the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 11 Apr 2025
High resolution acoustic recordings of wild free-ranging short-beaked common dolphins for etho-acoustical and repertoire studies
Abstract. Dolphins are highly vocal cetaceans with a complex acoustic repertoire. These marine mammals rely heavily on sound for critical activities: echolocation clicks for navigation and prey detection, whistles for social communication, and pulsed sounds for less well-documented purposes. Understanding their acoustic behaviour is essential for insights into their ecology, social structure, and responses to anthropogenic noise. However, to date, there is a lack of open-access datasets of acoustic recordings of wild free-ranging short-beaked common dolphins (Delphinus delphis), coupled with observations data. Here, we present a dataset (DOI:10.5281/zenodo.14637674, Lehnhoff (2025)) of high resolution acoustic recordings of (D. delphis) observed during various behavioural states, including foraging, travelling, socializing, milling, and attraction to the boat. The dataset was collected in the northern Bay of Biscay, France, from summers of 2020 to 2022 during surveys conducted as part of the DOLPHINFREE project. The dataset contains acoustic recordings of wild free-ranging short-beaked common dolphins (Delphinus delphis) observed during various behavioural states, including foraging, travelling, socializing, milling, and attraction to the boat. Audio recordings were performed during opportunistic encounters using two devices: a single high-quality hydrophone (sampling rate: 512 kHz, bit-depth: 32 bits) and a compact array of four hydrophones (256 kHz to 512 kHz, 16 to 24 bits) for localization purposes. The dataset comprises over 400 minutes of unedited audio recordings of D. delphis accompanied by visual observations. In total, we identified about 68,000 echolocation clicks, 4,600 whistle contours, and more that 350 pulsed sounds. This comprehensive resource is valuable for detailed studies of the acoustic repertoire of common dolphins and their two-dimensional movements.
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Status: closed
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RC1: 'Comment on essd-2025-193', Anonymous Referee #1, 08 Jun 2025
Ms. Ref. No.: essd-2025-193
Title: High resolution acoustic recordings of wild free-ranging short-beaked common dolphins for etho-acoustical and repertoire studies
Recommendation: Minor Revision (but check potential ethical issues)
Comments to Author
This manuscript describes open-access datasets of acoustic recordings (about 6.5 hours) of wild free-ranging short-beaked common dolphins (Delphinus delphis) collected in the northern Bay of Biscay, France, from summers of 2020 to 2022 during various behavioural states (including foraging, travelling, socializing, milling, and attraction to the boat).
The topic covered meets the objectives of the journal and is potentially useful and of interest to some of the journal's readers. However, this manuscript does not yet meet the quality standards required for acceptance for publication, as some developments are necessary, including revision of the English language and the removal of several repetitions.
SPECIFIC COMMENTS
Abstract
Line 9-11: The sentence is a repetition of the previous one.
Introduction
In my opinion, in its current state, the Introduction is quite confused, fails to give a comprehensive picture (details on the acoustic characteristics of D. delphis sounds, i.e. clicks, whistles and burst pulses, are missing, as well as correlation with behaviour) and needs English editing. Please consider the following suggestions.
Line 19-23: Please consider to remove the entire part or to use a portion of it at the end (see comments to line 64-65).
Line 23-26: Please start the Introduction with “This data descriptor …. D. delphis”,
Line 26-27: Please consider to remove the sentence “The present study … each recording” as it seems a repetition and it is not clear what you mean with “high-sapling”.
Line 29: Please consider to remove “including short-beaked common dolphin”.
Line 35: Please check English (“that form an other form”).
Line 35-36: Please consider to mitigate this sentence on communication function (at line 39 you correctly say that the function is still under investigation).
Line 36: Please add here a ref (e.g. Herman & Tavolga, 1980) after “pulsed sounds”.
Line 36-38: Please consider to re-phrase these sentences, possibly starting with ICI. Burst pulsed sounds were defined as "graded signals" by Murray et al. (1998), and that they were often recorded in arousal contexts.
Then, before starting the description of the dataset (from line 40), please consider to add info/details on the acoustic characteristics of D. delphis sounds and correlation with the behaviour.
Line 43-44: Please check English.
Line 51-52: It seems a repetition.
Line 52-62: Please consider to remove this part as it seems too methodological for the Introduction. I also suggest to move figure 1 at the end of line 95.
Line 63-64: Again, it seems a repetition.
Line 64-65: Please reshape the sentence to clearly underline the worth of the dataset, also contextualizing its usefulness in the context mentioned in line 19-23.
Material and surveys
Line 69: Please consider to renumber the figures if you move figure 1.
Line 70-74: Please check English. Please add a ref to the study area in the figure legend.
Line 79: Please consider to replace the word “parameters” with “procedures”.
Line 80: It is not clear to me what the Author mean with “computational processing”. Please better define it.
Line 90: The use of a fishing nets during your scientific surveys may raise ethical issues. Have you obtained an opinion from an ethics committee and an authorization to proceed from the government/local authorities? Is this document available? May we consider the Disclaimer at line 212? Please provide details on this relevant question.
In addition, please give specifics on the net characteristics (mesh size, length, etc) and on how you used it.
Conclusions
Conclusions would benefit from a paragraph that reinforces the key findings, their broader significance, and potential applications.
Citation: https://doi.org/10.5194/essd-2025-193-RC1 -
AC1: 'Reply on RC1', Loïc Lehnhoff, 10 Jun 2025
We appreciate the overall positive assessment of our work, and we thank you for the constructive and detailed comments. Below, we provide responses to each one of the comments. Please be assured that all corresponding changes have been (or will be) incorporated in the revised version of the manuscript.
In addition, to improve clarity and style, the manuscript has been reviewed by a native English speaker with experience in scientific writing.
Specific Comments
Abstract
- Line 9–11: Thank you for pointing this out. The repeated sentence has been removed to improve clarity.
Introduction
The Introduction has been reorganized for improved clarity and structure. A more extensive description of D. delphis clicks, whistles, and burst-pulsed sounds will be added, along with known correlations with behavior.
- Line 19–23: This section has been moved to the end of the Introduction, as suggested.
- Line 23–26: The Introduction now begins with “This data descriptor…”.
- Line 26–27: The phrase “high-sampling” referred to the high sampling rate of each recording. This sentence has been revised for clarity and to avoid redundancy.
- Line 29: The words “including short-beaked common dolphin” has been removed, as it appears unnecessary.
- Line 35: The sentence has been revised for clarity.
- Line 35–36: The sentence has been restructured to reflect that the communication function of pulsed sounds is still under investigation. The corresponding line (Line 39) has been moved up, and possible functions are now discussed later in the paragraph.
- Line 36: “Pulsed sounds” are now better defined, with relevant references.
- Line 36–38: This section now includes a more detailed description of burst-pulsed sounds, including their context and characteristics, as well as their known behavioral associations in D. delphis.
- Line 43–44: This sentence has been simplified for clarity.
- Line 51–52: The repetition has been removed.
- Line 52–62: These lines, along with Figure 1, have been moved to the “Materials and Surveys” section, as they were too specific for the Introduction section.
- Line 63–64: The repeated sentence has been removed.
- Line 64–65: Elements previously found in Lines 19–23 have been integrated here to better contextualize the dataset and highlight its significance.
Materials and Surveys
- Line 69: Figures have been renumbered to reflect the revised structure.
- Line 70–74: This passage has been rewritten for clarity and conciseness. The figure legend now includes the name of the study area.
- Line 79: The term “parameters” has been replaced with “procedures.”
- Line 80: The term “computational processing” has been replaced with a clearer description indicating that no filtering or modification was applied to the raw acoustic recordings.
- Line 90: It seems that the disclaimer (lines 212–214) added in the initial version of the manuscript was missing its second part. The disclaimer has been updated. Specifically, we added the following sentence: “The DOLPHINFREE project obtained a favorable opinion from the Ethical Committee for Animal Experimentation of Languedoc Roussillon (CEEA-LR) for request #26568.” However, these documents are not available online.
Additional details about the fishing net (e.g., mesh size, length, and material) and its use have also been included in the Methods section.
Conclusions
The Conclusions section now includes a more comprehensive paragraph reinforcing the value of the dataset, its potential applications in behavioral and conservation research, and its contribution to open-access marine mammal acoustic data.
Citation: https://doi.org/10.5194/essd-2025-193-AC1 -
RC2: 'Reply on AC1', Daniela Silvia Pace, 10 Jun 2025
Thanks.
Waiting for the complete revised version of the manuscript.
Best
Citation: https://doi.org/10.5194/essd-2025-193-RC2
-
AC1: 'Reply on RC1', Loïc Lehnhoff, 10 Jun 2025
-
RC3: 'Comment on essd-2025-193', Will Rayment, 12 Jun 2025
The paper describes the necessary information for what will likely prove a useful acoustic dataset from common dolphins. It seems to meet the requirements for this type of journal.
The introduction provides useful background on the acoustic signals of common dolphins, and the relevant information to understand the dataset that is being made available. The methods sections are comprehensive and well-explained. The results provide useful examples of the nature of the data available; Figure 5 for example is excellent.
My only concern is regarding the behavioural data. Assessing behavioural states is somewhat subjective, and potentially biased if not all animals in a group are performing the same behaviour. Furthermore, it is possible that individuals could be performing two types of behaviour at the same time, e.g. socialising while being attracted to the boat. I think adding a few caveats regarding interpretation of the behavioural data would be useful.
There are few typos and grammatical errors which need to be corrected – see below.
Line 5: change to “observational data”?
Line 10: sentence is a repeat of a previous one.
Line 16: “two dimensional movements” sounds a bit odd on this context. Perhaps clarify what you mean.
Line 35: change to “another”.
Line 40: change to “ … performed during the DOLPHINFREE project …”.
Line 49: change to “ .. data that are not …”.
Line 68: change to “non-systematic”.
Line 110: change to “bycatch occurs”.
Line 120: change to “which in total add up to “.
Line 128: change to “observation data were collected”.
Line 130: delete extraneous bracket.
Table 2” change “signification” to “description”?
Line 136: change to “audio recordings”.
Citation: https://doi.org/10.5194/essd-2025-193-RC3 -
AC2: 'Reply on RC3', Loïc Lehnhoff, 12 Jun 2025
We thank you for your constructive and overall positive comments on our manuscript. We particularly appreciate your recognition of the usefulness of the acoustic dataset, the clarity of the manuscript sections, and the quality of the figures.
In the final version, we plan to revise and improve the Introduction and Methods sections based on comments from all referees. Regarding your concern about behavioural state classification, we agree that these assessments can be subjective and may not always represent the entire group or account for overlapping behaviours. Therefore, we will include a brief description to acknowledge these limitations and provide context for interpreting the behavioural data.
We also appreciate your careful identification of typos and grammatical issues. These will be corrected in the revised version. We provide explanations below for some specific comments.
- Line 16: We agree that “two-dimensional movement” may be unclear in this context and does not accurately reflect the intention of the sentence. Since the dataset includes audio recordings from four synchronised hydrophones, the directionality of sounds can be analysed using polar coordinates (elevation and azimuth angles), hence the two dimensions. However, to improve clarity, we will revise this sentence to refer explicitly to these angular measurements.
- Table 2: The title will be revised to: “Description of column headers in visual observation data (XLSX) files” to better reflect its content.
Once again, we sincerely thank you for your helpful and thoughtful feedback.
Citation: https://doi.org/10.5194/essd-2025-193-AC2 - Line 16: We agree that “two-dimensional movement” may be unclear in this context and does not accurately reflect the intention of the sentence. Since the dataset includes audio recordings from four synchronised hydrophones, the directionality of sounds can be analysed using polar coordinates (elevation and azimuth angles), hence the two dimensions. However, to improve clarity, we will revise this sentence to refer explicitly to these angular measurements.
-
AC3: 'Reply on RC3', Loïc Lehnhoff, 18 Jun 2025
To address your concerns regarding behavioural data, we have added the following aspects in the revised manuscript and in the dataset available through Zenodo:
(i) The data was initially collected as relative percentages of each behavioural state, to reflect the different behaviours exhibited within a group of dolphins and/or the several behaviours exhibited simultaneously by a same individual (mainly attraction & socialisation during our surveys).
(ii) As a result, text in sub-section 'Observation notes' (lines 123-128) and Table 2 have been updated to precise the behavioural data collected.
(iii) The dataset available on Zenodo has been updated to include the initial relative percentage of each behavioural state recorded during the surveys
Again, we thank you for your constructive comments.Citation: https://doi.org/10.5194/essd-2025-193-AC3
-
AC2: 'Reply on RC3', Loïc Lehnhoff, 12 Jun 2025
Status: closed
-
RC1: 'Comment on essd-2025-193', Anonymous Referee #1, 08 Jun 2025
Ms. Ref. No.: essd-2025-193
Title: High resolution acoustic recordings of wild free-ranging short-beaked common dolphins for etho-acoustical and repertoire studies
Recommendation: Minor Revision (but check potential ethical issues)
Comments to Author
This manuscript describes open-access datasets of acoustic recordings (about 6.5 hours) of wild free-ranging short-beaked common dolphins (Delphinus delphis) collected in the northern Bay of Biscay, France, from summers of 2020 to 2022 during various behavioural states (including foraging, travelling, socializing, milling, and attraction to the boat).
The topic covered meets the objectives of the journal and is potentially useful and of interest to some of the journal's readers. However, this manuscript does not yet meet the quality standards required for acceptance for publication, as some developments are necessary, including revision of the English language and the removal of several repetitions.
SPECIFIC COMMENTS
Abstract
Line 9-11: The sentence is a repetition of the previous one.
Introduction
In my opinion, in its current state, the Introduction is quite confused, fails to give a comprehensive picture (details on the acoustic characteristics of D. delphis sounds, i.e. clicks, whistles and burst pulses, are missing, as well as correlation with behaviour) and needs English editing. Please consider the following suggestions.
Line 19-23: Please consider to remove the entire part or to use a portion of it at the end (see comments to line 64-65).
Line 23-26: Please start the Introduction with “This data descriptor …. D. delphis”,
Line 26-27: Please consider to remove the sentence “The present study … each recording” as it seems a repetition and it is not clear what you mean with “high-sapling”.
Line 29: Please consider to remove “including short-beaked common dolphin”.
Line 35: Please check English (“that form an other form”).
Line 35-36: Please consider to mitigate this sentence on communication function (at line 39 you correctly say that the function is still under investigation).
Line 36: Please add here a ref (e.g. Herman & Tavolga, 1980) after “pulsed sounds”.
Line 36-38: Please consider to re-phrase these sentences, possibly starting with ICI. Burst pulsed sounds were defined as "graded signals" by Murray et al. (1998), and that they were often recorded in arousal contexts.
Then, before starting the description of the dataset (from line 40), please consider to add info/details on the acoustic characteristics of D. delphis sounds and correlation with the behaviour.
Line 43-44: Please check English.
Line 51-52: It seems a repetition.
Line 52-62: Please consider to remove this part as it seems too methodological for the Introduction. I also suggest to move figure 1 at the end of line 95.
Line 63-64: Again, it seems a repetition.
Line 64-65: Please reshape the sentence to clearly underline the worth of the dataset, also contextualizing its usefulness in the context mentioned in line 19-23.
Material and surveys
Line 69: Please consider to renumber the figures if you move figure 1.
Line 70-74: Please check English. Please add a ref to the study area in the figure legend.
Line 79: Please consider to replace the word “parameters” with “procedures”.
Line 80: It is not clear to me what the Author mean with “computational processing”. Please better define it.
Line 90: The use of a fishing nets during your scientific surveys may raise ethical issues. Have you obtained an opinion from an ethics committee and an authorization to proceed from the government/local authorities? Is this document available? May we consider the Disclaimer at line 212? Please provide details on this relevant question.
In addition, please give specifics on the net characteristics (mesh size, length, etc) and on how you used it.
Conclusions
Conclusions would benefit from a paragraph that reinforces the key findings, their broader significance, and potential applications.
Citation: https://doi.org/10.5194/essd-2025-193-RC1 -
AC1: 'Reply on RC1', Loïc Lehnhoff, 10 Jun 2025
We appreciate the overall positive assessment of our work, and we thank you for the constructive and detailed comments. Below, we provide responses to each one of the comments. Please be assured that all corresponding changes have been (or will be) incorporated in the revised version of the manuscript.
In addition, to improve clarity and style, the manuscript has been reviewed by a native English speaker with experience in scientific writing.
Specific Comments
Abstract
- Line 9–11: Thank you for pointing this out. The repeated sentence has been removed to improve clarity.
Introduction
The Introduction has been reorganized for improved clarity and structure. A more extensive description of D. delphis clicks, whistles, and burst-pulsed sounds will be added, along with known correlations with behavior.
- Line 19–23: This section has been moved to the end of the Introduction, as suggested.
- Line 23–26: The Introduction now begins with “This data descriptor…”.
- Line 26–27: The phrase “high-sampling” referred to the high sampling rate of each recording. This sentence has been revised for clarity and to avoid redundancy.
- Line 29: The words “including short-beaked common dolphin” has been removed, as it appears unnecessary.
- Line 35: The sentence has been revised for clarity.
- Line 35–36: The sentence has been restructured to reflect that the communication function of pulsed sounds is still under investigation. The corresponding line (Line 39) has been moved up, and possible functions are now discussed later in the paragraph.
- Line 36: “Pulsed sounds” are now better defined, with relevant references.
- Line 36–38: This section now includes a more detailed description of burst-pulsed sounds, including their context and characteristics, as well as their known behavioral associations in D. delphis.
- Line 43–44: This sentence has been simplified for clarity.
- Line 51–52: The repetition has been removed.
- Line 52–62: These lines, along with Figure 1, have been moved to the “Materials and Surveys” section, as they were too specific for the Introduction section.
- Line 63–64: The repeated sentence has been removed.
- Line 64–65: Elements previously found in Lines 19–23 have been integrated here to better contextualize the dataset and highlight its significance.
Materials and Surveys
- Line 69: Figures have been renumbered to reflect the revised structure.
- Line 70–74: This passage has been rewritten for clarity and conciseness. The figure legend now includes the name of the study area.
- Line 79: The term “parameters” has been replaced with “procedures.”
- Line 80: The term “computational processing” has been replaced with a clearer description indicating that no filtering or modification was applied to the raw acoustic recordings.
- Line 90: It seems that the disclaimer (lines 212–214) added in the initial version of the manuscript was missing its second part. The disclaimer has been updated. Specifically, we added the following sentence: “The DOLPHINFREE project obtained a favorable opinion from the Ethical Committee for Animal Experimentation of Languedoc Roussillon (CEEA-LR) for request #26568.” However, these documents are not available online.
Additional details about the fishing net (e.g., mesh size, length, and material) and its use have also been included in the Methods section.
Conclusions
The Conclusions section now includes a more comprehensive paragraph reinforcing the value of the dataset, its potential applications in behavioral and conservation research, and its contribution to open-access marine mammal acoustic data.
Citation: https://doi.org/10.5194/essd-2025-193-AC1 -
RC2: 'Reply on AC1', Daniela Silvia Pace, 10 Jun 2025
Thanks.
Waiting for the complete revised version of the manuscript.
Best
Citation: https://doi.org/10.5194/essd-2025-193-RC2
-
AC1: 'Reply on RC1', Loïc Lehnhoff, 10 Jun 2025
-
RC3: 'Comment on essd-2025-193', Will Rayment, 12 Jun 2025
The paper describes the necessary information for what will likely prove a useful acoustic dataset from common dolphins. It seems to meet the requirements for this type of journal.
The introduction provides useful background on the acoustic signals of common dolphins, and the relevant information to understand the dataset that is being made available. The methods sections are comprehensive and well-explained. The results provide useful examples of the nature of the data available; Figure 5 for example is excellent.
My only concern is regarding the behavioural data. Assessing behavioural states is somewhat subjective, and potentially biased if not all animals in a group are performing the same behaviour. Furthermore, it is possible that individuals could be performing two types of behaviour at the same time, e.g. socialising while being attracted to the boat. I think adding a few caveats regarding interpretation of the behavioural data would be useful.
There are few typos and grammatical errors which need to be corrected – see below.
Line 5: change to “observational data”?
Line 10: sentence is a repeat of a previous one.
Line 16: “two dimensional movements” sounds a bit odd on this context. Perhaps clarify what you mean.
Line 35: change to “another”.
Line 40: change to “ … performed during the DOLPHINFREE project …”.
Line 49: change to “ .. data that are not …”.
Line 68: change to “non-systematic”.
Line 110: change to “bycatch occurs”.
Line 120: change to “which in total add up to “.
Line 128: change to “observation data were collected”.
Line 130: delete extraneous bracket.
Table 2” change “signification” to “description”?
Line 136: change to “audio recordings”.
Citation: https://doi.org/10.5194/essd-2025-193-RC3 -
AC2: 'Reply on RC3', Loïc Lehnhoff, 12 Jun 2025
We thank you for your constructive and overall positive comments on our manuscript. We particularly appreciate your recognition of the usefulness of the acoustic dataset, the clarity of the manuscript sections, and the quality of the figures.
In the final version, we plan to revise and improve the Introduction and Methods sections based on comments from all referees. Regarding your concern about behavioural state classification, we agree that these assessments can be subjective and may not always represent the entire group or account for overlapping behaviours. Therefore, we will include a brief description to acknowledge these limitations and provide context for interpreting the behavioural data.
We also appreciate your careful identification of typos and grammatical issues. These will be corrected in the revised version. We provide explanations below for some specific comments.
- Line 16: We agree that “two-dimensional movement” may be unclear in this context and does not accurately reflect the intention of the sentence. Since the dataset includes audio recordings from four synchronised hydrophones, the directionality of sounds can be analysed using polar coordinates (elevation and azimuth angles), hence the two dimensions. However, to improve clarity, we will revise this sentence to refer explicitly to these angular measurements.
- Table 2: The title will be revised to: “Description of column headers in visual observation data (XLSX) files” to better reflect its content.
Once again, we sincerely thank you for your helpful and thoughtful feedback.
Citation: https://doi.org/10.5194/essd-2025-193-AC2 - Line 16: We agree that “two-dimensional movement” may be unclear in this context and does not accurately reflect the intention of the sentence. Since the dataset includes audio recordings from four synchronised hydrophones, the directionality of sounds can be analysed using polar coordinates (elevation and azimuth angles), hence the two dimensions. However, to improve clarity, we will revise this sentence to refer explicitly to these angular measurements.
-
AC3: 'Reply on RC3', Loïc Lehnhoff, 18 Jun 2025
To address your concerns regarding behavioural data, we have added the following aspects in the revised manuscript and in the dataset available through Zenodo:
(i) The data was initially collected as relative percentages of each behavioural state, to reflect the different behaviours exhibited within a group of dolphins and/or the several behaviours exhibited simultaneously by a same individual (mainly attraction & socialisation during our surveys).
(ii) As a result, text in sub-section 'Observation notes' (lines 123-128) and Table 2 have been updated to precise the behavioural data collected.
(iii) The dataset available on Zenodo has been updated to include the initial relative percentage of each behavioural state recorded during the surveys
Again, we thank you for your constructive comments.Citation: https://doi.org/10.5194/essd-2025-193-AC3
-
AC2: 'Reply on RC3', Loïc Lehnhoff, 12 Jun 2025
Data sets
A dataset of acoustic recordings of wild free-ranging short-beaked common dolphins Loïc Lehnhoff, Hervé Glotin, Yves Le Gall, Eric Menut, Hélène Peltier, Jérôme Spitz, Olivier Van Canneyt, and Bastien Mérigot https://zenodo.org/records/14637675
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