Mark Wolfgang: If a Fish Laughs in the Ocean and No One is There to Hear it, Does it Really Make a Sound? April 21, 2017


NOAA Teacher at Sea

Mark Wolfgang

Aboard NOAA Ship Reuben Lasker

April 11 – April 22, 2017

 

Mission: Spring Coastal Pelagic Species (Anchovy/Sardine) Survey

Geographic Area of Cruise: Pacific Ocean

Date: April 21, 2017

Weather Data from the Bridge:

Lat: 38o 2.4’N        Long: 123o 6.2’W
Air Temperature: 13.9oC (57oF)
Water Temperature: 12.9oC (55oF)
Wind speed: 12 knots (13.8 mph)
Barometer:   1014.97 mbar
Conditions:  Clear skies and the seas are pretty smooth

Scientific and Technology Log:

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The Acoustics room on the Reuben Lasker

Today, I decided to learn more about the other key research part of the Coastal Pelagic Survey.  As the trawling is happening at night and the egg and larval collections during the day, acousticians are listening to what is below us.  Using this information, research scientists can assess the population of coastal pelagic species (CPS).  The acoustics room is full of stacks of computers, servers, monitors and organized wires.  NOAA researchers collect enormous amounts of data as we move down the 80 mile transects across the Pacific Ocean.  On this leg, we have not found many large schools of sardines or anchovies, but the data from acoustic-sampling did lead us to some jack mackerel.  I am going to try to explain some of the technology they use on the Reuben Lasker.reuben-lasker-acoustic-sampling

Simrad EK60 and EK80:  These are two sonar systems that use multiple frequencies to listen to the ocean right below the ship.  In the diagram, it is seen in green.  The EK80 is newer and is being tested on the Reuben Lasker.  It collects enormous amounts of data and acousticians are looking at how best to use that data.

Simrad ME70: This multibeam sonar (seen in orange in the diagram) listens to the water below and around the ship.  It would almost look like a fan.  This does not only tell us what is below, but what is beside the ship as well.

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The Simrad ME70

Simrad SX90: This is a long-range sonar (shown in gray) that looks at the surface for a good distance around the ship.  When I was there, they were analyzing 450 meter radius around the ship.  This is where the UAS would come in to use.  If a school of sardines or anchovies are seen on this sonar, they could possibly deploy the drone to fly over the school and take photographs.  Researchers could then analyze those photographs and collect appropriate data.  Researchers can also potentially use this system to see how the ship moving through the water effects the behavior of the school.

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The Simrad SX90

Simrad MS70:   The MS70 is a multibeam sonar that also analyzes the water off the side of the ship.  It almost fills in the imaging gap left by the ME70.

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The Simrad MS70

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K-SYNC

All of these sonars are linked together by a program called K-SYNC.  This program makes sure that the sonars don’t “ping” at the same time and cause interference with all of the systems.  The Reuben Lasker also a very quiet propulsion system to limit the interference of the sound of the ship moving through the water.  The ship also has 3 hydrophones that can be used to listen to marine mammals.

Together these five sonar systems give the Reuben Lasker an incredible view of what is in the water under and around the ship.  This informs the trawls at night and together gives a good picture of the CPS in the waters of coastal California.

Personal Log:

So what do we do during the time we are not working?  The ship is full of movies, an exercise room, and snacks are available all day.  I have been able to read a couple books, watch a few movies with the science team, work on my blog and talk to crewmembers, and even watch some TV (including seeing the Penguins play a couple hockey games).  When you are on shift, there will be some downtime and then a bunch of activity as the net is pulled in.  I have also tried to soak in the clean ocean air and take moments just to enjoy the experience.  My Teacher At Sea voyage has been enjoyable, but I am looking forward to arriving back in San Francisco on April 22nd and flying home that night to be with my family.

Did you know?

Sonar, an acronym for SOund Navigation And Ranging, is a technique that uses sound to navigate, communicate, or detect objects on or under the surface of the water.  American naval architect, Lewis Nixon, invented the first sonar-like device in 1906.  Because of the demands of WWI, Paul Langevin constructed the first sonar set to detect submarines in 1915.

 

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