Tag: passive acoustics

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Mandy Freeman: Life Between Sunrises and Humpbacks, May 24, 2026

Teacher Mandy Freeman stands on a pier in front of NOAA Ship Henry B. Bigelow. She wears a Lewisville Lions t-shirt and sunglasses. On the ship's hull, we can see the NOAA logo, the letters N O A A, and the ship's number, R 225. The sky is solid blue and cloudless.





NOAA Teacher at Sea

Mandy Freeman

Aboard NOAA Ship Henry B. Bigelow

May 19 – May 29, 2026

Mission: Sea Scallop HabCam Survey

Geographic Area of Cruise: Northeast Atlantic Ocean

Date: May 24, 2026

Weather Data from 13 miles due East of Monomoy Point, Massachusetts
Latitude: 41 32.7776 ° N
Longitude: 069 42.0435 ° W
Wind Speed: 12.5 knots E
Air Temperature: 10.5 °C (50.9°F)

Science and Technology Log

The Habitat Mapping Camera System (HabCam) has been taking LOTS of pictures of the life near the sea floor. As part of the nightshift, my duties include annotating the HabCam images, driving the HabCam vehicle as Pilot, and serving as Co-Pilot.

Annotating images involves identifying and measuring scallops, as well as identifying other animals like round fish, flat fish, skates, crabs and whelks.

As Co-Pilot, there are several monitors with varying data from both the ship and the HabCam that must be watched in order to see obstacles on the path to avoid a collision. The depth of the HabCam is controlled by a “joy stick” that deploys and retracts the cable attached to the frame surrounding the HabCam. Ideally the camera should be kept within 2 meters from the ocean bottom.

As the Pilot, I must constantly monitor and adjust for the ever-changing distance from the seafloor to keep the HabCam from touching bottom. Some areas are easy to navigate, while others are rocky with “surprise” boulders.

BEFORE Annotations

National Oceanic and Atmospheric Administration (NOAA) places a strong emphasis on producing reliable, standardized research data, so I was required to watch a training video, pass a verbal quiz, and then take a 200 image test to ensure my annotations met those standards.

view of a desktop computer at a workstation. we cannot really interpret anything on the screen. a sea scallop shell rests on the table off to the side.
Training and a test before I could annotate images
screenshot of an underwater view of a scallop on the seafloor
Live Sea Scallop from training session
Mandy sits at a corner desk with an array of computer monitors and a control panel with a joystick. she faces the screens intently as she grips the joystick with her right hand
Mandy piloting the HabCam
Mandy stands on deck in front of the HabCam, a large apparatus housing underwater cameras. she wears an orange hard hat and orange life vest.
Mandy standing on deck with the HabCam

Drifter Buoys

Through NOAA’s Adopt a Drifter Program, I also had the opportunity to deploy two drifter buoys while aboard the NOAA Ship Henry B. Bigelow. The mission of this program is “to connect classrooms around the world with NOAA data, and provide a real-life, interactive classroom experience to teach students about ocean science” (Adopt a Drifter Program). After decorating the buoys, we deployed both buoys from the starboard side of the ship at 5:21 AM and 5:22AM on Friday, May 22, 2026. As soon as I have a link to track them, I will post here!

If you or your school would like to adopt a drifter buoy, you can find out more information HERE.

close up of buoy portion of drifter showing a sticker that reads Lewisville High School, Richburg, SC and has a logo of a blue lion, the school's mascot
Lewisville High School side of buoy
close-up of the buoy portion of the drifter showing the orange outline of a cat's paw and the words "c/o 1998, 2020"
Clemson University side of buoy (Mandy is a 1998 & 2020 graduate of Clemson)
close up of the buoy portion of the drifter showing a sticker of the state of South Carolina with a moon and palm tree from the state flag, and a NOAA Teacher at Sea Program sticker
Representing Mandy’s home state of South Carolina and the NOAA Teacher at Sea Program
three people stand on the deck of ship, in front of the railing, at sunrise. Mandy is in the center. Andrew and Tommi to her left and right each hold up a heavy drifting buoy, which consists of the float, cable, and folded up drogue. All three wear hard hats and life vests.
Andrew Merlino (Survey Tech) and Tommi Truong (Able Seaman) assisted Mandy in the deployment of the buoys (Image courtesy of Kristen Jabanoski)
Mandy and Tommi, wearing hard hats and life vests, stand at the railing of the ship at sunrise and watch as the drifting buoy flies through the air toward the water. Tommi's arms are still extended from tossing. With low lighting, this photo is a little out of focus.
Deployment (Image courtesy of Zach Fyke, NOAA Watch Chief)
view of the drifting buoy in the water: a round blue and white float, attached to a cable, attached to a folded "drogue" or fabric tail. the cardboard packaging will dissolve and allow the drogue to extend. we can just barely see the Lewisville High School sticker.
Buoy In (Image courtesy of Zach Fyke, NOAA Watch Chief)
Mandy stands near the railing of NOAA Ship Henry B. Bigelow wearing a hard hat and life vests. She gives a thumbs up and smiles at the camera. We can partially see another science team member standing behind Mandy.
Deployed! Image courtesy of Zach Fyke, NOAA Watch Chief

Personal Log

Ship living isn’t all that bad, but night shift has been an adjustment! I am in a stateroom with three other ladies; two of us are on night shift (11:30 PM – 11:30 AM) and two are on day shift (11:30 AM-11:30 PM). When you leave for watch, it is common courtesy to NOT return to the stateroom when your bunkmates are sleeping. *It’s a good idea to set your things out before going to bed so your essentials aren’t left behind!*

close up view of a single lower stateroom bunk. we can see a nightlight mounted to the wall, a curtain drawn aside, and the ladder up to the top bunk
view of lockers in the stateroom, with luggage and backpacks visible on the floor in front of them.
view of a small desk and chair tucked next a locker in the stateroom. above the desk is a window with blackout curtains.
view of four bunks, stacked in pairs, in the shared stateroom. each bunk has its own curtain. we can also see a sink and a locker.
view of the head (bathroom) with toilet, shower, sink

My stateroom: four berths, storage lockers, desk, head

What day is it? Not really sure…But I have thoroughly enjoyed getting to know the crew and learning how the HabCam collects images of sea life and how NOAA uses this data to inform the local fisheries. More about the crew later!

I’ve had the opportunity to see some amazing sunrises…

view of sunrise over the railing of NOAA Ship Henry B. Bigelow. the water is calm and gray. an orange sun peeks over low gray clouds and illuminates parts of the horizon; it adds a golden tinge to the otherwise gray water
view over the railing at calm gray waters, cloudy gray skies, but a riotous streak of neon red-orange right at the horizon
view over the railing at very dark water, purple-black, and dark cloudy sky, as a line of bright pink-red appears just at the horizon

And today, we had the honor of watching humpback whales while SNOW fell!

  • a gray whale fluke pokes up above choppy gray waters
  • a humpback whale falls back toward the ocean's surface after breaching, its pectoral fins reaching toward the sky. the water is gray and choppy.
  • a humpback whale breaches above choppy gray water
  • a gray whale tail extends vertically above choppy gray waters

All humpback whale images courtesy of Zach Fyke.

Did You Know?

The Humpback whale can weigh up to about 40 tons, grow to around 60 feet (18 meters) long, and live roughly 80–90 years. They are known for their long migrations, complex songs, and acrobatic behaviors such as breaching and tail slapping. Humpback whales are found in oceans worldwide and feed mainly on small fish and krill (Humpback Whales – NOAA). They are also called the “singing whale,” because the male mating song can change from year to year and can last as long 30 minutes (Fun Facts About Wonderful Whales).

Although humpback whale populations are increasing, they remain on the endangered species list. Their greatest threats include entanglement in fishing gear and marine debris, vessel strikes, harassment from boats, ocean noise, and changing climate conditions (Humpback Overview – NOAA).

Did you know different animals (and fish) make specific sounds? Watch the following video to learn more about how NOAA Fisheries uses Passive Acoustic Monitoring to study not only the humpback whale, but many different types of sea life! Listening for Whales. Visit the NOAA Mammals: Sounds in the Ocean site to hear the differences between 32 mammals including the humpback whale and the minke whale!

Careers at Sea

portrait of a man in a fleece with a shoulder bag strap standing at a ship's railing at sunrise or sunset
Rhett Finley, NOAA Passive Acoustics Branch in the Northeast
(Credit Rhett Finley)

Meet Rhett Finley, a fieldwork team lead from the NOAA Passive Acoustics Branch in the Northeast. Rhett grew up in Tulsa, OK and developed a passion for science at just 6 or 7 years old. By the age of ten, he already knew he wanted to become a marine biologist, inspired by the nature documentaries he watched growing up. He later attended Texas A&M University at Galveston, where he earned a Bachelor of Science degree in Marine Biology.

When I asked Rhett how he became drawn to the field of bioacoustics, he said “it was because of its versatility and noninvasive nature and the ability to integrate it with other scientific disciplines, like genetics. This approach is an effective means of collecting detailed data on threatened species especially in remote or difficult to access areas and therefore can contribute to well-informed conservation management efforts for those species and their respective habitats.”

His job with the NOAA Fisheries Passive Acoustics Branch involves:
– placing underwater microphones (hydrophones) in designated areas, such as wind farm areas and marine sanctuaries
– assists with analyzing and interpreting acoustic data, which is visualized in the form of spectrograms (picture below).

His current focus is on the minke whale (Balaenoptera acutorostrata). More information on this whale found here. The goal of this NOAA division is to “use passive acoustic technologies to study the behavior and movements of marine animals, their contribution to the ocean soundscape, and how they are affected by human-made sounds” (Passive Acoustic Research in the Northeast)

a graph showing frequency (Hz) v time (m:ss). sounds show up as yellow or green markings against a darker purple background. annotations point out a humpback whale song (markings in a patter that extend the full length of the x-axis); North Atlantic right whale upcalls (a few vertical markings toward the left side of the x axis) and sei whale downsweep doublet (two curved downward markings toward the right side of the x-axis.) in the low frequency values there are a lot of scattered green markings from ship noise.
Spectrogram showing unique calls by multiple species including humpback whale song, North Atlantic right whale upcalls, and a sei whale downsweep doublet with low-frequency ship noise overlapping.
Credit: NOAA Fisheries

Interested in this type of career? NOAA offers internships to both undergraduate and graduate students, as well as high school students! Check out the opportunities and scholarships available HERE!

For more information and great pictures, check out the NOAA Fisheries New England/Mid-Atlantic Facebook page! Or their Instagram page.

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Alexandra Keenan: Singing Whales, June 23, 2012

NOAA Teacher at Sea
Alexandra Keenan
Onboard NOAA Ship Henry B. Bigelow
June 18 – June 29, 2012

Mission: Cetacean Biology
Geographical area of the cruise: Gulf of Maine
Date: June 23, 2012

Weather Data from the Bridge:
Air temperature: 14.4° C
Sea temperature: 13.3° C
Wind speed: 10.5 knots
Wind direction: from the SW

Science and Technology Log:

Whales are social creatures with a remarkable ability to communicate with one another over long distances using sounds. Male humpback whales, for example, can sing for days on end over mating grounds to attract the ladies, or over feeding grounds such as the ones on Georges Bank (where we are!) The acoustic behavior of sperm whales may even provide for distinct cultures within the species.

Listen: Song of a humpback whale (courtesy Denise Risch)

Given these vocalizations, it is possible to monitor the distribution and behavior of acoustically active marine animals using special recording units called “marine autonomous recording units” (MARUs). For the past few days, we have been zig-zagging and loopty-looping around Georges Bank to retrieve several of these MARUs (track our ship’s course here).

MARUs are little buoys designed to sit on the ocean floor and record all sounds within a certain range of frequencies. The MARUs we retrieved during this cruise have been on Georges Bank since the March cruise on the Delaware II (see Chief Scientist Allison Henry’s blog post).

To retrieve a buoy:

1. An acoustic signal (a sound) is sent out from a speaker lowered into the water that basically says to the buoy, “Hello! Are you there?” Listen: Signal used to contact buoy

pop-up buoy retrieval
Bioacoustician Denise Risch sends a signal to the MARU.

2. The buoy can then respond with another acoustic signal, “Yup!”

listening for the pop-up buoy
Research analyst Genevieve Davis and intern Julia Luthringer listen for a response from the MARU.

3. Upon hearing confirmation that the buoy is indeed in the area, the bioacoustician can send another signal to the buoy telling it to burn the wire anchoring it to the sandbags on the ocean floor.

4. The buoy is free! It floats to the sea surface and is retrieved from the side of the ship.

Denise Risch, Genevieve Davis, and Julia Luthringer wait for the ship to approach the MARU (small yellow dot in ocean).

5. Data is retrieved from flash memory on the buoy for further analysis.

MARU
MARU ready for data retrieval.

What will these MARUs be able to tell bioacousticians (scientists that study sounds produced by living organisms)?

Lots!  Using passive acoustic monitoring (recording the sounds that marine mammals make), scientists can study the distribution of acoustically active mammals and can couple distribution data with environmental measurements of the area to identify relationships between conditions on the ocean and acoustic activity. Scientists can also distinguish whale species based on their sounds, so certain species of whale can be monitored.

Physics break: Why do you think whales have evolved to use sound rather than sight or smell to communicate underwater?

Personal Log:

I have been amazed by the amount of maintenance being done while we are underway. Even with a relatively new ship like the Bigelow, there is always something to be done, whether it be grinding away at the deck for subsequent repainting or fixing a malfunctioning pump.

Maintenance on the Bigelow
Deck crew member Tony repaints the deck after grinding off the old paint while we are underway.

We spend most of our days out on the fly bridge watching for whales, and mostly we see whales.

whale watching
Equipment used for watching for whales from the flybridge.

However, once in a while a shark, turtle, or mola mola floats by. I really get a kick out of the mola molas. They look like they could be the subject of a Pokemon trading card– a big flat fish head with fins sticking out. They eat jelly fish and have few natural predators. Adults weigh an average of 2200 lbs!

mola mola
The other-worldly mola mola.

A short video of one in action below:

Finally, I wanted to introduce everyone on the science team for this cruise:

aglow following a blue whale sighting
From left to right: Me, Scientist Pete Duley, Bioacoustician Denise Risch, Chief Scientist Allison Henry, Scientist Jen Gatzke, Research Analyst Genevieve Davis, and Intern Julia Luthringer (photo courtesy CO Zegowitz)