February 10, 2026 — A new peer-reviewed study in PLOS One sheds light on why some beaked whale species are more detectable than others using passive acoustic monitoring. Researchers examined how differences in species-specific diving and echolocation behaviors affect the ability to detect beaked whales using underwater listening devices. Beaked whales are one of the ocean’s most elusive groups of whales.
The findings are particularly important for the Gulf of America (formerly the Gulf of Mexico), a heavily industrialized region where reliable beaked whale population estimates are needed. A recent study found that beaked whale populations in the Gulf may have declined by as much as 83 percent since the 2010 Deepwater Horizon oil spill. This highlights the need to better understand them to conserve them effectively.
Beaked whales are notoriously difficult to study because they spend little time at the surface to be seen during traditional infrequent visual surveys (vessel and aerial). Passive acoustic monitoring offers a powerful alternative as continuous data is recorded for months at a time. However, this method requires knowledge of whale behavior to understand how to interpret the detection of whale sounds for population monitoring.
Acoustic Detection is Species-Specific
The study shows that detectability varies among beaked whale species, as does their dive and echolocation behavior. Goose-beaked whales (Ziphius cavirostris), for example, were detectable for longer periods than Blainville’s (Mesoplodon densirostris) or Gervais’ (Mesoplodon europaeus) beaked whales. Goose-beaked whales performed deeper foraging dives, often close to the seafloor, and produced clicks with higher source levels. These behavioral differences significantly increase the likelihood of detecting goose-beaked whales compared to the other two species.