Phil Moorhouse: It’s Bongo Time! September 7, 2019

NOAA Teacher at Sea

Phil Moorhouse

Aboard NOAA Ship Oscar Dyson

August 27 – September 15, 2019

Mission: Fisheries-Oceanography Coordinated Investigations.

Geographic Area of Cruise: Gulf of Alaska (Kodiak – Aleutian Islands)

Date: September 7, 2019

Weather Data from the Bridge

Latitude: 56 15.09 N
Longitude: 157 55.74 W
Sea wave height: 8 ft
Wind Speed: 1.9 knots
Wind Direction: 179 degrees
Visibility: 10 nautical miles
Air Temperature: 12.8 C
Barometric Pressure: 1010.45 mBar
Sky:  Clear

Science and Technology Log:

One of the more technologically interesting pieces of equipment we are using is the Bongo net.  One of the main aspects of this cruise is the zooplankton survey. As I have stated before, this survey is important to studying the prey for the juvenile pollock and is done at the same stations where we trawl for juvenile pollock so that scientists looking at the data can compare the ecology of the pollock with the ecology of their prey.  The Bongo net is used to collect the zooplankton. This contraption is a series of two large and two smaller nets attached to metal rings. It gets its name because the frame resembles bongo drums.  

The diagram on the left shows a 20 cm bongo net set-up. (Photo credit: NOAA – Alaska Fisheries Science Center).  The picture on the right shows the Bongo we are currently using on the Oscar Dyson with two 60 cm nets and two 20 cm nets.

lowered bongo
The Bongo has just been lowered into the water and following its descent.

The bongo net design we are using includes two large nets on 60 cm frames with 500 micrometer nets and two small nets on a 20 cm frames with 153 micrometer nets.  The 500 micrometer nets catch larger zooplankton and the 153 micrometer nets catch smaller zooplankton.  The diagram above has just two nets, but our Bongo has 4 total nets.  At the top of the bongo net setup is a device called the Fastcat.  This records information from the tow including the depth that bongo reaches and the temperature, salinity, and conductivity of the water.

This whole process involves a lot of working together and communication among the scientists and crew.  It usually involves three scientists, one survey tech, a winch operator, and the officer on the bridge. All members involved remain in radio contact to ensure that the operations run smoothly.  Two scientists and the survey tech work on the “hero deck”.  They oversee getting the nets overboard safely and back on the deck at the end of the evolution.  The unit is picked up and lowered over the side of the ship by a large hydraulic wench attached to the side A-frame.  Another scientist works in the data room at a computer monitoring the depth and angle of the Bongo as it is lowered into the water.  As the Bongo net is lowered, the ship moves forward at approximately 2 knots (2.3 mph).  This is done to keep the cable holding the Bongo at a 45-degree angle. A 45-degree angle of the wire that tows the Bongo is important to make sure that water flows directly into the mouth opening of the net.  One of the scientists on the hero deck will constantly monitor the wire angle using a device called an inclinometer or clinometer and report it to the officer on the bridge.  The bridge officer will then adjust the speed if necessary, to maintain the proper wire angle.

monitoring the bongo tow
Here, I am monitoring the angle of the Bongo wire using the inclinometer.
The flat side of the inclinometer gets lined up with the wire and an arrow dangles down on the plate and marks the angle.

The depth the Bongo is sent down depends on how deep the water is in that area (you wouldn’t want an expensive piece of equipment dragging on the ocean floor).  The Bongo is deployed to a depth of up to 200 meters or to a depth of no less than 10 meters from the bottom. When the Bongo is at the designated depth, the survey tech will radio the winch operator to bring the Bongo back up slowly.  It is brought back up slowly at 20 meters per minute and the 45-degree angle needs to continue to be maintained all the way back up. When the Bongo reaches the surface and is lifted back into the air, the survey tech and two scientists grab it and guide it back onto the deck.  This operation can be difficult when the conditions are windy, and the seas are rough.  

Once the Bongo has been returned to the deck, the scientist that was in the data room will record the time of the net deployment, how long it took to go down and back up, how much wire was let out, and the total depth of the station.  They will also come back out to read the flowmeters in order to see how much water has flowed through the net during the deployment. If anything goes wrong, this is also noted on the data sheet.

Next the nets are washed down with sea water, rinsing all material inside the net towards the codend.  The codend is the little container at the end of the net where all the plankton and sometimes other organisms are collected.  The codends can then be removed and taken into the Wet Lab to be processed with all the collected material placed in glass jars and preserved with formalin for future study.  

These samples are then shipped to Seattle and then on to Poland where they are sorted, the zooplankton identified to species, and the catch is expressed at number per unit area.  This gives a quantitative estimate of the density of the plankton in the water column and can provide good information on the overall health of the ocean as they indicate health of the bottom of the food chain.  After all, a high density of pollock prey means there is a good feeding spot for juvenile walleye pollock, which in turn means more Filet-O-Fish sandwiches down the line.

Species caught during the last Shift:

        Common Name            Scientific Name

  • Capelin                                          M. villosus
  • Northern Smoothtongue                      L. schmidti
  • Walleye Pollock                                      G. chalcogrammus
  • Eulachon or Candlefish                        T. pacificus
  • Arrowtooth Flounder            A. stomas
  • Rockfish                S. aurora
  • Smooth lumpsucker            A. ventricosus
  • Prowfish                Z. silenus
  • Sunrise Jellyfish            C. melanaster
  • Lion’s Main Jellyfish            C. capillata
  • Moon Jellyfish            A. labiata
  • Bubble Jellyfish            Aequorea sp.
  • Fried Egg Jellyfish            P. camtschatica
  • Shrimp
  • Isopods

Personal Log:

As I have said, I am working with some interesting people with some very interesting stories.  I am going to start sharing a little of their stories here.

LT Laura Dwyer
LT Laura Dwyer is the Field Operations Officer on the Oscar Dyson.

How long have you been working with NOAA?  What did you do before joining NOAA?

Laura has been a commissioned officer with the National Oceanic and Atmospheric Administration (NOAA) Corps for almost seven years.  Before joining NOAA, Laura attended James Madison University, earning her degree in International Business.  She went to Bali, working as a dive instructor before moving on to Australia to do the same. While in Australia, she decided she wanted to study Marine Biology and came back to the states to study at George Mason University.  

Where do you do most of your work?

Most of the time, she can be found on the bridge navigating the ship.

What do you enjoy about your work? 

Laura said the most fun thing about the job is driving a 209-foot ship.  

Why is your work important?

She gets to safely navigate the ship safely while working with scientists to help them get their work done.

How do you help wider audiences understand and appreciate NOAA science?

Laura had the opportunity to be the second NOAA officer who completed a cross-agency assignment with the Navy.  While there, she said she was able to show the Navy personnel that they were using NOAA products such as navigational charts and weather data.  Most of them did not realize that these products were made by NOAA.  

When did you know you wanted to pursue a career in science an ocean career?

Laura said that while she was in Australia, she was working with another diver who was going out counting fish species for his PhD.  She said that experience made her realize her father was right all along and she should have studied science.

What tool do you use in your work that you could not live without?


What part of your job with NOAA did you least expect to be doing?

Driving ships.  She also stated that she never expected to be part of a Navy Command and shooting small arms weapons.

What classes would you recommend for a student interested in a career in Marine Science?

A lot of your regular classes, but definitely any conservation classes.

What’s at the top of your recommended reading list for a student exploring ocean or science as a career option?

  • “Unnatural History of the Sea” – about overfishing throughout history
  • “The Old Man and the Sea” by Ernest Hemmingway

What do you think you would be doing if you were not working for NOAA?

Laura said she would probably be going back to school to work on her Masters in Marine Biology, particularly coral conservation, or going to Fiji to be a dive instructor.

Do you have any outside hobbies?

Diving, reading, working on puzzles, and just being outside exploring (I also understand that she is a pretty good water polo player.)

Did You Know?

For each minute of the day, 1 billion tons of rain falls on the Earth.

Every second around 100 lightning bolts strike the Earth.

Question of the Day:

The fastest speed of a falling raindrop is __________.

a. 10 mph

b. 18 mph

c. 32 mph

d. 55 mph

Answer: b

Marla Crouch: I Bid You Adieu, July 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: July 14, 2013

Weather Data from the Bridge: as of 1700
Wind Speed 6.02 kts
Air Temperature 52.10°C
Relative Humidity 100.00%
Barometric Pressure 1,024.60  mb

Latitude:  57.16N   Longitude: 151.78W

Science and Technology Log

The 2013 Walleye Pollock Survey extends from the Isles of Four Mountains to Yakutat, Alaska.  As the crow flies that is a distance of 2371 statute miles.  By the time the Oscar Dyson reaches Yakutat the distance traveled will be over three times that distance.  The survey is completed in three segments, called legs; during the first leg of the survey we traveled 3448 nmi.  A nautical mile is longer than a statute mile, 1 nmi is equivalent to 1.15 statute mile.

Map of the Alaskan Coastline
Map of the Alaskan Coastline

When we were surveying the waters around the Shumigan Islands we frequently encountered large schools of juvenile pollock, identified as age 1.   I asked Patrick Ressler, the lead scientist on this leg, if this was a nursery area.  Patrick indicated that the science team would need to go back and review the data collected on previous surveys to determine if there was sufficient evidence to make that determination.  The high number of age 1 pollock is a good sign that the fish stocks are healthy.

In my “Gumbi Marla” blog I talked about NOAA’s Ship Tracker and the transects, or the course, the ship navigates during the survey.  Surveys are completed during daylight hours, as the pollock behave differently at night, by changing the depth at which they swim.  When the acoustics data show a school of pollock that the science team wants to fish the position is recorded and the science team communicates with the Dyson’s bridge officer about when they can safely return to the specific position to trawl the area.  When the bridge crew is ready to leave the current transect they contact the science team, the science team then records the time and the exact position where the Dyson left transect.  After the trawl is completed the Dyson returns to the exact position they left transect to continue the survey.  During night time hours one of the scheduled tasks was to use the camera to review areas of the sea floor that had previously been deemed “untrawlable” as the seafloor was to rocky and would snag or tear the nets.

One type of gas that is trapped in Earth’s lithosphere is methane.  Methane escapes the lithosphere under the seafloor through vents and along fault lines.  The screen shot of the acoustics monitor shows vertical columns believed to be methane.  One theory about the Bermuda Triangle is a massive release of methane that creates a massive bubble.  When the bubble bursts objects in the immediate area are sucked into the momentary void created by the bubble, and swallowed by the sea.

Acoustic image of probable methane seepage.
Acoustic image of probable methane seepage.

Personal Log

Trees, there are trees on Kodiak!  I saw trees for the first time in 18 days, and I realize that I have missed seeing trees.  It’s interesting that the first three people I talk to as we approach the island of Kodiak all ask if I saw the trees.  I guess I’m not the only one that has missed seeing trees.  Sometimes the simplest observation makes the biggest impression.

Thank you to the crew of the Oscar Dyson and Science Team and to NOAA for giving me a phenomenal experience with the Teacher at Sea Program. Many students will benefit from my experiences.  Pictured is the Science Team from Leg 1 of the Pacific Walleye Pollock Survey, from left to right:  Lead Scientist Patrick Ressler, Taina Honkelehto, Kresimir Williams, Rick Towler, Abigail McCarthy, Marla Crouch (that’s me), behind me is Charles Andersen and Mike Gallagher.

Science Team
Science Team

There were so many great experiences; I hope you enjoy the video giving you glimpses into the science, technology, sights and the Oscar Dyson.

 Thanks to everyone that made my experience possible!

Anne Mortimer: Thank you, Oscar Dyson! July 21, 2011

NOAA Teacher at Sea
Anne Mortimer
Onboard NOAA Ship Oscar Dyson
July 4 — 22, 2011 

Mission: Pollock Survey
Geographical area of cruise: Gulf of Alaska
Date: July 21, 2011

Weather Data from the Bridge

  • Conditions: overcast
  • Air Temperature: 11.6°C
  • Sea Temperature: 9.3°C
  • Air Pressure: 1007.6 mbar
  • Wind Speed: 12.71 knots
  • Wind Direction: 214°

Personal Log

My trip on the Oscar Dyson is coming to a close, so this will be my final blog as we make our 15-hour trip back to Kodiak. I have the night off, so after I finish this blog, I’ll take one last trip to the bridge to see how thick the fog is, and then I’ll try to go to sleep by midnight. Tomorrow will be a final stateroom cleaning and then off to the airport. I’ll be in Bellingham by late evening.

Sunset in Shelikof

This 3-week trip has been an incredible journey. Arriving in Kodiak, I was struck at the remoteness and scale of this beautiful place. Traveling through the Shumigan Islands and Shelikof Strait only solidified my understanding of how very vast, rugged, and wild Alaska is, and that was only my experience from a ship! I feel very fortunate that I was able to come here, and be welcomed by both the science team and ship’s crew aboard the Oscar Dyson. Living on a ship is a unique and challenging experience. Working alongside scientists that are passionate about their impact on the ocean was inspiring. Witnessing the challenges of making a 540-net successfully trawl through the ocean for an hour in wind and swell is impressive.

Our last trawl: Anne the Slimer, measuring juvenile pollock.

Although my adventure as a NOAA Teacher at Sea is over, I am confident that this will not be the end of my connections with NOAA and the science team. Being so close to Seattle, Neal, the lead scientist has invited me to come see the labs in Sandpoint and meet the other scientists that will  be using all of the stomachs, otoliths, and other data that I was able to assist with. This trip has shown me that science is messy, things get broken, and the weather may not always cooperate. Problems and challenges arise all the time and scientists must communicate with each other and the ship’s crew, problem-solve, and persevere in order to make this trip worthwhile and collect data that has a very important roll in Alaska fisheries. I am very grateful for all of their generosity in helping me be a part of their mission.

THANK YOU to NOAA, scientists, crew of Oscar Dyson, and Teacher at Sea Program support! I had an amazing time!