Aleutian Wing Trawl – NOAA Teacher at Sea Blog

September 8, 2017

Chelsea O’Connell-Barlow: To Fish Or Not to Fish?…A Question of Sound, September 4, 2017

NOAA Teacher at Sea

Chelsea O’Connell-Barlow

Aboard NOAA Ship Bell M. Shimada

August 28 – September 13, 2017

Mission: Pacific Hake Survey

Geographic Area of Cruise: Northern Pacific Ocean

Date: 9/04/2017

Weather Data from the Bridge:

Latitude: 53.59.372N

Longitude: 133 32.484W

Temperature 59 F

Wind 12.5 knots

Waves 1-2 feet

Science and Technology Log

After spending a few days observing what happens in the Acoustics lab and listening to our Chief Scientist Rebecca (RT) Thomas and acoustician Julia Clemons brainstorm aloud, I had one overriding question…”How do you decide when to fish?”

I asked RT this question and it is a multi-factored decision for sure, but seems like the decision could be broken down into 3 parts: what we see, what we know and what is currently happening.

What they see when deciding to fish or not is an echogram created by three acoustic sounders on the ship that send out 3 different frequency wavelengths. The image shows a relatively low frequency 18 kHz, 38 kHz, and a longer wavelength of 120 kHz. Keep in mind that sound travels faster in water than on land so this is a great way to gather information while being minimally invasive to the marine environment.

annotated bridge screens for 9.4 post — Bridge of Bell M. Shimada. The 3 screens we watch during a AWT trawl for Hake.

The backscatter, sound that scatters off of an object or its echo, on the echogram is what they look at to determine what marine life is on the transect we are scouting. As the sound wave bounces off of material in the ocean be it rock, flora or fauna it will create a spot or colored pixel on the echogram. Hake has a particular “look” of backscatter. When the echogram shows this particular hake sign we move in the direction of fishing.

Of course they only know what “hake sign” is because of gathering evidence throughout the course of this multi-year survey. During this survey they have created a huge reference database of hake sign and sign of other integral species to the hake’s environment, for example Euphausiid sp., one of the hake’s favorite food. RT and Julia have both interpreted many echograms and fished to confirm the identity the organisms that created the sign. They are able to rule out images on the echogram until they find the backscatter that most resembles what they have historically experienced as hake.

The third part of this decision making process is the most variable…what is currently happening. As the boat travels and the sounders are sending out the trio of wavelengths an image of the ocean shelf is created. The scientists are able to see topography and measure the depths of the shelf’s different contours. The Shimada is a 209 foot long boat weighing over 2,400 tons. When deciding to trawl for hake that we suspect are present because of backscatter sign in the echogram the scientists and Commanding Officer always consider the depth to bottom, contours, wind and the maneuverability of the ship. Deploying the Aleutian Wing Trawl (AWT) net to catch hake is a task that involves cooperation and communication between the deck crew, Boatswain, bridge officers and the Chief Scientist. When RT sees a sign on the echogram that she wants to fish, she and Commanding Officer Kunicki quickly discuss the approach, wind direction and depth to get an idea on how the net will be affected and how close the ship can get to the exact sign that she wants to sample.

This is my bare bones description of the process that goes into deciding when to fish on Leg 5 of the Pacific Hake Survey. Stay tuned to see what we learn from comparing the echogram of sign to the actual yield from the AWT fishing net.

For more specifics from NOAA on the Bell M. Shimada’s acoustic and trawling capabilities https://www.omao.noaa.gov/learn/marine-operations/ships/bell-m-shimada/about

Personal Log

This ship is filled with kind, creative and industrious people. I am reminded of this constantly and appreciate this often. To me it is astounding to consider all the work and thought that is involved in a fifteen-day research survey at sea. This is a science survey so there are specific tools, computer programs and labs that must run well. To me, coming in with a science focus, this is most obvious. What I am blown away by are all of the additional layers that work together to make science even possible on this successful voyage. There are several teams at play: engineering, technology, deck, science and the bridge officers. Engineers are constantly maintaining engines, generators (this ship has 4), plumbing, ventilation and so much more. I had a tour today with Engineering Chief Sabrina Taraboletti that I am still trying to process through.

Technology is handled by one person on this ship. He maintains and trouble shoots computers in the acoustics lab, the bridge, the chemical lab and even found time to help maximize signal for the Fantasy Football draft. The deck crew is as versatile as anyone on this ship. We have two types of nets that we fish with. The deck crew is responsible for getting the nets out to fish and back in with the catch. Way easier said than done when we are talking about over a ton of weight with net, camera, chain, and doors. On top of all their other responsibilities many of the men in the deck crew have been helping out in the galley (kitchen) on this leg of the hake survey. Larry is the chief steward (chef) on board this leg and he typically has someone working with him but not on this leg of the Survey. So in addition to working their 12 hour shift, many of the deck crew have been working with Larry to prep food, clean up the mess (dining area), do dishes or even create their own personal specialties for dinner. We have been spoiled by Matt’s rockfish, Joao’s fresh salsa and soups and our Operations Officer Doug’s amazing BBQ. Liz and I even got to help out and make some donuts with Larry. Eating is great on the Shimada!

Liz & OCB makin the donuts — Liz and OCB making the donuts – thanks for the lesson Larry.

The Shimada team is rounded out with the bridge crew made up of 4 officers. The officers on a NOAA ship have a foundation of science knowledge and extensive nautical training. Before we go fishing I get to participate in the marine mammal watch up in the bridge. As I look for whales, dolphins and other marine mammals near the boat I can listen to the Captain and officers working their magic. We have had an incredibly smooth trip thus far which I credit to our Officers and of course Mother Nature.

Did You Know?

Crazy cool catch of the day…can you figure out what type of fish this is?

Here is a clue…they have specially adapted cells called photocytes that create light producing organs called photophores. The photophores run along the sides of the fish and help them to lure prey and attract mates.

Viperfish from strangeanimals site — photo credit: http://www.strangeanimals.com

Answer:

This is a Viperfish.

Viperfish live in the deep ocean and migrate vertically as the day goes on in order to catch prey. They typically live around 1,500m (4,921 ft) and in the night will end up around 600m (1,969 ft) at night. This particular fish appears to have photophores along its mouth but it is difficult to be 100% sure from this specimen.

July 14, 2017

Sian Proctor: Nothing But Net!, July 12, 2017

NOAA Teacher at Sea

Sian Proctor

Aboard Oscar Dyson

July 2 – 22, 2017

Mission: Gulf of Alaska Pollock Survey

Geographic Area of Cruise: Gulf of Alaska

Date: July 12, 2017

Me next to chafing gear from AWT. Image by Meredith Emery.

Weather Data from the Bridge

Latitude: 56° 46.8 N
Longitude: 154° 13.7 W
Time: 0800
Sky:Clear
Visibility: 10 nautical miles
Wind Direction: 279
Wind Speed: 9 Knots
Sea Wave Height: 1-2 foot swell
Barometric Pressure: 1019.9 millibars
Sea Water Temperature: 11.1°C
Air Temperature: 12.0°C
Sunrise: 0531
Sunset: 2300

Science and Technology Log: Nothing But Net!

Once the scientists determine where and how deep they want to fish, based on analyzing the echogram, then the boat moves into position and the net is deployed. Safety is the top priority when working on the vessel. The deckhands all have to wear life jackets, hard hats, and good boots when working on deck because the conditions can be sunny one moment and stormy the next. There is some serious hardware at the back of boat. There are cranes, winches, and spools of wire ropes & chains. The Chief Boatswain is responsible for all deck operations and deploying any gear overboard. The following video illustrates the sampling process using an Aleutian Wing Trawl net.

There is a camera (aka camtrawl) attached to the net along with a small pocket net. The pocket net is designed to catch tiny animals that slip through the AWT meshes. The pocket mesh only catches a small amount of escaping animals which can then be used to determine what was in the water column with the bigger pollock. The camtrawl has a pair of cameras that shoot stereo images of what is entering the net. The camtrawl was developed by NOAA scientists and its goal is to estimate the size and identify the species that enter the net using visual recognition software from University of Washington. The ultimate goal of the camtrawl is to be able to identify everything entering the net without ever having to actually catch the fish.

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A limitation of the AWT is that it can’t go closer than a few meters from the sea floor. Pollock are semi-pelagic so they are sometimes down at the sea floor and a different net is used. The Poly Nor’Easter (PNE) is used to trawl along the bottom of the Gulf of Alaska because the bottom can be rocky. The PNE has roller gear along its bottom to keep it from getting stuck. The opening of the PNE is 6 meters tall and 15 meters wide and also funnels to a codend.

There is a third net on Oscar Dyson called the Methot and it is used to catch large plankton such as krill. The Methot is so small that it sits on the deck and is easily lifted and put into the water. The net you use is determined by what you are trying to catch and where they are located in the water column.

Interview with Ryan Harris

Chief Boatswain

Official Title
- Chief Boatswain
Normal Job Duties
- I am in charge of the deck operations on board the ship from deploying gear over the side to up keep of the ship.
How long have you been working on Oscar Dyson?
- 15 months
What is your favorite thing about going to sea on Oscar Dyson?
- I get to see things normal people do not.
When did you know you wanted to pursue a career in science or an ocean career?
- 11 years ago I fell in love with the excitement of travel.
What are some of the challenges with your job?
- Trying to keep all the gear working to complete the mission.
What are some of the rewards with your job?
- I get to serve my country and leave something behind that me and my family can be proud of.
Describe a memorable moment at sea.
- Seeing killer Whales 5 feet away.

Interview with Tom Stucki

Lead Fishermen

Official Title
- Lead Fishermen
Normal Job Duties
- I run the winches for trawls, Maintain and fix the nets, help with maintenance of our equipment. Paint and preserve the ship when time and weather allows, clean up inside of ship.
How long have you been working on Oscar Dyson?
- 2 months this time and a month long trip last year. I am a relief pool employee. I fill in where the fleet needs me.
Why the ocean? What made you choose a career at sea?
- I grew up on the coast in a fishing community.
What is your favorite thing about going to sea on Oscar Dyson?
- The crew and work we do.
Why is your work (or research) important?
- Our work is translated back to the commercial fleets so we don’t end up overfishing.
When did you know you wanted to pursue a career in science or an ocean career?
- Once I got out of the Army and went on my first successful Salmon fishing trip.
What part of your job with NOAA (or contracted to NOAA) did you least expect to be doing?
- Traveling as a relief pool employee.
What are some of the challenges with your job?
- Working 12 hour days for months at a time.
What are some of the rewards with your job?
- Knowing that the work I am helping with actually matters and hopefully will have positive implications down the road.
Describe a memorable moment at sea.
- There are lots but its always nice in the middle of a trawl when you look up the sun is setting the water is flat calm and you think to yourself “yeah, I get paid for doing this.

Interview with Jay Michelsen

Skilled Fisherman

Official Title
- Skilled Fisherman
Normal Job Duties
- Operations of equipment to facilitate the needs of the science party.
How long have you been working on Oscar Dyson?
- two years
Why the ocean? What made you choose a career at sea?
- I love the challenge of creating something stable from something so uncertain and ever changing as the ocean.
What is your favorite thing about going to sea on Oscar Dyson?
- Seeing some of the creatures that the ocean has living in its depth.
Why is your work (or research) important?
- My work is important more for personal reasons, I am able to support my family and make their lives more comfortable. My work on the ship is nothing special besides understanding the rigging and being able to trouble shoot issues that arise just as quickly as they show up.
When did you know you wanted to pursue a career in science or an ocean career?
- I have wanted to pursue a career on the water for as long as I can remember, however it was my mother five years ago who pushed me to follow that desire.
What are some of the rewards with your job?
- I enjoy seeing the creatures that we pull up from the ocean. The pay isn’t bad. If you are able to stay in for a long period of time, you can get a stable retirement.
Describe a memorable moment at sea.
- There was a time that we brought up a salmon shark in the net and I was able to get it back into the water by cutting a hole in the net and pulling it out with the help of another deckhand. It was exhilarating!

Personal Log

I will admit that my biggest concern with going to sea was the thought of falling overboard. Now that I have been on Oscar Dyson I have learned that safety is a top priority and there are a lot of procedures for keeping everyone productive yet safe. Every week there are safety drills such as fire, abandon ship, and person overboard. The one I like the most is the abandon ship because I get to try on the survival suit. The waters here are so cold that survival overboard is unlikely without the survival suit.

It is comforting to know that the crew of Oscar Dyson work hard to keep themselves and everyone on board safe. I am no longer afraid of falling overboard because I’ve learned to be safe when navigating around the vessel and I have finally developed my sea legs – well sort of! The weather has been amazing with smooth sailing almost everyday. We did have a few days with some rolling seas and I had to put a seasickness patch behind my ear.

Education Tidbit: NOAA Fisheries Website

Another cool NOAA website that lets you explore deeper into fisheries and this video shows you how to find information for educators and students.

Did You Know?

The average size of a Bering Sea commercial fishing net is 60m tall by 120m wide.

August 4, 2015August 21, 2021

Cristina Veresan, Nets and the Wet Lab, August 3, 2015

NOAA Teacher at Sea
Cristina Veresan
Aboard NOAA Ship Oscar Dyson
July 28 – August 16, 2015

Mission: Walleye Pollock Acoustic-Trawl survey
Geographical area of cruise: Gulf of Alaska
Date: Monday, August 3, 2015

Data from the Bridge:
Latitude: 58° 51.5 N
Longitude: 149° 30.8 W
Sky: Scattered Clouds
Visibility: 10 miles
Wind Direction: SSE
Wind speed: 8 knots
Sea Wave Height: <1 feet
Swell Wave: 0 feet
Sea Water Temperature: 16.3° C
Dry Temperature: 17.2 ° C

Science and Technology Log

Once it is determined where to fish, the scientists also have to decide which trawl to deploy and tow behind the ship in order to catch the targeted fish. The most common trawl we use to catch mid-water pollock is the Aleutian wing trawl (AWT). Our AWT is 140 meters long, and it can be fished anywhere from 30-1,000 meters underwater. A net echosounder is mounted at the top of the net opening and transmits acoustic images of fish going in the mouth of the net in real time to a display on a computer on the bridge that is monitored by the scientist and the Lead Fisherman. Additionally, at the entrance of the codend (the end of the net where the fish are collected), a stereo camera called the CamTrawl takes pictures of anything entering the codend. CamTrawl pictures are later analyzed to determine species and lengths of the fish that were caught. Sometimes the net is fished with the codend opened and the catch is only evaluated based on what is seen in the CamTrawl images. As this technology gets perfected less fish will need to be brought onboard.

A view of the stern as the deck crew prepares to deploy the AWT. Note the net reel at the bottom of the frame. — A view of the stern as the deck crew prepares to deploy the AWT. Note the AWT on the net reel at the bottom of the frame.

Cooperation among many different people is necessary during a trawl. The wet lab team prepares the CamTrawl to collect data. The deck crew physically handles all the gear on deck, including attaching the CamTrawl camera, net echosounders, and physical oceanography instruments to the net and deploying and recovering the net. From the bridge, the Lead Fisherman controls the winches that move the trawl net in and out of the water. Once the trawl net is in the water, the scientists work closely with the Lead Fisherman and the officers to ensure a safe, effective trawl. Sometimes the trawl net will be down for a few minutes, and other times it will be closer to an hour. Once the net is back on the ship and emptied out, the catch and CamTrawl images are ready to be analyzed by the scientist and wet lab team.

CamTrawl images were filmed by two cameras in stereo and so scientists can run a program that calculates length. — Fish are filmed in stereo so scientists can run a program that calculates their length.

Two other nets, more seldom used, are the bottom trawl net, known as the Poly Nor’easter (PNE) and the Methot net, used to catch krill and zooplankton. The PNE is deployed if there is a large concentration of fish close to the ocean floor. It is smaller than the AWT and it is usually lowered to just above the ocean floor. The Methot net was named after Dr. Richard Methot, a famous fisheries modeler who designed the net. This net has an opening of 5 square meters, and it has a finer mesh than the AWT or the PNE. At the end of the net is a small PVC codend where the sample is taken from.

Shipmate Spotlight: Interview with Kirk Perry

Kirk Smith, Lead Fisherman and Chief Boatswain — Kirk Perry, Lead Fisherman and Chief Boatswain

What is your position on the Oscar Dyson?
I am the Lead Fisherman and also sailing as active Chief Boatswain.

What training or education do you need for your position?
I went to Cal Poly San Luis Obispo and got a BS in Natural Resource Management. I have certifications from the Coast Guard like an AB (Able-Bodied Seaman) unlimited, which means I have over 1070 days sailing as an AB. I also have a Masters license to operate a 100-ton vessel. You need a lot of fishing experience.

What do you enjoy the most about your work?
Fishing! Obviously. You just never know what you are going to get, and it’s always exciting.

Have you had much experience at sea?
I have been fishing since I was 10 years old and I helped a neighbor build a boat and go salmon fishing in Monterey Bay. When I visited family in Hawai’i, we would go trolling, set net fishing, beach casting, and spearfishing. I have been sailing professionally with NOAA for 11 years on different vessels in Hawai’i, Mississippi, and here in Alaska.

Where do you do most of your work aboard the ship? What do you do?
As Lead Fisherman I operate the machinery from the bridge when we are trawling. Basically, I get the fishing gear in and out of the water safely. As Chief Boatswain, I am in charge of the Deck Department, so I schedule crew, assign daily crew duties, maintain supply inventories, oversee the ship’s survival gear, and operate deck equipment like winches, anchor, and cranes.

When did you know you wanted to pursue a marine career?
By 25 years old I knew I had to be on the water, full time, all the time, but I did not get to be here until I was 44 years old.

What are your hobbies?
When I’m not fishing, I like to hunt. Mainly ducks and geese.

What do you miss most while working at sea?
Home, my family. And my own bed!

What is your favorite marine creature?
Tuna because they are so fast powerful and so delicious! When you are fishing for them, it’s like nothing else. It can turn into a wide open frenzy.

Inside the Oscar Dyson: The Wet Lab

The wet lab is where we do most of our work, and it gets really busy in here after a trawl. It is called a “wet” lab because it is designed to get just that. When a trawl net is full of fish, it is emptied onto a table that tilts onto a conveyor belt feeding into the wet lab. We have controls to run the conveyor belt as well as tilt the tableAs the fish are brought in on the conveyor, we sort them in large and small baskets, and then collect data from the different species. The metal counters, outfitted with electronic balances and automated length readers provide us with workspace to process our samples. The work of the wet lab is messy and fun. When we process a catch, fish scales get everywhere! The shiny, sticky little discs coat every surface, especially areas that you touch like the computer screens and handles. It is fun to clean this lab because you spray everything down with the salt water from hoses that are rigged from the ceiling. You can even spray down the computer screens themselves, and then rinse them with fresh water. Water washes over everything and drips down, entering drains in troughs along the edges of the floor.

Processing pollock in the wet lab! Photo by Emily Collins

Personal Log

Whenever it’s time to process fish in the wet lab, I have to get geared up! What is the latest in fisheries fashion, you might ask? Rubber boots are a must. We take the lead of Alaskans and wear brown XtraTuf boots. Once I get my boots on, I put on my Grundens foul weather coveralls over my pants. The weather has been mild, so I have been forgoing the matching foul weather jacket and just wearing a long sleeved t-shirt or sweatshirt. I have not been wearing a hat, but I do pull my hair back. Lastly, I pull on elbow-length yellow rubber gloves over my sleeves.

Before you enter the wet lab, you get geared up here. Sometimes to make a quick entrance/exit, you leave your boots in your coveralls (bottom right)

These boots are made for fishin' — These boots are made for fishin’

I am really enjoying my time with this ship’s crew and the rest of the science party. Everyone has been very welcoming, and, though we work hard, we maintain a sense of fun. If we have down time between data collection, Emily and I play cribbage. Or we go out on deck and take in the sights, like the Holgate glacier we passed the other day. Quite a few people on board have spent time in Hawai’i, so we can ‘talk story’ about the islands from all the way up here in the North Pacific. It is amazing how we are all connected in some way through our love of the ocean.

My voyage of discovery continues…

glacier — We sailed within 4 miles of Holgate Glacier on a beautiful sunny morning

July 13, 2015August 11, 2021

Andrea Schmuttermair, Pollock Processing Gone Wild, July 12, 2015

NOAA Teacher at Sea
Andrea Schmuttermair
Aboard NOAA Ship Oscar Dyson
July 6 – 25, 2015

Mission: Walleye Pollock Survey
Geographical area of cruise: Gulf of Alaska
Date: July 12, 2015

Weather Data from the Bridge:
Latitude: 55 25.5N
Longitude: 155 44.2W
Sea wave height: 2ft
Wind Speed: 17 knots
Wind Direction: 244 degrees
Visibility: 10nm
Air Temperature: 11.4 C
Barometric Pressure: 1002.4 mbar
Sky: Overcast

Science and Technology Log

I’m sure you’re all wondering what the day-to-day life of a scientist is on this ship. As I said before, there are several projects going on, with the focus being on assessing the walleye pollock population. In my last post I talked about the transducers we have on the ship that help us detect fish and other ocean life beneath the surface of the ocean. So what happens with all these fish we are detecting?

The echogram that shows data from the transducers.

The transducers are running constantly as the ship runs, and the information is received through the software on the computers we see in the acoustics lab. The officers running the ship, who are positioned on the bridge, also have access to this information. The scientists and officers are in constant communication, as the officers are responsible for driving the ship to specific locations along a pre-determined track. The echograms (type of graph) that are displayed on the computers show scientists where the bottom of the ocean floor is, and also show them where there are various concentrations of fish.

This is a picture of pollock entering the net taken from the CamTrawl.

When there is a significant concentration of pollock, or when the data show something unique, scientists might decide to “go fishing”. Here they collect a sample in order to see if what they are seeing on the echogram matches what comes up in the catch. Typically we use the Aleutian wing trawl (AWT) to conduct a mid-water trawl. The AWT is 140 m long and can descend anywhere from 30-1,000 meters into the ocean. A net sounder is mounted at the top of the net opening. It transmits acoustic images of fish inside and outside of the net in real time and is displayed on a bridge computer to aide the fishing operation. At the entrance to the codend (at the end of the net) a CamTrawl takes images of what is entering the net.

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Once the AWT is deployed to the pre-determined depth, the scientists carefully monitor acoustic images to catch an appropriate sample. Deploying the net is quite a process, and requires careful communication between the bridge officers and the deck crew. It takes about an hour for the net to go from its home on deck to its desired depth, and sometimes longer if it is heading into deeper waters. They aim to collect roughly 500 fish in order to take a subsample of about 300 fish. Sometimes the trawl net will be down for less than 5 minutes, and other times it will be down longer. Scientists are very meticulous about monitoring the amount of fish that goes into the net because they do not want to take a larger sample than needed. Once they have determined they have the appropriate amount, the net is hauled back onto the back deck and lowered to a table that leads into the wet lab for processing.

Here the scientists, LT Rhodes, and ENS Kaiser assess the catch.

We begin by sorting through the catch and pulling out anything that is not pollock. We don’t typically have too much variety in our catches, as pollock is the main fish that we are after. We have, however, pulled in a few squid, isopods, cod, and several jellies. All of the pollock in the catch gets weighed, and then a sub-sample of the catch is processed further. A subsample of 30 pollock is taken to measure, weigh, collect otoliths from, and occasionally we will also take ovaries from the females. There are some scientists back in the lab in Seattle that are working on special projects related to pollock, and we also help these scientists in the lab collect their data.

The rest of the sub-sample (roughly 300 pollock) is sexed and divided into a male (blokes) and female (sheilas) section of the table. From there, the males and females are measured for their length. The icthystick, the tool we use to measure the length of each fish, is pretty neat because it uses a magnet to send the length of the fish directly to the computer system we use to collect the data, CLAMS. CLAMS stands for Catch Logger for Acoustic Midwater Survey. In the CLAMS system, a histogram is made, and we post the graphs in the acoustics lab for review. The majority of our pollock so far have been year 3. Scientists know this based on the length of pollock in our catch. Once all of the fish have been processed, we have to make sure to clean up the lab too. This is a time I am definitely thankful we have foul weather gear, which consists of rubber boots, pants, jackets and gloves. Fish scales and guts can get everywhere!

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Personal Log

Here is one of many jellies that we caught. .

I am finally adjusting to my nighttime shift schedule, which took a few days to get used to. Luckily, we do have a few hours of darkness (from about midnight until 6am), which makes it easier to fall asleep. My shift runs from 4pm-4am, and I usually head to bed not long after my shift is over, and get up around noontime to begin my day. It’s a little strange to be waking up so late in the day, and while it is clearly afternoon time when I emerge from my room, I still greet everyone with a good morning. The eating schedule has taken some getting used to- I find that I still want to have breakfast when I get up. Dinner is served at 5pm, but since I eat breakfast around 1 or 2pm, I typically make myself a plate and set it aside for later in the evening when I’m hungry again. I’ll admit it’s a little strange to be eating dinner at midnight. There is no shortage of food on board, and our stewards make sure there are plenty of snacks available around the clock. Salad and fruit are always options, as well as some less healthy but equally tasty snacks. It’s hard to resist some of the goodies we have!

Luckily, we are equipped with some exercise equipment on board to battle those snacks, which is helpful as you can only walk so far around the ship. I’m a fan of the rowing machine, and you feel like you’re on the water when the boat is rocking heavily. We have some free weights, an exercise bike and even a punching bag. I typically work out during some of my free time, which keeps me from going too crazy when we’re sitting for long periods of time in the lab.

Up on the bridge making the turn for our next transect.

During the rest of my free time, you might find me hanging out in the lounge watching a movie (occasionally), but most of the time you’ll find me up on the bridge watching for whales or other sea life. The bridge is probably one of my favorite places on the ship, as it is equipped with windows all around, and binoculars for checking out the wildlife. When the weather is nice, it is a great place to sit outside and soak in a little vitamin D. I love the fact that even the crew members that have been on this ship for several years love seeing the wildlife, and never tire of looking out for whales. So far, we’ve seen orcas, humpbacks, fin whales, and Dall’s porpoises.

Did you know? Otoliths, which are made of calcium carbonate, are unique to each species of fish.

Where on the ship is Wilson?

Wilson the ring tail camo shark is at it again! He has been exploring the ship even more and made his way here. Can you guess where he is now?

August 1, 2013August 20, 2021

Melissa George: Catch Me if You Can, July 31, 2013

NOAA Teacher at Sea
Melissa George
Aboard NOAA Ship Oscar Dyson
July 22 – August 9, 2013

Mission: Pollock Survey
Geographical Area of Cruise: Gulf of Alaska
Date: July 31, 2013

Current Data From Today’s Cruise

Weather Data from the Bridge (12 noon Alaska Daylight Time)
Sky Condition: Cloudy
Temperature: 12.8 ° C
Wind Speed: 14 knots
Barometric Pressure: 1024.7 mb
Humidity: 89%

Clouds Seen from Bow of Oscar Dyson on July 31, 2013

Sun and Moon Data
Sunrise: 6:03 am
Sunset: 10:28 pm

Moonrise: 1:06 am
Moonset: 5:58 pm

Geographic Coordinates at 12 noon (Alaska Daylight Time)

Latitude: 59° 39.3′ N
Longitude: 157° 51.2′ W

The ship’s position now can be found by clicking: Oscar Dyson’s Geographical Position

Science and Technology Log

The main goal of Leg 3 of this mission is to survey the mid-water portion of the pollock population using acoustics and trawls. Pollock usually inhabit the middle of the water column down to the seafloor. This mid-water survey is typically carried out once every two years. Another NOAA Fisheries survey observes the pollock that live close to the seafloor using bottom trawls.

Trawling

The Oscar Dyson carries three different types of trawling nets for capturing fish as part of the mid-water survey: the Aleutian Wing Trawl (AWT), a mid-water trawl net called the Poly Nor’Eastern bottom trawl, a net with special rubber bumpers so it can bounce along the ocean floor; and the Methot, a small encased net that gathers very small ocean creatures such as krill. I will be discussing trawling with the AWT in this blog.

leg 3 — Leg 3 of the Mid-Water Survey Began East of Kodiak and Will End Near Yakutat

First, I will describe the AWT net, then I will explain how it works. The AWT net is HUGE: the mouth is about 25 m high and 35 m wide while the net itself is over 150 m long (this is not counting the trawling wires that it is attached to!). To give you an idea of how big this is, let’s think in school buses. If we estimate a school bus to be about 10 m long, then this net would be 15 school buses long, and its mouth would be 3 school buses wide and 2 school buses (end to end) tall. The picture below also gives perspective in dimensions (keep in mind that the Blue Whale is only used to give relative dimensions, they are never caught in NOAA’s nets!)

Relative Dimensions of AWT Net (courtesy of Kresimir Williams)

I am going to describe how the net goes into the water, step by step. Then you can watch a short sped-up video that my fellow Teacher at Sea mate, Julia Harvey, created. She works the night shift (4 pm to 4 am) on the same cruise that I am on.

So here it goes…

Step 1: The Codend

When the net is deployed from the ship, the first part of the net to hit the water is called the codend (see the far right of the diagram above). This is where most of the fish end up after the trawl. The mesh size of the net is smallest at the codend (about 1 cm) and gets larger as it approaches the doors (about 1 m).

Labeled Scale Model of the Aleutian Wing Trawl (AWT) Net (courtesy of NOAA Scientist Kresimir Williams)

Step 2: The Trawl Camera

A trawl camera is the next major part that hits the water. This is a pair of cameras that help scientists identify and measure the fish that are caught in the net. This technology can also be used to help scientists validate their biomass estimate from trawling sampling counts. This piece of equipment has to be clipped into the side of the net each time the crew is instructed to deploy the AWT.

Step 3: The Kite

The next piece of the net to hit the water is the kite which is secured to the head rope. Attached to the kite is a series of sensors that help the scientists gather data about the condition of the net including depth, size, and shape underwater. The major acoustic sensor, affectionately termed the turtle, can tell the scientists if the fish are actually going into the net.

Close-up view of the AWT scale model to highlight the kite and the turtle that ride at the top of the net. The third wire holds the electrical wires that send data from the turtle to the bridge.

Step 4: Deployment from A-Frame

Once the kite is deployed, a pair of tom weights (each weighing 250 lbs), are attached to the bridal cables to help separate the head rope from the foot rope and ensure the mouth of the net will open. Then, after a good length of cable is let out, the crew transfers the net from the net reel to the two tuna towers and attaches the doors. The doors act as hydrofoils and create drag to ensure the net mouth opens wide.

The scientists use acoustic data to determine at what depth they should fish, then the OOD (Officer on Deck) uses a scope table to determine how much cable to let out in order to reach our target depth. Adjustments to the depth of the head rope can be made by adjusting speed and/or adjusting the length of cable released.

The scientists use more acoustic data sent from the turtle to determine when enough fish are caught to have a scientifically viable sample size, then the entire net is hauled in. Once on board, the crew uses a crane to lift the codend over to the lift-table. The lift-table then dumps the catch into the fish lab where the fish get sorted on a conveyor belt. Click on Julia’s video below to see the entire process (sped up to retain the your interest!)

Personal Log:

Belongingness

Continuing with Maslow’s hierarchy of needs, I will discuss some of the ways that the need of belongingness is met on the Oscar Dyson. There are several different ways that comaraderie is fostered on the ship: teamwork, common areas, meal time, and celebrations.

A Version of Maslow's Hierarchy of Needs — A Version of Maslow’s Hierarchy of Needs

Teamwork

Remember the main goal of Leg 3 of this mission is to survey by acoustic-trawl the mid-water portion of the pollock population. To ensure that the goal of the mission is accomplished, several crews are necessary: engineering, officer, deck, and science crews. People assigned to a crew work together, and there is cross-talk between crews. For example, on the bridge where the officers work, there are two to four people navigating the ship and instructing the deck crew. The deck crew works together to put out and pull in the trawling nets, and the engineering crew works together to make sure the ship is operating properly. Similarly, the scientist crew members consult with each other while: reading the acoustics on the computer screens; deciding when, where, and how long to trawl; determining the best way to process the trawl; and reconciling the “catch” with the acoustical data. The collaboration within and between the four crews mimics a sports team that has offensive and defensive strings working together to maintain their positions to accomplish a common goal.

Common Areas

The ship is like a house with many rooms. Most of the staterooms (bedroom/bath) are shared. In terms of “living space” there is one dining area (called the galley), a conference room with books where people meet for drills or quiet work, a movie room, a laundry room, and an extra rest room. Because all these areas are shared, “ship etiquette” is followed, meaning that every individual keeps his or her space neat and also keeps the other common areas clean and organized. Sometimes, reminders are placed in areas where ship etiquette needs polishing.

Reminder of Ship Etiquette in Common Restroom

Meal Times
Meals on the Oscar Dyson are during one hour windows three times a day. Breakfast is served from 7 to 8 am, lunch 11am to noon, and dinner 5 to 6 pm. Unless people are sleeping or actively involved in trawling or processing, they eat at these times. Therefore, mealtime is a time to chat, joke, ask questions, and tell stories.

Galley Reminder


Celebrations
We have had three celebrations. Two of these were for birthdays celebrated on the ship. The stewards made a cake for dessert in one instance and hosted an ice cream social in the second. Another celebration was when we were in Prince William Sound to pick up net repair supplies. Because we were near land for the first time in many days and the sun was shining, many people came on deck at the same time to take pictures. Some spotted porpoises which added to the excitement. Fellow Teacher at Sea, Julia Harvey, captured a wonderful video of this event.

Did You Know?

The ship stewards are the people who plan and prepare the meals for those on board. Adam (below) is the second cook on the Oscar Dyson. He worked in various restaurants in Portland before coming to NOAA as a General Vessel Assistant (GVA) helping with the different crews on various ships as needed. When the spot as a steward opened on the Oscar Dyson, Adam got the job. He has taken various NOAA training courses for stewardship and is on the ship nine months out of the year as it surveys both in the Bering Sea and the Gulf of Alaska.

Something to Think About:

Today’s episode of Trawling Zoology features the animal family, Cnidaria. Cnidaria is a word that originates from the Greek word cnidos which means “stinging nettle.” Although the cnidarians are a very diverse family, all the members contain nematocysts (combination of Greek words nema meaning “thread” and kystis meaning “bladder”), basically barbed threads tipped with poison. If you have ever been stung by a jellyfish, you have felt this stinging sensation.

There are four very diverse groups of cnidarians: Anthozoa which includes true corals, anemones, and sea pens; Cubozoa, the amazing box jellies with complex eyes and potent toxins; Hydrozoa, the most diverse group with siphonophores, hydroids, fire corals, and many medusae; and Scyphozoa, the true jellyfish. We have brought up several members of these groups in our trawling.

Anthozoa: We have brought on deck both sea pens and sea anenomes. In both groups there was only one species represented.

Sea Anenomes (hermit crabs in front are not anthozoans)

Schyphozoa: We brought up a couple of different species of jellyfish; we used a classification field guide to help us identify them.

Jellyfish from the Invertebrate Field Guide for Alaskan Waters

Many Jellies (members of the Aequorea genus) Found in the Methot Trawl

To learn more about the Cnidaria Family, click the Cnidaria on the picture below, and stay tuned for further exploration of this animal Tree of Life.

Can you spot the Cnidarian on the Tree of Life? Click on it to learn more.