POSSIBLE MISTICE SIGNAL DETECTED and the importance of paying attention to the low frequency spectrogram even outside the humpback season

Hello MAP operators and mysticete bioacoustic researchers!

Often, during passive acoustic monitoring that occurs as a mitigation of the potential effects of seismic research on cetaceans, we believe that one of the only, if not the only mysticete that we will detect is the humpback whale.

The reason for this is that the environment in which we work (seismic research vessels) by nature makes the marine environment quite noisy, especially in the lower frequencies, which is where mysticetes vocalize. 

Furthermore, most mysticetes also do not vocalize as frequently and knowledge about the group’s bioacoustic is also much lower.

Therefore, the humpback stands out as #PAM’s favorite, and that’s why we may end up not giving much importance to our low-frequency spectrogram when we are outside the species’ reprodution season or area of ​​occurrence. However, please take a look at this sign . 👀

This signal was detected by two different people, in different projects and in two different years in December, in the Campos Basin- Brazil.

The interesting thing is that the signal is quite stereotypical and was exactly the same in both recordings. The sound seemed biological to us, but we have no experience with the acoustics of other mysticetes than the humpback, but we believe that MAYBE it is a mysticete.

So, what do we want with this post?

· Raise the importance of paying attention to the low frequency spectrogram even outside of humpback season

· Raise reflection on the importance and usefulness of starting to use a spectrogram focusing on even lower frequencies to learn for ourselves whether it is possible to detect and mitigate, during seismic research, species such as the fin whale, for example, which vocalizes at 20Hz, and would be difficult to see on a spectrogram of 1000Hz or more (commonly used)

· It’s obvious and more fun: trying to find what that sound is.

How can you help us? SHARE, maybe an expert will recognize the sign! Thank you very much to all.