Adrienne Copeland, a Ph.D. zoology student at UH, was chief scientist for the cruise to the waters off the Kona Coast on the west side of the Island of Hawaii. She built on past work, using sonar to learn more about where whales feed. Toothed whales, known formally as odontocetes, sometimes dive down 1,000 meters or more, complicating the job of studying what attracts them and what holds their foraging attention.
Copeland used sonar to track diving whales and quantify how much food is available in the areas where they spend their time during dives. Her hypothesis was that whales may be targeting places where prey is particularly abundant within or below what’s known as the deep scattering layer.
The deep scattering layer (DSL) is a layer at which smaller fish, crustaceans, jellies, and other organisms tend to concentrate. During the day, this happens in deep waters below the reach of sunlight, where these smaller animals retreat to the relative safety of darkness to avoid predators. But many feed on algae in shallower waters, so each night about half of the organisms collectively move to shallower depths under the cover of darkness. This daily movement up and down constitutes the planet’s largest migration.
Studying all of this took a few components. First off, students stood watches on the observation deck during daylight hours looking for whales. This helped the team target areas for research. They also toke photos of the whales they spotted for use by NOAA researchers in ongoing programs that identify individual whales and track their movements using a photo database of the animals’ unique dorsal fins. To expand on observations the students also lowered hydrophones to confirm that their target whale species are eating in the area based on the whales’ characteristic echolocation clicks.
In areas where the whales congregated, the team ran surveys using Falkor’s advanced fisheries sonar system
Besides correlating DSL data with the areas where the whales are directly detected or observed, the team also was able to tie information about DSL structure and inhabitants in various spots with a longer-term record of whale locations. For about a year, the team had two Ecological Acoustic Recorders (EARs) deployed in the area where they worked. These acoustic listening devices recorded the whales’ clicks, which enables tracking. They also were comparing all their findings on this cruise against past work to look for any seasonal differences in the whales’ behaviors.
For the students involved, Falkor’s availability, announced in November, was welcome news and an opportunity that significantly advanced not just individual research projects, but also the skills and aspirations of the students aboard. “It’s really hard to get ship time,” says Copeland, “When this popped up it was a great opportunity and my colleagues and I jumped on it.”
The resulting shipboard dataset is being stored at the Rolling Deck to Repository and is now available.
The multibeam data from this cruise can be viewed through the NOAA National Center for Environmental Information (NCEI) map viewer. You can view all Falkor datasets by using the Filter Surveys button in the left sidebar.
Publications, Meeting Presentations, and Research Seminars based on this Cruise
Copeland, Adrienne, M., Au, Whitlow, Giorli, Giacomo and Jeffrey Polovina. 2014. Investigating the relationship between foraging odontocetes and ocean acoustic biomass off the Kona coast of the Island of Hawaii.The Journal of the Acoustical Society of America 135 (4), 2335. Won best student presentation in the Animal Bioacoustics session at the 167th Acoustical Society of America Conference in Providence, RI. here
Giorli, Giacomo, Copeland, Adrienne M., Au, Whitlow W., Polovina, Jeff. 2014. Deep sea organisms density estimation using a Dual Frequency Identification Sonar (DIDSON). The Journal of the Acoustical Society of America 135 (4), 2154. Presented at the 167th Acoustical Society of America Conference in Providence, RI.
Cruise Outreach
VOS2-17 Onboard the Falkor: Whale Watching Voices of the Sea TV November 8, 2015
An estimated 660 students and 17 classes in Hawaii followed The Secret Lives of Whales blog. Additionally, three classroom visits were made by the graduate students to share about their research and experiences, upon returning from the cruise.
All Things Marine radio show March 13, 2014
Hawaii News Now: Understanding Whale Behaviors Through Science Research March 11, 2014
University of Hawaii News February 14, 2014
Kaunana: The Research Publication of the University of Hawaii Manoa February 14, 2014
