otolith – NOAA Teacher at Sea Blog

August 4, 2025August 5, 2025

Cheryl Milliken: Fish On! August 1, 2025

NOAA Teacher at Sea

Cheryl Milliken

Aboard NOAA Ship Oregon II

July 25 – August 10, 2025

Mission: Bottom Longline Survey, Leg 1

Geographic Area of Cruise: Atlantic Coast of Florida

Date: August 1, 2025 (11:00 AM)

Weather Data from the Bridge

Latitude: 30° 30.1’N

Longitude: 081° 12.6′ W

Wind speed: 10 kts.

Wave height: 0-1 ft.

Air temp.: 31.5° C (89° F)

Sky: Clear

Science and Technology Log

“Fish on!” is what is called out whenever we have a fish on a hook. Everyone springs into action to collect data on the fish as efficiently as possible so it has a better chance of surviving. Their success is evidenced by the number of shark tags that have been returned after this release. Wednesday we caught a large female tiger shark that had been tagged by scientists out of the Apex Predators Program out of the NOAA Fisheries Narragansett lab. Here is a link to the work they conduct in that lab: https://www.fisheries.noaa.gov/new-england-mid-atlantic/atlantic-highly-migratory-species/northeast-shark-research. We are awaiting information about the tagged individual (where and when it was tagged, how much it has grown since she was tagged) from scientists in Narragansett.

NOAA Fisheries has been conducting the Southeast Bottom Longline Survey for 30 years! Scientists and crew participating in the survey have vital scientific data on sharks and finfish in U.S. waters from Cape Hatteras, North Carolina, to the Florida Keys and through the Gulf of America.

Each year, survey stations—randomly selected before each cruise—are sampled in both shallow and deep waters. Scientists and crew use standardized fishing protocols to collect data on abundance, distribution, size, sex, and maturity of captured species. For bony fish, they also remove otoliths—tiny calcareous structures in the ear—to count growth rings and estimate age, similar to how one might age a tree.

This long-term, standardized dataset is an invaluable resource. It provides critical baseline information about marine ecosystems, which is especially important when natural disasters strike. Managers can refer to this historical data to understand pre-disaster conditions and guide recovery efforts.

Best of all, the entire database is public. Researchers, policymakers, and curious minds alike can access this wealth of information to support science-based decision-making. Learn more about the Southeast fishery-independent surveys: NOAA Fisheries Southeast Surveys.

Teamwork in Action: Skilled Crew and Augmenters Keep the Survey Moving

This leg of the Southeast Bottom Longline Survey includes several augmenters—crew members temporarily reassigned from other NOAA ships or roles to help out where they’re most needed. Their skills and experience are a welcome asset on board, especially during a time when a federal hiring freeze has led staff to pitch in across vessels.

Among the augmenters are NOAA Corps officers either in training or assisting with training, the ship’s chief steward, and members of the deck crew. Their flexibility and teamwork ensure the survey continues smoothly and safely.

a man stands on deck, feet spread apart for balance, holding up a large barracuda for a photo. we see blue skies with puffy clouds and fairly even blue water in the background beyond the rail.

portrait photo of a man in a red t-shirt wearing sunglasses and a very wide-brimmed straw hat; he leans on a railing of the deck and looks off dramatically into the distance

a man, mostly in silhouette due to the lighting, fishing off the back deck of the ship. beyond the railing is a lovely orange sunset obscured by just a few bits of cloud over dark blue waters.

Left to right: Josh with a barracuda he trolled off the stern deck; Chuck Godwin in the best hat; Sean reeling in the line at sunset.

Fishing operations on this leg are led by a capable and experienced Deck Department:

Josh Cooper, Chief Boatswain, has served on board for 3 ½ years.
Chuck Godwin, the lead fisherman, brings years of experience working aboard NOAA Ship Oregon II.
Sean Gronquist, a skilled fisherman, just celebrated his one-year anniversary on board this week.
Aaron Walton, a seasoned Lead Fisherman from NOAA Ship Bigelow out of Rhode Island, is augmenting the night watch team.
Malachi Olson, a contractor, is also supporting night operations as an augmenter.

During fishing operations, this team handles critical tasks: setting longlines, hauling them back in after one hour, and moving a specialized mesh cradle into place when large sharks are brought aboard. Their coordination and expertise are essential to ensuring the data collection is efficient, humane, and safe for both crew and animals.

Interview with Sean Gronquist

This interview is with skilled fisherman Sean Gronquist. He has been around the Atlantic Ocean his whole life, but on NOAA Ship Oregon II for a year. Growing up, Sean and his friends used to take all kinds of watercraft out into the Intracoastal Waterway around St. Augustine, FL, from a dock behind his house. He learned some basic mechanics from his friend, Jordan, who was able to fix 2-stroke engines on the fly when they were out on the water together.

Sean graduated from the University of North Florida with a degree in anthropology and a dream to be an underwater “Indiana Jones.” He earned his captain’s license and worked as a charter fishing captain for 15 years, where the focus for him was locating the target species of his clients to catch whatever they requested, if possible. Sean literally helped customers check items off their bucket list (he runs Uno Mas Fishing Charters out of Stuart, FL). He could return to this profession if he ever needed to, but for now he finds joy in working toward the important goal of figuring out how many fish are off the southeastern coast of the US.

Why is your work important?

“We collect data that is used by multiple groups to set quotas or limits on fisheries. We’re one of the longest running surveys.”

What do you enjoy most about your work?

“Even during transits, no two days are the same. Straight up, I fish for the government. The fact that I found a job that pays me to do what I’m passionate about, you can’t beat it. I learn something new every day. “

What is the most important tool that you use for your job?

“My answer is simple: a sharp pocket knife comes in handy all the time. You can cut something, open things, all sorts of uses. “

If you could invent any tool to make your work more efficient and cost were no object, what would it be and why?

“It would have to be something to keep weeds off the line, a weedless spring to remove the sargassum weed from the trolling line. We fish off the stern when we have finished all that we need to do, and it’s a pain to have to pull in the lures all the time because they’re fouled with sargassum.”

When did you know you wanted to pursue an ocean career?

“I’ve always known I wanted that. I grew up on the water, so I just needed to figure out how to make a career out of it. I did marine mechanics on Yamaha engines at a guy’s shop but realized that the owner of the shop would always make a lot more money than I would. I did finish carpentry, too, but ultimately I decided to put down a hammer and picked up a wrench.

“My great grandfather was a merchant marine, and my grandfather was a See Bee in the Navy in Okinawa in World War II. It ran in my family, so I always figured I’d end up on a ship.”

Personal Log

I am having so much fun and learning so much on this trip. It’s always nice to interact with people who are like-minded about the wonder of the ocean. We have a range of people on this leg of the cruise (it takes 4 legs to sample all of the stations and regions). Here are the people on the day watch with me:

Trey Driggers, primary investigator for the project
Gretchen Kruizenga, survey technician (Ms. Fix-It!)
Tera Winters, survey scientist (and former veterinarian)
Evan Winters, volunteer entering college at West Florida University when we return

Everyone is pulling their weight (I always feel like I need to step up a little more, but I am trying to keep up at these new tasks) and getting along well. I will try to write more about these new friends in the future.

New Animals Seen

Spotted dolphins
Cannonball jellyfish
Lion’s mane jellyfish
Tiger sharks (large and small)
Sandbar sharks
Leech on the sandbar shark
Nurse shark
Bull shark
Sharpnose shark
Great hammerhead shark! (the other watch actually saw this shark, but they showed me the pictures! We are in competition now to see who catches the next hammerhead.)
Two large red snappers!

a somewhat out of focus view of two dolphins leaping above the surface of the water; blue, mostly clear skies, bright blue water.

a woman wearing a hard hat, life vest, and gloves crouches on deck to hold a large red-orange fish against a long wooden measuring board

a woman wearing a life vest, hat, and sunglasses smiles for the camera as she stands on deck grasping a small stripey shark behind its jaws

close-up view of a marine leech against the bright blue textured background of a fish glove. the leach is blue gray with a pattern of white spots in bands.

view of the underside of a hammerhead shark's head, held back by a blue gloved hand. the shark is suspended above the water in the mesh cradle.

a hammerhead shark in the water, caught on a line, as seen over the railing.

Photos clockwise, from top left: Spotted dolphins swimming in the wake for fun; Lila holding a baby tiger shark, a favorite!; great hammerhead shark on the longline, prior to hauling up; great hammerhead in the mesh cradle being measured, sexed, and tagged; leech (size approximately 2 cm) in my glove, removed from a large sandbar shark); Tera measuring a red snapper prior to removing otoliths (estimated to be around 15 years old).

Did You Know?

Otoliths, or fish ear stones, are the densest part of a finfish’s body and are made of calcium carbonate, the same material as seashells. They are suspended in a liquid to help the fish to know which end is up and to sense vibrations.

otoliths arranged in six neat columns against a black background. the otoliths have been dyed different colors prior to sectioning.

close-up view of two cleaned otoliths resting in the fingers of someone's upturned

Left: Otoliths from six species aligned at the core and ready to be sectioned. Photo: Sandy Sutherland, NOAA Fisheries. Right: Otoliths removed by Tera from the red snapper in the previous photos.

July 11, 2025July 11, 2025

Jojo Chang: See/Seafood, July 10, 2025

NOAA Teacher at Sea

Jojo Chang

Aboard Bell M. Shimada

June 30 – July 15, 2025

Mission: Integrated West Coast Pelagics Survey (Leg 2)

Geographic Area of Cruise: Pacific Ocean, California Coast

Date: July 10, 2025

portrait photo of Jojo wearing a Teacher at Sea beanie, a Teacher at Sea t-shirt, a raincoat, and gloves with cut off fingers. She's on the aft deck an flashes a peace sign with her right hand. — TAS Jojo Chang

Weather Data from the Bridge

It’s noon, and the weather is cloudy and foggy. We are passing the coastal city of Carmel, California, but only a tiny sliver of land is visible from the ship. We are sounding the fog horn and traveling slowly. Currently, the air temperature is 54.5 degrees Fahrenheit, and the wind speed is 14 knots.

Culinary: Art and Science

Let’s talk about Chef Phil, the Chief Steward on board. First things first: we are eating very well out here. And by “well,” I mean gourmet-level delicious. Chef Phil is a culinary artist, crafting remarkable meals that blend creativity and technique, even as the ship rocks and rolls like a theme park ride.

portrait photo of a man wearing a black baseball cap and a black and red apron. He stands in the mess hall with his hands resting on the backs of two dining chairs. Superimposed on the photo are the words: Phil / Chief Steward — Chef Phil Jones

His knife skills? Let’s just say they’re literally “rolling with it.” That’s how he describes chopping food at sea—adjusting in real-time to the ship’s motion.

Chef Phil has a rich background in the culinary world. He once spent six months perfecting the art of sushi rice with Morimoto, the world-renowned Japanese culinarian (made famous for his role on the TV series Iron Chef). Phil has also cooked for Disney at the Hilton Orlando and aboard multiple cruise lines.

Photo of a computer screen displaying the breakfast, lunch, and dinner menus in three columns. The dinner list is Louisiana themed: "duck & andouille gumbo, gator nuggets w/remi, blackened shrimp, dirty rice, cheddar grits, succotash" — Sample daily menu . YES! We did have real gator nuggets.

“I’m not looking for a Michelin Star,” he says. “I just love what I do.”

view of a metal cafetaria bar with the dinner items in removable metal trays. we can see gumbo, nuggets, shrimp, and other dishes beyond. — Louisiana dinner menu

And that love shows—every single day. His food doesn’t just nourish, it brings joy. Thank you, Chef Phil, for making this ship’s mess hall taste like world class cuisine. It’s not a Michelin Star, but I’d give you five Shimada Stars. Chef Phil is assisted by Ted in the mess hall, preparing three amazing meals every day.

portrait of a man wearing a blue baseball cap and making a shaka sign with his left hand. he is standing in the galley. — Ted Partosan: Kitchen assistant

Market Squid

In the wet lab, we encounter the ocean food web on a very real level every day with each trawl that comes up from the depths of the sea. It’s one thing to read about the food web; it’s an entirely different thing to see the organisms arrive in a basket for dissection and inspection. You should know that before I came on this boat, I had only dissected (reluctantly) one small frog in high school biology class. In college and graduate work, I studied education and American literature. There was nothing in my Captain Ahab/Moby Dick thesis paper that prepared me for this experience except background research into the Nantucket whaling industry of the 1800s.

Now, my scalpel skills have become quite remarkable. I have seen the insides of hundreds of hake fish and preserved many an ear bone for science. Inside, I’m telling myself, “I can do hard (and often gross) things.” When I say this is a life-changing experience, I’m not kidding. It is life-changing because of the wonder and amazingness of the life force of the underwater world, which is both fascinating and mysterious. I loved the ocean before I came out here, but now I’m just blown away by the life and living creatures that are under the sea.

One creature that comes into the wet lab regularly is the market squid. At first, they seem rather ordinary, but on further inspection, these creatures have the most beautiful pink, yellow, and brown random polka-dotted pattern. It turns out that this crazy cool feature is called chromatophores (cells that produce color) , and cephalopods use them to communicate, camouflage, and attract a mate.

Most days, we haul in 100s of these remarkable sea squids. The magic can be seen by tapping them lightly, and watching as the polka dots appear. The transformation is fleeting, but amazing. Unfortunately, it is an important feature for live squid, and as they die, they lose the chromatophores.

close up view of the skin of a squid; it has a translucent background but is covered in magenta spots of varying intensity — Chromatophores on market squid.

Video showing how the polka dots magically appear and disappear.

Fish Vocabulary

So, I have all these new science friends, and at first, they seem like totally normal ocean-loving people—you know, the kind who go on coastal vacations, talk about scuba diving, and swap fishing stories. But get them into the wet lab? Suddenly, it’s like flipping a switch. These folks light up over fish ovaries, otoliths, and fin clips like they just unwrapped an Apple Watch on Christmas morning—or scored Tiffany diamonds from a secret admirer. I’ve never seen someone so genuinely thrilled to dissect a hake fish. It’s both impressive and slightly shocking. However, what I see with everyone on board, from the deck crew to the engineers, is joy in their occupation. There’s a passion and a purpose to what they are doing that is both impressive and heartwarming.

Sabrina Beyer inspecting fish ovaries through a microscope.

two women in bright orange overalls stand at a metal table in the wet lab. they are both looking down and pointing at a wirebound fish field guide laying flat on the table. — Sabrina Beyer inspecting fish ovaries through a microscope.

Before arriving on this boat, I had never heard of an otolith, aka oties. This is a fish ear stone or ear bone, and is the most commonly used item for understanding the age of a fish. Scientists count the rings on a pair of otoliths to age a fish much like they count the rings on tree. Ear stones and tree rings are like nature’s timekeepers and just as trees lay down a new ring each year as they grow, many fish form growth rings on their otoliths. These rings can be counted to estimate the fish’s age, offering a biological calendar etched in bone.

extremely close up view of a pair of otoliths against a spongy green background. the otoliths are nearly mirrors of one another, very elongated, and we can see faint gray rings, like contour lines. against their white background. — A large pair of hake otholiths.
They look like feathers.

Jojo, wearing a jacket, a bandana, and a backpack, stands at a very large tree cross section, holding her hand up as if to present it. The tree cookie has been annotated with small metal signs noting major historical events in the tree's lifetime. — A large pair of hake otholiths.
They look like feathers.

Both items that appear in Mother Nature’s patterns reflect changes in growth rate, which are influenced by environmental conditions. For trees, wider rings typically suggest years of good rainfall and favorable climate, while narrow rings indicate harsher times. Similarly, in fish, the spacing between otolith rings can vary depending on water temperature, food availability, and seasonal changes. Scientists aboard NOAA ships collect fish oties because they tell a hidden story about the life history and environment of the organism.

These ear bones are important to living fish for other reasons. According to NOAA Fisheries, “Otoliths are part of the fish’s inner ear, allowing fish to hear and sense vibrations in the water and providing a sense of balance so they may better navigate their surroundings.” Once, when my children were small, we had a pet fish named “Bubbles”. Bubbles swam upside down. I guess he must have had an otie issue.

Animals recently spotted from the ship or in the wet lab

Common dolphin, Risso’s dolphin, rockfish, dogfish shark, strawberry squid, baby octopus, hake, butterfish, anchovy, market squid, king of the salmon

Live dogfish shark on board.

Three women work together to hold up a rather long, perhaps 4 ft, narrow fish with a large eye above a large bin of much smaller fish. The women all wear bright orange or yellow foul weather gear, personal flotation devices, and hard hats. Jojo stands at left and holds the fish's tail; the two other women hold the middle and the head. in the background, through a doorway, we see two other science team members and a portion of the trawl net. — Bringing in a ribbon fish known as king of the salmon. This is fish is not a salmon but is named such because of the legend that it leads salmon to its spawning area.

Works Cited

National Oceanic and Atmospheric Administration. “Age and Growth.” NOAA Fisheries, 28 Feb. 2025, https://www.fisheries.noaa.gov/national/science-data/age-and-growth.

August 31, 2024August 31, 2024

Lisa Werner: Introduction to OREGON (Not Alaska!) – August 29, 2024

NOAA Teacher at Sea

Lisa Werner

Aboard NOAA Ship Bell M. Shimada

August 29 – September 13, 2024

Mission: Expanding Pacific Research and Exploration of Submerged Systems (EXPRESS) Project

Geographic Area of Cruise: Pacific Coast, near Southern Oregon and Northern California

Date: August 29, 2024

Weather Data (Newport, OR)

Date: 08/29/2024
Time: 0730
Latitude: 44.6°N
Longitude: 124.05°W

Science and Technology Log

Originally I was scheduled to be a part of NOAA Ship Fairweather‘s hydrography mission, but ship repairs have changed my assignment. I am now going to be on NOAA Ship Bell M. Shimada, working on the EXPRESS mission. EXPRESS stands for Expanding Pacific Research and Exploitation of Submerged Systems.

This project has three main goals:

To guide wise use of living and non-living marine resources,
To inform potential offshore energy decisions, and
To improve offshore earthquake, landslide, tsunami, and nautical hazard assessments.

One of the main aspects of this larger project that I will be experiencing will be the use of an autonomous underwater vehicle (AUV) named Popoki. I am incredibly excited to see the variety of experiments being done for this project!

Before we get going on the project, I had the great fortune of getting a tour of the NOAA Fisheries Lab (part of the Northwest Fisheries Science Center) and the Hatfield Marine Science Center with Alicia Billings, a Fishery Research Biologist. Alicia showed me where her office and work spaces are, taught me about how fish ages are figured out by counting the growth bands of the otoliths (“Ear stones”), and taught me a lot about the nets used for her studies on Pacific Hake. She had just gotten back from being at sea aboard NOAA Ship Bell M. Shimada, so she had a lot of insights as to how the time at sea works and how much the scientists look forward to being able to work in the ocean environment.

close-up photo of a printed poster or bookpage. This section is titled Pacific Hake: Maximum age: 25 years. There is a photo of a hake resting on the seafloor, and two magnified images of otolith crossections. — Pacific Hake otolith example – note the rings to count!

I also had the opportunity to visit the Oregon Coast Aquarium, which had some incredible touch tanks and viewing tunnels showing the marine life of Oregon. I was able to find answers to many of the homework questions the students I teach gave me before I left (mainly about the octopus, crab, and jellyfish populations!)

view of a Pacific Giant Octopus hanging out near the window of an aquarium tank — Pacific Giant Octopus

a zookeeper wearing latex gloves kneels to offer a piece of squid to a sea otter floating on its back near the edge of the water of its enclosure — Pacific Giant Octopus

Oregon Coast Aquarium images:
(1) The students I teach really wanted to see how an octopus moves, so they will love the videos I took of this very large octopus! (2) I arrived at the aquarium just in time to see the sea otters being fed. (3) One of the 3 tunnels that immerses visitors in the sea life of Oregon.

We leave port later today, and I cannot wait to see the incredible work being done!

Personal Log

I am very excited to be sailing aboard NOAA Ship Bell M. Shimada. I am so grateful to Emily Susko for arranging this quick change (while on her week off of work) so that I could still be a part of the Teacher at Sea program, despite the delays with NOAA Ship Fairweather.

Lisa, wearing her Teacher at Sea hat and t-shirt, poses for a photo by pointing excitedly at her nameplate on a wooden door. There are three other nameplates on this door, as well as smaller papers with muster station assignments — My name is on my stateroom door!

The EXPRESS program will be an excellent example of interdepartmental work, as it will feature scientists from NOAA, University of Alaska, and the Bureau of Ocean Energy Management. Combined with the beautiful partnership between the NOAA Officer Corps (the people who run the ships) and the NOAA science team (the people working on the specific project that sails aboard the ships), it will be great to see how all of these groups of people contribute to the greater project – definitely some great lessons and examples to bring back to the students in our school!

Music Connection

Since it is my belief that music connects to everything, the last section of each blog post will feature connections to music. While I was getting a tour of the beautiful Gladys Valley Marine Studies Building from Alicia, I saw an exhibit on a musical instrument that has been made from hollow bull kelp. There was a listening station where you could hear a hollowed bull kelp being played. The beauty of this instrument is that it is environmentally responsible – the bull kelp wash ashore regularly, so they do not need to be harvested. Kelp decays quickly, so the horn must be played within a week of it washing ashore. The projects displayed were showing the collaboration between music and ecology.

photo of a printed photo and caption displayed on a wall. the image shows a single piece of bull kelp lying in the sand. Mounted beneath, the caption reads: "Bull kelp, Nereocystis leutkeana, meaning "mermaid's bladder" is an annual macroalgae. It has a lovely natural history that weaves the story of our narrative. By providing structure to the rocky subtidal, it gives life to many organisms, past and present, small and large. From tiny juvenile rockfish to massive grey whales, extinct sea cows to urchin divers, many call kelp forests home." — Picture of bull kelp. Alicia Billings mentioned that sea lions and seals sometimes hold onto the kelp while feeding.

a man wearing long orange gloves holds a stalk of bull kelp, with his right hand grasping one end as if it were a garden hose, and his left hand holding the other end of the kelp to his lips. His cheeks are puffed out from blowing into the horn. He stands on a beach with muted colors. — Picture of bull kelp. Alicia Billings mentioned that sea lions and seals sometimes hold onto the kelp while feeding.

July 16, 2024July 16, 2024

Nick Lee: In the Fish Lab, July 12, 2024

NOAA Teacher at Sea
Nick Lee
Aboard NOAA Ship Oscar Dyson
June 29 – July 20, 2024

Mission: Pollock Acoustic-Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date: July 12, 2024

Weather Data from the Bridge:

Latitude: 60° 02.17 N

Longitude: 176° 37.3 W

Wind Speed: 14 knots

Air Temperature: 5.5° Celsius (41.9° Fahrenheit)

Science and Technology Log

Once the trawl is completed, the codend is unloaded onto a conveyor belt for sorting. Usually, we just sort by species, picking out any organisms that aren’t pollock and storing them in separate baskets. Overall, I’ve been surprised with how “clean” or uniform the catches have been. We will usually have some jellyfish, but other than that we tend to have only a few fish of other species in a catch with hundreds or thousands of pollock.

Pollock on the conveyor belt. We can see the orange rain coats and long yellow gloves of two scientists standing nearby. — *The catch is first emptied onto a conveyor belt where it is sorted by species.*

When the catch has a mix of juvenile and adult pollock, we’ll also sort them by size, which roughly correlates to age group. The size cutoff used for sorting is only an approximation of age (the exact age is determined later), but it is still useful in ensuring that we sample a consistent number of each size class in every trawl.

Distinguishing between the larger juveniles and smaller adults on the belt can be tricky, so on one trawl we got creative and found what we named a “measuring fish.” This fish was the smallest length that had been designated as an adult in the previous trawls – anything smaller we left on the belt with the juveniles and anything larger we put in a separate basket with the adults. While not the most conventional solution, it served our purpose well and showed that anything can be made into a measuring instrument!

Nick is wearing a heavy orange rain coat and long yellow gloves. He holds up two pollock fish vertically, comparing their lengths to one another. We see more fish on a sorting table in the background. — *Using a “measuring” fish to sort the catch according to size (Photo Credit: Matthew Phillips).*

Once the fish are sorted, we take length and weight measurements for a representative sample of all species in the trawl. We measure the length of hundreds of pollock in a given trawl, so luckily the system is very efficient.

When I length a pollock, I’ll grab the fish in one hand and place it on the magnetic length board so that its head is against the end at zero. Then I’ll use my other hand to straighten the fish and place a magnet at the fork of the tail. The length board records where the magnet touches the length board, measuring what is known as the “fork length” of the fish.

Pollock on length board; its head faces toward the left side of the board, near a digital meter reading the length. toward the right side, a red magnet is placed at the fork of the fish's tail. — *The length board records where the red magnet is placed.*

For a subsample of pollock, we will also record the sex and maturity of each individual. To collect this data, we’ll first make a cut along the side of the pollock. This allows us to observe the pollock’s ovaries or testes and compare them to a chart showing the stages of development. Based on the time of year, most of the pollock we catch are in the “developing” stage. Also visible are the pollock’s liver and its stomach, which is often filled with krill!

Three people stand at a long metal table wearing heavy orange raincoats and gloves. White bins, a white cutting board, and a measuring board line the table. Matthew, in the foreground, holds a fish up with two hands over a measuring board, and looks at someone over his right shoulder. Nick, in the middle, looks down at the fish that Matthew holds, and a third scientist stands beyond Nick, looking on as well. — *Scientist Matthew Phillips showing me how to identify the sex and maturity of a pollock (Photo Credit: Mike Levine).*

For a subsample of the pollock in this group, we’ll also collect otoliths, which are similar to tree rings in that they allow scientists to visually determine the age of the individual. Otoliths are part of pollock’s inner ear, and they help the fish to detect vibrations in the water. Like tree rings, they grow throughout a fish’s life, adding visible layers each year. During times when the fish is actively feeding (usually during the summer), an opaque layer forms around the otolith. In contrast, when the fish is eating less, the otolith layer formed is translucent. By studying otoliths, scientists can determine the age of a fish, as one opaque layer and one translucent layer together represent one year. (Source: https://www.fisheries.noaa.gov/national/science-data/age-and-growth)

Teacher at Sea Nick Lee removing an otolith. Nick wears a heavy orange raincoat and long yellow gloves. He holds part of a pollock in his right hand and with his left hand holds up a small white object (the otolith) with tweezers. — *Extracting an otolith from the head of a pollock (Photo Credit: Mike Levine).*

One important and sometimes overlooked step in scientific data collection is the clean-up. At Codman Academy, we use the phrase “Leave No Trace,” and I try to model this idea in the fish lab as well. Working with fish can be smelly, and the smell only grows when fish are allowed to sit for extended periods of time. The process of recording sex and extracting otoliths can be especially messy, so we are constantly spraying down baskets and surfaces (and each other!) between data collection steps.

All of the fish that are processed are ultimately disposed of overboard – usually during the processing of the trawl dozens of seabirds follow the ship in search of discarded fish!

View through a doorway of an outer deck; over the railing we see seabirds flying past the fish lab. The sky and the water are gray. — *Seabirds flying past the fish lab.*

Personal Log

Outside of my stateroom, there is a tongue-in-cheek poster claiming to be a “Bering Sea Weather Guide.” The poster has the labels “Good Day,” “Some Days,” and “Other Days,” below paint swatches, all of them different shades of gray. There are also gray paint swatches for “Summer,” “Winter,” and “Days Ending in Y.”

"Bering Sea Weather Guide," a collection of gray paint swatches labeled: Most Days, Good Days, Some Days, Other Days, Last Week, Next Week, This Week, Days Ending in Y, Summer, Fall, Winter, Spring — *“Bering Sea Weather Guide” outside my stateroom.*

We’ve certainly had our share of gray days this cruise, and I’ve become used to falling asleep to the sound of the ship’s foghorn. However, we’ve also gotten a few moments of sunshine and blue sky, providing some great moments for bird and whale watching from the bridge. Being on the night shift, I’ve also been able to observe a couple of sunsets from the water!

View from the bridge on a clear day - blue skys, scattered fluffy white clouds — *View from the bridge on a clear day (left) and sunset at sea (right).*

Sunset behind NOAA Ship Oscar Dyson - nice mix of purples, pinks, blues, yellows — *View from the bridge on a clear day (left) and sunset at sea (right).*

Did you know?

Because we are so far north and west in the time zone, the sun sets very late here, usually around 1 am!

July 13, 2023July 19, 2023

Lisa Carlson: Where Did You Come From, Where Did You Go? July 13, 2023

NOAA Teacher at Sea

Lisa Carlson

NOAA Ship Bell M. Shimada

July 5, 2023 – July 19, 2023

Mission: Fisheries: Pacific Hake Survey (More info here)

Geographic Region: Pacific Ocean, off the coast of California

Date: July 13, 2023

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Weather Data from the bridge:

July 11 (1200 PT, 1500 EST)
Location: 37° 46.7’ N, 123° 26.6’ W
43nm (50mi) West of San Francisco, CA

Visibility: 2 nautical miles
Sky condition: Overcast, fog
Wind: 20 knots from N 250°
Barometer: 1015.2 mbar
Sea wave height: 2-3 feet
Swell: 6-7 ft from NW 320°
Sea temperature: 12.2°C (57.2°F)
Air temperature: 12.7°C (57.9°F)
Course Over Ground: (COG): 270°
Speed Over Ground (SOG): 10 knots

July 12 (1200 PT, 1500 EST)
Location: 38° 06.8’ N, 123° 01.6’ W
7nm (8mi) North of Point Reyes Lighthouse, Inverness, CA

Visibility: 2 nautical miles
Sky condition: Overcast, fog
Wind: 12 knots from N 350°
Barometer: 1016.0 mbar
Sea wave height: 1-2 feet
Swell: 3-4 ft from W 280°
Sea temperature: 11.0°C (57.2°F)
Air temperature: 11.5°C (57.9°F)
Course Over Ground: (COG): 270°
Speed Over Ground (SOG): 10 knots

July 13 (1200 PT, 1500 EST)
Location: 38° 17.3’ N, 123° 06.1’ W
2.5nm (4mi) Southwest of Bodega Bay, CA

Visibility: 3 nautical miles
Sky condition: Few clouds, fog
Wind: 13 knots from NW 300°
Barometer: 1015.9 mbar
Sea wave height: 1-2 feet 1-2
Swell: 3-4 ft from NW 300°
Sea temperature: 10.7°C (51.3°F)
Air temperature: 13.7°C (56.6°F)
Course Over Ground: (COG): 340°
Speed Over Ground (SOG): 10 knots

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In my July 6 post, I explained how NOAA Ship Bell M. Shimada is equipped to collect acoustic data in the form of echo grams and therefore find fish to trawl for. In my July 10 post, I explained how we get the fish onboard, and what we do with the sample once it is collected from the net. These entries described what work is done in the Acoustics Lab and the Wet Lab, but there is one more Lab onboard to explore and explain: the Chemistry Lab.

view down the starboard side of NOAA Ship Bell M Shimada shows a wooden nameplate (reading Bell M Shimada) on a railing, the fast rescue boat mounted aftward, and the Golden Gate Bridge in the background. — NOAA Ship *Bell M. Shimada* leaving Pier 30/32 in San Francisco, CA on July 5, 2023. (Just a nice photo taken by me that I wanted to include)

Science and Technology Log

Each morning after breakfast, we usually gather in the Acoustics Lab, determine what transect we are on, if we are inshore or offshore, and in some ways: hurry up and wait. Once certain patterns and blips show up on the echo grams, the Acoustics team talks with the bridge and may request to turn around and attempt a trawl. After all marine mammal observations are completed, the net is retrieved, and the samples are brought to the Wet Lab, we sort and collect data on the samples. These operations usually take place between 0800 and 2000. (8am to 8pm)

So what happens at night? In the Chemistry Lab, scientists work with the Deck and Surveys Departments to deploy a collection of electronic instruments and 12 Niskin bottles (open bottles used to collect and hold water samples, about one meter long) secured to a cylindrical frame called a rosette. It is deployed from the side sampling station instead of the stern. Scientists onboard NOAA Ship Bell M. Shimada use the instruments and collection of water samples in two ways: measuring Conductivity, Temperature, and Depth (CTD) within a water column to study oceanography, and collecting environmental DNA (eDNA).

photo of a large piece of sampling equipment on deck. a large white metal cylindrical frame houses a ring of perhaps ten tall gray canisters - the Niskin bottles. The bottles circle the conductivity, temperature, and depth probe, which is barely visible. Behind the frame, past the ship's rail, we see vivid blue water with a few white caps and a coastal mountain range beyond.

CTD Niskin bottles arranged on a circular rosette frame.

“Nighttime operations primarily consists of deploying the Conductivity-Temperature [-Depth] (CTD) rosette which gathers oceanographic data such as conductivity, temperature, dissolved oxygen, and chlorophyll fluorescence. The CTD can also be triggered to collect water at specific depths.”
NOAA Fisheries: “eDNA Part 2: There’s a Lot of Water in the Sea – and the Chemistry Lab”

NOAA Ocean Exploration: “What does “CTD” stand for?”

Conductivity, Temperature and Depth: CTD

CTD stands for conductivity (ability to pass an electrical current), temperature, and depth. Scientists use the rosette frame, which is attached to the ship by cables, and has the CTD and 12 Niskin bottles attached, to collect electronic data and multiple water samples.

“A CTD device’s primary function is to detect how the conductivity and temperature of the water column changes relative to depth. Conductivity is a measure of how well a solution conducts electricity and it is directly related to salinity. By measuring the conductivity of seawater, the salinity can be derived from the temperature and pressure of the same water. The depth is then derived from the pressure measurement by calculating the density of water from the temperature and the salinity.”
NOAA Ocean Exploration: “What does “CTD” stand for?”

Senior Survey Technician Elysha Agne gives commands to the Deck Department running the winch and cable to the rosette, and ensures quality data is being collected at each sampling depth.

“For more detailed analyses back in the lab, each of the large gray bottles captures a water sample at a different depth. The data provide scientists important information about the local aquatic environment.”
NOAA: “Photo story: Virtually cruise aboard a NOAA ship for a fish trawl survey”

Depending on the depth at which the vessel is currently operating, the rosette will descend to one to five predetermined depths (50m-500m) for sampling. For example, if the vessel depth reads 400m, water samples will occur at 50m, 150m, 200m, and 300m (more information in Table 1 below). A water sample is also taken just below the ocean surface using a through hull fitting, which allows seawater to be collected via a hole in the hull that feeds directly to the Chem Lab.

Table 1. Sample depths for eDNA. Two independent samples should be taken at each depth. The total ocean depth of location for the CTD cast determines the depths at which water samples will be collected. The rows of the table are labeled Sampling Depth (m) and the columns are labeled Topography depth of CTD cast. — Table 1 in Protocol manual, written by Chem Lab member and eDNA scientist Abi Wells.

While the rosette descends, data is recorded from multiple sensors and are later used by scientists to compare with Acoustic and Wet Lab data and compile and categorize new information from the survey. Pressure, depth, temperature, conductivity, salinity, oxygen, fluorescence, and turbidity were all being recorded during this leg of the survey mission.

photo of a computer screen displaying data. two graphs depict depth (m) on the y-axis and salinity or dissolved oxygen on the x-axes. — Program displaying data collected from the CTD rosette in real time.

Environmental DNA: eDNA

During the day, Hake stay in deeper waters, averaging around 200-350m, but at night the nocturnal feeders start their daily migration through the water column to shallower depths. They feed primarily on zooplankton, shrimp, myctophids (Lanternfish), and even young Hake at this depth. As Hake move throughout the water column, they leave behind DNA in the water that can be collected later as sort of a signature of their presence in that location. The collection, filtering, and preservation of sampled water in the ocean environment is categorized as collecting eDNA. This environmental DNA can be in the form of gametes (reproductive cells), fish scales, feces, etc.

Collecting water samples at different depths in the same vertical column can show what marine life was present at that location, and what depth they were at. I relate it to reviewing school security cameras or talking to other teachers at the end of the school day, to determine where a student was at a certain time and why.

Chem Lab member and eDNA scientist Abi Wells collecting a 2.5L water sample from a Niskin bottle after a successful CTD deployment.

When the rosette is back on deck, scientists use gloves and new collection bags called Whirlpacks, to collect approximately 2.5L of water from each 10L Niskin bottle. This process is conducted with a great emphasis on sterility, including wiping the bottle spigot with DNAway to remove any contaminants, using new materials, and not allowing fingers or the spigot to touch the collection bag.

White paper is taped down on a bench in the wet lab. On it are rows of water filtering cups mounted on gray horizontal pipes attached to hoses. Each filter cup is topped with a paper filter. Two have funnels attached; additional funnels, still sealed, line the workbench behind the filtering cups. — Sterile work site being set up to pour water samples into the cups and strain through the filters.

blue gloved hands pour water from a clear plastic bag into a funnel attached to a filtering cup. nearby, three plastic pitchers serve as holders for open plastic bags will filled with water. — Sterile work site being set up to pour water samples into the cups and strain through the filters.

Once the collection bags are filled and brought to the Chem Lab, filtration occurs using 1.0 micron filters. Although this size of filter, compared to smaller filters, allows some cells to pass through and not be collected, it is faster and results in less breakage of cells and loss of DNA. After 2.5L of the water sample is poured through individual filters for each depth sample, they are placed in pre-labeled (location and depth information) tubes with 2mL of preservative buffer. The tubes are stored at room temperature and away from UV light until NOAA Ship Bell M. Shimada is back in port and the samples can be further researched in on-land laboratories. Results from additional studies help to compile lists of marine life that was present in the water column and can be compared to acoustic data and species caught and logged in the Wet Lab.

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Personal Log

So, there you have it. Three Labs onboard that conduct very different research, but fit together in the puzzle of Hake development, migration, diet, niches, ecosystem, biomass, and supporting sustainable commercial fisheries. Each additional piece of data; whether it be echo sounds, physical samples, eDNA, or CTD information, strengthens the others and helps to create a cohesive summary of the data.

This was a lot to learn in the first few days, but as I’ve said before, all of the crew has been welcoming, supportive, and educational. Having a strong team that works together is priceless, and thoroughly noticed and appreciated.

A few days into the mission my Mom asked me what the best part of my day was. I had three answers and haven’t had a day yet with only one answer. I replied that it was the great salmon dinner, clean clothes, and seeing Risso’s Dolphins for the first time.

Video taken by me of Risso’s Dolphins surfacing for air. (Plays on loop)

We are now a little more than halfway through the mission and it has truly flown by. We’ve shared riddles and daily Final Jeopardy questions. We’ve laughed over daily experiences and the faces Hake fish make. We’ve played music and watched baseball during dinner. We enjoy watching marine life and breathe in the salt air while strengthening our sea legs. Sometimes we just drink coffee and snack and enjoy this opportunity with each other, and that makes every part of the day the best part.

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Did You Know?

Although Hake are occasionally cannibalistic, they are not at the top of their food chain. Humboldt Squid (Remember those 15 foot long tentacles in my Wet Lab post?), Dogfish Sharks, and marine mammals are all predators, as well as commercial fishing.
Today well over 100 Spiny Dogfish Sharks were inadvertently caught in the trawl, in the same location as the baskets of Hake we sampled from.
Maybe there were baby Hake fish in the sharks’ stomachs… we didn’t attempt to find out.

a white plastic basket of small sharks — Basket one of Spiny Dogfish

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New Terms/Phrases

Although I had learned the terms a few days earlier, I got to help Wet Lab Lead Ethan Beyer collect otolith and stomach samples for the first time from a sub-sample of Hake the other day.

I watched and learned, then helped scan barcodes of otolith sample bottles, add 95% ethanol that is diluted 50/50 with water, and delicately pick up the ear bones with tweezers and place them in the bottle.

Additionally, each Hake in the sub-sample has its weight recorded, along with length, sex, and developmental stage. From that sub-sample, five stomachs are removed for later analysis, and five have their stomachs opened and their diet is recorded. We often find Lanternfish (Myctophids), Krill (Euphausiidae) and small Hake.