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Article

Exploring the Occurrences of Beaked Whales off the West Coast of Ireland Through Passive Acoustic Monitoring (PAM)

by
Beatrice Cheung
* and
Joanne O’Brien
*
Marine and Freshwater Research Centre, Department of Natural Resources and the Environment, Atlantic Technological University, H91 T8NW Galway, Ireland
*
Authors to whom correspondence should be addressed.
J. Mar. Sci. Eng. 2025, 13(9), 1618; https://doi.org/10.3390/jmse13091618 (registering DOI)
Submission received: 15 May 2025 / Revised: 11 August 2025 / Accepted: 22 August 2025 / Published: 25 August 2025
(This article belongs to the Special Issue Recent Advances in Marine Bioacoustics)
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Abstract

Very little is known about goose-beaked whales (Ziphius cavirostris) and Sowerby’s beaked whales (Mesoplodon bidens), especially off the western coast of Ireland, due to their elusive behaviors. This study aimed to characterize the acoustics of these beaked whales and investigate whether temporal patterns may affect their occurrences. Using passive acoustic monitoring (PAM), beaked whale bioacoustic clicks were manually analyzed, revealing different click frequency ranges than expected. Double clicks and echoes produced by both beaked whale species were also present, which have previously been infrequently observed in these species. The occurrence of beaked whales and the presence of double clicks and echoes were further investigated, along with how the diel cycle may affect these click characteristics. Hourly presence of goose-beaked whale double clicks and echoes was found to have significance for both day and night. There was no significance found for Sowerby’s beaked whale double clicks and echoes for day and night, along with the hourly occurrences of both beaked whales and the occurrence of other beaked whales. These findings highlight the need for future research on PAM and beaked whale acoustics, which could aid in better monitoring of their presence to address the impacts of human activities.

1. Introduction

1.1. Beaked Whales and Their Conservation Status

Marine conservation is emerging as an essential and necessary field for maintaining and developing ecosystems with “good environmental status”, which is reached when a marine environment is deemed healthy and biodiverse [1]. Effective management is a critical component for achieving the goals of the European Union’s Marine Strategy Framework Directive [1]. Marine mammals may be utilized as indicators of “good environmental status,” especially baleen whales, toothed whales, seals, and mammals associated with ice [1]. New insight is needed, especially in the less-understood odontocete beaked whale family, the ziphiidae. Better knowledge of their habitat use, biology, population dynamics, behaviors, and ecology is also necessary [1,2,3,4,5,6,7,8,9,10] to understand species’ interaction with an ecosystem and to guide conservation and management efforts [11]. Increased insight into beaked whale occurrences within their habitats and the environmental conditions that attract them can help conservationists decipher what factors may affect these species and how management practices can be implemented to reduce pressure on their population status and habitats [1,12,13,14].
However, this has yet to be easily documented for beaked whales, which remain an elusive family to observe visually, causing a lack of knowledge about this family [15]. Beaked whales are one of the least understood families of marine mammals, even though they comprise almost 25% of the known species of whales and dolphins [16,17]. All but three of the 24 species have unknown population trends [18], with new species being classified as recently as 2021 with the addition of Ramari’s beaked whales (Mesoplodon eueu) [19]. This indicates that more information is needed to better understand the beaked whale family.
Beaked whales tend to be rare in deep abyssal basins and instead favor locations with variable bottom bathymetry [20], especially near slopes, escarpments, canyons, oceanic islands, ridges, and the continental shelf [6,21]. The Irish Atlantic Margin contains a suitable habitat for beaked whales, has a complex bathymetry, and is one of the highest biologically productive regions of the northeast Atlantic with high prey availability [22]. This area has upwelling, persistent eddy systems, the North Atlantic currents, and the continuous shelf edge currents that concentrate prey [22]. There are about 26 cetacean species found in Irish waters, including beaked whales [23]. The most frequently detected beaked whale species in Ireland, especially around the Rockall Trough margin, is the goose-beaked whale (Ziphius cavirostris) [24] off southwest Ireland, with Sowerby’s beaked whales (Mesoplodon bidens) off northwest Ireland [3,10,12,25]. The Irish Atlantic Margin may be very important, specifically to goose-beaked whales and Sowerby’s beaked whales, for breeding sites compared to other beaked whales [26].

1.2. Threats for Beaked Whales

However, there have been higher levels of beaked whale strandings off the coast of Ireland in the past twenty years, with many occurring during heightened naval activity in the region [27]. Navy mid-frequency active sonar (MFAS) exercises have especially led to the disproportionally large mass strandings of goose-beaked whales worldwide [21,28], with likely long-term effects [29]. Along the Irish Atlantic Margin, there has also been an increase in seismic airgun surveys for oil exploration [30,31]. These are of particular concern off the coast of Ireland, as its unique water mass properties and extreme sloping bathymetry may significantly increase the magnitude of anthropogenic noise toward the depths of the nearby canyon [32,33,34].
Goose- and Sowerby’s beaked whales are also threatened by echosounders, entanglement, vessel strikes, persistent organic pollutants (POPs), toxic metals, plastics, and oil spills [34], which they may encounter in this region. With climate change and higher sea surface temperatures, a range shift in cephalopod biodiversity, their primary prey source, is also expected in the northeast Atlantic [35]. This may lead to negative consequences for goose-beaked whales [36], which have a high site fidelity [37], and Sowerby’s beaked whales, which are range-restricted [21]. However, the current lack of information on these beaked whales will make it difficult to understand how these threats will affect them [38]. There is also little understanding of how different species of beaked whales interact with their habitats and the biotic and abiotic factors associated with them [39,40,41,42,43]. A clearer understanding of where and when these beaked whales occur can lead to more effective monitoring practices, especially by informing the timing and location of increased anthropogenic noise.

1.3. Passive Acoustic Monitoring of Beaked Whales

Habitat use of beaked whales is challenging to understand, as they spend limited time on the surface and have a deep-water habitat use [44], and the blows they exhale can be nearly invisible to observe [45]. Therefore, even though it is estimated that beaked whales are only acoustically active 20% of the time in an area, bioacoustic monitoring can detect more beaked whales than visual surveys [44,46,47]. Bioacoustic monitoring allows for the detection of sounds from a distance, with a more robust understanding of population dynamics and behaviors, while limiting the effects of researchers’ presence [9,44]. One method is passive acoustic monitoring (PAM), which records species actively vocalizing in a specific range of the device [48]. Generally, each beaked whale species produces unique echolocation clicks from each other, making species identification possible using bioacoustics [49].

1.4. Research Objectives

Using bottom-mounted passive acoustic monitoring, this study focuses on manually characterizing the bioacoustic echolocation clicks of goose-beaked whales and Sowerby’s beaked whales off the coast of Ireland, to better describe the vocalizations of Irish beaked whale populations, for the first time. The goals of this study were to provide new insights into acoustically detecting these species in a less-studied area and to determine temporal patterns of their occurrences. This study also aims to better describe the click characteristics of these species off the west coast of Ireland and compare them to those of each species. Understanding these factors can help monitor beaked whale occurrences, which can help guide mitigation efforts for these species in response to anthropogenic noise that may increase in this region.

2. Materials and Methods

2.1. Acoustic Data Collection and Processing

The Department of the Environment, Climate and Communications (DECC) and the Department of Environment, Heritage and Local Government (DEHLG) initiated the ObSERVE Acoustic project along the Irish Atlantic Margin. Eight moorings with Autonomous Multichannel Acoustic Recorder (AMAR) units (JASCO Applied Sciences, Halifax, NS, Canada) were deployed during four phases, ranging from May 2015 to November 2016, following the contours created from the unique bathymetry of the Rockall Trough, the Porcupine Bank, and the Porcupine Abyssal Plain. This survey revealed two beaked whale species: goose-beaked and Sowerby’s beaked whales, and a handful of northern bottlenose whales (Hyperoodon ampullatus) [31,50]. The mean daily detections were higher for both goose- and Sowerby’s beaked whales at Mooring Four [31,50], which was chosen for further acoustic analysis (Figure 1). A schematic diagram of this study’s methodology is presented in Figure 2.
Mooring Four was on a slope at a depth of 1920 m, sampled from 7 May to 30 August 2015, at 54.00138 and −14.04242 decimal degrees. The recorder was suspended about 25 m above the seafloor using a dual acoustic release array, which included an HTI-99-HF omnidirectional hydrophone (High Tech Inc., Long Beach, MS, USA). An acoustic recorder at this depth can detect echolocation clicks produced by beaked whales during foraging dives [14]. To measure the presence of species that produce higher frequencies, like beaked whales, the data was sampled at a higher frequency channel at 250 kilo samples per second (ksps) for a sampling time of 130 s, collected every eight minutes, creating a recording bandwidth of 125 kilohertz.

2.2. Raven Manual Click Annotation

Automatic click detections for all species were processed prior by JASCO, using a zero-crossing approach, a Teager-Kaiser energy detector, and selecting detections with the lowest Mahalanobis distance [31,50]. Each sample file for this site, containing detected clicks of goose-beaked whale or Sowerby’s beaked whale, was further reviewed manually to validate the clicks accurately and was of the highest quality for analysis. An occurrence of a beaked whale was defined as having one or more detected clicks in an hour. “Occurrences” denotes the presence of clicks from a species that was present and acoustically active in the area being recorded and is not related to the relative abundance of the species [47]. These beaked whale clicks were processed using the sound analysis software Raven Pro 1.6.4 (© Cornell Lab of Ornithology). The view of the spectrogram of the clicks was set to a Hann window, a −3 decibel (dB) filter bandwidth at 703 hertz (Hz), a time overlap of 50%, and a hop size of 256 samples. The discrete Fourier transformation frequency size was set to 512 samples, grid spacing of 488 Hz, brightness of 45, and contrast of 85.
The peak amplitude (U) and the root-mean-squared (RMS) amplitude (U) were used to help select the highest-quality clicks for each sample. Each click was annotated with its corresponding peak frequency (kHz) and center frequency (kHz). Each click’s frequency range (kHz) was calculated by taking the difference between the high and low frequencies (kHz). Click duration accounted for the difference between the start and end time in microseconds. This is difficult to compare with other studies, as it is calculated differently depending on the study [49,51,52,53], so subsequent comparisons were not made for this variable. However, as goose-beaked whales tend to have longer click durations than other species with similar frequencies, like northern bottlenose whales, it helps differentiate between them acoustically [53].
Each click was also annotated as having the presence or absence of a sweep (frequency-modulated (FM) sweep pulses), as upsweeps have been observed among beaked whales [54], with downsweeps identified in goose-beaked whales [55]. Each sample was also analyzed for the presence or absence of echoes and double clicks. Clicks produce echoes when they bounce off the seafloor and are received when they return to the bottom-mounted receiver [56]. Double clicks are when one click is observed, with a second click immediately detected after the first [57].

2.3. Temporal Covariates

The diel cycle was recorded to determine the temporal habitat use of the beaked whales and how their click characteristics may alter depending on the time of day. The diel cycle was calculated for each beaked whale detection, with each hour categorized as day or night in conjunction with sunrise and sunset. Daytime was determined from when the sun was 12° below the horizon until sunrise, along with the hours of sunlight. Nighttime was determined from when the sun was more than 12° above the horizon until sunset, along with the hours of darkness. The exact times for these were obtained from Reda and Andreas (2004) [58], which were about 7:00 to 19:00 for daylight and 19:00 to 7:00 for night for the area.

2.4. Data Analysis

Once the click characteristics were extracted, descriptive statistics (mean, standard deviation, 10th percentile, and 90th percentile) were calculated with R version 4.2.2 (R Core Team). The Shapiro-Wilks test was then applied to each variable for each species to assess normality and inform the selection of the appropriate statistical analysis. The variables investigated included the diel cycle and the hourly presence of double clicks and echoes for each species. Although the data was limited, an investigation into the hourly occurrences of goose- and Sowerby’s beaked whales was undertaken to initiate an understanding of how their occurrences might have influenced each other. As the data for the variables chosen were not normally distributed, a Kruskal–Wallis analysis of variance was used for each variable as a non-parametric alternative to ANOVA. Finally, the significance of the resulting chi-square statistic was used to indicate if the two variables differ from each other based on the rank used. A Mann–Whitney U post hoc test was then conducted for variables that showed significance in the Kruskal–Wallis analysis.

3. Results

3.1. Beaked Whale Click Characteristics and Occurrences

Clicks from the initial detection analysis were selected manually during Raven analysis to accurately identify clicks to the species level and select the best data for click characterization. The maximum detection range for the complete dataset was previously calculated as up to 14 km for goose-beaked whales and 4 km for Sowerby’s beaked whales [50]. During the sampled period, 116 days of sampling effort were collected and used for this study, recording approximately 683 h of acoustic data. There were 1690 goose-beaked whale clicks (Figure 3A,B) and 898 Sowerby’s beaked whale clicks (Figure 3D,E). Double clicks (Figure 3C,F) were observed in samples containing goose-beaked whales in 72 of the 401 sample files (18%). Echoes (Figure 3G,H) accounted for 154 of the goose-beaked whales’ sample files (38%). Conversely, double clicks accounted for 8 of the 249 sample files (3%) and echoes of 6 (2%) for Sowerby’s beaked whales. No sweeps were indicated for either species in the samples reviewed.
For the goose-beaked whale clicks, the mean peak frequency sampled was 38 kHz (±4 kHz), the mean center frequency was 38 kHz (±3 kHz), the mean frequency range was 69 kHz (±21 kHz), and the mean duration was 2837 microseconds (±847 microseconds). The mean peak amplitude was 656 U (±942 U), and the root-mean-squared (RMS) amplitude mean was 75 U (±88 U). For the Sowerby’s beaked whale clicks, the mean click peak frequency was 65 kHz (±4 kHz), the mean center frequency was 66 kHz (±2 kHz), the mean frequency range was 37 kHz (±11 kHz), and the duration mean was 1649 microseconds (±400 microseconds). The mean peak amplitude for this species was 117 U (±70 U), and the RMS amplitude mean was 20 U (±10 U) (Table 1 and Figure 4).
The overall occurrence of beaked whales in the sample varied by time and day, with some periods exhibiting high occurrences and others showing no detected clicks. Goose-beaked whale occurrences had higher peaks than Sowerby’s (Figure 5). Both species occurred more often during the day, with decreased occurrence at night. Goose-beaked whale clicks during the day accounted for 1182 clicks (70%), with 653 (73%) Sowerby’s beaked whale clicks. Among hours with goose-beaked whale double clicks, 41 of the 58 (71%) occurred during the day and 17 (29%) occurred during the night. Goose-beaked whale echoes during the day accounted for 87 of the 122 (71%) detected hours, and 35 (29%) at night. For Sowerby’s beaked whale double clicks, 4 of the 7 (57%) occurred during the day and 3 (43%) occurred during the night. Sowerby’s beaked whale echoes during the day accounted for 6 of the 6 (100%) detected hours, and none occurred at night (Figure 6). For each species, these occurrences further differed, with detections for each species rarely co-occurring within an hour of each other. Of the 648 sample files with either species, only 36 (6%) of the sample files had both species co-occurring within an hour.

3.2. Statistical Analyses

A Shapiro-Wilks test for normality was carried out, and all covariates used for the models were not normally distributed (p-values ≤ 0.05) and were resistant to transformations toward normality. As the data was non-linear, a Kruskal–Wallis analysis of variance was used, which indicated that the occurrence of goose- and Sowerby’s beaked whales had no statistical significance between each other. There was no significance found for either goose- or Sowerby’s beaked whale hourly occurrence in terms of diel cycle, or Sowerby’s beaked whale hourly presence of double clicks and echoes. However, goose-beaked whales showed significance (p-values ≤ 0.05) for the hourly presence of double clicks and echoes. Significance was found (p-values ≤ 0.05) from Mann–Whitney U post hoc tests using hourly occurrence of goose-beaked whales during the day and night, with hourly presence of double clicks and echoes.

4. Discussion

4.1. Click Characteristics of Irish Beaked Whales

This study presents the first in-depth analysis of the click characteristics of beaked whales off the coast of Ireland. It provides new insights into how these populations use echolocation compared to other populations. The site for this study encompassed the southern boundary of Sowerby’s beaked whales and the northern boundary of goose-beaked whales off western Ireland, which may be prey-driven [3,22,31,50] and likely represents a meeting point between the two species and other species in the area. As the click characteristics of both species had not previously been analyzed in such detail off the coast of Ireland, this study adds to the current knowledge of beaked whale acoustics and their occurrences.
The clicks of goose-beaked whales indicated peak and center frequencies similar to those found in other studies, although their frequency range was more variable and higher on average [16,47,51,53,56,59,60,61,62]. The variations in goose-beaked whale frequency ranges may be due to the ability to manually identify more details from the data than a detector, resulting in longer and higher values for each click. The variation may also be because beaked whales move their heads up, down, and side-to-side during foraging [59], which may affect the quality of the click data [13,53]. This potentially causes the echolocation not to be directed toward the receiver [63], limiting the full capture of clicks [52], and causing the acoustic receiver to miss some detections. This also may present unique characteristics for Irish goose-beaked whales, where the frequency ranges may differ from other areas.
For Sowerby’s beaked whale clicks, the peak frequencies, center frequencies, and frequency ranges were similar to those found in previous studies [49,57,61,64]. The peak frequency for Sowerby’s beaked whales, on average, followed the high peak frequency group first categorized by Cholewiak et al. (2013) [57] and later identified by Clarke et al. (2019) [64] and Cohen et al. (2022) [61]. This suggests that Sowerby’s beaked whales off the coast of Ireland may present similar peak frequencies to those of other populations. Cholewiak et al. (2013) [57] may have studied a unique population or unique local characteristics with more variation. A recent study was the first to find the lower peak frequencies that Cholewiak et al. (2013) described in their study [57,65]. This also suggests that such detections may be more easily identified in higher groupings, as these clicks are distinctive compared to other species.

4.2. Diel Cycle and Click Characteristics of Beaked Whales

Significance was found for goose-beaked whale echoes, for both day and night, but no significance was found for Sowerby’s beaked whales. This may be due to echoes being observed primarily with goose-beaked whale clicks and only faintly, a few times for Sowerby’s beaked whales. This might be because goose-beaked whales specifically have higher source levels, allowing their clicks to travel further and reach the seafloor more easily [50,66]. Echoes are easier to distinguish from the seafloor [50] and can be due to the forward-directed sonar beams of beaked whales and their active downslope swimming behavior as they forage [67]. This may be why echoes were observed in this study set on a slope, and it may indicate periods of active foraging along the slope. The returned echoes can help the beaked whale identify their surroundings and locate targeted prey [68].
Observations of double clicks of both species are unique and have not been obtained in most studies [57,69]. Goose-beaked whale double clicks showed significance, for both day and night, but no significance was found for Sowerby’s beaked whales. The reasons for the presence of double clicks, their purpose, and whether this is specific to certain populations or times are still being determined. There were no click sweeps observed in this dataset, which could be due to the population in Ireland having different click characteristics or due to sampling a phase when they may not use sweeps, as compared to other studies that observed them [54,55,66].
Regarding the diel cycle, the number of occurrences of goose- and Sowerby’s beaked whales present during the day was almost double that occurring at night, but did not show significance in the results. As the mooring was located 1920 m deep, perhaps the increased activity during the day at this depth resulted from the beaked whales spending more time foraging at deeper depths during the day than at night. The preference for foraging in daylight has been observed in other studies [70,71]. One explanation is that beaked whales avoid visually oriented predators that prefer to hunt with light [72] and spend more time in shallow depths at night when it could be safer from predators [40,73,74,75,76,77,78,79,80,81,82]. However, the lack of statistical significance points to other possible factors influencing beaked whale occurrences in the study area.

4.3. Beaked Whale Habitat Partitioning

Among beaked whales, their occurrence did not have any significance on the occurrence of other beaked whales. Within the dataset analyzed, there were only 36 co-occurrences of goose-beaked whales and Sowerby’s beaked whales within an hour of each other, which may have accounted for a lack of significance among goose- and Sowerby’s beaked whale co-occurrences. Goose-beaked whales have not been observed to cease echolocating in the presence of conspecifics [75], and so this was not likely a reason for this possible lack of a relationship. It is also unclear if the presence of other beaked whales or cetaceans would affect their vocalizations. There is already a strong habitat partitioning of the two species in this area [3,22,31,50], which might be prey-related or due to some other factor. There has only been one observation of these two species co-occurring, where two likely stray Sowerby’s beaked whales were associated with local goose-beaked whales in the Tyrrhenian Sea, and this suggests cooperation is possible if needed [39].
Among beaked whales, goose-beaked whales, and Sowerby’s beaked whales do not have any trophic niche overlap by mass or number, which may allow them to forage in similar areas [76]. It has been observed that beaked whales have ecological niches and fine-scale habitat partitioning when sharing foraging grounds with other cetaceans [47]. The average foraging dive for a goose-beaked whale is roughly 700 to 2000 m deep [9,16,40,71,73,77,78], with the deepest recorded dive for this species by one individual reaching a depth of 2992 m [74]. In comparison, Sowerby’s beaked whales are found at depths ranging from about 400 to 1400 m [9,21,49,79]. The differences in depths during foraging suggest it is likely prey-driven.
Goose-beaked whales primarily feed on oceanic bioluminescent mesopelagic and bathypelagic squids [80,81], which migrate to deeper depths during the day [82]. Their body mass and use of aerobic and anaerobic respiration, with longer inter-deep dive intervals, aid the increased dive times to catch prey [83]. The depths and durations of their dives may depend on location, as influenced by the prey type, density, or behavior [40]. The diet of Sowerby’s beaked whales is almost entirely mesopelagic and benthopelagic fish, with some cephalopods [84]. They forage opportunistically with little preference, feeding on prey abundant in midwaters [81,85]. This may help fill feeding niches in response to competition [49], as Sowerby’s beaked whales have a habitat preference similar to that of sperm whales [84]. The feeding preferences of both beaked whales indicate a possible reason for their habitat partitioning and the lack of a relationship between the two species.

4.4. Limitations, Recommendations, and Future Perspectives

Previous research used the extensive dataset from the ObSERVE Acoustic project, which initially documented habitat partitioning among beaked whales off the west coast of Ireland [22,31,50]. As this study focused only on one location on a slope during a single sampling period, it did not consider seasonal changes or differences in habitat types. These factors could influence the habitat partitioning observed at this site and the relationships of the variables explored. Additionally, acquiring information on the amount and geographic distribution of prey for beaked whales would help determine if prey availability drives certain beaked whales across the Irish Atlantic Margin. Gaining a better understanding of whether specific prey are more vital to these species could clarify the mechanisms behind the habitat partitioning between goose- and Sowerby’s beaked whales. As interspecific interactions of beaked whales are still unknown, it is important to begin understanding how the presence of other species may affect them. These interactions may be primarily prey-driven, and gaining a better understanding of the prey choice of cetaceans in Irish waters can help begin to address these questions.
This study exemplifies that bioacoustics, such as PAM, is an essential and necessary tool for the comprehensive study of beaked whales, which are challenging to study using other methodologies. PAM allows for many months of data to be collected across all 24 h, while visual observations are limited to daylight hours and are less efficient for elusive species, such as beaked whales. This study was able to describe their click characteristics and the influence of temporal patterns on their acoustical occurrences. Double clicks and echoes were observed in this study, giving new insight into beaked whale acoustics in western Ireland. These findings can help acoustically monitor future occurrences of goose- and Sowerby’s beaked whales, which can help guide more effective management practices. Knowing where and when these whales are present can help determine the best timing and location for conducting certain surveys. It is well established that MFAS and seismic surveys harm beaked whales [28,29,34,86,87,88,89,90,91], which may increase in the future in this region. Therefore, this study emphasizes the need for future research into the effectiveness of acoustically detecting beaked whales with PAM, which could support the protection and well-being of these whales. Understanding these factors can guide new regulations to reduce threats, including marine spatial planning and the creation of binding guidelines for visual and acoustic surveys during activities that increase the anthropogenic noise of the surrounding area [92,93,94]. Using PAM for detecting beaked whales can help make mitigating the harmful effects of anthropogenic noise more effective.

Author Contributions

Conceptualization, B.C. and J.O.; methodology, B.C. and J.O.; software, B.C.; validation, B.C. and J.O.; formal analysis, B.C.; investigation, B.C. and J.O.; resources, J.O.; data curation, B.C.; writing—original draft preparation, B.C.; writing—review and editing, B.C. and J.O.; visualization, B.C.; supervision, J.O.; project administration, J.O. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding.

Data Availability Statement

Data availability for this study is available through the Irish Department of Communications, Climate Action and Environment. Data can be accessed at https://www.gov.ie/en/publication/12374-observe-programme/#project-data (accessed on 8 February 2023).

Acknowledgments

We thank all those who helped with the analysis and editing, especially Julia Stepanuk for her advice and support. The data used in this study were collected as part of the ObSERVE Acoustic project, initiated and funded by the Department of Communications, Climate Action and Environment in partnership with the Department of Culture, Heritage and the Gaeltacht under Ireland’s ObSERVE Programme.

Conflicts of Interest

The authors declare no conflicts of interest.

Abbreviations

The following abbreviations are used in this manuscript:
AICAkaike Information Criteria
AMARAutonomous Multichannel Acoustic Recorder
DECCDepartment of the Environment, Climate and Communications
DEHLGDepartment of Environment, Heritage and Local Government
GAMGeneralized Additive Model
GBWGoose-Beaked Whale
MFASMid-Frequency Active Sonar
PAMPassive Acoustic Monitoring
POPsPersistent Organic Pollutants
REMLRestricted Maximum Likelihood
SBWSowerby’s Beaked Whale

References

  1. Santos, M.B.; Pierce, G.J. Marine mammals and good environmental status: Science, policy and society; challenges and opportunities. Hydrobiologia 2015, 750, 13–41. [Google Scholar] [CrossRef]
  2. Hare, M.P.; Nunney, L.; Schwartz, M.K.; Ruzzante, D.E.; Burford, M.; Waples, R.S.; Ruegg, K.; Palstra, F. Understanding and estimating effective population size for practical application in marine species management. Conserv. Biol. 2011, 25, 438–449. [Google Scholar] [CrossRef] [PubMed]
  3. Rogan, E.; Cañadas, A.; Macleod, K.; Santos, M.B.; Mikkelsen, B.; Uriarte, A.; Van Canneyt, O.; Vázquez, J.A.; Hammond, P.S. Distribution, abundance and habitat use of deep diving cetaceans in the North-East Atlantic. Deep. Sea Res. Part II Top. Stud. Oceanogr. 2017, 141, 8–19. [Google Scholar] [CrossRef]
  4. Curtis, K.A.; Falcone, E.A.; Schorr, G.S.; Moore, J.E.; Moretti, D.J.; Barlow, J.; Keene, E. Abundance, survival, and annual rate of change of Cuvier’s beaked whales (Ziphius cavirostris) on a Navy sonar range. Mar. Mammal Sci. 2021, 37, 399–419. [Google Scholar] [CrossRef]
  5. Smith, K.J.; Mead, J.G.; Peterson, M.J. Specimens of opportunity provide vital information for research and conservation regarding elusive whale species. Environ. Conserv. 2021, 48, 84–92. [Google Scholar] [CrossRef]
  6. MacLeod, C.D.; D’Amico, A. A review of beaked whale behaviour and ecology in relation to assessing and mitigating impacts of anthropogenic noise. J. Cetacean Res. Manag. 2006, 7, 211–222. [Google Scholar] [CrossRef]
  7. Cioffi, W.R.; Quick, N.J.; Foley, H.J.; Waples, D.M.; Swaim, Z.T.; Shearer, J.M.; Friedlaender, A.S.; Southall, B.L.; Baird, R.W.; Nowacek, D.P.; et al. Adult male Cuvier’s beaked whales (Ziphius cavirostris) engage in prolonged bouts of synchronous diving. Mar. Mammal Sci. 2021, 37, 1085–1100. [Google Scholar] [CrossRef]
  8. Solsona-Berga, A.; DeAngelis, A.I.; Cholewiak, D.M.; Trickey, J.S.; Mueller-Brennan, L.; Frasier, K.E.; Van Parijs, S.M.; Baumann-Pickering, S.; Kiel, S. Machine learning with taxonomic family delimitation aids in the classification of ephemeral beaked whale events in passive acoustic monitoring. PLoS ONE 2024, 19, e0304744. [Google Scholar] [CrossRef]
  9. DeAngelis, A.; Westell, A.; Baumann-Pickering, S.; Bell, J.; Cholewiak, D.; Corkeron, P.; Soldevilla; Solsona-Berga, A.; Trickey, J.; Van Parijs, S. Habitat utilization by beaked whales in the western North Atlantic Ocean using passive acoustics. Mar. Ecol. Prog. Ser. 2025, 754, 137–153. [Google Scholar] [CrossRef]
  10. MacLeod, C.D.; Mitchell, G. Key areas for beaked whales worldwide. J. Cetacean Res. Manag. 2006, 7, 309–322. [Google Scholar] [CrossRef]
  11. Matear, L.; Robbins, J.R.; Hale, M.; Potts, J. Cetacean biodiversity in the Bay of Biscay: Suggestions for environmental protection derived from citizen science data. Mar. Policy 2019, 109, 103672. [Google Scholar] [CrossRef]
  12. MacLeod, C.D.; Perrin, W.F.; Pitman, R.; Barlow, J.; Ballance, L.; D’AMico, A.; Gerrodette, T.; Joyce, G.; Mullin, K.D.; Palka, D.L.; et al. Known and inferred distributions of beaked whale species (Cetacea: Ziphiidae). J. Cetacean Res. Manag. 2006, 7, 271. [Google Scholar] [CrossRef]
  13. Delarue, J.; Moors-Murphy, H.; Kowarski, K.; Maxner, E.; Davis, G.; Stanistreet, J.; Martin, S. Acoustic occurrence of beaked whales off eastern Canada, 2015–2017. Endanger. Species Res. 2024, 53, 439–466. [Google Scholar] [CrossRef]
  14. Schoenbeck, C.M.; Solsona-Berga, A.; Franks, P.J.S.; Frasier, K.E.; Trickey, J.S.; Aguilar, C.; Schroeder, I.D.; Širović, A.; Bograd, S.J.; Gopalakrishnan, G.; et al. Ziphius cavirostris presence relative to the vertical and temporal variability of oceanographic conditions in the Southern California Bight. Ecol. Evol. 2024, 14, e11708. [Google Scholar] [CrossRef] [PubMed]
  15. Baumann-Pickering, S.; Roch, M.A.; Brownell, R.L., Jr.; Simonis, A.E.; McDonald, M.A.; Solsona-Berga, A.; Oleson, E.M.; Wiggins, S.M.; Hildebrand, J.A. Spatio-temporal patterns of beaked whale echolocation signals in the North Pacific. PLoS ONE 2014, 9, e86072. [Google Scholar] [CrossRef]
  16. Johnson, M.; Madsen, P.T.; Zimmer, W.M.; de Soto, N.A.; Tyack, P.L. Beaked whales echolocate on prey. Proc. R. Soc. Lond. Ser. B Biol. Sci. 2004, 271 (Suppl. 6), S383–S386. [Google Scholar] [CrossRef]
  17. Mead, J.G. Stomach anatomy and use in defining systemic relationships of the cetacean family Ziphiidae (beaked whales). Anat. Rec. Adv. Integr. Anat. Evol. Biol 2007, 290, 581–595. [Google Scholar] [CrossRef] [PubMed]
  18. International Union on the Conservation of Nature (IUCN). The IUCN Red List of Threatened Species: Beaked Whales 2022. Available online: http://www.iucnredlist.org/search (accessed on 11 December 2022).
  19. Carroll, E.L.; McGowen, M.R.; McCarthy, M.L.; Marx, F.G.; Aguilar, N.; Dalebout, M.L.; Dreyer, S.; Gaggiotti, O.E.; Hansen, S.S.; van Helden, A.; et al. Speciation in the deep: Genomics and morphology reveal a new species of beaked whale Mesoplodon eueu. Proc. R. Soc. B 2021, 288, 20211213. [Google Scholar] [CrossRef]
  20. Gannier, A.; Epinat, J. Cuvier’s beaked whale distribution in the Mediterranean Sea: Results from small boat surveys 1996–2007. J. Mar. Biol. Assoc. United Kingd. 2008, 88, 1245–1251. [Google Scholar] [CrossRef]
  21. O’Callaghan, S.A.; Overy, L.; Hunt, L.; Foxall, D.; Collins, M.; O’Connell, M. Strandings of a neonate and a pregnant Sowerby’s beaked whale (Mesoplodon bidens (Sowerby, 1804)) in Ireland. J. Mar. Biol. Assoc. United Kingd. 2022, 102, 309–314. [Google Scholar] [CrossRef]
  22. Barile, C.; Berrow, S.; O’brien, J. Oceanographic Drivers of Cuvier’s (Ziphius cavirostris) and Sowerby’s (Mesoplodon bidens) Beaked Whales Acoustic Occurrence along the Irish Shelf Edge. J. Mar. Sci. Eng. 2021, 9, 1081. [Google Scholar] [CrossRef]
  23. O’Callaghan, S.A. North Atlantic right whales (Eubalaena glacialis) in Irish waters: 1300–1987. Biol. Environ. Proc. R. Ir. Acad. 2019, 119, 111–122. [Google Scholar] [CrossRef]
  24. Rogers, A.D.; Lavelle, A.; Baird, R.W.; Bender, A.; Borroni, A.; Hinojasa, G.C.; Cioffi, W.R.; Elliott, B.W.; Harms, C.; Harshbarger, A.E.; et al. A call to rename Ziphius cavirostris the goose-beaked whale: Promoting inclusivity and diversity in marine mammalogy by re-examining common names. Mar. Mammal Sci. 2024, 40, e13150. [Google Scholar] [CrossRef]
  25. MacLeod, C.D.; Pierce, G.J.; Santos, M.B. Geographic and temporal variations in strandings of beaked whales (Ziphiidae) on the coasts of the UK and the Republic of Ireland from 1800–2002. J. Cetacean Res. Manag. 2004, 6, 79–86. [Google Scholar] [CrossRef]
  26. Berrow, S.; Meade, R.; Marrinan, M.; McKeogh, E.; O’Brien, J. First confirmed sighting of Sowerby’s beaked whale (Mesoplodon bidens (Sowerby, 1804)) with calves in the Northeast Atlantic. Mar. Biodivers. Rec. 2018, 11, 20. [Google Scholar] [CrossRef]
  27. Parsons, E.C.M. Impacts of navy sonar on whales and dolphins: Now beyond a smoking gun? Front. Mar. Sci. 2017, 4, 295. [Google Scholar] [CrossRef]
  28. D’Amico, A.; Gisiner, R.C.; Ketten, D.R.; Hammock, J.A.; Johnson, C.; Tyack, P.L.; Mead, J. Beaked whale strandings and naval exercises. Aquat. Mamm. 2019, 35, 452–472. [Google Scholar] [CrossRef]
  29. Hin, V.; de Roos, A.M.; Benoit-Bird, K.J.; Claridge, D.E.; DiMarzio, N.; Durban, J.W.; Falcone, E.A.; Jacobson, E.K.; Jones-Todd, C.M.; Pirotta, E.; et al. Using individual-based bioenergetic models to predict the aggregate effects of disturbance on populations: A case study with beaked whales and Navy sonar. PLoS ONE 2023, 18, e0290819. [Google Scholar] [CrossRef]
  30. Barile, C.; Berrow, S.; Parry, G.; Brien, J.O. Temporal acoustic occurrence of sperm whales Physeter macrocephalus and long-finned pilot whales Globicephala melas off western Ireland. Mar. Ecol. Prog. Ser. 2021, 661, 203–227. [Google Scholar] [CrossRef]
  31. Kowarski, K.; Delarue, J.; Martin, B.; O’bRien, J.; Meade, R.; Cadhla, O.Ó.; Berrow, S.; Thuesen, E.V. Signals from the deep: Spatial and temporal acoustic occurrence of beaked whales off western Ireland. PLoS ONE 2018, 13, e0199431. [Google Scholar] [CrossRef] [PubMed]
  32. Podesta, M.; D′Amico, A.; Pavan, G.; Drougas, A.; Komnenou, A.; Portunato, N. A review of Cuvier’s beaked whale strandings in the Mediterranean Sea. J. Cetacean Res. Manag. 2006, 7, 251. [Google Scholar] [CrossRef]
  33. Daly, E.; White, M. Bottom trawling noise: Are fishing vessels polluting to deeper acoustic habitats? Mar. Pollut. Bull. 2021, 162, 111877. [Google Scholar] [CrossRef]
  34. Feyrer, L.J.; Stanistreet, J.E.; Gomez, C.; Adams, M.; Lawson, J.W.; Ferguson, S.H.; Heaslip, S.G.; Lefort, K.J.; Davidson, E.; Hussey, N.E.; et al. Identifying important habitat for northern bottlenose and Sowerby’s beaked whales in the western North Atlantic. Aquat. Conserv. Mar. Freshw. Ecosyst. 2024, 34, e4064. [Google Scholar] [CrossRef]
  35. Hastie, L.C.; Pierce, G.J.; Wang, J.; Bruno, I.; Moreno, A.; Piatkowski, U.; Robin, J.P. Cephalopods in the north-eastern Atlantic: Species, biogeography, ecology, exploitation and conservation. Oceanogr. Mar. Biol. 2016, 47, 123–202. [Google Scholar]
  36. Benoit-Bird, K.; Southall, B.; Moline, M.; Claridge, D.; Dunn, C.; Dolan, K.; Moretti, D. Critical threshold identified in the functional relationship between beaked whales and their prey. Mar. Ecol. Prog. Ser. 2020, 654, 1–16. [Google Scholar] [CrossRef]
  37. McSweeney, D.J.; Baird, R.W.; Mahaffy, S.D. Site fidelity, associations, and movements of Cuvier’s (Ziphius cavirostris) and Blainville’s (Mesoplodon densirostris) beaked whales off the island of Hawai ‘i. Mar. Mammal Sci. 2007, 23, 666–687. [Google Scholar] [CrossRef]
  38. Learmonth, J.A.; MacLeod, C.D.; Santos, M.B.; Pierce, G.J.; Crick, H.Q.P.; Robinson, R.A. Potential effects of climate change on marine mammals. Oceanogr. Mar. Biol. 2006, 44, 431. [Google Scholar]
  39. Bittau, L.; Leone, M.; Gannier, A.; Gannier, A.; Manconi, R. Two live sightings of Sowerby’s beaked whale (Mesoplodon bidens) from the western Mediterranean (Tyrrhenian Sea). J. Mar. Biol. Assoc. United Kingd. 2018, 98, 1003–1009. [Google Scholar] [CrossRef]
  40. Shearer, J.M.; Quick, N.J.; Cioffi, W.R.; Baird, R.W.; Webster, D.L.; Foley, H.J.; Swaim, Z.T.; Waples, D.M.; Bell, J.T.; Read, A.J. Diving behaviour of Cuvier’s beaked whales (Ziphius cavirostris) off Cape Hatteras, North Carolina. R. Soc. Open Sci. 2019, 6, 181728. [Google Scholar] [CrossRef]
  41. Frouin-Mouy, H.; Mouy, X.; Pilkington, J.; Küsel, E.; Nichol, L.; Doniol-Valcroze, T.; Lee, L. Acoustic and visual cetacean surveys reveal year-round spatial and temporal distributions for multiple species in northern British Columbia, Canada. Sci. Rep. 2022, 12, 19272. [Google Scholar] [CrossRef]
  42. Ziegenhorn, M.A.; Hildebrand, J.A.; Oleson, E.M.; Baird, R.W.; Baumann-Pickering, S. Odontocete detections are linked to oceanographic conditions in the Hawaiian Archipelago. Commun. Earth Environ. 2023, 4, 423. [Google Scholar] [CrossRef]
  43. Heinen, J.H.; Rahbek, C.; Borregaard, M.K. Conservation of species interactions to achieve self-sustaining ecosystems. Ecography 2020, 43, 1603–1611. [Google Scholar] [CrossRef]
  44. Nowacek, D.P.; Christiansen, F.; Bejder, L.; Goldbogen, J.A.; Friedlaender, A.S. Studying cetacean behaviour: New technological approaches and conservation applications. Anim. Behav. 2016, 120, 235–244. [Google Scholar] [CrossRef]
  45. Zimmer, W.M.X.; Harwood, J.; Tyack, P.L.; Johnson, M.P.; Madsen, P.T. Passive acoustic detection of deep-diving beaked whales. J. Acoust. Soc. Am. 2008, 124, 2823–2832. [Google Scholar] [CrossRef] [PubMed]
  46. Hooker, S.K.; De Soto, N.A.; Baird, R.W.; Carroll, E.L.; Claridge, D.; Feyrer, L.; Miller, P.J.O.; Onoufriou, A.; Schorr, G.; Siegal, E.; et al. Future directions in research on beaked whales. Front. Mar. Sci. 2019, 5, 514. [Google Scholar] [CrossRef]
  47. Stanistreet, J.E.; Nowacek, D.P.; Baumann-Pickering, S.; Bell, J.T.; Cholewiak, D.M.; Hildebrand, J.A.; Hodge, L.E.; Moors-Murphy, H.B.; Van Parijs, S.M.; Read, A.J. Using passive acoustic monitoring to document the distribution of beaked whale species in the western North Atlantic Ocean. Can. J. Fish. Aquat. Sci. 2017, 74, 2098–2109. [Google Scholar] [CrossRef]
  48. Leeney, R.H.; Carslake, D.; Elwen, S.H. Using static acoustic monitoring to describe echolocation behaviour of Heaviside’s dolphins (Cephalorhynchus heavisidii) in Namibia. Aquat. Mamm. 2011, 37, 151–160. [Google Scholar] [CrossRef]
  49. Visser, F.; Oudejans, M.G.; Keller, O.A.; Madsen, P.T.; Johnson, M. Sowerby’s beaked whale biosonar and movement strategy indicate deep-sea foraging niche differentiation in mesoplodont whales. J. Exp. Biol. 2022, 225, jeb243728. [Google Scholar]
  50. Berrow, S.D.; O’Brien, J.; Meade, R.; Delarue, J.; Kowarski, K.; Martin, B.; Moloney, J.; Wall, D.; Gillespie, D.; Leaper, R.; et al. Acoustic Surveys of Cetaceans in the Irish Atlantic Margin in 2015–2016: Occurrence, Distribution and Abundance; Report to the Department of Communications, Climate Action & Environment and the National Parks and Wildlife Service (NPWS); Department of Culture, Heritage and the Gaeltacht: Dublin, Ireland, 2018; p. 348. [Google Scholar]
  51. Baumann-Pickering, S.; McDonald, M.A.; Simonis, A.E.; Berga, A.S.; Merkens, K.P.; Oleson, E.M.; Roch, M.A.; Wiggins, S.M.; Rankin, S.; Yack, T.M.; et al. Species-specific beaked whale echolocation signals. J. Acoust. Soc. Am. 2013, 134, 2293–2301. [Google Scholar] [CrossRef] [PubMed]
  52. Giorli, G.; Neuheimer, A.; Copeland, A.; Au, W.W. Temporal and spatial variation of beaked and sperm whales foraging activity in Hawai’i, as determined with passive acoustics. J. Acoust. Soc. Am. 2016, 140, 2333–2343. [Google Scholar] [CrossRef]
  53. Zimmer, W.M.X.; Johnson, M.P.; Madsen, P.T.; Tyack, P.L. Echolocation clicks of free-ranging Cuvier’s beaked whales (Ziphius cavirostris). J. Acoust. Soc. Am. 2005, 117, 3919–3927. [Google Scholar] [CrossRef]
  54. Yack, T.M.; Barlow, J.; Calambokidis, J.; Southall, B.; Coates, S. Passive acoustic monitoring using a towed hydrophone array results in identification of a previously unknown beaked whale habitat. J. Acoust. Soc. Am. 2013, 134, 2589–2595. [Google Scholar] [CrossRef]
  55. Guilment, T.; Sidorovskaia, N.; Li, K. Modeling the acoustic repertoire of Cuvier’s beaked whale clicks. J. Acoust. Soc. Am. 2020, 147, 3605–3612. [Google Scholar] [CrossRef]
  56. Gassmann, M.; Wiggins, S.M.; Hildebrand, J.A. Three-dimensional tracking of Cuvier’s beaked whales’ echolocation sounds using nested hydrophone arrays. J. Acoust. Soc. Am. 2015, 138, 2483–2494. [Google Scholar] [CrossRef] [PubMed]
  57. Cholewiak, D.; Baumann-Pickering, S.; Van Parijs, S. Description of sounds associated with Sowerby’s beaked whales (Mesoplodon bidens) in the western North Atlantic Ocean. J. Acoust. Soc. Am. 2013, 134, 3905–3912. [Google Scholar] [CrossRef]
  58. Reda, I.; Andreas, A. Solar position algorithm for solar radiation applications. Sol. Energy 2004, 76, 577–589. [Google Scholar] [CrossRef]
  59. Barlow, J.; Moore, J.E.; McCullough, J.L.K.; Griffiths, E.T. Acoustic-based estimates of Cuvier’s beaked whale (Ziphius cavirostris) density and abundance along the US West Coast from drifting hydrophone recorders. Mar. Mammal Sci. 2022, 38, 517–538. [Google Scholar] [CrossRef]
  60. Baumann-Pickering, S.; Wiggins, S.M.; Roth, E.H.; Roch, M.A.; Schnitzler, H.-U.; Hildebrand, J.A. Echolocation signals of a beaked whale at Palmyra Atoll. J. Acoust. Soc. Am. 2010, 127, 3790–3799. [Google Scholar] [CrossRef]
  61. Cohen, R.E.; Frasier, K.E.; Baumann-Pickering, S.; Wiggins, S.M.; Rafter, M.A.; Baggett, L.M.; Hildebrand, J.A.; Halliday, W.D. Identification of western North Atlantic odontocete echolocation click types using machine learning and spatiotemporal correlates. PLoS ONE 2022, 17, e0264988. [Google Scholar] [CrossRef]
  62. Rice, A.; Sirovic, A.; Trickey, J.S.; Debich, A.J.; Gottlieb, R.S.; Wiggins, S.M.; Hildebrand, J.A.; Baumann-Pickering, S. Cetacean occurrence in the Gulf of Alaska from long-term passive acoustic monitoring. Mar. Biol. 2021, 168, 72. [Google Scholar] [CrossRef]
  63. Hildebrand, J.A.; Baumann-Pickering, S.; Frasier, K.E.; Trickey, J.S.; Merkens, K.P.; Wiggins, S.M.; McDonald, M.A.; Garrison, L.P.; Harris, D.; Marques, T.A.; et al. Passive acoustic monitoring of beaked whale densities in the Gulf of Mexico. Sci. Rep. 2015, 5, 16343. [Google Scholar] [CrossRef]
  64. Clarke, E.; Feyrer, L.J.; Moors-Murphy, H.; Stanistreet, J. Click characteristics of northern bottlenose whales (Hyperoodon ampullatus) and Sowerby’s beaked whales (Mesoplodon bidens) off eastern Canada. J. Acoust. Soc. Am. 2019, 146, 307–315. [Google Scholar] [CrossRef] [PubMed]
  65. Boisseau, O.; Nowacek, D.; Roberts, J.; Pabst, D.A.; Clabaugh, A.; Moscrop, A.; McLanaghan, R.; Yack, T.; Levenson, J.J. Acoustic density estimates of beaked whales off the mid-Atlantic coast of the USA in winter and spring. Deep. Sea Res. Part I Oceanogr. Res. Pap. 2023, 199, 104108. [Google Scholar] [CrossRef]
  66. McCullough, J.L.K.; Wren, J.L.K.; Oleson, E.M.; Allen, A.N.; Siders, Z.A.; Norris, E.S. An acoustic survey of beaked whales and Kogia spp. in the Mariana Archipelago using drifting recorders. Front. Mar. Sci. 2021, 8, 664292. [Google Scholar] [CrossRef]
  67. Arranz, P.; de Soto, N.A.; Madsen, P.T.; Brito, A.; Bordes, F.; Johnson, M.P. Following a foraging fish-finder: Diel habitat use of Blainville’s beaked whales revealed by echolocation. PLoS ONE 2011, 6, e28353. [Google Scholar] [CrossRef]
  68. Madsen, P.T.; Johnson, M.P.; de Soto, N.A.; Zimmer, W.M.X.; Tyack, P.L. Biosonar performance of foraging beaked whales (Mesoplodon densirostris). J. Exp. Biol. 2005, 208, 181–194. [Google Scholar] [CrossRef]
  69. Dunn, C.A.; Tyack, P.; Miller, P.J.; Rendell, L. Short first click intervals in echolocation trains of three species of deep diving odontocetes. J. Acoust. Soc. Am. 2017, 141, 900–907. [Google Scholar] [CrossRef]
  70. Ziegenhorn, M.A.; Hildebrand, J.A.; Oleson, E.M.; Baird, R.W.; Wiggins, S.M.; Baumann-Pickering, S. Odontocete spatial patterns and temporal drivers of detection at sites in the Hawaiian islands. Ecol. Evol. 2023, 13, e9688. [Google Scholar] [CrossRef] [PubMed]
  71. Coates, S.N.; Sweeney, D.A.; Falcone, E.A.; Watwood, S.L.; Rone, B.K.; DeRuiter, S.L.; Barlow, J.; Dolan, K.A.; Morrissey, R.P.; DiMarzio, N.A.; et al. Insights into foraging behavior from multi-day sound recording tags on goose-beaked whales (Ziphius cavirostris) in the Southern California Bight. Front. Mar. Sci. 2024, 11, 1415602. [Google Scholar] [CrossRef]
  72. Baird, R.W.; Webster, D.L.; Schorr, G.S.; McSweeney, D.J.; Barlow, J. Diel variation in beaked whale diving behavior. Mar. Mammal Sci. 2008, 24, 630–642. [Google Scholar] [CrossRef]
  73. Baird, R.W.; Webster, D.L.; McSweeney, D.J.; Ligon, A.D.; Schorr, G.S.; Barlow, J. Diving behaviour of Cuvier’s (Ziphius cavirostris) and Blainville’s (Mesoplodon densirostris) beaked whales in Hawai ‘i. Can. J. Zool. 2006, 84, 1120–1128. [Google Scholar] [CrossRef]
  74. Schorr, G.S.; Falcone, E.A.; Moretti, D.J.; Andrews, R.D.; Fahlman, A. First long-term behavioral records from Cuvier’s beaked whales (Ziphius cavirostris) reveal record-breaking dives. PLoS ONE 2014, 9, e92633. [Google Scholar] [CrossRef]
  75. Alcázar-Treviño, J.; Johnson, M.; Arranz, P.; Warren, V.E.; Pérez-González, C.J.; Marques, T.; Madsen, P.T.; de Soto, N.A. Deep-diving beaked whales dive together but forage apart. Proc. R. Soc. 2021, 288, 20201905. [Google Scholar] [CrossRef] [PubMed]
  76. Spitz, J.; Cherel, Y.; Bertin, S.; Kiszka, J.; Dewez, A.; Ridoux, V. Prey preferences among the community of deep-diving odontocetes from the Bay of Biscay, Northeast Atlantic. Deep. Sea Res. Part I Oceanogr. Res. Pap. 2011, 58, 273–282. [Google Scholar] [CrossRef]
  77. DeAngelis, A.I.; Valtierra, R.; Van Parijs, S.M.; Cholewiak, D. Using multipath reflections to obtain dive depths of beaked whales from a towed hydrophone array. J. Acoust. Soc. Am. 2017, 142, 1078–1087. [Google Scholar] [CrossRef]
  78. Barlow, J.; Griffiths, E.T.; Klinck, H.; Harris, D.V. Diving behavior of Cuvier’s beaked whales inferred from three-dimensional acoustic localization and tracking using a nested array of drifting hydrophone recorders. J. Acoust. Soc. Am. 2018, 144, 2030–2041. [Google Scholar] [CrossRef] [PubMed]
  79. Breen, P.; Pirotta, E.; Allcock, L.; Bennison, A.; Boisseau, O.; Bouch, P.; Hearty, A.; Jessopp, M.; Kavanagh, A.; Taite, M.; et al. Insights into the habitat of deep diving odontocetes around a canyon system in the northeast Atlantic ocean from a short multidisciplinary survey. Deep. Sea Res. Part I Oceanogr. Res. Pap. 2020, 159, 103236. [Google Scholar] [CrossRef]
  80. Blanco, C.; Raga, J. Cephalopod prey of two Ziphius cavirostris (Cetacea) stranded on the western Mediterranean coast. J. Mar. Biol. Assoc. United Kingd. 2000, 80, 381–382. [Google Scholar] [CrossRef]
  81. MacLeod, C.D.; Santos, M.B.; Pierce, G.J. Review of data on diets of beaked whales: Evidence of niche separation and geographic segregation. J. Mar. Biol. Assoc. United Kingd. 2003, 83, 651–665. [Google Scholar] [CrossRef]
  82. Santos, M.B.; Martin, V.; Arbelo, M.; Fernández, A.; Pierce, G.J. Insights into the diet of beaked whales from the atypical mass stranding in the Canary Islands in September 2002. J. Mar. Biol. Assoc. United Kingd. 2007, 87, 243–251. [Google Scholar] [CrossRef]
  83. Joyce, T.W.; Durban, J.W.; Claridge, D.E.; Dunn, C.A.; Fearnbach, H.; Parsons, K.M.; Andrews, R.D.; Ballance, L.T.; Li, S. Physiological, morphological, and ecological tradeoffs influence vertical habitat use of deep-diving toothed-whales in the Bahamas. PLoS ONE 2017, 12, e0185113. [Google Scholar] [CrossRef]
  84. Wenzel, F.W.; Polloni, P.T.; Craddock, J.E.; Gannon, D.P.; Nicolas, J.R.; Read, A.J.; Rosel, P.E. Food habits of Sowerby’s beaked whales (Mesoplodon bidens) taken in the pelagic drift gillnet fishery of the western North Atlantic. Fish. Bull. 2013, 111, 381–389. [Google Scholar] [CrossRef]
  85. Pereira, J.; Neves, V.; Prieto, R.; Silva, M.; Cascão, I.; Oliveira, C.; Cruz, M.; Medeiros, J.; Barreiros, J.; Porteiro, F.; et al. Diet of mid-Atlantic Sowerby’s beaked whales Mesoplondon bidens. Deep. Sea Res. Part I Oceanogr. Res. Pap. 2011, 58, 1084–1090. [Google Scholar] [CrossRef]
  86. Cox, T.M.; Ragen, T.J.; Read, A.J.; Vos, E.; Baird, R.W.; Balcomb, K.; Barlow, J.; Caldwell, J.; Cranford, T.; Crum, L.; et al. Understanding the impacts of anthropogenic sound on beaked whales. J. Cetacean Res. Manag. 2005, 7, 177–187. [Google Scholar] [CrossRef]
  87. Weilgart, L.S. The impacts of anthropogenic ocean noise on cetaceans and implications for management. Can. J. Zool. 2007, 85, 1091–1116. [Google Scholar] [CrossRef]
  88. DeRuiter, S.L.; Southall, B.L.; Calambokidis, J.; Zimmer, W.M.X.; Sadykova, D.; Falcone, E.A.; Friedlaender, A.S.; Joseph, J.E.; Moretti, D.; Schorr, G.S.; et al. First direct measurements of behavioural responses by Cuvier’s beaked whales to mid-frequency active sonar. Biol. Lett. 2013, 9, 20130223. [Google Scholar] [CrossRef] [PubMed]
  89. Falcone, E.A.; Schorr, G.S.; Watwood, S.L.; DeRuiter, S.L.; Zerbini, A.N.; Andrews, R.D.; Morrissey, R.P.; Moretti, D.J. Diving behaviour of Cuvier’s beaked whales exposed to two types of military sonar. R. Soc. Open Sci. 2017, 4, 170629. [Google Scholar] [CrossRef]
  90. de Quirós, Y.B.; Fernandez, A.; Baird, R.W.; Brownell, R.L., Jr.; de Soto, N.A.; Allen, D.; Arbelo, M.; Arregui, M.; Costidis, A.M.; Fahlman, A.; et al. Advances in research on the impacts of anti-submarine sonar on beaked whales. Proc. R. Soc. B 2019, 286, 20182533. [Google Scholar] [CrossRef]
  91. Simonis, A.E.; Brownell, R.L., Jr.; Thayre, B.J.; Trickey, J.S.; Oleson, E.M.; Huntington, R.; Baumann-Pickering, S. Co-occurrence of beaked whale strandings and naval sonar in the Mariana Islands, Western Pacific. Proc. R. Soc. B 2020, 287, 20200070. [Google Scholar] [CrossRef]
  92. Todd, V.L.G. Mitigation of underwater anthropogenic noise and marine mammals: The ‘death of a thousand’cuts and/or mundane adjustment? Mar. Pollut. Bull. 2016, 102, 1–3. [Google Scholar] [CrossRef]
  93. Southall, B.L.; Benoit-Bird, K.J.; Moline, M.A.; Moretti, D.; Januchowski-Hartley, S. Quantifying deep-sea predator–prey dynamics: Implications of biological heterogeneity for beaked whale conservation. J. Appl. Ecol. 2019, 56, 1040–1049. [Google Scholar] [CrossRef]
  94. Mustika, P.L.K.; High, K.K.; Putra, M.I.H.; Sahri, A.; Ratha, I.M.J.; Prinanda, M.O.; Agung, F.; Purnomo, F.S.; Kreb, D. When and Where Did They Strand? The Spatio-Temporal Hotspot Patterns of Cetacean Stranding Events in Indonesia. Oceans 2022, 3, 509–526. [Google Scholar] [CrossRef]
Jmse 13 01618 g001
Figure 1. The deployment site of the acoustic receiver chosen for this study. Data was obtained from GEBCO Grid and Esri. Map created using QGIS 3.20 Odense.
Figure 1. The deployment site of the acoustic receiver chosen for this study. Data was obtained from GEBCO Grid and Esri. Map created using QGIS 3.20 Odense.
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Figure 2. Schematic diagram of the materials and methods used in this study.
Figure 2. Schematic diagram of the materials and methods used in this study.
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Figure 3. Click amplitude (A), click frequency (B), and double clicks (C) of a goose-beaked whale. Click amplitude (D), click frequency (E), and double clicks (F) of a Sowerby’s beaked whale. Echoes from the goose-beaked whale click (G) and Sowerby’s beaked whale click (H). Images created in Raven with milliseconds (ms) on the x-axis and kilohertz (kHz) on the y-axis. Color denotes the relative spectral level (dB FS/Hz), with higher levels as red and lower levels as blue.
Figure 3. Click amplitude (A), click frequency (B), and double clicks (C) of a goose-beaked whale. Click amplitude (D), click frequency (E), and double clicks (F) of a Sowerby’s beaked whale. Echoes from the goose-beaked whale click (G) and Sowerby’s beaked whale click (H). Images created in Raven with milliseconds (ms) on the x-axis and kilohertz (kHz) on the y-axis. Color denotes the relative spectral level (dB FS/Hz), with higher levels as red and lower levels as blue.
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Figure 4. Box plots of goose-beaked whale and Sowerby’s beaked whale click peak frequencies (kHz) (A), click center frequencies (kHz) (B), click frequency ranges (kHz) (C), and click durations (microseconds) (D).
Figure 4. Box plots of goose-beaked whale and Sowerby’s beaked whale click peak frequencies (kHz) (A), click center frequencies (kHz) (B), click frequency ranges (kHz) (C), and click durations (microseconds) (D).
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Figure 5. Total beaked whale occurrences, each line representing the hourly sum for goose-beaked whales (GBW). And Sowerby’s beaked whale (SBW). Gray indicates no occurrence.
Figure 5. Total beaked whale occurrences, each line representing the hourly sum for goose-beaked whales (GBW). And Sowerby’s beaked whale (SBW). Gray indicates no occurrence.
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Figure 6. Proportion of beaked whale occurrences for each diel cycle of goose-beaked whales (A) and Sowerby’s beaked whales (B) for the overall data, and out of the total amount of hours with double clicks and echoes for each species.
Figure 6. Proportion of beaked whale occurrences for each diel cycle of goose-beaked whales (A) and Sowerby’s beaked whales (B) for the overall data, and out of the total amount of hours with double clicks and echoes for each species.
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Table 1. Descriptive statistics of analyzed goose-beaked whale clicks for the sampling period (a) and Sowerby’s beaked whale clicks for the sampling period (b).
Table 1. Descriptive statistics of analyzed goose-beaked whale clicks for the sampling period (a) and Sowerby’s beaked whale clicks for the sampling period (b).
Goose-Beaked WhaleSowerby’s Beaked Whale
N = 1690N = 898
Mean ± Standard Deviation10th
Percentile		90th
Percentile		Mean ± Standard Deviation10th
Percentile		90th
Percentile
Peak Frequency (kHz)38 ± 4354165 ± 46071
Center Frequency (kHz)38 ± 3354066 ± 26369
Frequency Range (kHz)69 ± 21439837 ± 112751
Duration (Microseconds)2837 ± 847184539141649 ± 40011902234
Peak Amplitude (U)656 ± 9421291263117 ± 7056204
RMS Amplitude (U)75 ± 882113920 ± 101233
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MDPI and ACS Style

Cheung, B.; O’Brien, J. Exploring the Occurrences of Beaked Whales off the West Coast of Ireland Through Passive Acoustic Monitoring (PAM). J. Mar. Sci. Eng. 2025, 13, 1618. https://doi.org/10.3390/jmse13091618

AMA Style

Cheung B, O’Brien J. Exploring the Occurrences of Beaked Whales off the West Coast of Ireland Through Passive Acoustic Monitoring (PAM). Journal of Marine Science and Engineering. 2025; 13(9):1618. https://doi.org/10.3390/jmse13091618

Chicago/Turabian Style

Cheung, Beatrice, and Joanne O’Brien. 2025. "Exploring the Occurrences of Beaked Whales off the West Coast of Ireland Through Passive Acoustic Monitoring (PAM)" Journal of Marine Science and Engineering 13, no. 9: 1618. https://doi.org/10.3390/jmse13091618

APA Style

Cheung, B., & O’Brien, J. (2025). Exploring the Occurrences of Beaked Whales off the West Coast of Ireland Through Passive Acoustic Monitoring (PAM). Journal of Marine Science and Engineering, 13(9), 1618. https://doi.org/10.3390/jmse13091618

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