey in deeper channels. Notably, the waters in front of the port itself showed elevated tonal sounds during low and flood tide, indicating that this area, too, is important for social behavior.

Then came the dramatic moment. Beginning in the first week of September, detections of both clicks and tonal sounds dropped sharply at both locations, with the upstream site declining by up to two orders of magnitude from mid-August onward. The timing coincided with the strongest winds and heaviest precipitation of the monitoring period, with gusts peaking at 80 kilometers per hour on September 7. It also occurred shortly before a 137-meter general cargo ship entered the estuary on the morning of September 8 and departed the next day. Because belugas can detect vessel noise over considerable distances, they may have perceived the approaching ship before it arrived. The authors caution that vessel traffic and weather cannot be disentangled with the present dataset, and that no marked increase in background noise appeared in the spectrograms, making reduced detectability alone an unlikely explanation. A modest rebound in vocalizations the following week suggests some belugas returned while others may have moved offshore.

The seasonal decline itself likely reflects the onset of fall migration, consistent with decades of visual observations documenting belugas leaving the estuary between late August and early September. But migration timing may be shifting. Recent satellite-tagging work indicates departures occurring as late as early October, potentially linked to changing sea-ice conditions that prolong the open-water season. Meanwhile, climate change is projected to increase the frequency and intensity of Arctic storms, which could conversely trigger earlier departures. Multi-year acoustic monitoring will be needed to determine whether beluga migration timing in the estuary is responding to climate change.

The conservation stakes are high. The estuary lies within an Ecologically and Biologically Significant Area and is proposed for inclusion in a National Marine Conservation Area, while the Port of Churchill, the only rail-serviced deep-water port in North America with Arctic access, has announced upgrades, dredging, and potential ice-breaking operations to extend the shipping season. Given the strong site fidelity of Western Hudson Bay belugas, which return to the same estuary each year and pass knowledge of these summering grounds across generations, the overlap between persistently high vocal activity in the deeper central estuary and port operations raises concern about increasing exposure to disturbance. The acoustic benchmark established during this quiet summer now provides a critical pre-expansion reference, allowing future recordings to reveal whether growing maritime activity is silencing the world’s largest beluga gathering.

Subject of Research: The first passive acoustic survey of the Churchill River estuary reveals tidal and diel patterns in beluga vocal activity and a marked decline in calls recorded just before the first cargo ship of the season entered the river, establishing a critical acoustic benchmark before planned port expansion.

Article Title: Establishing an acoustic benchmark of beluga habitat use in the Churchill River estuary, Manitoba

Article References: Coppolaro, V. L. M., Kirillov, S., Isleifson, D., Loseto, L. L., & Marcoux, M. (2026). Establishing an acoustic benchmark of beluga habitat use in the Churchill River estuary, Manitoba. Frontiers in Mammal Science, 5, Article 1903254. https://doi.org/10.3389/fmamm.2026.1903254

Image Credits: AI Generated

DOI: 10.3389/fmamm.2026.1903254

Keywords: beluga whales, Churchill River estuary, passive acoustic monitoring, Western Hudson Bay, vessel traffic, underwater noise, marine conservation, Port of Churchill, tide patterns, fall migration, Establishing, acoustic

The platform under study is no small fixture. Stretching 101 meters long and 47.5 meters wide, with an aquaculture draft of 15 meters and roughly 60,000 cubic meters of farming water, it represents the new generation of offshore infrastructure designed to relieve pressure on saturated nearshore waters. Powered by a hybrid system of photovoltaic panels and diesel generators, these truss platforms are becoming the mainstream equipment for deep-sea aquaculture across coastal provinces like Guangdong, Shandong, and Hainan. Yet until now, almost nothing was known about how their operations reshape the underwater soundscape that marine organisms depend on for foraging, communication, predator avoidance, and navigation.

The research team deployed hydrophones at three strategic locations: inside the central net pen where fish are actually farmed, near the propulsion hatch on the platform deck, and at a distant reference station 1.5 kilometers away. A sound level meter simultaneously recorded airborne noise on the deck corridor, while a self-contained current meter and high-precision tide gauge tracked the hydrodynamic conditions. Everything ran continuously for 46 hours under unusually calm sea conditions, with mean wind speeds of just 4.3 meters per second and sea state below Force 2, providing a clean baseline for isolating the platform’s acoustic signature from natural background noise.

What emerged from the data was striking. During generator operation, the underwater near-field exhibited a discrete harmonic skeleton centered on a fundamental frequency of 24.41 Hz, with power spectral density reaching 122.29 dB re 1μPa²/Hz, approximately 16 dB higher than the idle baseline. Sharp narrowband peaks appeared at harmonic multiples including 48.8, 73.2, 100, and 122 Hz, forming a fingerprint unmistakably tied to the platform’s propulsion system. Above 500 Hz, the interference rapidly faded, and beyond 2 kHz the spectral curves before and after startup completely overlapped with the natural environmental background, which remained within the 72 to 86 dB range.

Perhaps the most compelling evidence came from the moment of generator startup and shutdown. The researchers observed pixel-level temporal synchronization between the deck’s airborne sound field and the underwater near-field radiation. When the 25 Hz spectral line abruptly vanished from the air spectrum, the bright high-energy band in the underwater low-frequency range collapsed in a vertical cliff-like manner. Simultaneously, the baseline at the 1.5-kilometer distant station experienced a spontaneous drop to the quietest state of the entire monitoring period. This triple alignment across three independent measurement domains pointed to a single conclusion about how the acoustic energy reaches the water.

Because air and seawater have an acoustic impedance mismatch of roughly 3,600 to 1, atmospheric noise incident at the sea surface experiences significant reflection losses, making direct airborne transmission into the water negligible. Instead, the structural elastic waves excited by the propulsion system travel as solid-borne vibrations through the rigid truss pile foundation, conducted along the steel columns to their underwater outer walls, where they radiate into the water column. This finding has immediate engineering implications: noise control for such platforms should prioritize structural isolation and vibration damping at equipment foundations rather than relying solely on sound-absorbing barriers within deck machinery rooms.

The distant acoustic environment told its own story. Within the observation window, the low-frequency soundscape at the 1.5-kilometer station appeared modulated by semidiurnal tidal dynamics, with noise peaks lagging behind tidal peak levels by approximately 6 hours. During neap tide periods, when current velocity dropped below 0.3 meters per second, the acoustic background fell below -40 dB re 1μPa²/Hz, forming regular low-energy troughs. Conversely, during stronger tidal-current transitions, the low-frequency energy rose in phased association with the surging flow. The researchers interpret this as flow noise excitation driven by turbulent boundary layer pressure fluctuations and vortex shedding across the seabed topography, processes that decay substantially when currents weaken below the empirical threshold.

Day-night differences added another layer of complexity. The team measured sound-speed profiles in the shallow-water channel and found a distinct minimum at approximately 4 meters depth during the day, creating a natural acoustic waveguide that confines sound energy. At night, surface cooling and evaporative heat loss flipped the profile into a positive gradient with upward refraction, forcing sound rays to strike the sea surface repeatedly. Under the rougher nocturnal sea surface, this enhanced incoherent scattering plausibly explains the observed decay of the distant-station characteristic sound after dark, allowing the ambient soundscape to return to its natural quiet trough. The total sound-speed change across the water column at night reached approximately 1.96 meters per second, significantly greater than daytime fluctuations.

The ecological stakes are considerable. Fish rely on acoustic signals for essential life functions, and anthropogenic underwater noise can disrupt these behaviors through auditory masking, physiological stress, and behavioral avoidance. Repeated exposure to vessel noise has been shown to damage sensory hair cells in fish inner ears and trigger irreversible declines in auditory sensitivity, while noise exposure alters daily swimming patterns and escape responses. Because modern aquaculture management increasingly depends on acoustic technologies, including sonar-based biomass estimation, acoustic virtual fencing, and passive monitoring of fish behavior, understanding the platform’s own noise characteristics becomes a core prerequisite for optimizing equipment deployment and improving detection accuracy.

The researchers are careful to frame their conclusions appropriately. These findings derive from a single 46-hour campaign under calm conditions and should be regarded as process-level evidence rather than climatological statistics, applicable only to the observation window and not extrapolatable to other seasons or sea states without further measurements. Limitations include single-range sampling, the absence of direct in-situ structural vibration measurements, and the lack of sediment acoustic parameters. Future work will employ multi-node, multi-range arrays and full-waveform inversion to achieve precise reconstruction of the three-dimensional acoustic radiation, propagation, and attenuation boundaries of large fixed offshore facilities. For now, the study provides foundational data for acoustic environment monitoring, ecological impact assessment, and the optimized deployment of aquaculture acoustic equipment on similar deep-sea platforms worldwide.

Subject of Research: Underwater noise characteristics and tidal modulation of the acoustic environment around a large truss-type deep-sea aquaculture platform

Article Title: A study on the evolutionary patterns of the acoustic environment of large-scale truss-type deep-sea aquaculture platforms

Article References: Wu, D., Qu, K., Yang, B., Deng, X., Chen, X., Ling, W., & Qi, Y. (2026). A study on the evolutionary patterns of the acoustic environment of large-scale truss-type deep-sea aquaculture platforms. Frontiers in Marine Science, 13, Article 1962198. https://doi.org/10.3389/fmars.2026.1962198

Image Credits: AI Generated

DOI: 10.3389/fmars.2026.1962198

Keywords: deep-sea aquaculture, underwater noise, truss platform, passive acoustics, tidal dynamics, solid-body transmission, underwater soundscape, acoustic monitoring, marine ecology, Frontiers in Marine Science, evolutionary, patterns

The study was led by Til Böttner as part of his doctoral thesis at the Department of General Zoology and Neurobiology at Ruhr University Bochum. As he explains, the team set out to determine which components of low-frequency, vibroacoustic stimuli actually elicit behavioral responses in the sea squirt. To answer that question, the researchers combined two complementary approaches: field experiments conducted in the Mediterranean, where Halocynthia papillosa lives naturally, and controlled laboratory conditions that allowed them to isolate and manipulate individual components of acoustic stimulation. This dual design matters, because in the real ocean, sound pressure, particle motion, and substrate-borne vibrations are physically intertwined, and teasing apart their relative contributions is one of the hardest problems in modern bioacoustics.

The behavioral results were clear and, in one respect, surprising. The sea squirts responded with contractions mainly to stimuli in a frequency band between 50 and 800 Hertz, a range that overlaps substantially with the low-frequency noise produced by shipping, construction, and other human activities at sea. Interestingly, these reactions were associated with increased vibrations in the substrate, the solid material on which the animals sit. In other words, when the seafloor itself trembled, the sea squirts noticed, contracting in a measurable defensive response. The frequency specificity of the reaction suggests a genuine sensory process rather than a generic startle, and it places these seemingly primitive animals within the growing roster of marine invertebrates known to detect and react to anthropogenic noise.

The most striking result, however, was what the animals did not do. Even when the underwater sound pressure levels exceeded 130 decibels, a level that would be considered significant by many standards used in noise-impact assessments, the sea squirts showed no comparable reactions, provided that the substrate vibrations remained below the thresholds the team had determined experimentally. As researcher Huhn concludes, the results show that sound pressure alone cannot explain the observed behavioral reactions. That single sentence carries considerable weight. Much of the regulatory and scientific framework for underwater noise relies on sound pressure measurements, and this study demonstrates that for at least one benthic species, such measurements may simply miss the stimulus that matters.

The physics behind this distinction is worth unpacking. Underwater sound is conventionally described by two related but distinct quantities: sound pressure, the oscillating compression of the water, and particle motion, the back-and-forth displacement of water molecules, which can be characterized in terms of displacement, velocity, or acceleration. Most fish and many invertebrates are thought to be sensitive to particle motion rather than pressure, yet pressure is far easier to measure and remains the standard metric in noise monitoring. To complicate matters further, at low frequencies a portion of the acoustic energy couples into the seabed and propagates as seismic waves, producing substrate-borne vibrations. For an animal cemented to a rock, like an ascidian, the substrate may effectively be the most direct pathway through which mechanical energy from a distant noise source reaches its body.

What sensory machinery might these animals be using? The answer is not yet certain, and the researchers are careful on this point. However, sea squirts possess specialized ciliated mechanoreceptor cells in the region of their siphons, the twin openings through which they draw in and expel water for filter feeding. These cells are particularly concentrated in a structure known as the coronal organ, and they may register local movements in the water or mechanical deformations of the body surface. Böttner notes that further physiological and neurobiological studies are required to determine whether these receptors are stimulated by particle motion in the water or by vibrations transmitted via the substrate and the mantle, the tough outer covering of the animal. Resolving that question will require direct recordings from the sensory cells and their associated neural pathways, work that is now on the research agenda in Bochum.

The coronal organ itself is a fascinating structure in evolutionary terms. Ciliated mechanoreceptor cells lining the siphons of ascidians are considered homologous, in a broad sense, to the hair cells of vertebrate ears, making tunicates a valuable model for understanding the deep evolutionary origins of mechanosensation. If Halocynthia papillosa is indeed detecting noise through these cells, the study would suggest that sensitivity to low-frequency mechanical disturbance is an ancient trait, present in animals whose lineage split from ours hundreds of millions of years ago. It would also imply that the coronal organ, long studied for its role in detecting water flow and potential threats as the animal adjusts its pumping behavior, may serve double duty as a vibroacoustic sensor tuned to the frequency range where human noise is loudest.

The researchers are candid about the limits of the current work. Sound pressure, particle motion, and substrate-borne vibrations are physically closely intertwined under water, especially at low frequencies, which makes it impossible to completely separate these factors, including in this study. Every acoustic stimulus delivered to an animal in a tank or on a reef carries some mixture of all three components, and even the most careful experimental design can only approximate the isolation of one pathway. Nevertheless, the findings show, as the researchers in Bochum put it, that the mechanical components of underwater sound have to be more closely considered in the examination of benthic organisms, the animals that live on or in the seafloor. For a field that has historically focused on fish, whales, and other free-swimming species, that is a significant redirection of attention toward the sessile majority of marine life.

The broader context makes this redirection urgent. Anthropogenic underwater noise, from commercial shipping and seismic surveys to pile driving and coastal construction, has increased dramatically over recent decades and is now recognized as a global environmental concern. Most impact assessments rest on sound pressure thresholds derived from studies of vertebrates, and the possibility that attached invertebrates respond primarily to substrate vibrations suggests that current metrics may systematically underestimate or mischaracterize the exposure of benthic communities. Since ascidians, mussels, corals, and other sessile animals cannot swim away from a noise source, their behavioral responses, such as the contractions observed in this study, may represent one of the few defenses available to them, and repeated disturbances could carry energetic or ecological costs that have yet to be quantified.

Future studies at Ruhr University Bochum aim to identify which mechanical stimuli are actually perceived by the sea squirts and how these stimuli are sensorially and neuronally processed, integrating marine biology, bioacoustics, and neurobiology into a single research program dedicated to understanding the effects of anthropogenic underwater noise in greater detail. The work has already drawn international recognition: Til Böttner received the prize for the best presentation by an early-career researcher at the International Tunicate Meeting for his presentation of this research. For now, the message of the study is both simple and disruptive to conventional thinking. An animal without ears can still feel the noise of the ocean, and it feels it through the ground. Any serious effort to understand, predict, or mitigate the impact of underwater noise on marine ecosystems will need to listen not only to the water, but to the seafloor beneath it.

Subject of Research: Behavioral responses of the sea squirt Halocynthia papillosa to underwater vibroacoustic stimuli and substrate-borne vibrations

Article Title: How sea squirts perceive underwater noise

Article References: How sea squirts perceive underwater noise. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: sea squirts, ascidians, underwater noise, substrate vibrations, sound pressure, particle motion, mechanoreceptors, coronal organ, bioacoustics, marine biology, anthropogenic noise, benthic organisms

The scientific and legal momentum behind tools like TUNE stems largely from the European Union’s Marine Strategy Framework Directive, the landmark 2008 legislation that obliges member states to achieve Good Environmental Status in their marine waters. Under the Directive’s Descriptor 11, which covers the introduction of energy, including underwater sound, two distinct criteria apply. The first addresses low- and mid-frequency impulsive sounds, such as the hammering of pile drivers during offshore construction, while the second targets continuous low-frequency noise, dominated overwhelmingly by commercial shipping. Shipping noise is the most pervasive form of underwater noise pollution and dominates ambient sound levels below one kilohertz across much of the world’s oceans. Criterion D11C2 specifically requires monitoring programs to report sound pressure levels within decidecade frequency bands centered at 63 and 125 hertz, two narrow slices of the acoustic spectrum that serve as proxies for overall shipping-related noise exposure.

Meeting that regulatory requirement sounds straightforward, but in practice it has been anything but. Reliable estimation of these acoustic quantities depends on robust and reproducible signal processing workflows, and the software landscape has long been fragmented. Raven Pro, a mainstay of bioacoustics research, offers limited flexibility in calibration and requires a commercial license. MATLAB-based tools such as CHORUS provide advanced processing capabilities but are not distributed as freely available standalone applications. The open-source MANTA package has improved accessibility and standardization for long-term ocean soundscape analysis, but it produces outputs in hybrid millidecade bands rather than the decidecade bands adopted for Marine Strategy Framework Directive reporting. Many other packages remain proprietary or closed-source, preventing users from inspecting and verifying the algorithms that ultimately feed into official environmental assessments. TUNE was engineered to close this gap by combining calibration accuracy, usability and regulatory compliance in a single freely available package distributed under the GNU General Public License.

At its core, TUNE processes calibrated acoustic recordings in wav format and computes a suite of standard underwater noise metrics. These include broadband sound pressure level, decidecade sound pressure level, zero-to-peak sound pressure level and power spectral density estimates. The software embraces recent international standardization: it uses the term decidecade in place of one-third octave band, following the 2025 update of the relevant ISO standard, which considers the two metrics approximately equivalent, and it adopts the sound pressure symbol conventions of ISO 18405:2017 for the definitions and equations of all four metrics. Processing is carried out over user-defined time intervals called snapshots, a concept aligned with the temporal observation windows introduced in recent ISO documents. Each recording can be segmented into consecutive, skipped or overlapping snapshots, allowing fully time-resolved estimates of how noise levels rise and fall, for example as a vessel approaches and then recedes from a monitoring station.

A distinguishing technical feature of TUNE is its support for frequency-dependent calibration. Hydrophones, the underwater microphones that record ocean sound, do not respond uniformly across frequencies, and their sensitivity can vary substantially across the acoustic spectrum. Many existing tools accept only a single calibration factor, which introduces errors when the hydrophone response is uneven. TUNE instead accepts a two-column text file containing frequency values and corresponding hydrophone sensitivity, expressed either as voltage sensitivity in decibels relative to one volt per micropascal or as an equivalent calibration factor in pascals per volt, with a minimum of three frequency points required. Spectral estimates are corrected bin by bin using this sensitivity curve, improving the accuracy of the resulting sound pressure levels. The software also allows optional high-pass, low-pass or band-pass digital filtering before analysis, with filters designed to fixed passband ripple and stopband attenuation specifications, and it supports flexible FFT parameters including window type, overlap and transform length.

Internally, the software follows a modular architecture organized into five stages: user input, data import, calibration, signal processing and output generation. A single-window graphical user interface lets users configure directories, calibration files, time ranges, spectrogram settings and filtering options, and the entire parameter set can be saved and reloaded as a setup file to guarantee reproducibility across monitoring campaigns. Processing proceeds through three nested loops at the file, channel and snapshot levels, with multi-channel recordings handled channel by channel. For each snapshot, the software computes a series of Fast Fourier Transforms over signal subsegments and averages them into a single representative spectrum, then corrects that spectrum against the calibration curve. Decidecade integration is performed using the nearest available FFT bins rather than exact theoretical band edges, a pragmatic approximation that benchmarking described in the paper’s supplementary materials shows produces negligible discrepancies for standard monitoring applications, while dramatically accelerating computation. One creative addition is the option to overlay Knudsen curves for sea states zero through six, letting analysts compare measured ambient noise against classic empirical predictions of wind-driven sea-state noise.

To demonstrate the tool, the researchers analyzed a real recording of a ship passing through a harbor, captured with a Teledyne Reson TC4040 hydrophone and VP1000 preamplifier feeding a Tascam DR-100 recorder at 96 kilohertz sampling with 24-bit resolution. The ten-minute recording was processed in ten-second snapshots using 131072-point FFTs with a Hann window and fifty percent overlap, and the entire computation completed in just two minutes and thirty-five seconds. The results were vivid: mean sound pressure levels in the 63 and 125 hertz decidecade bands reached 111 and 117 decibels respectively, the mean broadband level was 123 decibels, and the maximum zero-to-peak level hit 156 decibels at 256 seconds into the recording, precisely the closest point of approach of the vessel. All four metrics rose clearly during the first half of the recording, matching the ship passage documented in the campaign logs, and every output was delivered both as figures and as numerical text files ready for statistical aggregation across recordings, sites and seasons.

The impact of the software is already visible in practice. By providing a consistent, transparent and reproducible framework for acoustic data processing, TUNE directly addresses a long-standing problem: differences in signal processing workflows can produce substantial discrepancies in reported sound pressure levels, undermining the comparability of environmental assessments across institutions and countries. Perhaps most significantly, the tool has been adopted by multiple Regional Environmental Protection Agencies in Italy, establishing a shared national framework for underwater noise monitoring and overcoming methodological fragmentation among regional programs. This software-driven harmonization improves the consistency of reported indicators, increases transparency in reporting and supports the coordinated implementation of national monitoring obligations under the Marine Strategy Framework Directive. Because TUNE can process long-term acoustic datasets and generate decidecade-band time series, it also supports the estimation of baseline conditions, trend analysis and threshold exceedance assessments in line with recent European Commission guidance on threshold values.

The developers see TUNE as a foundation rather than a finished product. Future versions will extend the range of computed metrics to include the Sound Exposure Level, which would allow the software to cover the Directive’s impulsive-sound criterion in addition to continuous noise, along with greater flexibility in temporal analysis. Beyond European regulatory monitoring, the authors note that the tool’s applicability extends to a broad range of marine and freshwater acoustic studies, from low-noise calibration sites to research linking low-frequency noise shifts to changes in fin whale song. In a field where proprietary licenses and closed algorithms have often stood between environmental agencies and their legal obligations, TUNE represents a quietly radical proposition: that the measurement of a pollutant threatening ocean life should be accurate, transparent and free for anyone who needs it.

Subject of Research: A free standalone software tool for standardized evaluation of underwater noise pollution under the Marine Strategy Framework Directive

Article Title: TUNE: a Tool for Underwater Noise Evaluation

Article References: Caradonna, V., Buogo, S., Azzellino, A., Vicinanza, D., & Borsani, J. F. (2026). TUNE: a Tool for Underwater Noise Evaluation. SoftwareX, 35, Article 103008. https://doi.org/10.1016/j.softx.2026.103008

Image Credits: AI Generated

DOI: 10.1016/j.softx.2026.103008

Keywords: underwater noise, TUNE software, Marine Strategy Framework Directive, shipping noise, hydrophone calibration, sound pressure level, decidecade bands, power spectral density, ocean acoustics, marine monitoring, MATLAB, environmental protection