Eastern Bering Sea – NOAA Teacher at Sea Blog

July 28, 2026July 28, 2026

Jo Slavitz: Getting There is Half the Fun, July 20, 2026

NOAA Teacher at Sea

Jo Slavitz

Aboard NOAA Ship Oscar Dyson

July 19th – August 10th

Mission: Summer Pollock Acoustic Survey, Leg 3

a travel coffee mug sits on the window sill of a ship's square window. out the window, we see a green mountain at some distance, perhaps across a harbor; the sky is cloudy and gray. — View of Dutch Harbor out the ship’s window

Geographic Area of Cruise: Bering Sea, Alaska

Date: July 20, 2026

Weather Data from Dutch Harbor, AK

Latitude: 53° 50.68′ N

Longitude: 166° 34.79’ W

Winds: NW at 7-10 mph

Air Temperature: 49.5° F (9.7° C)

“A ship in harbor is safe — but that is not what ships are built for.” — John A. Shedd

Personal Log

a view of waters off of Dutch Harbor; from a rocky shoreline, with a purple lupine prominently in the foreground, we look across gray waters to a line of green-covered mountains. two ships are visible transiting between the land masses. — Lupines in Dutch Harbor

A lot has to happen before the first pollock net is even cast. First the crew, including officers, engineers, deckhands and scientists must meet the NOAA Ship Oscar Dyson in Dutch Harbor, Alaska. If you are traveling from Dover, NH the trip is over 4,200 miles or about ⅙ circumference of the Earth. Dutch is a remote community nestled within an archipelago of volcanic islands which formed approximately 60 million years ago where the Pacific tectonic plate forces under the North American Plate. This meetup takes planning, time, and sometimes patience as the Aleutian Islands are often windy and foggy, making air travel from mainland Alaska unpredictable. Read more information about NOAA Ocean Exploration’s geological studies in Alaska’s Aleutian Islands.

a nautical chart of the Eastern Bering Sea, on which someone has drawn with different colored markers the planned north-south transect lines for Leg I (orange), Leg II (pink), and Leg III (green). Taped on top of the chart are two pieces of paper containing titles: "DY26-04" and "Summer Pollock" — Survey Transect Map

Once everyone is onboard, NOAA officers pilot Oscar Dyson out of Dutch Harbor and the Aleutian Islands into the Bering Sea. Check out this map of the Summer Acoustic Pollock Survey. The black line represents the path of the summer pollock survey which takes place over the course of 3 separate trips. I am traveling on the final survey of the summer, so it’s the farthest western side of the Bering Sea pollock survey that needs to be completed, the black line on the map not yet highlighted. It takes over a day to get out to this part of the ocean, but the crew and scientist have lots to do to get ready for the trawl during the trip.

Science and Technology Log

Running a science research center in a remote part of the ocean comes with “boatloads” of STEM challenges. Without the ability to order things online, go to a local home improvement store, or buy specialized parts off the shelf, the scientists and crew need to create their own solutions to the challenges that arise. Just like a STEM makerspace, NOAA Ship Oscar Dyson is well stocked with a tool workshop, 3D printer, and rolls and rolls of duct tape. Here are some of the amazing inventions from the super simple to the more complex that were designed onboard the ship.

pegboard holding tools - funnel-shaped plastic holders have been attached to the peg board to hold the tools in place — Pegboard holding tools

Pegboard Modifications: On the high sea, wave and wind motion can be powerful, traditional pegboard hooks are just not going to cut it. These bright-colored accessories were custom designed and 3D printed on board to secure tools in their place. The calipers proved a bit trickier due to their asymmetrical design.

Underwater Camera: This underwater camera was created because the science team needed more information about what is going on beneath the ocean’s surface. To keep it from crashing into the ocean floor and becoming damaged, it was designed with sensors that move the robotic cameras up and down as it detects obstacles.

underwater camera: at this angle, we mostly see a sideboard and buoys or rollers. — Underwater camera

view of a scanner with the top pulled open; on the bed of the scanner is a 3-D printed grid with squares of two different sizes — Krill scan insert

Krill Scan: Needing a way to get tiny organisms measured and recorded, NOAA scientists came up with this 3D printed gadget designed to fit on the ship’s scanner. Soon after a trawl is pulled in, a pocket net (a small net used to recapture small fish that escape the larger net) is emptied and krill samples are sorted into their own square within the grid. Images are scanned and recorded while the creatures are still fresh. Marking around the squares allow scientists to calculate krill size easily and the boxes keep specimens from clumping together.

a red plastic cell phone stand on a bench next to a microscope — Camera stand

Microscope Camera Stand:This tool was designed and 3D printed to hold a cell phone in place to capture images of objects under the microscope.

Ichthystick: When fish come aboard, data on their length needs to be quickly calculated. The motion of the moving boat, and the slipperiness of a squirming fish make using traditional tools such as rulers and tape measures cumbersome and impractical. Meet the Ichthystick. This nifty device was designed by a NOAA scientist on Oscar Dyson for just these situations. Simply put the fish on the measuring board, set the magnetic marker at the fork of the fish’s tail and it instantly gives the fish’s length on screen. It can also toss the data right into a data collecting program. Look up the prefix “Ichthy” and find out why I think the name “Ichthystick” is such a perfect name for a device designed for keeping tabs on native Alaskan Pollock who often end up in your freezer.

view of the electronic fish measuring board, with the name Ichthystick and a simplified image of a pollock printed in the bottom corner. a red magnet that ends in a point, which sports a matching pollock picture, rests on top. — Ichthystick and magnetic reader

Try It on Dry Land

STEM Scholars don’t just gripe about problems, they create solutions to these challenges. Think about things around you that don’t work quite right or annoy you as you try to complete your work. Design a device that helps you solve a reccuring challenge in your environment. Diagram your idea, or build a prototype to see if it works.

Here are some common middle school challenges or think up your own:

Your pencil frequently rolls of your desk
Your pet leaves muddy footprints across the floor
You can never find your sports gear when it’s time to leave
You can’t reach something you want on a top shelf
Your backpack is not keeping you organized

July 7, 2026July 16, 2026

Guy Sturdevant: The Cave part 2, July 6, 2026

NOAA Teacher at Sea

Guy Sturdevant

Aboard Oscar Dyson

June 21 – July 15, 2026

Mission: Summer Pollock Acoustic Survey, Leg 2

Geographic Area of Cruise: Bering Sea, Alaska

Date: July 6, 2026

Weather Data from the Bridge

N 59.52° W 172.60 °, 0 AMSL

Conditions: Overcast, Seas at < 1’

Visibility: >5 NM

Wind: 90°/ 5 kt

Barometric Pressure 1016.1 mBar

Dry Bulb Temp: 45.3 ° F

Science Log

In my last post, we left off our acoustics 101 with the emergence of the first modern echosounders in the 1990s. Today, we will look at the current system aboard Oscar Dyson and learn how the science team can use their knowledge of acoustics to estimate fish populations. First, let’s look at the physical components that make up the EK80 echosounder system.

the EK80 echosounder system, which looks like a stack of black computer housings with cables sticking out of them — *Each frequency requires its own transceiver. These six transceivers are the heart of the EK80 echosounder.*

Transceiver – a combination of a transmitter and a receiver; in other words, it both produces an electrical pulse to be sent to the transducer and converts the backscattered signal into usable data a computer can understand. You can think of the transceiver as the electronic brain that manages all of the signal inputs and outputs.

Transducer – Just like you might plug a microphone into your laptop to record audio, each transceiver needs a transducer to first convert the electrical pulse into an acoustic pulse that is transmitted into the water, and to measure the acoustic backscatter that returns. You can actually see the transducers in the photo of the centerboard below. The transceivers measure frequencies ranging from 18 kHz (those really annoying mosquito ringtones that only young people can hear are around 18 kHz) to 330 kHz.

close-up view of a center board - normally mounted beneath the ship, but currently hoisted up in the air attached to some sort of crane. an arrow points out red circles at the base of the centerboard, identifying these as transducers

The red circles on the bottom of the centerboard are the faces of the transducers. These sensitive instruments are mounted at the lowest point of the ship to isolate them from the vessel’s noisy hull. (Photo credit: NOAA)

The Echogram

Once the transceivers process the acoustic backscatter, the data is displayed on a screen for interpretation.

screenshot of acoustic backscatter readings, represented as a color-coded dots, across several panels. a superimposed text box identifies the depth as 109.5 m. — There’s quite a lot going on here! Let’s break it down into smaller pieces so we can learn to look at the data like a scientist.

the previous image of acoustic backscatter readings is repeated here, now with annotation. six vertical panels are identified with different frequencies: 18 kilohertz, 38 kilohertz, 70, 120, 200, 330. along the base of these panels, Guy has added a two arrow ranging from "bigger reflectors" to the left to "smaller reflectors" to the right. An illustration of a cod is at the "bigger reflectors" end of the scale, while krill and copepods appear toward the right side of the range. on the left side of the backscatter panels, there are now a few words along the y-axis, identifying the Surface of the water; the "Munge" (using the mock up album cover) just beneath the surface, Fish question mark in the middle of the water column, and seabed. — Each of the six frequencies appears as a vertical section that scrolls from right to left as the vessel moves. The top of each plot represents the ocean surface, and the thick red layer near the bottom shows the seafloor. The space in between lets us look at what is below the ship! Weak backscatter appears blue; stronger backscatter appears yellow and even red.

Our old friend munge is making an appearance in this echogram! It is the heavy backscatter layer just beneath the surface that is strongest at 18 kHz. Lower in the water column, we see that most backscatter occurs at higher frequencies, with only sparse backscatter in the lower-frequency plots. Backscatter that is observed only at higher frequencies indicates smaller organisms, such as krill or copepods. Backscatter that appears across all frequencies is likely generated by fish.

As you spend more time looking at this scrolling echogram, you can begin to recognize patterns and draw reasonable inferences. Below are some examples of the variety you can see in just a few hours in the cave.

a close up view of three panels (three frequencies) of an acoustic backscatter plot, or echogram. an arrow points to a thin vertical patch of red to identify it as "probable schools of juvenile pollock" — *Younger pollock can gather in schools 20-40 meters tall that appear as very thin red ellipses.*

close-up view of panels of an echogram showing acoustic backscatter readings. an arrow points to blue dots in the 18 kilohertz panel and identifies them as possible dispersed adult pollock. — You can clearly see occasional reflectors on the 18 & 38 kHz channels; these may well correspond to adult fish. The only way to be certain is to trawl in an area that looks like this and see what the net brings up!

example of an echogram (acoustic backscatter plot) with very little shading and few dots. it is labeled "Nobody is home." — *We know that large fish like pollock return a relatively even acoustic signal across every channel that we look at; there do not appear to be any significant pelagic fish present in this echogram.*

Now that we can read echograms, we are ready to call for our first trawl! Come back next time to see what we data we can scoop up in “The Anatomy of a Midwater Trawl”.

Personal Log

Things aboard Oscar Dyson have settled into a routine. We travel along acoustic transects during daylight hours, stopping 2-3 times a day to do a midwater trawl. Routine doesn’t mean boring, though! Maintaining a ship of this size and complexity is more than enough to keep everyone busy. The checklist for this leg included checking on the smaller craft that service and support Oscar Dyson on her mission. Conditions cleared on 06/29, and the Peggy D, the workboat that lives on the starboard hero deck, was given a thorough check and taken for a 30-minute voyage.

a small boat with a blue hull attached to the deck of NOAA Ship Oscar Dyson, in part by cables extending from davit arms. — *Peggy D secured to the aft hero deck of Oscar Dyson.*

a man and a woman in float coats and hard hats pose for a photo against the railing of the small boat as it churns away from NOAA Ship Oscar Dyson, visible on the horizon — *Peggy D secured to the aft hero deck of Oscar Dyson.*

Guy, wearing a life vest and neon green hard hat, takes a selfie on the small boat. we can see a woman in a float coat and hard hat sitting or crouching in the background, and a third person at the helm in the small boat's cabin. — *LCDR LeeAnn Keener and I enjoying the scenery.*

inside the small boat's cabin, Guy sits at the helm and another crewmember looks on. they both wear life vests and hard hats. — *LCDR LeeAnn Keener and I enjoying the scenery.*

first of three similar images: a person in a float coat and hard hat reaches a pole over the side of the small boat in motion

second of three similar images: a person in a float coat and hard hat reaches a pole over the side of the small boat in motion as a life preserver comes into view

Safety drills and practice are a part of the routine as well. ENGR Connor Rauch practices recovery during a man-overboard drill on Peggy D. In the case of an actual man overboard, the smaller vessels are used for recovery, as they can respond much more nimbly and are far safer in close quarters with a swimmer.

Wildlife

a very, very round fish, mouth agape, in a green plastic basket — *This smooth lumpsucker (Aptocyclus ventricosus) is just as surprised to see me as I am to see him.*

underside of the very, very round fish revealing its ventral suction disk — *This smooth lumpsucker (Aptocyclus ventricosus) is just as surprised to see me as I am to see him.*

August 21, 2018

Emily Cilli-Turner: Back on Land, August 13, 2018

NOAA Teacher at Sea

Emily Cilli-Turner

Aboard NOAA Ship Oscar Dyson

July 24 – August 11, 2018

Mission: Pollock Acoustic-Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date: August 13, 2018

Weather Data for Claremont, CA from National Weather Service:

Latitude: 34.1368º N

Longitude: 117.7076º W

Wind Speed: 12 mph

Wind Direction: SSW

Air Temperature: 29.4º Celsius

Humidity: 36%

Personal Log

Well, NOAA Ship Oscar Dyson docked in Dutch Harbor on August 11^th from the 19-day journey in the Eastern Bering Sea. During our time at sea, I learned so much and got to know both the NOAA scientists and the crew and officers on the ship. When I applied for the Teacher at Sea program, I knew that it would be an invaluable experience, but it far exceeded my expectations. I learned about the work of the NOAA scientists pretty much non-stop and any question I had was answered in detail, which allowed me to have a robust picture of the work the NOAA scientists do, the different types of scientific instruments they use and the underlying principles behind them as well as the day-to-day operations of a scientific vessel such as NOAA Ship Oscar Dyson. Additionally, I also ate the best food of my life made by the stewards; there was always amazing entrees and dessert at every meal!

After we came into port, I was able to explore the town of Dutch Harbor as well. Along with other NOAA Scientists and the ship’s medic, I explored the Museum of the Aleutians in town and learned about the native people of the island and their traditions as well as the military encampments that were built on Unalaska (the island where Dutch Harbor is) during WWII. The next day we went up Ballyhoo mountain and saw the ruins of one of the WWII bases. The view from there was amazing and we saw all around Unalaska. I was surprised in Dutch Harbor to see so many bald eagles everywhere! The next day I said goodbye to the many people I got to know aboard the Oscar Dyson, many of whom were staying aboard for the next leg or for a long time thereafter. I was surprised how easily I transitioned to life aboard the boat and it still feels a bit weird to not be moving all the time!

Unalaska Island from Ballyhoo

Coming in to Dutch Harbor

Dutch Harbor, Alaska

One of the many eagles in Dutch Harbor

The fish lab crew!

One of the WWII base ruins near Dutch Harbor

August 21, 2018

Emily Cilli-Turner: Journey’s Coming to an End, August 9, 2018

NOAA Teacher at Sea

Emily Cilli-Turner

Aboard NOAA Ship Oscar Dyson

July 24 – August 11, 2018

Mission: Pollock Acoustic-Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date: August 9, 2018

Weather Data from the Bridge:

Latitude: 60º28.02 N

Longitude: 175º25.19 W

Wind Speed: 8.77 knots

Wind Direction: 236.54º (SW)

Air Temperature: 8.8º Celsius

Barometric Pressure: 1010.7 mb

Sea Wave Height: 2-3 feet

Visibility: less than 1 nautical mile

Science Log

I had a chance to interview the chief scientist aboard NOAA Ship Oscar Dyson, Taina Honkalehto, and ask her about her career path to working at NOAA as well as recommendations she has for anyone interested in an ocean career.

Taina knew that she wanted to pursue a career in science ever since she was a child as she has always been interested in the outdoors and collecting and observing things. During college, she took an oceanography course as a junior and knew she wanted to work with the ocean. Her college advisor recommended that if she wanted to pursue science she needed to do a field program. As a junior, she was able to secure participation at a marine lab in the U.S. Virgin Islands, which inspired her choice to go to graduate school and study invertebrate zoology.

At NOAA, Taina really enjoys her colleagues and the field work, which includes the pollock counting work she is currently doing on NOAA Ship Oscar Dyson. She feels that her work at NOAA is an opportunity to contribute to the preservation of our planet. Additionally, she enjoys doing outreach at NOAA and talking to people about her work and answering questions about the ocean. Often, discussions with the public involve balancing what they have heard about fisheries and overfishing in the news versus the reality and experiences Taina has had in the field counting pollock in the Bering Sea and Gulf of Alaska.

The advice that Taina has for those wanting to work for NOAA is to get an internship. Students can find internship opportunities through the NOAA website and there are avenues into NOAA experience for students at the middle and high school level as well as college students. These internships are a great way to get hands-on experience (as I can attest!) and some of them are even paid if students apply for the Hollings scholarship. Taina also recommends reading some of the following books to get an idea about what it is like on a field placement: “The Log from the Sea of Cortez” by John Steinbeck, “Moby Duck” by Donovan Hohn, and “Cod” by Mark Kurlansky.

Chief Scientist aboard NOAA Ship Oscar Dyson, Taina Honkalehto

Personal Log

The wet lab aboard NOAA Ship Oscar Dyson is where most of the action happens during my shift. When a haul comes in, we are responsible for processing the catch and obtaining the needed measurements so that the MACE team can put together their report on the health of the pollock population. The catch is released from the trawling net onto a hydraulic table that can be dumped onto a conveyor belt. The first job to be done is to sort the catch, where all species that are not adult pollock are separated out.

Pollock on belt — Adult pollock from a haul on the sorting belt

The next task is to measure the length of a subsample of about 300 of the adult pollock in the catch. This helps the NOAA scientists to create histograms of pollock lengths to compare between hauls. Finally, about 30 pollock are separated to measure length, weight and to determine gender and maturity and another 30 have length and weight measured, otoliths taken, and ovaries weighed and collected if the pollock is a spawning female. During my shift, there are six of us in the fish lab and we are working like a well-oiled machine!

Length distributions from several hauls

Determining if a pollock is male or female

TAS Emily Cilli-Turner collecting otoliths from a pollock

Today we are starting the long transit back to Dutch Harbor. It is bittersweet since I feel like we have a nice routine down in the fish lab and I finally feel used to the motions of the ship. However, I am grateful for this opportunity and for all the great people that I have gotten to know during my time on NOAA Ship Oscar Dyson. Also, we finally saw some blue sky again and a rainbow even came out for a moment!

Did You Know?

The NOAA Ship Oscar Dyson was launched on October 17, 2003. It is named after Alaskan fisherman Oscar Dyson and there is a smaller boat on board named after his wife, Peggy Dyson.

August 9, 2018

Emily Cilli-Turner: Plenty of Fish in the (Bering) Sea, August 6, 2018

NOAA Teacher at Sea

Emily Cilli-Turner

Aboard NOAA Ship Oscar Dyson

July 24 – August 11, 2018

Mission: Pollock Acoustic-Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date: August 6, 2018

Weather Data from the Bridge:

Latitude: 58 04.81 N

Longitude: 174 06.88 W

Wind Speed: 6.88 knots

Wind Direction: 275.19 (NW)

Air Temperature: 10.0 C

Barometric Pressure: 1013.2 mb

Visibility: 6 nautical miles

Sea Wave Height: 4 feet

Sky: Overcast

Science Log

While the techniques written about in the previous blog post ensure that when we use the trawling nets we mostly catch pollock, there is usually a small amount of by-catch in each haul. By-catch means ocean life other than pollock (the desired catch) that we bring up in a haul using the trawling net. This post will focus on some of the creatures that I have seen in the catches during my time on NOAA Ship Oscar Dyson.

Principal species of interest:

Pollock: The scientific name for these pollock (known as Alaska pollock or walleye pollock) is Gadus chalcogrammus. We often catch many different ages of pollock, from age 0 pollock up to large adult pollock and these range in length from a few centimeters up to about 62 centimeters. Pollock is most of what we catch, and they are easy to identify by their three dorsal fins and speckling. Pollock mainly eat euphausiids and copepods, but also sometimes eat the age 0 pollock.

By-catch species:

Chum Salmon: Chum salmon (Oncorhynchus keta) is one of the five types of salmon and lives for about 6 years on average. Like all salmon, they are spawned in freshwater and then migrate out to the ocean. Once they return to the freshwater and spawn, they die about two weeks later. They mostly eat zooplankton and insects, but have been known to eat comb jellyfish as well.

Jellyfish: We see several types of jellyfish in each catch, but we mainly see the Northern Sea Nettle (Chrysaora melanaster). We have also seen Northern Sea Nettle swimming near the surface before sunrise when we are pole fishing for pollock. The word melanaster translates to “black star,” which you can identify in the pattern on the bell of this jellyfish. The bell diameter can reach up to 12 inches and the tentacles can grow as long as 10 feet. As climate change has warmed the surface temperatures of the Bering Sea, the population of Northern Sea Nettle is increasing. Northern Sea Nettles mostly eat zooplankton, but sometimes also eat pollock!

Smooth Lumpsucker: Smooth lumpsuckers (Cyclopterus lumpus) are named so because of an adhesive disc on their underside that helps them suction onto the ocean floor. These fish spend most of their time on the bottom of the ocean and are not particularly good swimmers. The roe (eggs) of the lumpsucker is a delicacy in Scandinavia.

TAS Emily Cilli-Turner holding a lumpsucker.

Smooth lumpsucker

Flatfish: Alaska Plaice & Yellowfin Sole: We have also caught two types of flatfish during my time aboard the ship: yellowfin sole (Pleuronectes aspera) and Alaska Plaice (Pleuronectes quadrituberculatus). These peculiar looking fish can be identified by having both eyes on top of their head. When they are spawned, these fish have eyes on either side of their head, but as they get older the eyes migrate to be on the same side. These fish mainly reside on the ocean floor, where they eat polychaetes and amphipods, such as worms and mollusks.

Alaska plaice

Yellowfin Sole

Capelin: The capelin (Mallotus villosus) is a small fish in the smelt family reaching a length of about 10 inches. It feeds mainly on plankton and krill. The most interesting thing about capelin is their smell; if you put their scales close to your nose you will smell cucumbers!

Personal Log

While the weather since boarding the NOAA Ship Oscar Dyson has largely consisted of some high winds and big swells, there have been one or two nice days in the Bering Sea. On these days, we have taken the opportunity to go outside. On one particularly nice day where the sun was shining, there was a mini corn-hole tournament on the deck. After thinking that my time on the ship was the least amount of time spent outside during the summer, this was a nice way to spend the after-dinner time.

corn hole — Operations officer LT Carl Noblitt and student intern Grace Workman playing corn-hole on the deck.

I am also grateful for NOAA scientists Mike Levine and Darin Jones, who have made me feel like an expert in the fish lab. At this point, I know more about pollock than I ever thought I would. In the fish lab, I primarily am responsible for measuring the length of the pollock sample. However, Mike and Darin have also taught me about pollock anatomy and how to tell if a pollock is male or female. I have also become good at extracting the otoliths, which involves a precise cut of the pollock. For a person with almost no experience working with biological specimens, much less fish, I finally feel like a useful part of the team.

Did You Know?

The Bering Sea is an extremely important fishing location and the United States catches over $1 billion of seafood here each year.