Figure 6. PBD dataset UMAP ordination at ~1 min
resolution. Samples grouped by hydrophone deployment location (left).
Samples grouped by sound source (right). All other samples are shown in
grey.
Samples labelled as seismic airgun noise and ship noise separated and
occupied two distinct portions of the UMAP ordination plot (Fig. 6). A
small number of samples from the two sources overlapped, indicating ship
transits occurring during seismic exploration. However, we could not
observe a clear distinction between presences and absences of the
sources.
Lastly, we inspected how UMAP ordinated the ~1 s
acoustic features labelled by their chance of containing a humpback
whale vocalization (Fig. 7). Detections per hour peaked at 1:00 and
13:00 and 15:00 for the Burin samples, while the Red Island samples
showed a single distinct peak at 12:00 (Appendix S2.1). The
~1 s resolution UMAP ordination showed a concentration
of humpback whale detection scores (> 0.8) towards the
right end of the plot, with samples densely aggregated along the second
UMAP dimension. However, and similarly to the anthropogenic noise
sources, we could not observe a clear separation between presences and
absences.