Answers.Body: <p>It is hard to say for sure just from the spectrogram image, but it looks a lot like fish sounds to me. There are a number of species producing these types of sounds (grunts and knocks) off Vancouver Island all year round, including (but not limited to) copper rockfish, quillback rockfish, and lingcod.</p>
  <p>The spectrogram below shows an example of fish sounds I recorded off Hornby Island, BC (water depth: ~10 m). I also uploaded the corresponding audio file <a href="https://drive.google.com/file/d/1Dsc0mvUqXsro65Nl_lZBt95gHGfZVR_C/view?usp=share_link" rel="noreferrer">here</a>.</p>
  <p><a href="https://i.sstatic.net/yBdQ8.png" rel="noreferrer"><img src="https://i.sstatic.net/yBdQ8.png" alt="enter image description here" /></a></p>
  <p>We have a paper in revision at the moment that includes some of these fish sounds off Vancouver Island, but in the meantime you can find some more examples in my thesis <a href="http://dspace.library.uvic.ca/bitstream/handle/1828/13731/Mouy_Xavier_PhD_2022.pdf" rel="noreferrer">here</a>.</p>
  
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Answers.UserDisplayName: Xavier Mouy
Answers.Body: <p>Because of your location near Vancouver Island and the low-frequency, harmonic nature of the calls, my mind immediately jumped to the fish, plainfin midshipman (<em>Porichthys notatus</em>), perhaps being a possibility. They can produce short-duration grunts and growls, and the growls are harmonic with possible frequency modulation. I don't know enough about the exact timing of their calling season or your study location to be sure that they are even a reasonable possibility, but perhaps you can look more into them, or others who might know more about them can chime in. Below is a reference that describes their different sound types and their acoustic characteristics in detail, and you can find a list of other studies that have studied their sound production as well as a few representative recordings on their <a href="https://fishsounds.net/fish.js?id=af8fd4e3-ba35-417c-93a1-efe85b81f293" rel="nofollow noreferrer">species page on FishSounds.net</a>.</p>
  <p>McIver EL, Marchaterre MA, Rice AN, Bass AH (2014) Novel underwater soundscape: acoustic repertoire of plainfin midshipman fish. J Exp Biol 217:2377–2389. <a href="https://doi.org/10.1242/jeb.102772" rel="nofollow noreferrer">https://doi.org/10.1242/jeb.102772</a></p>
  
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Answers.UserDisplayName: Audrey Looby
Answers.Body: <p>Others may correct me, but Very Low Baleen whale sounds, i.e. 20Hz Fin whale and 50/100 Hz Blue whale calls are more tonal and not pulsed sounds (with related pseudo harmonics) as shown in spectrogram. Fish sound is therefore a very likely explanation.</p>
  
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Answers.Body: <p>I think this is a humpback whale. Attached is a recording from Southeast Alaska that looks very similar. I believe this call has been described in humpback whales in the Salish Sea (although feel free to correct me).</p>
  <p>Link to sound and spectrogram: <a href="https://drive.google.com/file/d/1JsTtUXwA3zJeE17u3AXWld3VlL2JbRTq/view?usp=sharing" rel="nofollow noreferrer">https://drive.google.com/file/d/1JsTtUXwA3zJeE17u3AXWld3VlL2JbRTq/view?usp=sharing</a></p>
  
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Answers.Text: Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer).
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Answers.UserDisplayName: Melanie Smith
Body: <p>hoping to get some assistance identifying this sound type. I'm currently in the process of reviewing some data collected from a stationary hydrophone off the southeastern coast of Vancouver Island, British Columbia, and I have found these low-frequency calls that I have as yet been unable to positively ID as a specific species. The ones collected in the picture below were collected in September 2021, and they are typically below 600 Hz and last about 0.5 seconds. I have seen them before in data collected by a towed hydrophone in October 2022 within the Gulf Islands of British Columbia. My current thoughts are that they are some type of baleen whale call, as the calls seem to be collected alongside what appear to be gray whale &quot;knocking&quot; calls,  but a colleague of mine has pointed out the potential that they may be a fish species in the area as well. Any help identifying these calls would be greatly appreciated. Thanks!</p>
  <p>Image Description: Spectrogram of the low-frequency (&lt;600 Hz) sound, where each individual call is outlined by a light blue bounding box. Listening to the files, it sounds like a low, quick grunt.</p>
  <p><a href="https://i.sstatic.net/62PnJ.jpg" rel="noreferrer"><img src="https://i.sstatic.net/62PnJ.jpg" alt="Spectrogram of the low-frequency (&lt;600 Hz) sound, where each individual call is outlined by a light blue bounding box. Listening to the files, it sounds like a low, quick grunt. " /></a></p>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2023-01-24T00:12:52.317Z
Comments.Text: It would be helpful if you could provide a link to the sound (I recommend SoundCloud), and if possible a zoomed in spectrogram with waveform of one of these calls).
Comments.UserDisplayName: Shannon
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2023-01-24T00:20:31.843Z
Comments.Text: Also, would you mind updating your title to be a little more specific (and perhaps help attract a useful answer). Perhaps "Help identify low frequency pulsed sound offshore British Columbia" or such
Comments.UserDisplayName: Shannon
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2023-01-24T02:33:51.967Z
Comments.Text: Any chance it could be humpback whales? I think they're around your area at that time of year. If you give a link to the sound file, maybe also link a longer recording so we can get a feel for the soundscape - that always helps.
Comments.UserDisplayName: Dave Mellinger
Tags: <marine-species><marine-mammals><call-identification><species-identification><mystery-sound>
Title: Help Identifying Low-Frequency Sound
ThreadText: # Help Identifying Low-Frequency Sound
  
  (Asked by: username_0 on 2023-01-23)
  
  hoping to get some assistance identifying this sound type. I'm currently in the process of reviewing some data collected from a stationary hydrophone off the southeastern coast of Vancouver Island, British Columbia, and I have found these low-frequency calls that I have as yet been unable to positively ID as a specific species. The ones collected in the picture below were collected in September 2021, and they are typically below 600 Hz and last about 0.5 seconds. I have seen them before in data collected by a towed hydrophone in October 2022 within the Gulf Islands of British Columbia. My current thoughts are that they are some type of baleen whale call, as the calls seem to be collected alongside what appear to be gray whale "knocking" calls, but a colleague of mine has pointed out the potential that they may be a fish species in the area as well. Any help identifying these calls would be greatly appreciated. Thanks!
  
  Image Description: Spectrogram of the low-frequency (<600 Hz) sound, where each individual call is outlined by a light blue bounding box. Listening to the files, it sounds like a low, quick grunt.
  
  [![Spectrogram of the low-frequency (<600 Hz) sound, where each individual call is outlined by a light blue bounding box. Listening to the files, it sounds like a low, quick grunt. ](https://i.sstatic.net/62PnJ.jpg)](https://i.sstatic.net/62PnJ.jpg)
  
  **Tags:** marine-species, marine-mammals, call-identification, species-identification, mystery-sound
  
  > **Comments:**
  > **username_1**: It would be helpful if you could provide a link to the sound (I recommend SoundCloud), and if possible a zoomed in spectrogram with waveform of one of these calls).  
  > **username_1**: Also, would you mind updating your title to be a little more specific (and perhaps help attract a useful answer). Perhaps "Help identify low frequency pulsed sound offshore British Columbia" or such  
  > **username_2**: Any chance it could be humpback whales? I think they're around your area at that time of year. If you give a link to the sound file, maybe also link a longer recording so we can get a feel for the soundscape - that always helps.  
  
  ---
  
  ## 4 answers
  
  ### Answer by username_3 on 2023-01-27. Score: 5
  
  It is hard to say for sure just from the spectrogram image, but it looks a lot like fish sounds to me. There are a number of species producing these types of sounds (grunts and knocks) off Vancouver Island all year round, including (but not limited to) copper rockfish, quillback rockfish, and lingcod.
  
  The spectrogram below shows an example of fish sounds I recorded off Hornby Island, BC (water depth: ~10 m). I also uploaded the corresponding audio file [here](https://drive.google.com/file/d/1Dsc0mvUqXsro65Nl_lZBt95gHGfZVR_C/view?usp=share_link).
  
  [![enter image description here](https://i.sstatic.net/yBdQ8.png)](https://i.sstatic.net/yBdQ8.png)
  
  We have a paper in revision at the moment that includes some of these fish sounds off Vancouver Island, but in the meantime you can find some more examples in my thesis [here](http://dspace.library.uvic.ca/bitstream/handle/1828/13731/Mouy_Xavier_PhD_2022.pdf).
  
  
  ---
  
  ### Answer by username_4 on 2023-01-24. Score: 4
  
  Because of your location near Vancouver Island and the low-frequency, harmonic nature of the calls, my mind immediately jumped to the fish, plainfin midshipman (*Porichthys notatus*), perhaps being a possibility. They can produce short-duration grunts and growls, and the growls are harmonic with possible frequency modulation. I don't know enough about the exact timing of their calling season or your study location to be sure that they are even a reasonable possibility, but perhaps you can look more into them, or others who might know more about them can chime in. Below is a reference that describes their different sound types and their acoustic characteristics in detail, and you can find a list of other studies that have studied their sound production as well as a few representative recordings on their [species page on FishSounds.net](https://fishsounds.net/fish.js?id=af8fd4e3-ba35-417c-93a1-efe85b81f293).
  
  McIver EL, Marchaterre MA, Rice AN, Bass AH (2014) Novel underwater soundscape: acoustic repertoire of plainfin midshipman fish. J Exp Biol 217:2377–2389. <https://doi.org/10.1242/jeb.102772>
  
  
  ---
  
  ### Answer by username_5 on 2023-01-23. Score: 1
  
  Others may correct me, but Very Low Baleen whale sounds, i.e. 20Hz Fin whale and 50/100 Hz Blue whale calls are more tonal and not pulsed sounds (with related pseudo harmonics) as shown in spectrogram. Fish sound is therefore a very likely explanation.
  
  
  ---
  
  ### Answer by username_6 on 2023-01-30. Score: 1
  
  I think this is a humpback whale. Attached is a recording from Southeast Alaska that looks very similar. I believe this call has been described in humpback whales in the Salish Sea (although feel free to correct me).
  
  Link to sound and spectrogram: <https://drive.google.com/file/d/1JsTtUXwA3zJeE17u3AXWld3VlL2JbRTq/view?usp=sharing>
  
  > **Comments:**
  > **username_7**: Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer).  
  
  ---
  
  