Hello and welcome! My name is Guy (Clark) Sturdevant from Northwest High School in Wichita, KS. You join me as I make final preparations for my two-day journey to Dutch Harbor, Alaska. Once there, I will board the Oscar Dyson and join an amazing science team and crew for a month-long leg of the biennial Eastern Bering Sea Pollock Survey.
As I prepare for this incredible opportunity, I find myself reflecting on the amazing science educators and communicators that helped define my relationship with science. From Mr. Patton’s sixth grade life science class through graduate studies in the department of Geology at the University of Kansas, the passion, character, and enthusiasm of my mentors and teachers was infectious. In my seven years in the classroom, I have worked to immerse my students in the hands-on practice of science. NOAA’s Teacher at Sea Program will be another amazing opportunity for me to learn from world-class scientists and technicians in hopes of bringing the exciting world of marine science into my high school classroom.
Check in here for regular updates from the Bering Sea!
Science and Technology Log
Next Monday, I will board NOAA Ship Oscar Dyson in Dutch Harbor, Alaska. The Oscar Dyson is a 208 ft. purpose-built research vessel which hosts the Midwater Assessment & Conservation Engineering (MACE) team for the Summer Pollock Survey. The full survey spans nearly three months and hundreds of nautical miles of the Bering Sea and the Gulf of Alaska.
NOAA Ship Oscar Dyson. Photo credit: Ensign Haley Glos (Photo from @NOAAShipOscarDyson Facebook account)
Did You Know?
The Oscar Dyson is named in honor of a fisherman and sustainable fisheries advocate, Oscar Dyson.
A photo of Oscar can be found hanging in the galley aboard his namesake.
Oscar’s fame, however, is eclipsed by his wife, Peggy. Peggy Dyson acted as the “Voice of the North Pacific”, broadcasting out marine weather forecasts as WBH-29 twice daily for over 30 years. Her voice served fishing communities in the North Pacific, providing valuable information and a familiar voice across the vast span of the open ocean.
Peggy Dyson christening NOAA Ship Oscar Dyson. Photo credit: Ray Broussard.
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 19, 2024
Weather Data from the Bridge:
Latitude: 53° 44.5 N
Longitude: 166° 54.0 W
Wind Speed: 15 knots
Air Temperature: 10.9° Celsius (51.62° Fahrenheit)
Science and Technology Log:
As my cruise begins to wrap up, I wanted to highlight some of the people I’ve been working closest with – the scientists on the night shift. Work on the ship continues 24 hours a day, seven days a week, and the night shift works from 4 pm – 4 am. The night shift has the same responsibilities as the day shift of monitoring acoustic data and processing trawls, tasks completed by scientists Sarah Stienessen, Matthew Phillips, and Robert Levine. To learn more about the scientists and their careers, I interviewed each of them:
Why did you decide to become a marine scientist?
Sarah: The short answer is in kindergarten, I checked out a book on dolphins and fell in love with the ocean!
Matthew: I grew up near the ocean, and as a kid, I always loved exploring and finding new fish. I knew I didn’t want to spend every day in an office, and so marine science seemed like a great way to pursue my passion and explore new places.
Robert: I actually wasn’t planning to. I was majoring in geology and environmental science, and I did a field semester in Hawaii. We did a three week class in conservation ecology using passive acoustics, and I thought it was the coolest thing. I did a marine mammal internship with acoustics, and after college, I worked in a zooplankton lab – the rest is history.
Sarah Stienessen on marine mammal watch.
What are your responsibilities during the cruise?
Sarah: My responsibilities are to monitor and analyze the acoustic data and decide when and where to collect a biological sample (trawl) – that’s the daily stuff. I work on combining the acoustic data with the biological sample data to produce abundance and distribution estimates. I also coordinate pre- and post-cruise logistics.
Matthew: I’m the fish lab lead, so I’m responsible for supervising all of the trawl processing.
Robert: I’m here as an assistant to the fish lab lead and to explore new data types that we could use to enhance our data collection.
Robert Levine unloading the trawl catch onto the sorting table.
What do you enjoy the most about your work?
Sarah: On the boat, it’s teamwork and camaraderie with colleagues. On land, it’s the strategizing and planning around the logistics of fieldwork, both small scale and large scale.
Matthew: Seeing a species that’s new to me! I love seeing new fish, birds, and marine mammals.
Robert: I enjoy the balance between office work, getting to do fieldwork, and working on instrumentation. This group does a lot of research, but it’s all applied, which is the best part.
What part of your career did you least expect?
Sarah: Acoustics, fish, and Alaska!
Matthew: I never expected to be spending so much time in Alaska.
Robert: I never would have thought I would be on a boat actually doing the fishing.
Matthew Phillips troubleshooting PelagiCam
What advice do you have for a young person interested in a career in marine science?
Sarah: Take lab-based course work that’s marine related and hands-on. Also, volunteer, intern, try to get a glimpse of the real life experience of what marine science is like. It’s good for giving you connections and for seeing if it’s something you really want to do.
Matthew: Be open-minded about different opportunities and unthought-of locations!
Robert: Find the thing that you like to do or are really good at. If you like chemistry or computer science, get a degree in that. Then apply it to marine science – you don’t have to have a biology degree and you can actually be more effective with an outside perspective.
Personal Log:
When I first boarded NOAA Ship Oscar Dyson I was hoping to be assigned the day shift (4 am – 4 pm). However, after I adjusted to the different sleep schedule, I found myself enjoying the nighttime hours when the ship was quieter. There is still a lot of fish processing to do during the night shift – this cruise, the ship has actually processed more trawls during our shift!
While nights are often busy in the fish lab, we’ll also have some downtime between trawls. During a few of these breaks, we played cribbage, a card game that scientist Robert Levine taught me early in the cruise. We’ll also frequent the galley for midnight meals together and to finish off the last of the dessert that our awesome stewards – Danielle and Missy – prepared that day (some highlights include butter mochi, lemon meringue pie, and a zucchini chocolate cake)!
Cribbage Game
On a couple nights, we’ve tracked our candy consumption, competing with the day shift to see who eats more. Being a science team, we felt compelled to convert between different units, expressing our final answer in terms of portion of the bag, mass, and individual sour patch kids!
Did you know?
Because pollock behavior changes at night, the scientists on this particular cruise don’t trawl between sunset and sunrise.
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.
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!
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.
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!
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)
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!
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” 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 (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!
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 6, 2024
Weather Data from the Bridge:
Latitude: 61° 15.0 N
Longitude: 174° 56.8 W
Wind Speed: 13 knots
Air Temperature: 5.3° Celsius (41.5° F)
Science and Technology Log:
On NOAA Ship Oscar Dyson, the science party’s mission is to understand the population of walleye pollock in the Eastern Bering Sea. To collect data, scientists rely on two main tools: acoustics and targeted trawling. Before any trawling can happen, scientists must first locate fish using acoustics, so I’ll be focusing on acoustics in this blog post – stay tuned for a post on trawling next time!
Scientists use two kinds of acoustics: active and passive. Many of my students are familiar with how bats use echolocation to navigate in the dark – active acoustics relies on the same principle. First, the echosounder on the ship emits a pulse of sound, or ping. This sound travels through the water and bounces off of objects that have different densities than water (such as fish, krill, or the ocean floor). The echosounder then “listens” for and records these echoes, also known as backscatter. Passive acoustics work similarly, except the echo sounder only listens for sound and doesn’t emit any itself.
The echosounder emits a pulse of sound, which gets reflected by objects of different densities, like pollock.Image Credit: Wieczorek, Schadeberg, Reid (2021) “How do Scientists Use Sound to Count Fish in The Deep Sea?” Frontiers for Young Minds. https://kids.frontiersin.org/articles/10.3389/frym.2021.598169
The greater the distance between the echo sounder and the object reflecting the pulse, the greater the amount of time between when the signal was emitted and backscatter. Based on this time, echosounder can determine the depth of the object producing the backscatter. This information is represented visually in an echogram:
Screenshot of an echogram. The space between vertical grid lines represents 100 pings, and the space between horizontal grid lines represents 10 meters of depth.
The echogram shows depth on the y-axis and time on the x-axis. The intensity of backscatter is color-coded, where more intense backscatter is represented with red and brown, and less intense backscatter is represented with blue and green. The vertical grid lines represent all the backscatter from one ping, and the space between lines represent 100 pings.
On the cruise, pings are typically emitted at a rate of 1 Hz, or once every second. With every new ping, the echo sounder adds data to the right end of the echogram. This means that the horizontal grid lines represent the backscatter at one depth over time (or distance, if the ship is traveling at a constant speed).
At least one scientist monitors the backscatter throughout the duration of the transect. During the first day, the echogram was blank except for some lower-intensity backscatter near the surface and high-intensity reflection from the ocean floor. Because the mission of this cruise is to survey pollock, which tend to live at greater depths, we don’t pay much attention to the backscatter near the surface which is comprised of smaller organisms like krill. However, when scientists notice backscatter consistent with scattering from pollock, they may trawl to collect a sample for more detailed biological information.
Echograms from two different locations showing low-intensity backscatter (left) and high-intensity backscatter (right). When the backscatter looks as it does on the right, the science team may decide to fish in that area.
As we traveled along the first transect line, there was very little backscatter that the science team thought represented pollock. Our CTD (conductivity, temperature, depth) measurements also showed that the water temperature was cold, right around freezing. This may suggest that we were traveling through the Bering Sea cold pool, a mass of cold water that forms from melting ice. This water tends to be too cold for pollock and other fishes, however, other animals, such as snow crabs, can still survive the lower temperatures. Fish like cod prey on snow crab, so the cold pool offers these crab an important refuge from predators. Read more about the importance of the cold pool for crab here!
Historical bottom temperature showing cold pool in blue / purple (Image Credit: NOAA Fisheries)
Personal Log:
The start of the cruise has been busy learning new faces, maritime practices, and scientific terms. However, in the past few days, with the help of meclizine (seasickness medication), I’ve begun to feel more settled and like I have some sense of routine.
When I’m on shift, I bounce around between a few different places. The science team tends to be in the acoustics lab, where we monitor backscatter and make decisions on when to fish.
Acoustics lab, also called “the cave” for its lack of windows.
Once the scientists decide to fish, we first go up to the bridge, where NOAA officers control the direction and speed of the ship. The bridge has windows on all sides, so we’re able to make sure there are no marine mammals before putting the net in the water.
From the bridge, you can also see the trawl deck, where the deck crew works in collaboration with NOAA officers to put the net in the water. Once the fish are caught and hauled back to the ship, the science team processes the catch in the fish lab.
The bridge and its view of the trawl deck.
When we’re not working, we’ll grab food from the galley / mess deck. The stewards on the ship serve three meals a day, but since I’m on the night shift, I often heat up leftovers or take advantage of the wide selection of snacks they leave out. There’s also a lounge, two gyms, and places to do laundry while at sea!
The galley, where food is available 24 hours a day!
Did you know?
NOAA Ship Oscar Dyson has six onboard laboratories including a wet lab, dry lab, electronics lab, bio lab, acoustics lab, and hydrographics lab. Read more about the ship here!
Mission: Acoustic Trawl Survey (Leg 3 of 3) Geographic Area of Cruise: Pacific Ocean/ Gulf of Alaska Date: Friday, August 18, 2023
Weather Data Lat 58.18 N, Lon 148.82 W Sky condition: Partially Cloudy Wind Speed: 10.55 knots Wind Direction: 32.58° Air Temp: 14 °C
Science and Technology Blog
Meet Sandi Neidetcher, she is a fish biologist investigating fish reproductive status. Why care about fish reproduction? Well, the seafood industry is extremely important to Alaska and other coastal states. And they would not have an industry if those “little fishes” could not reproduce. But the ocean is changing due to climate and different types of pollution.
Climate change is making our oceans a warmer place—just a couple of degrees, but that may be enough to really change how fish reproduce and spawn. A few degrees in temperature could change when and where fish reproduce, and then cascade to the fishing industry, the food market, and the people who depend on them as food.
NOAA wants to have background information on fish reproduction so they can recognize whether the fish have changed their reproductive strategies over time and how that could impact fisheries.
Sandi received her Masters degree studying the ovaries of Pacific cod to determine the phenology and geography, or the timing and location, of spawning. She specialized in histology, which is the study of microscopic tissue structures, for her it was specifically the ovaries. To understand the reproductive process and ovary maturation, she studies slides with ovary tissue mounted and stained to show oocyte (unfertilized egg) structures that develop as the spawning season progresses.
Examples of histograms from Sandi’s research, showing the progression of Pacific cod oocyte structure development over the course of the spawning season
Now she is involved in a study looking at the reproductive states of Walleye Pollock. Pollock are multi-batch spawners. They have the ability to spawn (lay eggs) more than once in a season. So the female ovaries can be in different stages of reproduction throughout the season.
The first step in this analysis is to collect the ovaries from the pollock.
Sandi Neidetcher and Robert Levine work together to collect data on a pollock.
In the photo above, the fish will be measured for length and weight, then the ovary and the liver will be removed, weighed, and saved for analysis. The fish’s ear bones (otoliths) will also be removed and used to determine its age. Samples are sent back to Sandi at NOAA AFSC (Alaska Fisheries Science Center) in Seattle, Washington. Half of the ovary will be sent to a histology lab where technicians will prep the tissues and return the sides ready to be analyzed. The other half of the ovary is scanned on the ship.
Sandi is comparing the histological samples to Raman Spectroscopy Analysis that she does aboard the OscarDyson. A long time ago when I was an undergraduate student in chemistry, Raman spectrometers were very large. The one I worked with in my physical chemistry class was in the basement of a building on a special concrete slab that stopped any vibrations from disturbing the path of the laser. Did I mention that the whole setup took up almost half of the basement?
The computer displays a scan of the ovarian tissue
Raman spectrometers have come a long way since my undergrad. Today, Sandi has a small wand that contains a laser connected to a spectrometer the size of a donut box. A small desktop computer connected to the spectrometer will give an immediate readout of the analysis.
The wand with the laser is held over the ovary to collect data on large macromolecules like lipids, proteins, and DNA.
You can see the laser light as it penetrates the ovary.
The analysis that Sandi does is to compare the molecular composition identified through the spectral patterns with the structures seen in the histology samples, and to determine if the maturation status can be identified through the spectral patterns. The ultimate goal would be to have a small hand-held spectrometer that a scientist could use right as the ovaries are extracted. This would greatly increase the amount of ovaries analyzed quickly and efficiently and reduce the cost and time required for histological analysis
Sandi at her work station on the Oscar Dyson
Pollock have variability in their reproductive strategies and may be impacted by environmental conditions. One strategy is down regulation, where a fish will reabsorb a number of eggs during maturation and, as a result, reduce the resources spent on reproduction. This reduces the fecundity, or number of eggs released by that fish in a season. Knowing how fecund a fish population is helps managers determine how many fish can be removed by a fishery. Atresia is the resorption of an oocyte and can be seen histologically. Mass atresia is where a whole ovary of oocytes is be reabsorbed. If the fish is not finding enough food or the temperature is not correct then, then a female fish can save energy by reducing, or stopping the whole process of reproduction.
Recent warming sea temperatures have been seen in the Gulf of Alaska, and this may be impacting fish reproduction. In 2020, the number of Pacific cod predicted had dropped so low that the federal waters fishery was closed. That same year, crew fishing for Pacific cod reported seeing a number of Pacific cod with mass atresia. Scientists do not know if the observation of atresia, during a warming period, is related to the population crash but studies like this will give more information for the future. Predicting population crashes that may be related to climate change, fish health or temperature differences are an important part of fisheries management and impact us all because the ocean is an important resource.
Personal Blog
Crew Members in the Spotlight
Pictured left to right, Juliette Birkner – Engineering, and Ben Boswell – Survey Technician
The Commanding Officer runs the ship, but there are many important jobs that the OscarDyson would not function without. Engineering is one of them. There is a small team of Engineers aboard that are constantly monitoring the ship when on shift.
Juliette is a member of the OscarDyson’s Engineering department and may have been on the staff the longest. Her personality is direct, friendly and capable. Before becoming an Engineer, she attained her bachelor of science degree at the University of Washington. After receiving her degree she did not really have a clear plan for a job. So she went to a community college and received the equivalent associates degree of a Junior Unlicensed Engineer. Eventually, through NOAA, she can be a fully qualified Engineer with time aboard ships.
Juliette has a wildly creative side and interest in science. The scarf she is wearing in the picture has different layers present in sedimentary rock. She is also a big fan of dinosaurs, placing several all over the ship for people to find when work is slow. Honestly, it is the kind of humor that keeps everyone moving around with a smile. Some dinosaurs even have sweaters that she knitted, in her down time. Her knitting is extremely impressive.
Ben is the Survey Technician for the ship. Survey Technician is the kind of job you would never know exists as a high school student. There are jobs out there in this world that people would never specifically train for in high school or college , but are highly needed where you have different groups collaborating in complex situations. Ben’s job description is a pretty long list; calibrate scientific instruments, collect data, assist scientists, help the deck crew, and act as a liaison between science and the deck crew.
How did he arrive at this position? He attained a bachelor of science in Wildlife Biology and worked in the field for a while. Unfortunately, he found the job hard to make a living with the low pay. Fishing’s siren song came in the form of factory trawling and other crew positions in smaller boats. Because of his academic training and work experience the “perfect storm” of a Survey Technician was born.
Soon we will be taking our last trawl sample and heading to port in Kodiak. There have been moments on the cruise where time crawled in the dead of night while I was struggling to stay awake. Mostly, it has been a trip of a lifetime, with an incredibly capable and adaptive team of scientists and crew members willing to share stories that keep you awake and lull you to sleep, dreaming about tomorrow.
