Gail Tang: HARPs and Hearts, August 25, 2023

NOAA Teacher at Sea

Gail Tang

Aboard NOAA Ship Oscar Elton Sette

August 4, 2023 – September 1, 2023

Mission: Hawaiian Islands Cetacean and Ecosystem Assessment Survey (HICEAS)

Geographic Area of Cruise: Hawaiian archipelago

Date: Aug 25, 2023

Science and Technology Log

Visually surveying for marine mammals has its limitations because they spend so much time underwater. To account for these limitations, a number of acoustic techniques are used to study cetaceans (whales and dolphins). There are four main passive acoustic instruments used by the Pacific Islands Fisheries Science Center’s Cetacean Research Program during ship surveys: towed arrays, drifting acoustic spar buoy recorders (DASBR), high-frequency acoustic recording packages (HARP), and sonobouys. Each instrument has its pros and cons so the data from each instrument provide a fuller picture of what’s under the sea.

On board the ship, every morning just before sunrise the acousticians deploy the towed array of hydrophones, which streams 300 m behind the ship. ​​The towed array provides real-time information on calls and clicks of the whales and dolphins. Each section of the towed array has three hydrophones and a depth sensor (see picture below). The design comes from the National Marine Fisheries Service and are all built by Lead Acoustician Jennifer McCullough (to read more about Jennifer, see my previous post). While the towed array can pick up sounds from the cetaceans around the ship in real-time, it also picks up the sounds of the ship, thus obfuscating other calls. As such, autonomous recorders (DASBRs, HARPs, and sonobouys) are used to collect more data, as well as match species data collected from the towed arrays.

view of the array resting on deck - it looks like curled up plastic tubing (with some purple sections) connected to a cable
A section of the towed array with three hydrophones (seen in purple). Photo credit: NOAA Fisheries/Gail Tang
on deck, Jennifer stands at a large spool in the center while Alexa leans over a coiled pile of cable attached to the plastic tubing that contains the hydrophones. Erik stands near the railing to help guide the array to the water.
Acoustician team Jennifer McCullough, Alexa Gonzalez, and Erik Norris deploy the towed array. Photo Credit: NOAA Fisheries/Gail Tang
illustration of the ship at the surface of the water (depicted by a horizontal line) with the array towed behind at a depth of about 10 meters. an inset box shows a larger illustration of the two arrays - one "end array" and one "inline array" with 20 m baseline cable in between. the three hydrophones in each array are spaced 1  m apart from each other.
A depiction of array towed behind a ship. Photo Credit: Barkley et al. (2021 p. 1122)

The HARP is a long-term acoustic recorder that sits on the seafloor at depths of 650-900 m depending on the site. Developed by the Whale Acoustics Lab at Scripps Institute of Oceanography, they are site-specific and sit out for one to two years. The one we retrieved during Leg 2 was deployed August 2022. The HARPs provide 1) time-series data that help with understanding seasonal occurrence of cetaceans and other marine life, 2) periodic data on the presence of animals that pass through the site, and 3) ocean noise reference points. The latter is important in measuring the potential impact of ship and construction noise on marine mammal behavior. For example, slowly over time, blue whales are shifting their call types to a lower frequency to compensate for the rise of ocean noise in their natural call range (Rice at al., 2022).

Matt, wearing a blue hard hat, a life vest, and gloves, stands on deck, tethered to something on deck by a yellow strap hooked into the back of his life vest. We are looking down at him as he faces away from the camera, hands raised in the air to guide a large yellow piece of equipment as a crane lifts it back on deck. Matt grasps a line (rope) connected to the crane's hook with his left and uses the right to steady the equipment.
Matt Benes (Able-bodied Seaman) retrieves HARP. Photo Credit: NOAA Fisheries/Suzanne Yin

DASBRs are floating acoustic recorders deployed from the ship and retrieved sometime between 1-30 days later depending on their location from the ship. The DASBR collects acoustic data away from the ship and at a depth deeper in the water column than the towed array (about 150 m from the surface). This means there’s no noise from the ship that may disturb the animals and no surface noise from crashing waves or rain. A clear advantage of the DASBR is its ability to record beaked whale vocalizations, super high-frequency echolocation clicks.  Beaked whales are only vocal during the lower portions of their foraging dives, which last for about 60-90 mins. On the ship with the towed array, we don’t spend enough time to capture their vocalizations. The DASBR on the other hand has time to capture an entire dive cycle of a beaked whale. Depending on the frequency and amplitude of the animal, the distance at which the DASBR can detect animals (or detection range) varies by species. For example, Kogia (pygmy and dwarf sperm whales) need to be near the sensor and facing it to pick up their calls, while the baleen whales have a larger detection range. To give you an idea of the overall advantages of the DASBR, it can pick up about 10 times more cetaceans than the towed array and help us learn more about their vocalizations and study their habitat range.

Matt, wearing a hard hat, life vest, gloves, and a harness, tethered by a yellow strap to something on deck for safety, looks away from the camera, into the dark of the ocean at night. a spotlight extending from an upper deck highlights the location of the DASBR in glowing blue light.
With grapple hook in hand and eyes on the DASBR, Matt Benes (Able-bodied Seaman) prepares for retrieval. Photo Credit: NOAA Fisheries/Marie Hill
screenshot from Google Earth of the Hawaiian Islands showing segmented lines outlining a path north of the islands. some segments are labeled with dates from Aug 26 to Sept 1 (back at Honolulu). a short yellow arrow and a green parabola show the locations of DASBR 4 and 3 respectively.
This map shows the tracklines where we surveyed, as well as the DASBR paths. Photo Credit: NOAA Fisheries/Marie Hill

There are many recorded calls for which there is no visual match, so sonobouys are deployed after the visual team identifies a particular baleen whale species. Because the ship masks the very low frequency sounds made by most baleen whales, sonobouys are deployed to evaluate their call types. The hydrophones in the sonobouys are set at 90 ft from the ocean’s surface and they collect data for up to 8 hours.

I like the idea that these four instruments work in concert towards a shared goal, each with its strengths and weaknesses.

Career Log

The information above was provided by the acoustics team. I will focus on a couple in particular, Yvonne Barkley (Cruise Lead in Training) and Erik Norris (Acoustician), who met on NOAA Ship Oscar Elton Sette 13 years ago!

Eirk and Yvonne on deck; Yvonne is seated in an observation chair and Erik is holding his right arm out to take the selfie
Erik Norris (Acoustician) and Yvonne Barkley (Cruise Lead-in-Training)

Yvonne Barkley first went to University of California, San Diego and then transferred to Santa Barbara City College for a pipeline into University of California, Santa Barbara (UCSB). At UCSB, she studied aquatic biology.  A friend told her about a temporary job as an acoustic analyst for a local research firm invested in mitigating the impact of oil companies on the bowhead whale migration through the Beaufort Sea. It is at that job that she received her first acoustic training. On a path towards marine mammals, Yvonne’s cousin alerted her to an internship at the US Navy’s Marine Mammal Program in Pt. Loma, California prepping dolphin food, cleaning, etc. The program itself trained bottlenose dolphins to be swimmer detectors and California sea lions to be sea mine detectors! For example, bottlenose dolphins are used at different naval bases and combat zones to detect anomalous scuba divers. Yvonne was accepted into the internship where a seminar given by a NOAA Fisheries representative piqued her interest about marine mammal research. She found an acoustic analyst internship at the Southwest Fisheries Science Center (one of NOAA’s six science centers). There, she learned about field projects to collect cetacean data at sea for months at a time. In contact with Erin Oleson (HICEAS 2023 Chief Scientist), she embarked on her first mission from Hawaii to Guam in 2010 on the very ship we are currently on! That cruise brought Yvonne and Erik together, but more on that later.

After collecting data that weren’t intended to be used in stock assessments, like a true scientist, Yvonne began to wonder, “How can we use these data?” This curiosity, the advancement of acoustic data collection methods, and the drive to uncover data gaps in the literature converged into a puzzle for Yvonne to solve. I listened in awe as Yvonne described the three main chapters of her doctoral thesis. The first one involved species classification for false killer whales (a priority species for HICEAS). Her research used whistle data to distinguish the whales acoustically at the population level. She found that the classification machine learning model yielded low accuracy rates. Access the paper here:

The next chapter focused on improving localizing methods for deep diving whales using sperm whale acoustic data. I was drawn to the research of this chapter because of the modeling components.  Probabilistic models are used to estimate the location of cetaceans. An ambiguity volume is an example of such a probabilistic indicator.  It is computed from source location estimates that are most accurate to the actual measured locations. As the number of different detections for the same whale at different positions from the ship increases, the ambiguity volume decreases, thereby narrowing down the possible location of the whale. The increased location accuracy is depicted in the figure below through the progression of subfigures a) – f); subfigure a) has fewer detections for the same whale than subfigure f). As we move to subfigure f), we can see that the margins of location estimates are much smaller, giving us a more accurate location estimate for the whale.

Six subfigures showing three dimensionsal plots. the Y axis shows depth, from zero to -3000 m below sea surface. the x and z axes are West-East km and North-South km. caption reads: "Fig 2. Cumulative ambiguity volumes [(a)-(f)] for detections of simulated echolocation clicks from a stationary whale located 1.2 km directly below the transect line (denoted by a white asterisk.) The product of all volumes results in a volume representing all possible location estimates for the whale (f). The color scale represents the ambiguity volume values ranging from 0 (white) as low probability to 1 (black) as high probability. The dotted lines (white or black) indicate the trackline traveling in the direction of the arrow."
Progression of ambiguity volumes as detection data points increase. Photo Credit: Barkley et al. (2022, p. 1122)

The final chapter used the ambiguity volumes for location estimates from the previous chapter and available environmental data from remotely sensed satellite data sets that lined up with those locations to learn about the habitat preferences of sperm whales. Check out the paper:

Erik Norris got his Bachelor’s degree at James Madison University in integrated science and technology. He was initially working with energy production and city planning, dredging company shipping channels up and down the east coast.  He left and traveled for a while. When I asked him to share one of his fondest memories, he mentioned his time in a small fishing village called Nomozaki, Japan. What struck him most about this village was the community-oriented nature of the villagers. At the end of the day, local fishermen took a portion of their catch of the day and shared it with the entire village. The whole community came out to have a big party together, enjoying the catch and the company. The expression of an economy focused on people rather than on profits really speaks to me. I am reminded of a couple of quotes from Braiding Sweetgrass by Robin Kimmerer:

“A gift comes to you through no action of your own…the more something is shared, the greater its value becomes. This is hard to grasp for society is steeped in notions of private property, where others are by definition excluded from sharing.”

(Kimmerer, 2013, p. 23 and 27, respectively)

While Erik worked on a boatyard, he saw people working on the escort vessel for the Hōkūle’a, a wa’a (voyaging canoe) that uses traditional Polynesian wayfinding techniques (no technology, not even a watch) to navigate the ocean. (The Hōkūle’a is currently on its 15th voyage. Follow along here: He approached the crew and volunteered to work on the escort vessel in-port. When the vessels were ready to commence their voyage, Erik had become so familiar with that vessel that they asked him to join, which turned into a 6-month journey. When I inquired about Erik’s attraction to the maritime industry, he quipped that he’s Moana from the Disney movie. For the sake of research, I had the ship’s movie DJ, Octavio De Menas (General Vessel Assistant), put on the movie. From what I gathered, this quote from Moana’s song “How Far I’ll Go” must represent his draw to the ocean:

“See the line where the sky meets the sea, it calls me.”


Through conversations with others on the ship, it seems like the ocean has a similar allure for many. Having been out here for three weeks, I get it. We first saw land last week and it felt like an intrusion. Enough about me, back to Erik!

Later, while talking to his friend’s dad who was a NOAA Corps Officer about his passion for the ocean, he joined the NOAA Corps himself. He met Yvonne as an Ensign on the Sette. He went on to become Lieutenant Junior Grade, and then “retired” from NOAA Corps as a Lieutenant because he was about to rotate from his land billet at Pacific Islands Fisheries Science Center (PIFSC) to another land billet which would have taken him away from Hawaii. He found a civilian job in Hawaii with PIFSC as a vessel operations coordinator in charge of small boats, fabrication and design, field logistics, and HARPs. He attributes his entry into the world of acoustics to Yvonne and HARPs. His current interests include using autonomous vehicles (e.g. sea glider) for a range of oceanographic environment missions.

I asked Yvonne and Erik the same questions separately and we laughed about the different approaches they took in their answers. Erik first noticed Yvonne because she was moving equipment and he was in charge of the equipment on the ship. Yvonne first noticed Erik’s sense of humor juxtaposed with her expectations from someone in the uniformed services. On their time at sea, they shared conversations over meals. Erik was captivated by the way Yvonne talked about her oma’s (grandmother’s) Indo-Dutch cooking. For more on Erik and Yvonne’s food connection, visit the Food Log below. Once in Guam, Yvonne was struck by Erik’s thoughtfulness in preceding her on a hike in the jungle so he could clear off all the spider webs; his distaste for spiders elevated Yvonne’s appreciation for his sacrifice. This is not the only time Erik put Yvonne before himself. Yvonne was really sick in Bali and ended up in a hospital in Malaysia. Erik took leave from work and (according to him) flew to comfort her and accompany her home. According to others, he rescued her. With a ring attached to the keyring on his swimming trunks, under a rainbow and surrounded by sea turtles, Erik proposed to Yvonne while surfing. They have been married since 2016. They currently live in their house, Gertrude, with their dog Sweetpea.

Personal Log with Career Highlight

I started teaching this week. Classes are going well! Shout out to my Abstract Algebra students who never cease to amaze me with their curiosity and courage. Brave Space–IYKYK! I told them our picture below looks like the Brady Bunch, which they did not understand so they have additional homework to watch the opening credits.

a screenshot of a zoom meeting between Gail (on the ship) and 9 students (two sharing a window), creating a 3 x 3 collage
University of La Verne’s Fall 2023 Abstract Algebra class!

Everyday, I try to do one thing I didn’t do the day before. I had two memorable events from this week. The first was during drills. We have weekly fire and abandon ship drills, so this week a few of us practiced the fire hose off the bow. Below you can see Yvonne assisting me as I cycled through the different spraying options.

view from an upper deck over the bow as Gail sprays the firehose over the railing and Yvonne help steady the hose
Gail Tang (Teacher at Sea) and Yvonne Barkley (Cruise Lead-in-Training) test out the fire hose during weekly drills. Photo Credit: NOAA Fisheries/Ernesto Vásquez

The second non-routine thing I enjoyed was helping Joe Roessler (Electronic Technician–ET) install a cable to the outdoor wifi antenna. Our work is the reason I can compose this blog post on the boat deck in my outdoor office, wind whipping my hair to the sounds of the ships’ wake. We worked in the trawl house to solder connector pins to cable ends. Joe’s approach to teaching is familiar. In my classrooms, I provide the tools for students to solve problems with very little instruction. If they need some, I am there to help answer questions. Joe set up the soldering station, provided the leatherman, rubber tape, the connectors, the cable and we went to work. There were many parallels in his methods and mine. We first attempted a connection to the cable, but the pins were not sitting right. Joe evaluated the situation and quickly thought of a different approach to connect the cables. Trying a solution and then pivoting when it doesn’t work out is a skill we try to develop in my classes!

Joe got his amateur radio license at 13! At that time, kids were particularly into shortwave radio because of the US human moon landing. As a young adult he went to the Navy for naval aviation aircraft maintenance. After he was discharged from active duty, Joe continued working in the Naval Reserve and also at private sector companies where he tested robotic equipment. Later, he joined the Civil Service as an aircraft electrician at a naval air rework facility in San Diego. He then transferred to the Army at Dugway Proving Ground in Utah where he returned to the position of an ET. Joe worked with a biological integrated detection system for weapons of mass destruction, in biological warfare defense, with instrumentation and testing equipment and research development. He took a short 4-year detour a businessman and realized it was not what he wanted to do. NOAA had openings in Seattle so he applied and was hired! His first season was on NOAA Ship Rainier in Alaska. Having had enough of the cold weather, he asked for a relocation to Hawaii. He worked on our very ship, the Sette, installing equipment before its very first mission! He met his wife in Samoa and has been working for NOAA 22 years! 

Joe, wearing a hard hat and sunglasses, stands for a photo in the middle of his office, surrounded by electrical boxes and wires. He is wearing a t-shirt that reads: Don't fear the beard. He has a beard.
Joe Roessler (Electronic Technician) in his office! Photo Credit: Gail Tang

Food Log

This week Chef Chris Williams [see previous blog post for more about Chris] made some yummy meals, my favorite pictured below!

When Erik first mentioned Yvonne’s Oma’s Dutch-Indo cooking, I was intrigued because I haven’t had much of either, let alone their fusion. Though Erik insisted that all of Yvonne’s dishes are his favorite dish, after much encouragement he narrowed it down to Oma’s croquette recipe. It’s a fried potato dish with meat inside, best when served with Chinese or Dijon mustard. Yvonne’s favorite dish is her oma’s lemper ayam. The moment she mentioned that it’s sticky rice stuffed with chicken inside I asked if it’s wrapped in any type of leaf. After researching some recipes, I found that it’s traditionally wrapped with banana leaves. 

photo of sticky rice stuffed with chicken wrapped in banana leaves
Lemper. Photo Credit: Wikipedia

I am going to search for lemper when I get home because I have a certain fondness for food wrapped in leaves. I am particularly tickled by the similarities in leaf-wrapped food across different cultures. For example, there’s law mai gai (wrapped in lotus leaf with Chinese origins), zong (wrapped in bamboo leaf also with Chinese origins), dolmas (wrapped in grape leaves with origins in the Levant), tamale (wrapped in corn husk with Aztec origins), and cochinita pibil (wrapped in banana leaves with Mayan origins). This may be a stretch, but I also like onigirazu/handrolls/onigiri (wrapped in seaweed with Japanese origins) and gimbap (wrapped in seaweed with Korean origins).

There is even a Hawaiian version of a leaf-wrapped food called lau lau! It was the second thing I tried when I landed in Honolulu. Usually lau lau consists of pork and salted butterfish first wrapped in kalo (taro) leaves, which are edible, and then in ki (ti) leaves, which are not edible. Finally, traditionally it is steamed in an imu pit (underground pit). It can be found in restaurants and served at luaus. Though it was new to me, it felt so wonderfully familiar.

While searching for the history of lau lau, I found a beautifully written memory that describes lau lau as an embodiment of the beach, the valleys, and the mountains through the ingredients of butterfish, kalo/ki, and pig. Not only does the final product connect these landscapes, but the preparation connects families and friends.

“Early Hawaiians lived in valleys that provided them protection and food. Villages were organized by families and by land divisions, which, in old Hawaii, were divided from the beach to the mountains. That meant that each village and family had complete accessibility to the beach and the mountains and all their offerings. Lau Lau represents these familial land divisions because its ingredients come from the beach, the valleys, and the mountains. The preparation was always my favorite part, because we’d be together for hours sharing stories, laughing, and having fun. Wrapping Lau Laus was where we all became familiar with who we were.”

 Chad Schumacher,

Did you know?

The Big Dipper points to the North Star and the angle of elevation from the horizon to the North star is your latitude! This tip was brought to you by Erik Norris, himself.

Staci DeSchryver: Fair Winds and Following Seas, July 8, 2017

NOAA Teacher at Sea

Staci DeSchryver

Aboard NOAA Ship Oscar Elton Sette

July 6 – August 2, 2017

Mission:  HICEAS Cetacean Study

Geographic Area:  South of Oahu, heading toward the Big Island

Current Location:  20.20 N 156.37 W

Date:  July 8, 2017

Weather Data From the Bridge: 


Science and Technology Log

We have arrived!  Today members of the incoming crew on Oscar Elton Sette picked me up from Waikiki and we made our way over to Ford Island for training.  The HICEAS study is seven “legs” long, each lasting about a month with a one week break in between legs – ours is the first “leg” of the mission, and the training took place for all scientists and crew who would be traveling and conducting research through any of the four parts of the mission.  In August and September, two of the legs will run simultaneously, so the project is significant in size with respect to time, manpower, and data collection.  We had a very full house of various research teams, some of which will overlap among the various legs of the trip.  The full crew is a tight family, with hugs and greetings all around during breaks and meal times.  How nice to know that leaving for 28 days (some of them longer) doesn’t necessarily mean leaving your family.

Wanted:  pseudorca (Alias: False Killer Whales) For High Crimes of Adorableness and shyness from ships.  Photo Credit:  NOAA Fisheries/Corey Sheredy

During training, scientists reviewed procedural protocols to follow for different species sightings and learned the protocol changes for a few other species.  The primary target for this particular leg of the HICEAS is pseudorca, or False Killer Whale.  They are a socially interesting bunch – a little reminiscent of the hallways at Cherokee Trail High School.  Whereas most whale species travel as a “class” in one large group all together, pseudorca behave as though all day every day is passing period.  The entire group of pseudorca may travel together (similar to being in school all day), but they don’t all congregate together in the same location.  They are a rather “cliquey” bunch – with smaller groups milling about together on their own in different corners of the main group but all keeping at least somewhat in eyesight or earshot of the other groups.  Because of this, scientists must identify the group, and then each individual subgroup, making note of any groups that join up or split apart.  We haven’t spotted any pseudorca yet, but with some time, talent, and a little luck, we will soon!

In a broad sense, the search for cetaceans on a daily basis is executed a little something like this:  Three mammal observers take their positions at port (left), center, and starboard (right) on the “flying” bridge – or the topmost deck of the ship.  There is also a space reserved just right of center for the Seabird observers.  Each observer will rotate through these three positions for a total of a two-hour shift.  If, for example, an observer begins at the port side “Big Eye” station, they will scan the water in search of cetaceans for 40 minutes from that position, rotate to the center, and then finally to the starboard side.  Where does the starboard side observer go when he or she has completed the rotation?  There’s plenty to do onboard and to help with until the next two-hour rotation begins.  There are two seabird observers working alongside the mammal observing team, and they alternate in two-hour rotations, so only one bird observer is on the flying bridge at a time in an official capacity.  All visual observers work from sunrise to sunset.

Each position at the marine mammal observation area is responsible for visually sweeping the ocean’s surface during observations.  The two side observers are only responsible for scanning from 0 degrees (the bow of the ship) to 90 degrees to their direct left on the port side, or direct right on the starboard side.  They use a very imposing pair of binoculars called the “Big Eyes” to scan their respective areas.  These binoculars are impressive in size and abilities.  They can bring even the smallest birds far on the horizon into sharp focus.  The center observer does not have Big Eyes, but stands ready to take data if there is a sighting.  He or she can scan the area in general, but the big eyes offer much more detailed observation abilities at a much greater distance.  The center observer is also responsible for keeping time on the rotations, monitoring the weather, the sun’s position in the sky, and Beaufort sea state.

While the visual observers are on the flying bridge, two scientists work in the acoustics lab to listen for cetacean vocalizations.  The two groups work in parallel universes, but only the acousticians can cross dimensions.  In other words, if the visuals see cetaceans, they can tell the acoustics about what they are seeing, but if the acoustics scientists hear vocalizations, they will not tell the observers.    More often than not, the acousticians will hear clicks, whistles, and moans from the acoustics lab well before the visuals make a sighting, because the acoustics team has a large advantage over the visuals team.  The visuals team is restricted to what they can see at the surface, and the acoustics team can “see” many miles away and deeply into the water column, which significantly increases their volume of searchable space.

When the acousticians “see” or hear a vocalization, they plot the distance from the ship. They continue to listen for vocalizations and continue with the plots.  Eventually, they have enough data to narrow down the potential location of the cetacean to two spots. This process is not unlike earthquake triangulation, except the observers can narrow down the location to two spots, rather than just one.  There will be much more to come as to how this process works in future blogs, so stay tuned!  

Personal Log

At the end of training today, Dawn, one of the ornithologists (that’s a seabird “pro”) informed us of the third and far lesser-known Pearl Harbor Memorial, USS Utah.  Utah was the very first ship capsized by Japanese bombs on the early morning of December 7th, 1941.  Found on the opposite side of the island from USS Arizona, the Utah is only accessible by folks who have military clearance to get on the base, making the memorial incredibly secluded from exposure to the general public.  Utah took 64 lives with her when she sank, and a small monument now stands on the shore as a memento to the crew lost that fateful morning.  What makes Utah interesting is that she still stands partially above water, her mangled and rusted metal piercing through the water’s surface like the grasping hand of a drowning sailor.  There was a brief attempt by the military to right and raise her, but it proved futile, and they made the call to leave her remains be.  Her finest and final duty is to serve her watch over the men caught in her belly on the day she fell prey to the Axis forces.

Utah found herself in the wrong place at the wrong time on the morning of December 7. She was moored on a pier normally reserved for aircraft carriers, and her flat and shiny deck betrayed her identity to the incoming Japanese pilots.  Due to this mistaken identity, the Japanese attacked her on appearance, and she capsized almost instantly.  More interesting is that much like the beginning of a bad cop movie, she was nearing her retirement.  She was in port awaiting her execution date,  friendly-fire style, her technological abilities waning and falling out of favor compared to the newer commissioned ships.  Her final resting place was originally supposed to be somewhere in the Pacific as a victim of a practice bombing drill by the Air Force.  The Japanese pilots got to her first.  She wasn’t even at work that day.

Utah was built in 1909 and commissioned in 1911, the second of two Florida-class battleships built for service during World War I.  After a long stint in the service as a battleship, the Utah was re-appropriated as an auxillary ship for gunnery training and target practice for the allied forces.  On the day of the attack, the aircraft carriers that should have been in-port at the time were out to sea, and so Utah moored in one of the empty spaces intended to be held by the aircraft carriers.  In the confusion of the attack, it was determined that Utah was a carrier, and the Japanese navy opened fire.  The Chief Water Tender, Peter Tomich, served bravely as he assisted crew in their evacuations when the abandon ship call came over the ship’s systems.   While everyone was running off the ship, Tomich was running back onboard. He lost his life in that selfless move and is remembered as a hero of the day.

Today Utah sits idly close to shore alongside what used to be a dock.  Her neighbor is NOAA Ship Okeanos Explorer, and just a little further up the harbor, our ship, Oscar Elton Sette.  It was sobering honor to be so close to the memorial before we left port, and though USS Utah is one of the smaller memorials on Ford Island, I certainly will not forget her.

Species Report:

Number of cetaceans seen visually:  0 so far

Number/types of cetaceans “seen” acoustically:

*Blainsville’s Beaked Whale

*Sperm Whale


Birds Seen:

Frigate Bird


Red Footed Booby

Brown Footed Booby

Land Bird who shouldn’t have been out so far in the ocean (so possibly my spirit animal).  Let’s hope he eventually finds his way home.

Wes Struble: What in the World Is a CTD Cast? March 2, 2012

NOAA Teacher at Sea
Wes Struble
Aboard NOAA Ship Ronald H. Brown
February 15 – March 5, 2012

Mission: Western Boundary Time Series
Geographical Area: Sub-Tropical Atlantic, off the Coast of the Bahamas
Date: March 2, 2012

Weather Data from the Bridge

Position: 26 degrees 19 minutes North Latitude & 79 degrees 55 minutes West Longitude (8 miles west of Florida’s coast)
Windspeed: 14 knots
Wind Direction: South
Air Temperature: 25.4 deg C / 77.7 deg F
Water Temperature: 26.1 deg C / 79 deg F
Atm Pressure: 1014.7 mb
Water Depth: 242 m / 794 feet
Cloud Cover: none
Cloud Type: NA

Science/Technology Log:

There are four different ship’s stations that are involved in a CTD (Conductivity, Temperature, & Depth) operation: the bridge, the survey team, the winch operator, and the computer room. The bridge is responsible to keep the ship on position and stable over a predetermined latitude and longitude. The survey team is responsible for preparing the CTD platform for deployment and securing it back on deck at the completion of the cast. The winch operator controls the actual motion of the CTD platform by the use of a hoist.  The computer lab relays commands to the winch and survey team in reference to testing and sampling depths, and when to start and stop the ascent and descent of the platform. The CTD platform can carry many types of instruments depending upon the nature of the research being conducted. During this cruise our platform usually contained two each of a temperature gauge, conductivity gauge (from which you can obtain salinity), and oxygen gauge.  In addition there is one pressure gauge and a transmissometer (that measures the turbity of water which is an indicator of the phytoplankton), 23 Niskin water sampling bottles, and two Acoustic Doppler Range finders – one pointing toward the surface and one pointing at the sea floor.

The CTD (Conductivity, Temperature, & Depth) platform on the Ron Brown. The long grey cylinders are the water sampling Niskin bottles, the yellow and blue device at the bottom in the Acoustic Doppler Current Profiler (for measuring distance to the sea floor) for measuring the distance to the sea floor during descent phase of a cast, the grey cylinders are weights, and the green cylinder is the power supply.

A Niskin Bottle with my Nike shoe for scale

The CTD platform being lowered over the side for start of another cast.

The "downlooking" ADCP (Acoustic Doppler Current Profiler mounted on the CTD.

The "up-looking" ADCP (Acoustic Doppler Current Profiler) mounted on the CTD

The Niskin Bottle trigger release. This device is used to remotely close the Niskin bottles at depth

The bridge of the Ron Brown during a CTD cast

     A CTD cast begins when the ship arrives at prearranged coordinates of latitude and longitude. The bridge will announce that we are “on station”.

A photo of the Ron Brown off the coast of Grand Bahama Island

   The survey team acknowledges and then raises the CTD platform and places it is the water at the surface for a minute or two. Then after receiving a signal from the computer operator that all functions are operating within normal parameters the platform is lowered to 10 meters and held there for two minutes to allow the instruments to stabilize.

Here I am starting my midnight to 6 :00 am shift at the CTD computer control station in the computer lab of the NOAA Ship Ronald H Brown

The "brains" of the CTD. This device also contains the pressure sensor.

   After the two minute hold at 10 meters the entire platform is brought back to the surface and the log is started as the package is lowered. The descent begins at about 30 meters/minute and eventually reaches 60 meters/minute. Many of the deep water casts on this cruise were between 4000 m and 5500 meters (about 13000 ft and 18,000 ft) and take over an hour to reach the bottom. While the descent takes place all the instruments are recording data which is stored and plotted in real time at the computer monitor.   When the CTD platform is 10 meters from the bottom the descent is stopped and the first water sample is collected by sending a signal that closes the first Niskin bottle. At this point the CTD slowly begins its climb back to the surface (another hour or more) stopping at designated depths to collect water samples.After the last Niskin bottle is closed at the surface, the CTD platform is brought back on deck, the water samples are removed, and the entire platform is prepared for the next cast.

Here I am on the weather deck in my favorite chair on the ship. I enjoy relaxing here in the sun in the morning after a night shift at the CTD computer station.

Another beautiful western Atlantic pre-sunset. I enjoyed many of these during the cruise.

The early sun rising in the east off the stern of the Ron Brown brings another night of CTD's to an end.

Katie Turner, July 30, 2008

NOAA Teacher at Sea
Katie Turner
Onboard NOAA Ship Miller Freeman
July 10 – 31, 2008

Mission: Pollock Survey
Geographical Area: Eastern Bering Sea
Date: July 30, 2008

Screen shot 2013-11-03 at 10.15.47 AMWeather Data from the Bridge 
Visibility:  10 miles
Wind Direction:  050
Wind Speed:  7 knots
Sea Wave Height:  0-1 foot
Swell Wave Height:  2-3 feet
Seawater Temperature: 8.3 ˚C.
Present Weather Conditions: partly cloudy

Science and Technology Log 

This was the final day at sea for this cruise and we have just returned Dutch Harbor.  The cruise has been challenging for the scientists as they have had to scale back their study, and even eliminate some experiments.  Fifteen days of cruise time were lost while repairs were made to the ship. Conditions while working at sea are unpredictable and require acceptance, patience, and flexibility.

Ship's cruise path
Ship’s cruise path

The Buoy Experiment 

In addition to the side by side comparison study, a unique experiment was designed and performed during this cruise to investigate how walleye pollock (Theragra chalcogramma) behave in the absence versus presence of either vessel, to augment the comparison study.  Transducers were mounted on a buoy, which was deployed from OSCAR DYSON, and allowed to drift while collecting acoustic data on pollock schools with the ships at a distance.  As the buoy drifted along, MILLER FREEMAN and OSCAR DYSON alternately passed by the buoy on a “racetrack” 6 nautical miles (nm) long.  Each ship passed the buoy within 10 meters along the racetrack about every 30 minutes, and maintained a position opposite one another.

The racetrack pass experiment will provide information on how fish respond to the ship as it approaches and passes over them, and then as it moves away. The acoustic data collected by the transducers on the buoy was monitored aboard OSCAR DYSON during the operation, and was downloaded in entirety once the buoy was retrieved for analysis. We made a total of seven buoy passes, which took about 3 ••• hours.  This experiment was done at night when pollock schools migrate up from the bottom of the ocean into mid-water regions.  It was interesting to observe the navigation operations from the bridge as ships maneuvered around the racetrack in the dark. The computer screenshot below shows the track (in red) of the MILLER FREEMAN after our 6th pass of the buoy.  The short, blue vertical line at the end of the red track line at the top of the screen represents the ship. (Green lines are depth contours.) After completing the buoy experiment we picked up the transect from where we had left off and continued the side-byside study.

View of Unalaska
View of Unalaska

On the bridge bringing MILLER FREEMAN into Captain’s Bay, Executive Officer Natasha Davis (official owner of ship’s cat) and Ensign Otto Brown
On the bridge bringing MILLER FREEMAN into Captain’s Bay, Executive Officer Natasha Davis and Ensign Otto Brown

Another Setback 

Later that day the ship developed engine problems and it was necessary to shut down the main engine to investigate. Leaks in the cooling system involving two separate cylinders had developed. This same problem occurred recently with a different cylinder, and was one of the problems that originally delayed our cruise out of Dutch Harbor.  The engineers repaired the system and we were underway again within a few hours.  At this point we were nearly 450 nautical miles from Dutch Harbor, with limited resources for additional repairs.  In the best interest and safety of all aboard, the Commanding Officer decided to discontinue our north and westward direction along the cruise course and head the ship back to Dutch Harbor.

Ship's cat
Ship’s cat

Personal Log 

Our final day in the Bering Sea was mostly sunny.  Dall’s porpoise and whales were occasionally sighted off in the distance, and we watched ash clouds rise from Okmok volcano off our starboard side all afternoon as we closed in on Unalaska.  The wind seemed to be carrying the ash cloud to the southwest, and we hoped that it would not affect flights out of Dutch Harbor for those of us who are flying home.  We arrived in Unalaska before 10 pm, leaving just enough time to anchor and repeat the acoustic calibration. After the scientists and I leave the ship in the morning, she will head back to her home port of Seattle, where she will have a maintenance check before the next cruise. I have thoroughly enjoyed my stay on MILLER FREEMAN and owe many thanks to the officers and crew for their hospitality. It has been a pleasure to get to know everyone and I will have good memories of this cruise, despite the breakdowns and delays. I am especially grateful to the scientists on board, Patrick Ressler and Paul Walline, for sharing their work, helping me understand a little about acoustic surveys, and for their friendship during this experience.

Katie Turner, July 26, 2008

NOAA Teacher at Sea
Katie Turner
Onboard NOAA Ship Miller Freeman
July 10 – 31, 2008

Mission: Pollock Survey
Geographical Area: Eastern Bering Sea
Date: July 26, 2008

Rescue crew retrieves a dummy man overboard. It is a maritime custom to refer to the man overboard as “Oscar." This comes from an international regulation requiring the raising of the Oscar flag when a vessel is responding to a man overboard, warning other vessels to be on the lookout
Rescue crew retrieves a dummy man overboard. It is a maritime custom to refer to the man overboard as “Oscar.” This comes from an international regulation requiring the raising of the Oscar flag when a vessel is responding to a man overboard, warning other vessels to be on the lookout

Weather Data from the Bridge 
Visibility:  3 miles
Wind Direction:  050
Wind Speed:  8 knots
Sea Wave Height:  0-1 foot
Swell Wave Height:  2-3 feet
Seawater Temperature: 7.8˚ C.
Present Weather Conditions: cloudy

Science and Technology Log 

After leaving Captain’s Bay early Friday morning, the trip to the rendezvous point with OSCAR DYSON took nearly 20 hours. During that time we had our mandatory fire, abandon ship, and man overboard drills.  For our fire drill the Captain staged a mock fire, with smoke reported from the acoustics lab.  The fire fighting team had to respond, find the point of origin of the fire and figure out how to treat it. A debriefing was held afterward so that responders could discuss strategies and learn from the experience.

The rescue boat is brought back aboard the MILLER FREEMAN
The rescue boat is brought back aboard the MILLER FREEMAN

The abandon ship drill is regularly performed so all crew are ready to respond to a severe emergency by mustering at their assigned stations and getting into survival suits to be ready to board life rafts. It’s a good way for new crew members, such as me, to make sure they know where to go and what to bring. We made our rendezvous with OSCAR DYSON late Friday evening in the Bering Sea and immediately moved into position to run the first side by side transect. We are working on a comparison study to determine whether acoustic estimates of pollock (Theragra chalcogramma) abundance made by MILLER FREEMAN and OSCAR DYSON are comparable.  Pollock may have different behavioral responses to these vessels during surveys due to the differences in the amount of noise each vessel radiates into the sea from its propeller, engines, and other equipment.  These behaviors could affect the acoustic estimates of abundance.  OSCAR DYSON is taking over the task of acoustic pollock surveys in the Bering Sea and has been built under new specifications that require a lower level of radiated noise. MILLER FREEMAN has been doing the Bering Sea pollock surveys since 1977.  This study is important because it will ensure that future biomass estimates will be continuous with those done in the past. During this cruise the two ships will continuously collect acoustic backscatter data while traveling side by side along a transect line where pollock schools are known to occur. The distance between the two ships is maintained at 0.5 nautical miles (nm), while they travel at about 12 knots. Every 50 nm along the transect, the vessels switch sides.

OSCAR DYSON from the bridge of the MILLER FREEMAN in the Bering Sea
OSCAR DYSON from the bridge of the MILLER FREEMAN in the Bering Sea

For this to happen one vessel will slow down and cross behind the stern of the other vessel, then catch back up on the other side. The beginning and end of each transect section must be carefully coordinated between the scientific team in the acoustics lab The remainder of our time on this cruise will be spent working with the OSCAR DYSON to cover as much of the study area as possible before returning to the port of Dutch Harbor.  After the study is complete, the acoustic data collected by each vessel will be carefully compared to see if there is any consistent difference between them. At the same time officers on the bridge are in constant communication to coordinate navigation and maneuvering of the ships.

The figure above shows the final transect path of MILLER FREEMAN in the Bering Sea as straight lines in red. The parallel lines running nearly north and south were traversed from the east to the farthest westerly point. The zigzag red line across the parallel lines represents the path taken as we head back to the southwest on our return. Other colored lines on the map are depth contour lines.  Red lines indicate depths from -75 to -100 meters, yellow to -130 meters, green to -155 meters, and blue greater than  -160 meters.

Ship transect
Ship transect

Personal Log 

During these few days at sea the scientists onboard have taught me a lot about acoustic studies. It’s a complex science that requires both an understanding of the physical science of acoustics and the technology involved, but also the biology, behavior, and ecology of pollock.

One of the opportunities I have especially enjoyed has been watching and photographing the seabirds. They are an important part of this ecosystem and one that can be observed without acoustics. We have seen mostly northern fulmar (Fulmaris glacialis) and black-legged kittiwake (Rissa tridactyla), but also an occasional long-tailed jaeger (Stercorarius longicaudus), and flocks of thick-billed murre (Uria lomvia). Northern fulmar (Fulmaris glacialis) exhibit a lot of variation in color from very light, to light, and dark versions, with gradations in between. These different color morphs all mate indiscriminately. They are gull sized birds with moderately long wings, a short, stout, pale bill, and a short rounded tail. A key characteristic is their dark eye smudge.  They are common in the Bering Sea but also in the northeast Atlantic.

Northern fulmar, light morph
Northern fulmar, light morph

Northern fulmar, dark morph
Northern fulmar, dark morph

Fulmars are well known among commercial fisherman for scavenging waste thrown off fishing boats, which explains why they have been nearly constant companions to the MILLER FREEMAN on this cruise. Fulmars are members of the family Procellariiformes, also known as the “tube-nose” birds, along with albatrosses, petrels, and shearwaters. The term comes from the tubular nostril, a structure that looks like a tube on top of their beak.  Their beak, as you can see in the photo, is made up of many plates. This specialized nostril is an adaptation that enhances their sense of smell by increasing the surface area within to detect scent. They also have enlarged brain structures that help them process those scents. Learn more at the Cornell and U.S.G.S. websites.

Katie Turner, July 25, 2008

NOAA Teacher at Sea
Katie Turner
Onboard NOAA Ship Miller Freeman
July 10 – 31, 2008

Mission: Pollock Survey
Geographical Area: Eastern Bering Sea
Date: July 25, 2008

Bald eagles are abundant around the port in Dutch Harbor
Bald eagles are abundant around the port in Dutch Harbor

Weather Data from the Bridge 
Visibility: 10 nautical miles
Wind Direction: 075
Wind Speed: 13 knots
Sea Wave Height: 1-2 feet
Swell Wave Height: 3 feet
Seawater Temperature: 7.1˚C.
Present Weather Conditions: Cloudy, 9.3˚C, 94% humidity

Science and Technology Log 

After spending 3 weeks at the dock in Dutch Harbor, MILLER FREEMAN finally began the cruise with less than a week left to complete the study. We pulled away from the dock Thursday afternoon, 24 July, and sailed to nearby Captain’s Bay to calibrate the acoustic instruments.

A line diagram of MILLER FREEMAN showing the location of the centerboard below the hull
A line diagram of MILLER FREEMAN showing the location of the centerboard below the hull


Acoustics is the scientific study of sound: its generation, transmission, and reception.  Sound travels in waves at known rates, and the physical properties of the material the waves travel through affect the speed of sound.  These properties of sound waves enable their use in medical diagnosis, testing critical materials, finding oil-bearing rocks underground, and counting fish in the ocean. Sound travels through seawater of average salinity about 5 times faster than through air (~1,500 m/s, or about 15 football fields in one second).  Many animals that live in the ocean rely on sound more than vision for communication and survival. You are probably already familiar with echolocation and communication vocalizations in whales and porpoises.

Picture of the transducers in the centerboard, which is lowered when the ship is at sea. Lowering the transducer away from the hull reduces the noise interference of bubbles running along the hull while underway.
Picture of the transducers in the centerboard, which is lowered when the ship is at sea. Lowering the transducer away from the hull reduces the noise interference of bubbles running along the hull while underway.

The speed of sound in water increases as temperature and salinity increase.  It also increases with depth due to the increase in pressure.  Therefore, in order to know the speed of sound at a given location in the sea, you need to know the temperature, salinity, and depth. There are other factors that are important to consider as well.  As sound travels through seawater it loses energy because of spreading, scattering and absorption.  When sound waves strike bubbles, particles suspended in the water column, organisms, the seafloor, and even the surface, some of the energy bounces off or is scattered. When the sound energy is scattered at angles greater than 90 degrees it is referred to as backscatter.

Fish Assessment 

Scientists use acoustics to measure fish abundance in the ocean by emitting sound waves at specific frequencies and then measuring the amount of backscatter.  Different organisms and other objects will have a characteristic backscatter that is dependent on many biological factors as well as the physical properties of the medium. The most important biological factor is presence and the size of a swim bladder, but also the organism’s size, shape and orientation.  If scientists know the backscatter signature of the target species (which can be determined experimentally or by mathematical models), they can use sound to identify and measure certain fish populations in the ocean. Onboard the ship, sound waves are emitted from an instrument called a transducer, which is located in the centerboard of the ship. The transducer generates sounds directly beneath the ship into the water column below (pings).  When these sound waves are backscattered from the fish below back to the transducer, they are converted to an electrical signal that is sent to the scientist’s computer.  There, a profile can be created that represents the fish in a graphical image.

Chief Scientist, Patrick Ressler, attaches calibration spheres to the line that will be lowered beneath the ship.
Chief Scientist, Patrick Ressler, attaches calibration spheres to the line that will be lowered beneath the ship.

Before making any actual measurements during this study, it is necessary to calibrate the acoustic instruments on board the ship. Calibrations of instruments and other measuring devices are done by using a known standard to compare the output of the instrument. So for example, if I wanted to calibrate a stick as a measuring device, first I would compare its length to a known standard such as a ruler. We anchored in Captain’s bay, on both bow and stern to keep the ship from moving much, and spheres with known acoustic properties were suspended beneath the ship at a known distance below the transducers. Acoustic data were then collected on backscatter from the spheres. Knowing the distance to the spheres, their acoustic qualities (how they will backscatter the sound), and the physical qualities of the medium (seawater temperature and salinity) allowed the scientists to standardize their equipment.   While acoustic calibrations were performed by the scientists, the survey technicians collected seawater temperature and salinity. The way these properties are measured is standard practice on research vessels.  An instrument package called a “CTD” measures conductivity (which is converted to salinity), temperature, and depth.  Sensors for each of these make up the package, and are mounted on a metal frame called a rosette. The rosette is lowered into the water column by a crane, and the data collected is transmitted via a cable to a computer on board. Once the calibration and CTD measurements were completed, we pulled anchor and headed northwest into the Bering Sea to meet up with NOAA Ship OSCAR DYSON.  We expect to reach our rendezvous point by late Friday to begin our study.

Survey Technician Tayler Wilkins monitors the CTD data transmission while communicating with the crane operator as the rosette is lowered through the water column. The computer automatically produces a profile of temperature and salinity with depth.
Survey Technician Tayler Wilkins monitors the CTD data transmission while communicating with the crane operator as the rosette is lowered through the water column. The computer automatically produces a profile of temperature and salinity with depth.

Personal Log 

The long stay in Dutch Harbor made the departure that much more exciting.  I am looking forward to what little time is left.  The crew of MILLER FREEMAN have all made me feel welcome, and have been helpful in answering my questions and educating me on shipboard operations.

New Terms 

acoustics, calibration, backscatter, centerboard, transducer, CTD rosette

Learn more here