“Inside every good scientist is a curious kid. ” —Ms. Frizzle
Ms. Frizzle takes her class to the Ocean. Illustration by Bruce Degan via Scholastic Inc.
Personal Log
I am home. The floors have stopped swaying, my seabag is unpacked and the fish scales are washed from my boots. I have had time to rest and reflect. Looking over my endless photographs of indescribable landscapes, fascinating animal life and the hardworking but always enthusiastic crew, it would be easy to be wistful, sad that the journey all went by in the blink of an eye. But the thing is, it’s not over. The journey was never just about me, I was assigned this adventure to be the eyes and ears of my students.
I love the Magic School Bus series. For some, it’s unclear whether Ms. Fizzle’s class actually goes to all those incredible places or if their trips have only been imagined. But I know Ms. Frizzle’s secret, she is an extraordinary teacher. Her lessons are so engaging, so powerful, that her class feels transported to those unbelievable locations making lessons real, relatable and meaningful. And that is NOAA’s charge for their Teachers At Sea.
The NOAA Teacher at Sea program provides the adventures, we the teachers, go home to take our students back to these magical places and exciting experiences. It’s no small task, but one I take on with great seriousness and excitement. I want my students to feel the wind and fog blowing in across Dutch Harbor. I want them to puzzle over colorful echograms searching for fish. I want them to measure, weigh and record pollock and jellyfish splashed across the culling board. I want them to envision themselves as NOAA officers, or engineers, or scientists. But most of all, I want them to care deeply about the health and well-being of the world’s oceans. So I am frantically writing lessons, building hands-on activities and creating project based STEM challenges in hope that my students will feel like they too have been to the Bering Sea on the Summer Pollock Acoustic Survey. May the Frizzle be with us.
Looking back from the fly-bridge on the Bering Sea.
Mission: Summer Pollock Acoustic-Trawl Survey, Leg 3
Geographic Area of Cruise: Bering Sea, Alaska
Date: July 30, 2026
Weather Data from Bering Sea
Latitude: 58° 38.303’ N
Longitude: 176° 17.674’ W
Winds: SW at 9 mph
Air Temperature: 46.94° F (8.3° C)
“It is that range of biodiversity that we must care for – the whole thing – rather than just one or two stars.” – David Attenborough
Science and Technology Log
NOAA scientists conducting the Acoustic-Trawl survey are skilled at finding pollock, but even, so tiny amounts of other species also sometimes slip into the net. These unexpected creatures are called “bycatch.” Although not targeted, it doesn’t mean that these species are not important. A healthy pollock population depends on a complete and healthy ecosystem, so the science team also measures and takes data on these creatures before releasing most of them back to the water. Sometimes, the science team also gathers information about these species for other scientists on land conducting special projects for other programs. Here are some of the interesting fish that came in with trawls aboard Oscar Dyson on Leg 3.
Jellyfish
Outside of pollock, jellyfish have been the most frequent visitor to the trawl. Existing before dinosaurs, jellyfish trace their origin back over 500 million years, their closest relatives being corals and anemones. They are invertebrates (meaning they do not have a backbone) in the phylum Cnidaria, subphylum Medusozoa. Jellyfish are found around the planet in the world’s oceans and even in some fresh water ponds/lakes. Not a fish at all, jellies contain no brain, bones, gills or hearts. They are considered a keystone organism, one that holds the ecosystem together because it interacts with so many other species within the food web. Jellyfish’s main diet consists of tiny animals and plankton. They serve as food for sea turtles, fish, crabs, birds and even humans. Even though they can often sting, small animals will swim among jellies to hide from predators. So far we have seen 3 species of jellyfish in the trawls in the Bering Sea:
Chrysaora: The most common jellyfish found in the trawls this trip are by far Chrysaora. These stunning animals get their name from mythology. Chrysaor was the warrior child of Poseidon the sea god and Medusa, and his name means “adorned in gold” or “golden warrior.” It’s the perfect name for this golden beauty. Chrysaora are in the family commonly referred to as sea nettles. They can grow to reach up to 2’- 3’ in diameter. Chrysaora is typically found at depths up to 100 meters in the Bering and Arctic Seas. Since the 1990’s the total biomass of this species has been increasing. Biomass is the total amount of mass of an animal population in a specific area.
Chrysaora Jellyfish
Aequorea: Less showy and bright than Chrysaora, Aequorea jellies are predominantly clear with a flat smooth disk-shaped bell. Its name is taken from the Latin words aequor “from the sea” and aequus “even, flat or level.” Their family is commonly known as crystal jellies. This family of jellyfish fascinates scientists because they contain photoproteins that allow them to fluoresce with bioluminescence. Bioluminescence is the ability for animals to create their own light. Animals such as backyard lightning bugs and deep-sea fish are also capable of this unique adaptation.
Aequorea Jellyfish
Aurelia Jellyfish
Aurelia: Aurelia or moon jellyfish are one of the most widely distributed family of jellies. A. limbata, or brown moon jellies are native to the Bering Sea and coastal Alaska. They range in size from about 9 to 12 inches in diameter. They have a clear cup-shaped bell with brown to orange organs arranged in a circle around the center.
Fish
Pacific Cod: A relative of the Alaskan pollock, Pacific cod are also a cold water whitefish. Also similar to pollock, many people like to cook and eat cod, so this fish ended up as our guest in the mess later that night for dinner.
A Pacific cod in sample basket; later, plated for dinner in the mess hall
Northern Rock Sole: As a bottom dweller, the northern rock sole has both eyes on a single side of its head. His topside is a splotchy brown color, while his underside is a translucent white.
Northern Rock Sole
Chum Salmon: Though this one is not so big. Chum salmon are the second largest pacific salmon after chinook. Males of this species develop large canine-like fangs
Chum Salmon
Smooth Lumpsucker: A deep-sea fish, the smooth lumpsucker has a slippery, scaleless skin. Look closely to see the circle on its underside. The pelvic fins in this species are modified to form a disk used to help secure the fish to ocean surfaces in fast moving waters.
Smooth lumpsucker
Try It on Dry Land
Although you may not be able to hitch a ride out to the Bering Sea for the pollock acoustic survey, you can create your own trawling simulation with a box of Trix cereal and a few kitchen materials.
Trix Trawl
Materials:
1 box Trix Cereal
1 cookie sheet or shallow baking pan
A ruler
Tape
1 Tbs measuring spoon or scoop
Data chart (downloadable pdf)
* Optional small kitchen scale
Instructions
Use ruler to measure and mark with tape both long sides of the cookie sheet in 2” segments. These are your transects lines that you will sample from.
Drag the tablespoon from the mark on one side to the corresponding mark on the opposite side. This is your trawl net. You may not touch the cereal with anything but the spoon.
Sort the cereal into groups of the same shape/color type and record on data sheet.
Repeat until all steps until transects are complete.
Did you get the same number for each shape/color?
Do you feel like it was an accurate representation for all the cereal in the box?
Did you find anything unexpected in the cereal box?
NOAA scientists also gather the weight for each species group. If you have a small kitchen scale you can weigh each shape/color group and record. Is the set with the most individual pieces also the heaviest?
“The charm of fishing is that it is the pursuit of what is elusive but attainable, a perpetual series of occasions for hope.” – John Buchan
Science and Technology Log
As the saying goes “there are lots of other fish in the sea,” so how exactly does NOAA Ship Oscar Dyson find mostly Alaskan pollock in such a huge ocean? It’s a combination of structured transect planning, analyzing complex acoustic data and a little bit of luck.
Transects: At first glance the map of the 3 legs of the Alaskan Pollock Survey look like a crazy zig-zag path, so what’s going on and where are we going? The Oscar Dyson is traveling on a transect. A transect is a line drawn by scientists across an area used to measure, count and record the species living there. Oscar Dyson scientists are tasked with figuring out how many pollock are living in the Bering Sea, what age they are and their reproductive stage. As Oscar Dyson travels along each transect, the scientists decide where good places are to sample the pollock population using a long trawl net. It’s difficult to look into the ocean (though we will talk about cameras later) so NOAA scientists actually “listen” for the fish as they swim under the boat.
The sounding board on the bottom of Oscar Dyson sends and receives frequency information. (NOAA Fisheries)
EchoSound: Many people are familiar with the way animals such as bats and dolphins emit sounds and use echoes to gather information about their surrounding environment. The scientists on the Oscar Dyson also use sound and echoes to gather information about their environment in the Bering Sea. The boat has a sounding board underneath called a transducer that emits energy pulses at different frequencies and receives the echoes as they are bounced back. Objects with different densities send back different amounts of echo energy. Scientists in the Acoustic Lab onboard Oscar Dyson watch a screen for echo patterns that match the patterns that are expected from individuals and schools of pollock.
An echogram is a visualization of an echosound
Check out this image of an echogram. Echograms are a visualization of detected echo sounds. The bright red lines at the top and the bottom of the screen represent the surface and the dense ocean floor. The top wave of blues and greens is referred to as the “munge” ; it is a mixture of stirred up air bubbles, algae, plankton and other things that the team has determined is not pollock. Pollock are primarily in the area just above the bottom to about the middle of the water column. Boney fish such as pollock have a specialized organ called a swim bladder which allows them to take in and release gas, thus changing their density and allowing them to rise and fall in depth like a submarine. Not only is this organ useful to the fish, the air it contains has a different density from the surrounding water and reflects the echo energy that is emitted and picked back up by the ship’s transducer. Look carefully and you can see little colored dots and patches just above the ocean bottom depicted on the echogram. Those are fish and schools of fish. The scientists are confident that they are pollock but to be sure they need to collect a sample of the fish in those areas and get measurements from them.
Trawl: Once a spot has been identified by the scientists, a call goes out to the crew, “Fishing, Fishing, Fishing”. This alerts all aboard that the vessel is going to break from the transect and drop the nets into the spots that had lit up with fish patterns on the echogram. The net is rolled out from a giant spool controlled by the deck crew rather than the scientists. The tip of the net is called the codend, from the old English word “cod” meaning a bag or pouch and this is where the fish are collected. At the opposite end of the net is the opening where fish enter. The weave, or meshes, of the net gets progressively tighter the closer it is to the codend.
“Turtle” being attached to the kiteFS70 Echoscan
Attached to the net are several pieces of equipment that allow the scientist to analyze what is going into the net and when, during the trawl. The FS70, or netsounder, is a bright yellow device that also uses echoes to gather information. This piece is also sometimes called the “turtle.” You can see the crew here connecting it to a special part of the net called the kite. The kite and netsounder are attached and fly just above the opening of the net allowing the scientist to monitor what is going in.
Next to the picture of the crew you can see the image of what is being recorded by the netsounder on an information panel. This image of the “turtle” shows whether it is flying correctly, or oriented in the correct direction. The 2/3 circle image is a visualization of the echos the netsounder is receiving. The rainbow of color on the very bottom of this circle is the echo bouncing back from the bottom of the ocean, above that is another rainbow that represents the bottom of the net, above that if you look closely there are small blue marks just forming an oval with the rainbowed net bottom, those are the top of the net. When fish go into the net, they are represented as small dots, or blobs if a whole school is captured within this oval. The screen showing the echogram from below the ship and the screen with the netscan are placed next to each other on the control panel so that scientists can see the fish coming and hopefully adjust the nets accordingly to catch them.
The control panel on the Bridge.
Scientists only want a sample of the fish, so they monitor the netsounder until they feel they have enough fish to accurately represent what they are seeing and then call “Haul Back.” This call tells the crew to raise the net back onto the boat, and the science crew to put on their wetlab gear in preparation for fish processing.
Try It on Dry Land
Swim bladders allow fish to change the density and buoyancy of their bodies, allowing them to change their position in the water column. Buoyancy is an upward force of an object causing it to float or sink. You can make a simple model of a fish’s swim bladder (and a fun catch game) using items found around your house.
You need:
Paperclips
1 pen cap (Bic pen or other with the stick part)
1 soda bottle with cap
Clay
Instructions:
Source: sciencebob.com
Fill bottle to top with water
Secure clay around stick of pen cap (do not cover opening)
Bend paperclip to form hook
Attach paperclip into clay with hook pointing down
Drop cap/hook into soda bottle so that it floats
Twist another paperclip into an L shape and drop to bottom
Put cap tightly on bottle
To Activate:
Squeeze the bottle and watch the pen cap drop
Release your grip and pen can will rise
Practice controlling where in the water column you can direct the cap
Can you dive the cap to the bottom and hook on to the L shaped paperclip?
What in the Science is going on… The cap holds a bubble of air underneath which allows it to float. When you squeeze the bottle the pressure makes the bubble smaller and changes the density of the cap causing it to sink. A fish’s swim bladder works by the same principles. Find out more here: www.instructables.com/Cartesian-Divers/
Personal Log
Sun Path Diagram
Life on Oscar Dyson is different in many ways then life on land. For one, the scientists work in shifts. There is a 4 am to 4 pm shift considered the dayshift and another from 4 pm to 4 am considered the nightshift. Acoustic monitoring and fishing happen all day and all night. I am on the day shift. Adding to the change in daily rhythms is the extended amount of daylight during the Alaskan summer season. The sun is up and bright when I hit my bunk to sleep. The sun will not set until approximately 12:30am, some nights I have gotten up in the night to watch the sunset out my window. I report to the Acoustic Lab at 4 am in the dark to find out what the night shift has been working on, the sun will then rise again at around 7 am. It takes some getting used to as the sun is a natural trigger for my body to know when to be active and when to rest. It makes for a long day, but who can complain with such a stunning beginning.
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 15, 2024
Weather Data from the Bridge:
Latitude: 59° 51.9 N
Longitude: 173° 53.5 W
Wind Speed: 11 knots
Air Temperature: 6.1° Celsius (42.9° Fahrenheit)
Science and Technology Log:
On my cruise, scientists take acoustic measurements along the length of each transect. To ensure that they are accurately estimating the abundance of pollock, they take steps to separate out any backscatter that they believe didn’t come from pollock.
Scientists then apply algorithms to the data in order to estimate pollock abundance over the entire survey area. First, they break up the transect into 0.5 nautical mile (NM) sections and record the average backscatter for that section. Specifically, scientists are interested in the areal density – the amount of backscatter per square nautical mile (NM2).
This data can be challenging to interpret, so one way the scientists represent it visually is with a stick plot over the survey area:
Acoustic backscatter from the 2022 pollock survey.
In this graphic, the transect lines are shown in black, and the density of acoustic backscatter for each 0.5 NM section is represented with a yellow stick. The longer the stick, the greater the density of backscatter at that location.
Scientists then use this data to perform calculations on the entire survey area, including the space in between transects. For each 0.5 NM section of transect, the acoustic density is extrapolated halfway to the next transect on either side.
In this diagram, the red line represents a 0.5 NM section of transect for which acoustic density is calculated. This acoustic density is then applied to the entire pink rectangle, which extends halfway to the next to the transect on either side.
By doing this process for every 0.5 NM section of transect studied, scientists are able to calculate values of acoustic density for the entire survey area.
Map of current survey area and transect lines (black), with boxes (purple) indicating the area over which data from each transect is extrapolated.
Getting from acoustic density to pollock abundance takes another set of calculations, this time making use of trawl data. The pollock caught in each trawl can vary drastically in terms of size – some trawls are mostly juveniles, some trawls are mostly adults, and some are an even mix of both. For a given location, scientists use data from the nearest geographic trawl to estimate the distribution of fish in that area.
In some trawls, the most fish were within 20-30 cm in length (above) while in others, most fish were over 40 cm in length (below).
Having trawl data is necessary to convert the acoustic data into fish abundance because small and large pollock do not reflect backscatter equally. Scientists have studied this, and they have created a relationship for the different backscatter reflected by different length pollock. Using the distribution of pollock in the nearest trawl, scientists are able to proportionally allocate the observed backscatter to pollock of different lengths.
As pollock length increases, backscatter also increases. (Equation from Lauffenburger et al., 2023. Mining previous acoustic surveys to improve walleye pollock (Gadus chalcogrammus) target strength estimates, ICES Journal of Marine Science, Volume 80, Issue 6, August 2023, Pages 1683–1696, https://doi.org/10.1093/icesjms/fsad094)
As an example, let’s simplify the two locations sampled in the graphs above. Suppose the first location had only 20 cm pollock, the second had only 40 cm pollock, and equal backscatter was observed at both sites. Scientists know that, all else being equal, 20 cm pollock produce less backscatter than 40 cm pollock. This means that in order to reflect the same backscatter, there must be a greater number of 20 cm pollock than 40 cm pollock.
By repeating a similar process for each geographic location, scientists are able to estimate the number of pollock in the entire survey area!
Personal Log
The sailing and many of the operations of NOAA Ship Oscar Dyson are done by NOAA Corps officers. I hadn’t heard of the NOAA Corps before sailing, but I’ve since learned that they play an important role in facilitating NOAA research.
To learn more about the experience of NOAA Corps officers, I interviewed Ensign Savi Morales.
Ensign Savi Morales (left) on the bridge collaborating with John Swenson, a member of the deck crew.
Why did you decide to become a NOAA Corps officer?
I’ve always wanted to support the protection of the environment and mitigating climate change. After college, I was trying to figure out where I would contribute the most. I really loved being out on the water, and I had sailed plenty but I wanted to find a way to combine my interests in an environment I contribute the most. The NOAA Corps felt like it was a combination of those things.
I also loved the idea of working with the crew, engineering department, and science. I really enjoy that mixture of groups we have aboard Dyson, which makes every trip’s dynamic different. There’s also a lot of hands-on experience on the bridge deck making our 12 days packed with projects I work on. The NOAA Corps embraces a diverse skill set in order to think and act like a Swiss army knife and be a jack of all trades.
What are your responsibilities on board the ship?
My responsibilities are two 4-hour bridge watches as a Junior Officer of the Deck as I work towards becoming a fully qualified Officer of the Deck. In between my watches I work on tasks related to my responsibilities as the Dyson’s damage control officer, assistant navigation officer, and assistant public affairs officer. I track the sea service hours for our augmenting and personal crew, which they can use to upgrade their license. I maintain flags, and I do monthly safety rounds, inspecting fire extinguishers and fire stations.
What do you enjoy the most about your work?
I enjoy meeting the characters that come to the Dyson, definitely an eclectic but fun group. I also enjoy how much they’ve thrown me into the mix and had me figure things out. It’s a little bit of a trial by fire, but I learn really quick and I’d rather learn by doing.
What part of your job with NOAA did you least expect to be doing?
Checking fire extinguishers, there’s about 100 on board and they all need to be checked monthly. It takes about 3-4 hours.
Here in the Bering Sea you hear about the big, massive waves, but it’s not always like that. The Aleutian Islands are gorgeous with lots of wildlife. I don’t think I’ve seen this many bald eagles, orcas, or puffins in my entire life. They always brighten my day.
What advice do you have for a young person interested in a career in the NOAA Corps?
NOAA Corps requires you to have a four-year college degree in order to apply. Other than that, I’d say find opportunities to go out on the water. There’s high school scholarships, there’s college scholarships. You can also volunteer if you have time. I volunteered at the UC Davis Bodega marine lab. I visited once a week just to hang out with the scientists, with the crew to see if this is what I liked. Be curious and experience things for yourself!
Did you know?
NOAA Corps is one of the country’s eight uniformed services, and its officers operate NOAA ships and aircraft around the country. After completing basic training at the US Coast Guard Academy, NOAA officers assist in fisheries research, seafloor mapping, monitoring atmospheric conditions, and may respond to natural disasters and extreme weather. Learn more at the NOAA Corps website here!
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!
