Marla Crouch: The Mystery and Surf Your Berth, June 14, 2013

NOAA Teacher at Sea
Marla Crouch
Aboard NOAA Ship Oscar Dyson
June 8 – 26, 2013 

Mission:  Pollock Survey
Geographical area of cruise:  Gulf of Alaska
Date: June 14, 2013

Weather Data from the Bridge: as of 1900
Wind Speed 9.57 kts
Air Temperature 6.84°C
Relative Humidity 81.00%
Barometric Pressure 1,030.5 mb

Latitude:  53.52N   Longitude: 166.34W

Science and Technology Log

The sonar on the Oscar Dyson recently created the graph below.  The graph displays the sea floor, the red, yellow, and green bands toward the bottom and along the top a few meters from the surface the layer of green and red, is the mystery.

Graphic provided by NOAA

Graphic provided by NOAA

The echoes, that create the graph do not look like fish.  The scientists recognize that something is there, the questions is, what?  Further exploration is done, but nothing definitive is found. This creates a bit of a dilemma, which initiates a whole series of conversations about trouble shooting the equipment, using different data gathering techniques (something different than a trawl), and hypothesizing about what is creating the image since there are no apparent biology.  Could the image be created by something physical in the water?  Until the make-up of the image can be identified the sonar signature, is titled and recorded as Mystery Mix One.

Taina Honkalehto, one of the scientists on this cruise, tells me that they have been encountering Mystery Mix One for a number of years here, in the Gulf of Alaska, and in different parts of the ocean at different times of the year. Mystery Mixes Two and Three are floating around as well.

Investigating Mystery Mix One:  Time stamp 12 June 2013, 050952 GMT (This time stamp equates to 8:09 almost 8:10 p.m. June 11, 2013 PDT.)

The stereo camera, which I talked about in my last blog, is a new piece of equipment that scientists are using to collect data about the ocean floor and the biology of the region.  The stereo camera was launched and submerged to a depth of 50m into the middle of Mystery Mix One, and left at that depth for 30 minutes while the Oscar Dyson drifted with the mix.  When the pictures were downloaded, the only identifiable objects were copepods, big copepods. Remember “big” is a relative term, big compared to what? Copepods can be smaller than 1 mm in length.  These big copepods are probably 6 to 8 mm.

The light image in the upper left-hand corner is a copepod.  Picture provided by NOAA

The light image in the upper left-hand corner is a copepod. Picture provided by NOAA

This is a clearer picture of a copepod. This is a clearer picture of a copepod.     Picture courtesy of

This is a clearer picture of a copepod.
Picture courtesy of

The strong sonar image created by the copepods heighten the mystery; starting another round of questions and discussions by the scientists.  Why are copepods creating such a strong sonar signature?  Why are the copepods so prominent on 18 kHz? (18 kHz is a low frequency that usually captures echoes from large objects, while small things like copepods would be seen at higher frequencies, like 200 kHz.)   Could something else be in Mystery Mix One, something that was not seen by the camera?  The discussion goes on creating a working hypothesis; the signature is being created by a combination of the copepods themselves, whatever they are feeding on and gases, being produced.  Not all the scientists are in agreement.  If Mystery Mix One was to be sampled again, would you get similar results?

Pictures from the stereo camera provided one piece of possible evidence that may lead to answering the question, “What is in Mystery Mix One?”

The next day another piece of possible evidence is added.  Oscar Dyson’s sea water intake filter is cleaned and what is found?  Krill and big copepods.  Pictures are taken and the evidence is recorded in the scientists’ journal. More evidence needs to be collected, but advances are being made to identify Mystery Mix One.

Krill are in the red ringed filter.  Copepods can be seen at the bottom of the bucket.

Krill are in the red ringed filter. Copepods can be seen at the bottom of the bucket.

Personal Log 

The first few days out at sea the waters were really calm, 1 to 3 foot swells or seas, which feels like the soothing glide of a rocking chair.  Now however, weather is moving in; wind speed is up around 15kts and the swells are about 9 ft.  Friday’s forecast is for 30kt winds and 12ft. seas.  Looking at the big picture, 9 to 12 foot seas are not very big.  But, walking around the ship with seas of that height requires due diligent to safely navigate the passage ways and steep stairs.  And you definitely need to mind the doors, make sure the door is securely latched and when opening hold on tight, as you don’t want the door to get away from you. Somebody might be standing on the other side.  Another activity that can prove challenging is getting into and out of your bunk.

The berths, or rooms, aboard ship are, for the most part, designed for two people. Look at the picture of my berth.  You can see a desk, chair, dresser and two draped bunk beds.  Mine’s the top bunk.  Our room is just about even with the water line.  That is important to know, because the lower you are in the ship the less dramatic the motion.  I’ll talk about the pitch and roll of the ship in a future blog

This is my berth.

This is my berth.

Now imagine yourself lying on a teeter totter.  You are right above the fulcrum, so you are nice and level.  An unbalanced force is now affecting your teeter totter, your feet go up your head goes down and you slide a little.  Then there is a change and you head goes up your feet go down and you slide back.  This back and forth motion is continuous, and the motion presses you into the teeter totter.  I call this the sloshing phenomena, because all the while you are teeter tottering you hear the sea water rushing pass the hull.  But wait, there is more.  Your teeter totter only moves in two dimensions, but we live in three dimensions.  Keep your teeter totter going, up and down, hear the water stream by and add a sideways roll, back and forth.  Don’t fall off your teeter totter.  You are not quite ready to surf your berth yet, sometimes the up and down, and side to side movements occur so quickly that you actually loose contact with your teeter totter.  Now you’re surfing!  I have yet to find the seat belt for my bunk.

Remember I said that my berth was low in the ship, there are only a few berths on this level, and more berths are two and three floors above me. Now think about a metronome.  If you’re not sure what a metronome is think about a windshield wiper on a car.  Both the metronome and the windshield wiper make small movements at the pivot point or fulcrum; the further away from the fulcrum the greater the range of motion. Think about how the motion is magnified as you move up from the water line.  Those folks above me are really surfing.

Did You Know?

When Taina and I were talking about Mystery Mix One she said the 18 kHz frequency ensonifying the larger fish.  I think ensonify is a cool word. I wonder if Mrs. Sunmark or Mrs. Delpez (our school’s band and orchestra teachers) have used the word ensonify in their classes?  Can any of you tell me what ensonify means?

Did you know you can follow my voyage on NOAA’s ship tracker website?  Here is the link.

In my next blog, I have another fashion statement – Gumbi Marla!  And maybe something about the moon and Apollo 17.

Jason Moeller: June 25-27, 2011

JUNE 11 – JUNE 30, 2011

NOAA Teacher at Sea: Jason Moeller
Ship: Oscar Dyson
Mission: Walleye Pollock Survey
Geographic Location: Gulf of Alaska
Dates: June 25-27, 2011

Ship Data
Latitude: 55.58 N
Longitude: -159.16 W
Wind: 14.11
Surface Water Temperature: 7.2 degrees C
Air Temperature: 9.0 degrees C
Relative Humidity: 90%
Depth: 85.61

Personal Log
Anyone who has seen the show Deadliest Catchknows how dangerous crab fishing can be. Fishing for pollock, however, also has its dangers. Unfortunately, we found out the hard way. One of our deck hands caught his hand between a cable and the roller used to pull up the trawl net and hurt himself badly.


The cable and the roller.

Fortunately, the injuries are not life threatening and he will be fine. The injuries did require a hospital visit, and so we stopped at Sand Point to treat him.


This is the town of Sand Point.


Clouds hang over the hills at Sand Point. The airstrip is in the left edge of the photo.

We stayed at Sand Point for nearly 48 hours. What did we do? We fished, of course! We used long lines and hooks, and had a great time!


Bill and Alex cast fishing lines in the harbor. We tied the lines off on the boat and hauled them up from time to time to check the bait.


Alex with a flounder that he caught! He also caught several cod and a 32-lb Pacific halibut!


Cod and the flounder in a bucket!


As with every fishing trip, we also managed to catch things that we didn't mean too! Tammy (the other NOAA Teacher at Sea) especially liked the kelp!


A few visitors always hitched a ride on the kelp we caught. Here is a tiny sea urchin.


This crab was another hitchhiker on the kelp.


We were bottom fishing for Halibut, and a starfish, the largest one I've ever seen, went after the bait!

A one-day fishing license in Alaska costs $20.00. We had internet, so five of us went online and bought the fishing passes. Was it worth it?


You bet it was! This is the 25-lb halibut I caught! It was AWESOME!!!

We filleted it and had the cooks make it for dinner. With the halibut, we also cut out the fleshy “cheeks” and ate them as sushi right on the spot! It doesn’t get any fresher (or tastier!) than that!

Science and Technology Log
Today we will look at the acoustic system of the Oscar Dyson! Acoustics is the science that studies how waves (including vibrations & sound waves) move through solids, liquids, and gases. The Oscar Dyson uses its acoustic system to find the pollock that we process.

The process begins when a piece of equipment called a transducer converts an electrical pulse into a sound wave. The transducers are located on the underside of the ship (in the water). The sound travels away from the vessel at roughly 1500 feet per minute, and continues to do so until the sound wave hits another object such as a bubble, plankton, a fish, or the bottom. When the sound wave hits an object, it reflects the sound wave, sending the sound wave back to the Oscar Dyson as an echo. Equipment onboard listens to the echo.

The computers look at two critical pieces of information from the returning sound wave. First, it measures the time that it took the echo to travel back to the ship. This piece of information gives the scientists onboard the distance the sound wave traveled. Remember that sound travels at roughly 1500 feet per minute. If the sound came back in one minute, then the object that the sound wave hit is 750 feet away (the sound traveled 750 feet to the object, hit the object, and then traveled 750 feet back to the boat).

The second critical piece of information is the intensity of the echo. The intensity of the echo tells the scientists how small or how large an object is, and this gives us an idea of what the sound wave hit. Tiny echos near the surface are almost certainly plankton, but larger objects in the midwater might be a school of fish.

good fishing

An image of the computer screen that shows a great number of fish. This was taken underneath the boat as we were line fishing in Sand Point.

poor fishing

The same spot as above, but with practically no fish.


An image of the screen during a trawl. You can actually see the net--it is the two brown lines that are running from left to right towards the top of the screen.

One of the things that surprised me the most was that fish and bubbles often look similar enough under water that it can fool the acoustics team into thinking that the bubbles are actually fish. This is because many species of fish have gas pockets inside of them, and so the readout looks very similar. The gas pockets are technically called “swim bladders” and they are used to help the fish control buoyancy in the water.


Swim bladder of a fish.

Species Seen
Northern Fulmar
Pacific Halibut
Sea Urchin

Reader Question(s) of the Day
Today’s questions come from Kevin Hils, the Director of Chehaw Wild Animal Park in Chehaw, Georgia!

Q. Where does the ship name come from?
A. Oscar Dyson was an Alaska fisheries industry leader from Kodiak, Alaska. He is best known for pioneering research and development of Alaska’s groundfish, shrimp, and crab industry. Dyson was a founding partner of All Alaskan Seafoods, which was the first company actually controlled by the fishermen who owned the vessel. He also served on the North Pacific Fisheries Management council for nine years. He is in the United Fishermen of Alaska’s hall of fame for his work. The ship was christened by his wife, Mrs. Peggy Dyson-Malson, and launched on October 17, 2003.


Oscar Dyson


The launching of the Oscar Dyson

Q. How do you see this helping you teach at Knoxville Zoo, not an aquarium?
A. This will be a long answer. This experience will improve environmental education at the zoo in a variety of different ways.

First, this will better allow me to teach the Oceanography portion of my homeschool class that comes to the zoo every Tuesday. For example, I am in the process of creating a hands on fishing trip that will teach students about the research I have done aboard the Oscar Dyson and why that research is important. Homeschool students will not just benefit from this experience in Oceanography, but also in physics (when we look at sound and sonar) and other subjects as well from the technical aspects that I have learned during the course of the trip.

Scouts are another group that will greatly benefit from this experience as well. The Girl Scout council wishes to see a greater emphasis in the future on having the girls do science and getting real world experiences. While the girls are still going to desire the animal knowledge that the zoo can bring, they will also expect to do the science as well as learn about it. My experience aboard the Dyson will allow me to create workshops that can mimic a real world animal research experience, as I can now explain and show how research is done in the field.

The same can be said of the boy scouts.

In addition, one of the most common badges that is taught to boy scout groups that come in is the fish and wildlife merit badge. In the past, the badge has primarily focused on the wildlife aspect of this topic. However, I now have the knowledge to write and teach a fisheries portion for that merit badge, as opposed to quickly covering it and moving on. This will enrich future scouts who visit the zoo for this program.

A major focus for all scouts is the concept of Leave No Trace, where scouts are supposed to leave an area the way they found it. The fisheries research being done aboard the Dyson is focused toward that same goal in the ocean, where we are attempting to keep the pollock population as we found it, creating a sustainable fishery. The goal aboard the Dyson is similar to the goal in scouting. We need to be sustainable, we need to be environmentally friendly, and we need to leave no trace behind.

School children on field trips will greatly benefit, especially students in the adaptations section. There are some bizarre adaptations that I never knew about! For example, sleeper sharks slow, deliberate movement coupled with their fin and body shape basically make them the stealth fighter of the fish world. They can catch fish twice as fast as they are! Lumpsuckers are neat critters too! This knowledge will enhance their experience at the zoo during field trip programs.

Finally, I can pass the knowledge from this experience on to my coworkers. This will not only better the experience of my students, but it will also improve the outreach programs, the bedtime programs, the camps, and other programming done at the zoo.

Q. Are you old enough to be on a ship? You look like you’re 13???!!!!
A. SHHHHHHH!!!! You weren’t supposed to tell them my real age! They think I’m 24!