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.
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?

Radar

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

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