Hawaiian Islands Humpback Whale National Marine Sanctuary partners with Scripps Institute of Oceanography

April 29, 2025

Between March 12 and 25, the Hawaiian Islands Humpback Whale National Marine Sanctuary team collaborated with Dr. Aaron Thode, a researcher in applied science at Scripps Institution of Oceanography, and his students on an innovative acoustic study in the Maui Nui region.

Using the research vessel Koholā, the Scripps team deployed and retrieved four Tiny Directional Acoustic Logger (TiDAL) instruments—directional acoustic vector sensors that measure the particle velocity of sound. This allows researchers to determine the direction, or bearing, of a sound source. When used together, these sensors can help locate and track sound sources in the ocean.

TiDAL devices continuously record underwater sound for four to seven days, making them a powerful tool for studying the migration patterns of marine animals. The goal of this collaboration is to identify the locations of individual singing humpback whales and other ocean sounds, helping researchers better understand whale distribution, movement, and population density.

The project involved two dive operation days, with four dives each day to deploy and retrieve the TiDAL instruments. Two devices were placed off the coast of Lāna‘i and two off West Maui, creating an "acoustic window" into whale behavior in the channel between the islands and beyond.

These were preliminary trials, and the sanctuary team looks forward to refining the methods and continuing this partnership with Dr. Thode and the Scripps team.