A team at the Southeast Fisheries Science Center is spending the summer studying the demographics and foraging behavior of sperm whales (Physeter macrocephalus), which are facing several threats. It’s all part of the Evaluating the Cumulative Impact of Multiple Stressors on Cetaceans project.
A key part of the study involves deploying digital acoustic recording tags, which are suction-cup devices that stick to whales temporarily. Originally, these tags were developed to assess the effects of sound in the environment on animal movement and behavior. However, their functions have greatly expanded. This version of the tag is equipped with a VHF (very high frequency) antenna to track and recover the tag and sensors to measure:
- Ambient sound
- Movement orientation
- Swim speed
- Animal vocalizations
- Pressure (a proxy for depth)
- Temperature
- Acceleration
Together, these data give scientists a window into what these deep-diving giants are doing when they dive into the abyss.
Tagging a sperm whale isn’t exactly straightforward and comes with its challenges, even for our highly experienced team. The process depends on calm seas and careful coordination. A small boat team is launched from the NOAA Ship Gordon Gunter, and patience becomes the name of the game. Sperm whales can stay submerged for over 2 hours and only surface briefly. With the help of an expert team of acousticians and visual observers guiding from the ship, the small boat team is steered towards the whales as soon as they surface, maximizing their slim opportunity to place a tag during the short time sperm whales spend at the surface.
After a few hours on the water in the heat of the day, the small boat team successfully tagged an individual and returned to the ship.
Now, the waiting begins. The digital acoustic recording tag is programmed to release after 24 hours, but it can pop off early. While it is still attached, it emits a VHF signal each time the whale surfaces, which the team can track through the night and into the next day. This tag was programmed to detach after 24 hours. Then began the next challenge of trying to find a 6-inch orange tag floating in the ocean.
Using the tag’s surface signal, the crew managed to track it down. Science team member, Emma Beretta, was the first to spot it, and the bridge team on the Gordon Gunter maneuvered the ship into position.
The bridge team of the Gordon Gunter pulled alongside the tag and allowed the deck team to retrieve the device from the water.
Once on deck, Dr. Nikki Vollmer was on hand with gloves to collect the tag with a smile on her face as the suction cups contained samples of the whale’s skin, which will be used for genetic analysis.
Once the sample was collected and the tag cleaned, it was time for the final step: downloading the data. Now, the real story begins—analyzing what this whale did over the past 24 hours. Dr. Matthew Bowers took a quick look at the data to see if everything was accounted for and produced a quick figure that shows the diving behavior of the whale over the 24 hours. This data can give us a brief glimpse of the animal's diving depths, foraging behavior, and surfacing intervals between dives. But the full picture will be revealed when the complete suite of dive and acoustic parameters is analyzed for tagged animals.
This single tag deployment was a group effort. While not everyone can be named, it couldn’t have happened without the deck crew, engineers, bridge team, scientists, galley staff, and the dedicated office team back at the Southeast Fisheries Science Center supporting operations behind the scenes. It’s teamwork in its truest form. And this is just the beginning. The aim now is to keep diving deep into the lives of sperm whales as the survey continues.
During the first leg of the cruise, the science team and crew of the Gordon Gunter successfully deployed and recovered three digital acoustic recording tags, each providing fresh insights on sperm whale diving and movement behavior in the Gulf of America.
The project was funded through the Open Ocean Trustee Implementation Group, as part of their Monitoring and Adaptive Management activities. These activities are assessing how projects to restore natural resources injured in the Deepwater Horizon oil spill are making progress towards recovery in the Gulf. All activities are conducted under a scientific research permit (Permit #27867) and approval from the NOAA Institutional Animal Care and Use Committee.
Meet the Blogger
Jonny has been conducting fieldwork with SEFSC as an acoustic technician since 2020, as well as using his photography skills to capture encounters with marine life. When he’s not on the ships he can be found spending his time hiking in the mountains or working as an expedition guide in Antarctica.
