CamTrawl – NOAA Teacher at Sea Blog

August 11, 2026August 11, 2026

Jo Slavitz: 1,000 Words: Aug 2, 2026

NOAA Teacher at Sea

Jo Slavitz

Aboard NOAA Ship Oscar Dyson

July 19 – August 10, 2026

Mission: Summer Pollock Acoustic-Trawl Survey, Leg 3

Geographic Area of Cruise: Bering Sea, Alaska

Date: July 30, 2026

Photography is an austere and blazing poetry of the real. — Ansel Adams

Science and Technology Log

The internet is filled with selfies created by everyone from silly kittens to the Kardashians, but why are photos so addictive to us as humans? Cameras allow us to not only record where we have been, but also allow us to take others along on our adventures. They give proof of phenomena, chronicle history and record changes over time. Photography, since its invention in the 1820-1830’s, has played an important role in the toolbox of scientists (and also travel enthusiasts). The scientists of Oscar Dyson are no different. They too love a good photo, and continue to innovate new technology to capture and utilize photography for research. These photos take others along with them into the Bering Sea, but also provide important scientific information. NOAA scientists are earth influencers helping those on shore to understand this unique environment and inform decisions about the health of the Alaskan fisheries.

There are many different tools to capture pictures on Oscar Dyson because there are lots of different types of research that need to be recorded. Several of these specialized camera devices have been designed and built by innovative NOAA scientists to complete specific tasks in diverse locations. Two of my favorites are CamTrawl and CATCam.

three crewmembers, wearing float coats, live vests, hard hats, and gloves, stand on both sides of trawl net as it extend over the deck from the spool (out of frame) to the water (out of frame.) they reach their arms in to position an underwater camera array — CamTrawl coming in with the trawl net

CamTrawl: CamTrawl is a camera that attaches to the side of the pollock trawl net near where the fish collect. It takes images of the things flowing through the net. This is valuable information as it can be compared to the FS70 on the mouth of the net and Echosound data from the ship (both explained in a previous blog) to show what species was captured at specific locations and depths.

CamTrawl captures two pictures from different perspectives at the same time allowing scientists to measure the size of each specimen. NOAA scientists use a program specifically written to view CamTrawl images to look at each image set and use computer clicks to label each creature’s species. The program also lets scientists measure the length of the pollock and view the depth at which they are captured. Knowing the size of the pollock helps to determine its age/stage of life, important information when reporting on the health of the Alaskan fisheries.

photo of a computer screen displaying underwater photos of fish on the left and an annotated echogram (acoustic backscatter v time) on the right — CamTravel image added to Echogram

Look at the image of the data sources combined together. On the left is the photo taken by CamTrawl that was labeled by scientists. The location this photo was taken is marked on the chart next to it by an open red circle (center bottom). The black line represents the path of the trawl net. The bright colored circles are the groups of each species, the more that have been identified on a photo, the larger the circle. The background is the echogram information gathered by the boat during fishing.

Can you find krill, pollock and jellyfish? Do they appear at the same or different ocean depths? These different data sets allow NOAA scientists to determine if the fish patterns on the echogram were actually the fish they expected.

close up view of a camera apparatus resting on the deck of the ship — Constant Altitude Towed Camera (CATCam)

CATCam: CATCam (Constant Altitude Towed Camera) is a device used to capture deep underwater images from the seafloor. Dropped over the side, CATCam is a remote control submersible camera. It is designed to keep a constant height from the bottom and photograph the seafloor while slowly being towed by the ship. CATCam has sensors that detect the seafloor and activate thrusters that keep the cameras from crashing into the bottom. Scientists onboard the ship are also able to control the thrusters to guide CATCam into just the right spot. It is also equipped with bright lights to light up the dark bottom waters.

Because the pollock trawl doesn’t typically move along the bottom, often the species photographed are especially fun to see. Here are some of my favorite CATCam pictures:

underwater image from above of an orange rockfish swimming just above the ocean floor, near an anemone — Rockfish & Anemone

underwater image of a stake on the seafloor, next to a sea cucumber — Rockfish & Anemone

Under Pressure: In designing and building underwater cameras like CamTrawl and CATCam, NOAA scientists need to consider the issue of water pressure. These camera systems need to go deep down into the ocean and the deeper they go the higher the pressure becomes. Underwater pressure is called hydrostatic pressure and it increases dramatically as you travel deeper.

Check out these styrofoam cups. They were sent down on various deep water missions. They show the effect of underwater pressure. Styrofoam is made up of plastics filled with tiny pockets of trapped airy open space. When brought down under the water, these airy spaces are crushed inward on all sides, shrinking the cup. My middle school teacher had a tiny styrofoam cup that was towed behind a WHOI submarine that fascinated me: I can’t believe I now have one of my own. You can learn more about hydrostatic pressure with the fun interactive WHOI simulation.

four decorated styrofoam cups in a line on the table; these have all been shrunk and are now a bit misshapen. a fifth cup rolls on its side in the background. — shrunken styrofoam cups

Try It on Dry Land

Just like styrofoam, marshmallows are filled with tiny little pockets of air surrounded by a flexible material. Both styrofoam and marshmallow react to changes in pressure in similar ways. It took me decades to catch a ride to a deep sea environment and get a tiny styrofoam cup. If you aren’t that patient, you can create a similar environment at your desk with a few simple materials.

A.I. generated illustration of a marshmallow inside a syringe — Illustration of a marshmallow inside of a syringe, created with Gemini AI

Marshmallows from the Deep

Materials:

2-3 Mini Marshmallows
60ml Plastic Syringe
Sharpie

Instructions

Use Sharpie to decorate mini marshmallows
Take plunger out of syringe and add marshmallows
Replace plunger
Hold finger over tip (or add a drop of hot glue tip)
Gently push plunger in to increase the pressure inside the syringe

What happens to the marshmallow?
What happens to the decoration?
If you gently pull the plunger in the opposite direction you are decreasing the pressure inside the syringe. What happens to the marshmallow?

Personal Log

Alongside all the scientific photographs being taken, I have been frantically clicking away behind my camera. I hope my photos introduce my story to my students. I hope they can feel the vastness of the ocean, the magic of life teeming underneath it and the breathtaking majesty of a return to the Alaskan mainland. I hope these photos cause students to ask questions I can’t answer, to think about careers far beyond those in our neighborhood, and dream of new innovations of exploration and preservation of this incredible place.

view, entirely in shades of dark teal-blue, of mountains rising above the ocean's surface, surrounded by dark clouds. — Return to land

July 12, 2024August 8, 2024

Nick Lee: Fishing, Fishing, Fishing, July 10, 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 10, 2024

Weather Data from the Bridge:

Latitude: 50° 40.9 N

Longitude: 178° 29.9 W

Wind Speed: 20 knots

Air Temperature: 6.2° Celsius (43.1° Fahrenheit)

Science and Technology Log:

Last blog post, I talked about acoustic backscatter, which scientists on board use to locate fish. When scientists notice high-intensity backscatter – or backscatter that they’re interested in collecting more biological data about – they’ll call the bridge and ask to go fishing. The bridge then makes the announcement over the radio:

“All stations. This is the bridge. We will be fishing, fishing, fishing.”

This announcement sparks a flurry of action from scientists, NOAA officers, and the deck crew. A few scientists go up to the bridge for a marine mammal watch, where they make sure that there are no marine mammals in the area of the operation. NOAA officers navigate to the science team’s target fishing area, and the deck crew prepares the net to go in the water.

Teacher at Sea Nick Lee on marine mammal watch. Nick stands at a window on the bridge and looks out through binoculars at gray waters under a gray sky. — *Marine mammal watch on the bridge.*

Before my cruise, I thought fishing nets were relatively simple and uniform. However, I’ve since learned that the net has many different components and sensors, which help scientists collect additional information about the fish seen with acoustics.

Codend

During the trawl, the net is dragged behind the boat. Near the opening at the mouth of the net, the net’s mesh is over a meter wide. This helps reduce drag from the water, while still funneling fish toward the back of the net. The net gradually gets smaller until the very end of the net – called the codend – where the fish are collected. At the end of each trawl, the net is hauled out of the water, and the contents of the codend are emptied into a sorting table for further processing in the fish lab, where length, weight, sex, and maturity are recorded for a representative sample.

Pocket Nets

In portions of the net with larger mesh, small fish and other organisms can escape through the holes in the mesh. This creates a problem for scientists – a trawl could show that only adult pollock are present in a certain area when in reality the population is mixed, but all of the juveniles escaped! Since scientists will be using trawl samples to understand the overall population of pollock, they want to avoid bias as much as possible in their data.

To get around this problem, scientists are studying the rates at which different sized pollock (and other organisms) escape from the net. They use pocket nets, or small nets made of the same fine mesh as the codend, to get an idea of what escaped from each trawl. Nine pocket nets are attached to the side, top, and bottom of three different sections of the net with varying mesh sizes. As the trawl net is being hauled back on the boat, one of my jobs is to help empty these pocket nets and collect what’s inside.

We’ve mostly found krill and jellyfish, but occasionally we’ll find a larval fish or squid!

CamTrawl

Near the codend, there is also a camera, referred to as CamTrawl. This camera provides scientists with a visual of what is going into the net, and can be used to help identify species and length of fish that are caught.

Scientists deploying PelagiCam. View through a doorway of two scientists in orange foul weather gear and green and white hardhats standing close to one another at the railing of the ship. They face away from the camera. In the foreground, on the deck, is a spool containing yellow cable. — *CamTrawl (left) and scientists Matthew Phillips and Mike Levine deploying PelagiCam (right).*

On this cruise, scientists are also testing a camera that they lower over the side of the ship (without a net), known as PelagiCam. They are hoping that PelagiCam may be able to collect species and length data, supplementing the data captured when processing fish from the trawl. If PelagiCam can record this data accurately, it could provide an efficient complement to trawling, which requires a lot of time and collaboration between different teams of people.

Pollock seen on PelagiCam — *A pollock seen on PelagiCam (left). Posing with scientist Mike Levine in front of the PlagiCam (right).*

Teacher at Sea and scientist posing in front of PelagiCam. They are wearing foul weather gear and hard hats; Mike is also wearing a mask and gloves. — *A pollock seen on PelagiCam (left). Posing with scientist Mike Levine in front of the PlagiCam (right).*

FS70 Net Sounder

The FS70, nicknamed the Turtle, collects acoustic data and produces a live image of the net’s opening when it is in the water. This data allows scientists and the deck crew to monitor the shape of the net while fishing, ensuring that the net opened correctly. It also monitors when fish enter the net.

Live data from the FS70. a square screen mounted in a console displaying sonar data. — *FS70 (left), nicknamed the turtle, and the live data it shows scientists during a trawl.*

Personal Log:

Going fishing can sometimes be a lot of “hurry up and wait.” After the marine mammal watch, at least one scientist stays on the bridge to monitor the net using the FS70, and the others get ready to process the trawl. Letting the net out and hauling it back in is far from simple, however. It requires constant communication between the bridge and the deck crew, and it can be made more complicated by the weather or equipment malfunctions. Once the net is in the water, trawling can take anywhere from 15 minutes to over an hour.

Opening the codend is always exciting, because we’re never quite sure what we caught. While our target is always pollock, we’ll often find other interesting organisms mixed in as well. Some highlights include rockfish, squid, and a smooth lumpsucker.

close-up of a Rockfish in a white bin — *Organisms caught in the trawl so far include rockfish, squid, and smooth lumpsuckers.*

Squid in a white bin — *Organisms caught in the trawl so far include rockfish, squid, and smooth lumpsuckers.*

Did you know?

The net used on NOAA Ship Oscar Dyson was specifically designed for this survey!

August 15, 2023August 15, 2023

Germaine Thomas: What Does Acoustic Trawl Sampling Really Tell Us? August 13, 2023

NOAA Teacher at Sea

Germaine Thomas (she/her)

Aboard NOAA Ship Oscar Dyson

August 7 – August 21, 2023

Mission: Acoustic Trawl Survey (Leg 3 of 3)
Geographic Area of Cruise: Pacific Ocean/ Gulf of Alaska
Date: Sunday, August 13, 2023

Weather Data
Lat 59.12 N, Lon 150.11 W
Sky condition: Partly Cloudy
Wind Speed: 13 knots
Wind Direction: 330°
Air Temp: 14 °C

Science and Technology blog

The ocean is a really big place. We have really only mapped about 5% of the ocean bottom. How do we manage fisheries if we have to count fish in an area that is overwhelmingly large? This is where the genius of acoustics and trawl sampling complement each other. The scientists aboard NOAA Ship Oscar Dyson use the echo sounders to find fish or other animals lurking in the ocean and then they can extrapolate and upscale that data to a much larger area which is covered by their transects.

Wait! That is a lot of information using language that folks don’t really use at the dinner table. Could you please explain this in more basic terms? You bet, as a matter of fact in the last couple of days I have been swimming in a sea of new vocabulary, talking to really smart people and trying to keep up with the conversation that it almost makes my head explode. Don’t worry, I am safe. But it’s really impressive how scientists have developed ways to accurately know fish and marine organism populations in the ocean with out having to sample all of it.

Acoustics

Acoustics uses the echo-sounders a lot like a fish finder, but the ones on NOAA Ship Oscar Dyson are much more capable than the type you would find on your boat. The echo-sounders are attached to the bottom of a lowered centerboard—essentially a large keel—in the center of the boat, and they measure five different frequencies with different wavelengths.

A photo of a computer screen displaying five echograms (graphs of recorded echoes) in a row. Germaine has added annotation: a black arrow points at the top of the echogram with the label "Top of the ocean," and another points to a solid, dark red bar midway down the echogram with the label "bottom of the ocean." Dashed marks, angled up or down, are scattered across the echograms, concentrated in upper portions. Germaine has drawn a black circle around some of these, with the label "The colored marks in the oval indicate "backscatter," which could indicate fish or other marine organisms." At the top of each echogram, in its title, Germaine has circled the frequency measured, but they are difficult to read. — View of the 5 different frequencies measured by the echosounders, one in each frame. The darker marks on the screen could be fish, jellyfish, krill or other marine organisms, this is referred to as “backscatter.” The red circles show the different frequencies used to measure the backscatter.

So, if we can see the fish using acoustics, why do scientists need to sample using a trawl net? As you can see above, the marks in the backscatter can show the depth and the approximate shape of objects, but there is not enough detail to tell exactly what kind of organism is present. Most of the scientists on board have a pretty good idea what kind of fish or organisms are present, but the most definitive way to know is to take a trawl sample.

Trawl Sampling

The trawl net as seen in the picture below is being set off the aft deck.

A crewmember wearing a hard hat, life vest, and heavy work overalls stands off to the side as the trawl net is lowered off the aft deck from a large yellow A-frame. — The part that is in the air is called the codend. That is the section of the net where the specimens are ultimately collected.

view of two rollers - like large spools - containing rolled up fishing nets. the net on the right is orange. the net on the left is white and partially paid out. — The trawl is a about 172 meters long and it stored on these rollers on the back deck.

When the trawl is deployed to the depth that the scientists want to sample, the net will funnel fish and other organisms into it. This is called flying the net.

The screen above diagrams three different views of the net as it is pulled through the water. You can see that the trawl net was not directly behind the boat and went to a depth of 21.5 m.

photo of a computer screen displaying data about the position of the net, along with a more detailed diagram. Germaine has added arrows to label "The doors help open the net" and "the codend at the end of the net that collects the sample." We can see that the set length measures 457 meters. — In this image you can see the net and how far back it trails behind the *Oscar Dyson*.

I just have to include one more view of the trawl net from the bridge as it is pulled behind the boat.

A photo of a computer screen showing a 3-d rendering of the deployed trawl net and the following measurements: door depth port - 16.5 m. door depth starboard.- 15.7 m. door spread - 59.4 m. door pitch port - 4.7 degrees. door pitch starboard - 6.1 degrees. headrope horizontal range - 204 m. headrope true bearing - 326.0 degrees. depth - 21.0 m. change meters/minute - -0.2 m. — This image was taken when the crew was bringing the net back into the boat, so the depth is shallower.

The next image shows the path that the net was pulled through the water.

photo of a computer screen displaying an echogram (graph of recorded echoes.) This echogram shows the returns from a single frequency. Germaine has annotated it with arrows pointing to: Header rope or top of the trawl path, and Footer rope or bottom of the trawl path. Another arrow points to colored specks and reads: The echosounders show backscatter, which could be fish or other organisms. — The acoustics show the backscatter which the scientists make the trawl target. The next step is to process what is captured in the codend of the trawl and see exactly what is present.

Because the trawl is dragged through the water, it catches different organisms at different times. The scientists want to know when the different organisms were caught so they have cleverly attached a camera to the side of the net. Through the camera they can see which type of fish came into the trawl. Ultimately, this links the kind of acoustic backscatter viewed in the echograms recorded during the trawl to exactly the type of organism caught by the trawl.

view of a trapezoidal metal apparatus, containing underwater cameras and floats, attached to a blue trawl net, spread out on deck — The camtrawl: a camera that records the type of fish entering the net and when they enter.

Below is a picture of some fish as they enter the trawl net and move towards the codend.

a photo of a computer screen displaying a black-and-white underwater camera feed. a few fish (pollock) are visible swimming by the net. — The camera is looking across the net as the fish move past. The fish in the picture are pollock, the type of fish we are looking for on this leg of the cruise.

Transect Lines

So how do scientists take this information and extrapolate the data to a broader area? While the Oscar Dyson is out at sea they run transect lines while recording acoustic data. Transect lines are specific paths in the ocean. The picture below shows the transect lines that we plan to do and have done on this leg of the cruise.

a screenshot of an electronic nautical map of the Gulf of Alaska. straight lines extending toward and away from the coast are superimposed across the map. — The red lines are the transects we have done and the blue lines are the transects scientists plan to do in the remainder of this leg of the cruise. If you look closely there are pictures of fish symbols on the transect lines where the ship has made trawl samples.

Using the acoustic data that the echo-sounders provide and verifying the types of fish and other marine organisms through the trawl sampling allows the scientists to predict, with a high level of certainty, the amount and types of marine organisms that are present along the transect lines that were not trawl-sampled. Thus saving the taxpayers money, and allowing fisheries managers to use good data, keeping the fishery viable, and allowing commercial fishing boats to have reasonable catch limits.

Scientist in the Spotlight

Honestly it takes a team to make all of this happen. But, half of our team is sleeping at the moment, I have the night shift from 4pm to 4am, so I am going to introduce one fabulous expert in acoustics and fisheries:

Abigail, wearing a blue hoodie featuring a drawing of a salmon, sits back from a long computer desk with eight computer montiors mounted above and to the side. She smiles at the camera. — Abigail McCarthy in the Acoustics Lab

Abigail McCarthy has been working for MACE: Midwater Assessment and Conservation Engineering Program since 2007. She received her undergraduate degree in Biology from Wellesley College and then obtained a Masters in Fisheries from Oregon State University.

For fun, she surfs and enjoys long-distance prone paddle board races. She has recently found a new love with fly fishing.

Aboard the Ship Oscar Dyson, she is working as a specialist helping to run the acoustics lab.

I asked Abigail what she thought of about her educational experience? She immediately said, “I love learning! High school and college were both a lot of fun.”

What would be a good suggestion for a young aspiring high school student pursuing a degree related to ocean studies or science in general?

Her response was great: “Being curious and working hard is more important than being brilliant. Persistence and determination will get you where you want to be in the future.” Finally, “Learn to code! Become familiar with programing languages like Python and R.”

Hopefully, I answered your burning questions about the use of acoustic trawl sampling, and surveys. Yet, there is so much more to learn. Why not take a trip yourself? Check NOAA’s website out and just apply.

June 20, 2023June 20, 2023

Laura Guertin: Collecting data: Trawl Sonar and CamTrawl, June 20, 2023

rectangular frame with four orange round balls on top and two eyes on a metal cylinder in the middle

NOAA Teacher at Sea

Laura Guertin

Aboard NOAA Ship Oscar Dyson

June 10 – June 22, 2023

Mission: 2023 Summer Acoustic-Trawl Survey of Walleye Pollock in the Gulf of Alaska

Geographic Area of Cruise: Islands of Four Mountains area, to Shumagin Islands area
Location (2PM (Alaska Time), June 19): 55^o 30.9384′ N, 159^o 47.6478′ W

Data from 2PM (Alaska Time), June 19, 2023
Air Temperature: 8.2 ^oC
Water Temperature (mid-hull): 6.8^oC
Wind Speed: 18 knots
Wind Direction: 62 degrees
Course Over Ground (COG): 30 degrees
Speed Over Ground (SOG): 11 knots

Date: June 20, 2023

To conduct a fisheries survey or any oceanographic research expedition, there’s an enormous checklist of items you need on a ship. Jokingly, those on board will tell you that food and internet access are at the top of the list. But there’s no doubt that technology and its function, application, durability, etc., are critical during the time at sea. For example, see NOAA’s explainers for Ocean Exploration Technology: How Robots Are Uncovering the Mysteries of the Deep and Collecting and Visualizing Deep-Sea Data. For a broader look at the technologies NOAA uses to explore the ocean (vessels and submersibles, observing systems and sensors, communication technologies, and diving technologies), see Exploration Tools.

Leg 2 of this Summer Survey will be bringing on board the DriX, an uncrewed surface vehicle (USV), to see if this technology can improve the efficiency of collecting acoustic and biological data to estimate pollock abundance when working alongside Oscar Dyson. To read more/see a video, check out NOAA’s article, Uncrewed Surface Vehicles Complement NOAA Vessels for More Efficient Fisheries Surveys.

Trawl Sonar

A sonar device (housed in a yellow hard plastic casing marked SIMRAD) sits on deck on a pile of coiled ropes — The Simrad FS70 on the back deck of *Oscar Dyson* (June 2023)

Trawl sonar units are used to provide a rough estimate of how many fish are going into the trawl net. The device (which we’ve been using on our expedition, a Simrad FS70 nicknamed “the turtle”) is a third wire system that in real time establishes communication between the submerged sonar head and the bridge. On this cruise, the trawl sonar unit is placed on the headrope of the trawl net (i.e., on the top of the mouth of the net). It communicates its depth back to the ship. It also scans the mouth of the net and relays any acoustic images of things going into the net back to the ship. These data allow the scientists and crew to adjust the depth of the net and length of time the trawl net remains in the water to collect samples. Our goal is to collect enough fish (approximately one ton) to have a representative sample of the various species and lengths of fishes in the water column.

Screenshot of the display returned by the FS70 during a trawl. The display is broken into three columns. The rightmost column is a list of settings. — Screenshot of the display returned by the FS70 during a trawl. The pink/yellow/blue line in the left column is where you see the bottom of the net. This is also represented in the middle column by the multi-colored horizontal line you see in the third circle from the center. (Screenshot from Leg 1 provided by Rick Towler).

The Simrad FS70 makes an appearance in the NOAA video Alaska’s Pollock Fishery: A Model of Sustainability. NOAA Ship Bell M. Shimada uses this FS70 trawl sonar unit for Pacific hake acoustic trawl surveys (see article).

CamTrawl

One fascinating piece of technology we’re using on this pollock survey is the CamTrawl. This article I found will give you everything you would want to know about CamTrawl in a non-technical summary:

–> Developing 3D Stereo Camera Technology to Support Sustainable Fisheries (from NOAA)

Introduced in 2012, the CamTrawl is a stereo camera system when attached to a trawl net, can provide data about fish without ever touching a fish. This 3D imagery records fish passing by the camera towards the codend (the closed end of the trawl net), which provides species and size composition data as well as how fish behave in the trawl net to be collected from within a midwater survey trawl. CamTrawl is used to verify the trawl catch and specimen data, and in some cases, can be used to determine where in the water column the species entered the net. These data help inform ecosystem-based fisheries management.

The CamTrawl on Oscar Dyson for 2023 Summer Survey. The orange balls are flotation devices, the two “eyes” in the middle are the stereo camera and computer system, with the battery power across/under the eyes. The four round devices in the corner are lights used during the image recording.
Top-down view of the CamTrawl. The front of the camera set-up is the wider side of the trapezoidal frame (top of image) which is then attached to the trawl net.
Figure 1 from Williams et al. (2016). CamTrawl system description.
CamTrawl attached to trawl net about to be set off the back of Oscar Dyson.

The CamTrawl has uses and applications beyond our walleye pollock survey. It can go to depths of the ocean where it is not possible to lower a trawl net and capture data on other fish species like the bottom-dwelling rockfish. CamTrawl can explore and map deep-sea corals, and there is potential for collaborative research with the fishing industry.

Some CamTrawl footage from Leg 1 of 2023 Summer Survey.

The CamTrawl was developed by NOAA scientists Kresimir Williams and Rick Towler (both of whom I’m sailing with on Oscar Dyson for Leg 1). I feel incredibly fortunate to have sailed with these two scientists and to hear how NOAA encourages their researchers to be creative and experiment with developing technologies to advance NOAA’s overall mission and expedition objectives.

people around a net removing equipment, while standing on the back of a ship at sea — CamTrawl being detached from a trawl net after a mid-water trawl (June 16, 2023, on *Oscar Dyson*)

Curious to see more? Check out this Salmon shark caught on CamTrawl underwater camera. Below is a picture of a salmon shark from the Shumagin Islands, Alaska area in February 2017 (photo provided by Sarah Stienessen).

Additional sources for exploration:

Using AI and 3D stereo cameras to support fisheries (National Fisherman, March 12, 2023)

Boldt et al. (2018). Development of stereo camera methodologies to improve pelagic fish biomass estimates and inform ecosystem management in marine waters. Fisheries Research, 198. https://doi.org/10.1016/j.fishres.2017.10.013

Williams et al. (2018). A method for computing volumetric fish density using stereo cameras. Journal of Experimental Marine Biology and Ecology, 508. https://doi.org/10.1016/j.jembe.2018.08.001

Williams et al. (2016). Automated measurements of fish within a trawl using stereo images from a Camera-Trawl device (CamTrawl). Methods in Oceanography, 17. https://doi.org/10.1016/j.mio.2016.09.008

June 25, 2018

Lacee Sherman: Teacher With Fish Scales in Her Hair, June 22, 2018

NOAA Teacher at Sea

Lacee Sherman

Aboard NOAA Ship Oscar Dyson

June 6 – 28, 2018

Mission: Eastern Bering Sea Pollock Acoustic Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date: June 22, 2018

TAS Lacee Sherman getting in rain gear to process a haul

Weather Data from the Bridge at 19:00 on 6/24

Latitude: 56° 0.7 N

Longitude: 169° 34.5 W

Sea Wave Height: 3-4 ft

Wind Speed: 16 knots

Wind Direction:107° (E)

Visibility: 10 nmi

Air Temperature: 8.1°C

Water Temperature: 7.7° C

Sky: Overcast

Science and Technology Log

With this blog, I will be focusing on the biodiversity in the Eastern Bering Sea. Biodiversity includes all of the different types of plant and animal species in a given environment. All of the species that I will be discussing I’ve seen come up in the trawl net, or have seen from the ship.

Adult Walleye Pollock

Common Name: Walleye Pollock

Scientific Name: Gadus chalcogrammus

Identifying Features: 3 Dorsal Fins, large eyes

Ecological Importance: Polllock influence the euphausiid populations and are food to many larger marine species, and humans.

Interesting Facts: Walleye pollock produces the largest catch by volume of any single species inhabiting the 200-mile U.S. Exclusive Economic Zone.

Krill (Euphausiid)

Krill (Euphausiids)

Common Name: Krill

Scientific Name: Euphausiidae (Family)

Identifying Features: 1-2 centimeters in length on average. They look similar to very small shrimp, and often swim in schools.

Ecological Importance: Krill are a very important food source for many fish and also larger marine mammals such as whales.

Interesting Facts: They are filter feeders and eat zooplankton and phytoplankton, which makes them omnivores.

Chrysaora melanaster

Common Name: Northern Sea Nettle, Brown Jellyfish

Scientific Name: Chrysaora melanaster

Identifying Features: 16 lines from the center of the bell to the outer edges of the bell. Large range in sizes, from very small to very large.

Interesting Facts: Jellyfish may become a problem for the Bering Sea in the future because they reproduce in large numbers and they can dominate an entire environment easily.

Pacific Ocean Perch

Common Name: Pacific Ocean Perch

Scientific Name: Sebastes alutus

Identifying Features: Bright to light red with brown blotches dorsally near fins, large spines on dorsal and anal fins, knob on lower jaw

Ecological Importance: delicious

Interesting Facts: Pacific Ocean Perch are a type of Rockfish. Pacific Ocean Perch have a swim bladder similar to that of pollock, so they reflect similar acoustic signals and can sometimes be acoustically confused for pollock if no sample is taken in a specific area.

Yellowfin Sole

Common Name: Yellowfin Sole

Scientific Name: Limanda aspera

Identifying Features: Black line between body and dorsal and ventral fins, fins may appear yellow in color

Ecological Importance: Yellowfin sole are benthic (live and feed on the ocean floor).

Interesting Facts: Yellowfin sole grow slowly and may be 10.5 years old by the time they reach 30 cm in length.

Magister Armhook Squid

Common Name: Magister Armhook Squid

Scientific Name: Berryteuthis magister

Identifying Features: 8 tentacles and two larger feeding arms, dark red in color, but white when damaged

Ecological Importance: Prey on fishes and other squid

Interesting Facts: These are the most abundant squid found in the waters of Alaska.

Chum Salmon on the conveyer belt with pollock

Common Name: Chum Salmon

Scientific Name: Oncorhynchus keta

Identifying Features: Metallic dark blue on the top and silvery on the sides

Ecological Importance: Chum Salmon have adapted to live in saltwater and freshwater. They mainly eat copepods, fishes, squid, mollusks and tunicates.

Interesting Facts: Chum salmon eggs are hatched in freshwater rivers and streams. They then travel downstream to live most of their life in the ocean. When it is time, Chum Salmon spawn (reproduce) in the same freshwater stream they hatched in. Once a salmon spawns, they die.

Pacific Herring

Common Name: Pacific Herring

Scientific Name: Clupea pallasii

Identifying Features: Large scales that are shiny silver along the sides and shiny blue along the top of the fish. Tail has a fork and there is only one dorsal fin.

Ecological Importance: Eat phytoplankton and zooplankton. Herring and their eggs are eaten by fish, birds, marine mammals, and humans.

Interesting Facts: Herring eggs (roe) are considered a traditional delicacy in Japan called kazunoko.

Yellow Irish Lord

Common Name: Yellow Irish Lord

Scientific Name: Hemilepidotus jordani

Identifying Features: Yellowish tan to dark brown, white to yellow bottom, and yellow gill membranes

Ecological Importance: Since they are usually found close the ocean floor, they regularly eat things like fish eggs, isopods and amphipods, worms, and small fishes.

Interesting Facts: There is another species of Sculpin that is similar called a Red Irish Lord.

A photo of our fish lab gloves

Personal Log

During our hauls, a member of the science team is needed on the bridge to watch for the presence of marine mammals and endangered bird species. I am one of the people that gets to do this, and I must admit, there is a slight conflict of interest. I, of course, want to see all of the marine mammals possible, but if they are nearby during a haul, we are required to give them space until they pass so that they are not injured in any way by the ship. This can definitely slow down the process of hauling if we see them, but of course I don’t mind it if I get to see more whales. Most of the time I don’t see any marine mammals and just end up enjoying a beautiful view of the open ocean.

I am definitely feeling more comfortable and at home on the ship now. Constant motion from the swells is the new normal, and the creaks and sounds of the ship are a new soundtrack to listen to (on repeat). Sometimes I like to push the limits and see how far forward or backward I can lean during larger swells to maintain balance and have a few superhero moments as I pretend to defy the laws of physics.

I’m getting to know more about the other people on the ship every day and it’s nice to get into a rhythm and start to really work well together and have a good flow, especially in the fish lab. If we are motivated to finish before meal times, we can process a good haul of Pollock in around 45 minutes. That is much quicker than we started at, and it’s because we have really learned how to capitalize on each other’s strengths and just being willing to do whatever job is needed in the lab, even if it is not our favorite task.

Some of the science team in the fish lab. (left to right) TAS Lacee Sherman, Darin Jones, Sarah Stienessen, Denise McKelvey, Matthew Phillips, and Mike Levine

I have claimed a workspace in “the cave” (acoustics lab) that is perfectly in the way of the phone when it rings, but it’s usually quiet in there and I can focus on these blogs, reading, or planning for next school year. I’ve also been reading the transcripts to a ton of TED talks when we don’t have access to the internet.

Did You Know?

In Alaska, during the summer, they experience what is called “the midnight sun”. It is rarely ever dark enough to see the stars during the summer. This happens because of how far north it is!

This photo was taken just after midnight on 6/21/18 (summer solstice).

Bonus! Cool Photo time!

Cam Trawl image of pollock and pacific ocean perch. Can you tell the difference?

This bird flew into the table where the fish are held before being processed. It was just hoping for a free meal, but ended up getting stuck. After realizing it couldn’t get out on its own, a survey technician helped to get it out and back on its way.

The black bars on the sides of the doors hold it shut and are controlled by the black lever on the left of the photo. Talk about a tough door!

References:

Alaska Fisheries Science Center. “Yellowfin Sole Research.” NOAA Fisheries, 25 Oct. 2004, http://www.afsc.noaa.gov/species/yellowfin_sole.php.

“Crustaceans.” Crustaceans , Marine Education Society of Austrailasia, 2015, http://www.mesa.edu.au/crustaceans/crustaceans07.asp.

“Facts.” Facts | Pacific Herring, http://www.pacificherring.org/facts.

Jorgensen, Elaina M. Field Guide to Squids and Octopods of the Eastern North Pacific and Bering Sea. Alaska Sea Grant College Program, University of Alaska Fairbanks, 2009.

Mecklenburg, Catherine W., et al. Fishes of Alaska. American Fisheries Society, 2002.

NOAA. “Chum Salmon (Oncorhynchus Keta).” NOAA Fisheries, 21 Jan. 2015, http://www.nmfs.noaa.gov/pr/species/fish/chum-salmon.html.

TenBrink, Todd & W Buckley, Troy. (2013). Life-History Aspects of the Yellow Irish Lord ( Hemilepidotus jordani ) in the Eastern Bering Sea and Aleutian Islands. Northwestern Naturalist. 94. 126-136. 10.1898/12-33.1.