Linda Kurtz: Hydrographic Surveys – Not your Mama’s Maps! August 17, 2019

NOAA Teacher at Sea

Linda Kurtz

Aboard NOAA Ship Fairweather

August 12-23, 2019


Mission: Cascadia Mapping Project

Geographic Area of Cruise: Northwest Pacific

Date: 8/17/2019

Weather Data from the Bridge

August 17th 2019

Latitude & Longitude: 43◦ 53.055’ N 124◦ 47.003’W
Windspeed: 13 knots
Geographic Area: @10-15 miles off of the Oregon/California coast
Cruise Speed:  12 knots
Sea Temperature 20◦Celsius
Air Temperature 68◦Fahrenheit

Future hydrographer button
Is this you?

Navigation is how Fairweather knows its position and how the crew plans and follows a safe route.  (Remember navigation from the last post?)  But what “drives” where the ship goes is Hydrographic survey mission.  There is a stunning amount of sea floor that remains unmapped, as well as seafloor that has not been mapped following a major geological event like an earthquake of underwater volcano.

Why is Hydrography important?  As we talked about in the previous post, the data is used for nautical safety, creating detailed maps of the ocean floor,  setting aside areas are likely abundant undersea wildlife as conservation areas, looking at the sea floor to determine if areas are good for wind turbine placement, and most importantly to the residents off the Pacific coast, locating fault lines — especially subduction zones which can generate the largest earthquakes and cause dangerous tsunamis.

In addition to generating the data needed to update nautical charts, hydrographic surveys support a variety of activities such as port and harbor maintenance (dredging), coastal engineering (beach erosion and replenishment studies), coastal zone management, and offshore resource development. Detailed depth information and seafloor characterization is also useful in determining fisheries habitat and understanding marine geologic processes.

The history of hydrographic surveys dates back to the days of Thomas Jefferson, who ordered a survey of our young nation’s coast.   This began the practice and accompanying sciences of the coastal surveys.  The practice of surveys birthed the science of Hydrography (which we are actively conducting now) and the accompanying science of Bathymetry (which we will go into on the next post.)  This practice continues of providing nautical charts to the maritime community to ensure safe passage into American ports and safe marine travels along the 95,000 miles of U.S. Coastline. 

Want to learn more about Hydrographic Survey history?  Click on THIS LINK for the full history by the NOAA.

Scientists have tools or equipment that they use to successfully carry out their research.  Let’s take a look at a few of the tools hydrographic survey techs use:

Want to learn more about the science of SONAR? Watch the video below.

ps://www.youtube.com/watch?v=8ijaPa-9MDs

On board Fairweather (actually underneath it) is the survey tool call a TRANSDUCER which sends out the sonar pulses.

Multibeam sonar illustration
Multibeam sonar illustration

The transducer on Fairweather is an EM 710- multibeam echo sounder which you can learn more about HERE

The Transducer is located on the bottom of the ship and sends out 256 sonar beams at a time to the bottom of the ocean.  The frequency of the 256 beams is determined by the depth from roughly 50 pings per second to 1 ping every 10 seconds.  The active elements of the EM 710 transducers are based upon composite ceramics, a design which has several advantages, which include increased bandwidth and more precise measurements. The transducers are fully watertight units which should give many years of trouble-free operation.  This comes in handy since the device in on the bottom of Fairweather’s hull!

Here is the transducer on one of the launches:

transducer
View of transducer on a survey launch

The 256 sonar beams are sent out by the transducer simultaneously to the ocean floor, and the rate of return is how the depth of the ocean floor is determined.  The rate of pulses and width of the “swath” or sonar beam array is affected by the depth of the water.  The deeper the water, the larger the “swath” or array of sonar beams because they travel a greater distance.  The shallower the water, the “swath” or array of sonar beams becomes narrower due to lesser distance traveled by the sonar beams.

The minimum depth that this transducer can map the sea floor is less than 3 meters and the maximum depth is approximately 2000 meters (which is somewhat dependent upon array size).  Across track coverage (swath width) is up to 5.5 times water depth, to a maximum of more than 2000 meters. This echo sounder is capable of reaching deeper depths because of the lower frequency array of beams. 

The transmission beams from the EM 710 multibeam echo sonar are electronically stabilized for roll, pitch and yaw, while they receive beams are stabilized for movements. (The movement of the ship) What is roll, pitch, and yaw? See below – these are ways the Fairweather is constantly moving!

Roll, Pitch, and Yaw
Roll, Pitch, and Yaw

Since the sonar is sent through water, the variable of the water that the sonar beams are sent through must be taken into account in the data. 

Some of the variables of salt water include: conductivity (or salinity) temperature, depth, and density.

Hydrographic scientists must use tools to measure these factors in sea water, other tools are built into the hydrographic survey computer programs. 

One of the tools used by the hydrographic techs is the XBT or Expendable Bathy Thermograph that takes a measurement of temperature and depth.  The salinity of the area being tested is retrieved from the World Ocean Atlas which is data base of world oceanographic data. All of this data is transmitted back to a laptop for the hydrographers.  The XBT is an external device that is launched off of the ship to take immediate readings of the water. 

Launching the XBT:  There is a launcher which has electrodes on it, then you plug the XBT probe to the launcher and then XBT is launched into the ocean off of the back of the ship.  The electrodes transmit data through the probe via the 750-meter copper wire.  The information then passes through the copper wire, through the electrodes, along the black wire, straight to the computer where the data is collected.  This data is then loaded onto a USB then taken and loaded into the Hydrographic data processing software.  Then the data collected by the XBT is used to generate the sound speed profile, which is sent to the sonar to correct for the sound speed changes through the water column that the sonar pulses are sent through.  The water column is all of the water between the surface and seafloor. Hydrographers must understand how the sound moves through the water columns which may have different densities that will bend the sound waves.  By taking the casts, you are getting a cross section “view” of the water column on how sound waves will behave at different densities, the REFRACTION (or bending of the sound waves) effects the data.

See how the XBT is launched and data is collected below!

Videos coming soon!

The other tool is the MVP or moving vessel profiler which takes measurements of conductivity, temperature, and depth.  These are all calculated to determine the density of the water.  This is a constant fixture on the aft deck (the back of the ship) and is towed behind the Fairweather and constantly transmits data to determine the speed of sound through water.  (Since sonar waves are sound waves.)

MVP and launching wench
MVP (left) and the launching wench (right)

The sonar software uses this data to adjust the calculation of the depth, correcting for the speed of sound through water due to the changes in the density of the ocean.  The final product?  A detailed 3d model of the seafloor!

current survey area
Our current survey area! (Thanks Charles for the image!)

All of this data is run through the survey software.  See screen shots below of all the screens the hydrographers utilize in the course of their work with explanations.  (Thanks Sam!)  It’s a lot of information to take in, but hydrographic survey techs get it done 24 hours a day while we are at sea.  Amazing!  See below:

ACQ software screenshot
Hydrographic Survey “Mission Control”
HYPACK Acquisition Software
HYPACK Acquisition Software
Real time coverage map
Real time coverage map

Did You Know?  An interesting fact about sonar:  When the depth is deeper, a lower frequency of sonar is utilized.  In shallower depths, a higher sonar frequency. (Up to 900 meters, then this rule changes.)

Question of the Day:  Interested in becoming a hydrographic survey tech?  See the job description HERE.

Challenge yourself — see if you can learn and apply the new terms and phrases below and add new terms from this blog or from your research to the list!

New Terms/Phrases:

Multibeam sonar

Sound speed

Conductivity

Salinity

Sonar

Sound waves

Refraction

Water column

Roll, Pitch, and Yaw

Animals seen today:

Humpback Whale

Bathymetry and USGS friends coming soon!

Plot room
Hydro-technician Sam Candio (right) collaborating with USGS Research Geologist James Conrad and Physical Scientist Peter Dartnell.

Brad Rhew: The Sounds of the Sea, July 31, 2017

NOAA Teacher at Sea

Brad Rhew

Aboard NOAA Ship Bell M. Shimada

July 23 – August 7, 2017

 

Mission: Hake Fish Survey

Geographic Area of Cruise: Northwest Pacific Ocean, off of the coast of Oregon

Date: July 31, 2017

 

Weather Data from the Bridge

Latitude: 44 49.160 N
Longitude 124 26.512

Temperature: 59oF
Sunny
No precipitation
Winds at 25.45 knots
Waves at 4-5ft

 

Science and Technology Log

TAS Rhew 7-31 acoustics lab2

Inside the acoustics lab

The scientists on the Hake survey project are constantly trying to find new methods to collect data on the fish. One method used is acoustics. Scientists Larry Hufnagle and Dezhang Chu are leading this project on the Shimada. They are using acoustics at a frequency of 38 kHz to detect Pacific Hake. Density differences between air in the swimbladder, fish tissue, and the surrounding water allows scientists to detect fish acoustically.

The purpose of the swim bladder in a fish is to help with the fish’s buoyancy. Fish can regulate the amount of gas in the swim bladder to help them stay at a certain depth in the ocean. This in return decreases the amount of energy they use swimming.

TAS Rhew 7-31 echosounder

The screen shows the data collected by the echosounder at different frequency levels.

Larry and Chu are looking at the acoustic returns (echoes) from 3 frequencies and determining which are Hake. When the echosounder receives echoes from fish, the data is collected and visually displayed. The scientists can see the intensity and patterns of the echosounder return and determine if Hake are present.

The scientists survey from sunrise to sunset looking at the intensity of the return and appearances of schools of fish to make the decisions if this is an area to fish.

TAS Rhew 7-31 scientists Larry and Chu

Scientists Larry Hufnagle (left) and Dezhang Chu (right) monitor the nets and echosounder while fishing for hake.

The ultimate goal is to use this data collected from the echosounder to determine the fish biomass. The biomass determined by the survey is used by stock assessment scientist and managers to manage the fish stock.

Personal Log

Everyday aboard the Shimada is a different experience. It has been amazing to be able to go between the different research labs to learn about how each group of scientists’ projects are contributing to our knowing more about Hake and marine ecosystems. My favorite part so far has been helping with the sampling of Hake. Some people might find dissecting fish after fish to determine length, sex, age, and maturity to be too much. However, this gives me an even better understanding and respect for what scientists do on a daily basis so we can have a better understanding of the world around us. We have also caught other fascinating organisms that has helped me explore other marine species and learn even more about their role in the ocean.

Even though the wind is a little strong and the temperatures are a little chilly for my southern body I wouldn’t trade this experience for anything…especially these amazing sunsets…

TAS Rhew 7-31 sunset

View of sunset over the Pacific Ocean from NOAA Ship Bell M. Shimada

Did You Know?

Before every fishing operation on the boat we must first do a marine mammal watch. Scientists and other crew members go up to the bridge of the boat to see if any mammals (whales, seals, dolphins) are present near the boat. This is to help prevent these animals from being harmed as we collect fish as well as making sure we are not running a risk of these mammals getting caught in the fishing nets.

Fascinating Catch of the Day!

Today’s fun catch in the net was a Brown Catshark! These creatures are normally found in the deeper parts of the Pacific Ocean. They are typically a darker brown color with their eyes on the side of their head. Their skin is very soft and flabby which can easily lead to them being harmed. They have two dorsal fins and their nostrils and mouth on the underside of their body. One of the sharks we caught was just recently pregnant.

 

TAS Rhew 7-31 catshark egg sack string

This catshark was recently pregnant; the yellow stringy substance is from an egg sack.

Notice to yellow curly substance coming out of the shark? That is from the egg sac. Sharks only produce one egg sac at a time. It normally takes up to a full year before a baby shark to form!

Marsha Lenz: Celebrating Science and the Solstice, June 21, 2017

NOAA Teacher at Sea

Marsha Lenz

Aboard Oscar Dyson

June 8-28, 2017

Mission: MACE Pollock Survey

Geographic Area of Cruise: Gulf of Alaska

Date: June 21, 2017

thumb_IMG_2352_1024.jpg

Though modern technology is used daily, one can still find traditional charting tools on the Bridge.

Weather Data from the Bridge

Latitude: 55 15.0 N

Longitude: 160 06.7 W

Time: 1300

Visibility: 10 Nautical Miles

Wind Direction: VAR

Wind Speed: LT

Sea Wave Height: <1 foot

Barometric Pressure: 1003.4 Millibars

Sea Water Temperature: 9.8°C

Air Temperature: 7.0°C

Science and Technology Log

            We have been surveying transect lines (sometimes we fish, sometimes we don’t). During the times that we aren’t fishing, I find myself looking out at the ocean A LOT! During these quiet times on the ship, I am reminded of how large the oceans are. I found a quiet window to sit by in the Chem Lab and enjoy watching as the waves dance off of the side of the ship.

IMG_1975

Abigail enjoys singing to the fish.

During some of these times when we are not collecting data from fish, identifying species from the DropCam, or preparing for the next haul, I find myself reading, which is a luxury all in itself. A friend of mine lent me to book to read and as I was reading the other day, the author quoted Jules Verne, author of 20,000 Leagues Under the Sea. Verne said, “Science, my lad, is made up of mistakes, but they are mistakes which it is useful to make, because they lead little by little to the truth.” I found this to be fitting for what I am doing on this survey, for the three weeks that I am a Teacher At Sea.   Though I am surrounded by trained and educated professionals, I have realized that mistakes still happen and are something to be expected.   They happen regularly. Often, actually. And, it’s a good thing that they do. They are important for learning. When humans make mistakes, hopefully, we can adjust our actions/behaviors to reduce the chances of that same “mistake” from happening again. When applied to science, the same idea is also true. When  we can collect data from something that we are studying, we learn about the ways that it interacts with its surroundings. Through these findings, we not only learn more about what we are studying, but then take measures to protect its survival.

We had a real experience like this happen just the other day. For days, the “backscatter” was picking up images of fish that the scientists didn’t think were pollock on the bottom of the ocean. Backscatter is what the scientists use to “see” different groups of fish and quantify how many are in the water. The ship uses various echosounders.  Several times, the science team decided to collect fish samples from these areas.  Every time that they decided to “go fishing”, we pulled up pollock. The team was baffled. They had a hypothesis as to why they were not catching what they thought they saw on the backscatter. They thought that it was rockfish that were hanging around rocks, but the pollock were being caught as the net went down and came back up.  Finally, after several attempts of not catching anything but pollock, they decided to put down the DropCam and actually try to see what was going on down there.

At that point, the Chem lab was filled with scientists. Everyone wanted to see what was going to show up on the monitor. The NOAA Corps Commanding Officer even came to see what was going to show up on the monitor.  The room will filled with excitement.

 

Abigail steers the DropCam and watches the monitor simultaneously.

We see rockfish!

          It was just as they predicted!  The rockfish were hanging out in the rocks.  It was a moment of great satisfaction for the scientists. They were able to identify some of the fish on the backscatter that was causing them so much confusion! Yay, science!

19433465_10211635923631739_1269694918_n

This is a pollock!

Later in the day, we went fishing and collected the usual data (sex, length, weight, etc.) from the pollock.  There are usually 4 of us at a time in the Fish lab.  We are getting into a routine in the lab and I am getting more familiar with my responsibilities and duties. I start by controlling the door release, which controls the amount of fish released onto the conveyor belt. After all of the fish have been weighed, I separate the females and males.  Once that has been done, I take the lengths of a sample of the fish that we caught. When I finish, I assist Ethan and Abigail in removing and  collecting the otoliths from a selected fish sample.  Then, its clean-up time.  Though we all have appropriate gear on, I somehow still end up having fish scales all over me.  Imagine that!

Every time that we “go fishing”, a “pocket net” is also deployed.  This is a net that has finer mesh and is designed to catch much smaller marine life.  On this haul, we caught squid, age “zero” pollock, and isopods.

In the evening, we headed towards Morzhovoi Bay.  There, we were greeted by a pod of Pacific white-sided dolphins.  They spent some time swimming next to us.  When they discovered that we were not that interesting, they swam off.  They did leave us though with a great sense of awe and appreciation (and a few great pictures!).

This slideshow requires JavaScript.

Personal Log

Happy Summer Solstice!  Today is the longest day of the year!  We have had some spectacular days. We were all excited as we got up this morning to welcome the rising of the sun. We woke up and were holding position in front of Mt. Pavlof.  We saw the sunrise and went up to the  Flying Bridge to do some morning yoga.  After a wonderful breakfast of a bagel with cream cheese, salmon, Larrupin sauce, and Slug Slime, I went back up to the Bridge to get a full 360 degree view of the bay.  There I saw a humpback whale swimming around.  This will definitely be a summer solstice to remember!

This slideshow requires JavaScript.

Did You Know?

A humpback whale is about the size of a school bus and weighs about 40 tons! They also communicate with each other with songs under the water.

sidenote: I know I wrote in my last blog that I was going to discuss the fishing process today, but there were so many other amazing things that happened that it is going to have to wait until next time. Sorry!

 

Cassie Kautzer: Alaska or Bust! August 11, 2014

NOAA Teacher at Sea
Cassie Kautzer
(Almost) Aboard NOAA Ship Rainier
August 16 – September 5, 2014

Mission: Hydrographic Survey
Geographical area of cruise: Cold Bay, Alaska
Date: August 11, 2014

Personal Log

Hi! My name is Cassie Kautzer and I am writing to you from my couch in Northwest Arkansas. I am hiding inside with the air conditioning today because my thermometer shows it being 95 degrees Fahrenheit, and that is too hot for this former Wisconsin girl! I am finishing packing and doing some final research before I head to Alaska on August 16! (I am also very much looking forward to cooler temperatures!)

Science girl power!

Alaska or Bust! This science girl is ready!

 

I am a fifth grade teacher at Monitor Elementary in Springdale, Arkansas! I have loved MONITOR and all my little Mallards since 2008 when I had the honor of joining the Monitor Team. Monitor Elementary houses a very diverse population of around 800 students each year. This school year, I will have the pleasure of teaching science to 112 of those students, and I cannot wait to share this amazing experience with them! Since Arkansas is not a coastal state, neither my students nor I have a lot of experience with marine ecology or tidal influences. In the Paleozoic Era, however, the entire state was covered by relatively shallow ocean, the Ouachita Basin.

I applied for this wonderful learning opportunity for several reasons:

• I am like my students, I learn by DOING! I can’t take all of my students with me (though I would if I could), so I will learn and gather new information, first hand, and take back pictures, videos, stories, lessons, and activities to share with them!
• I want my students to see the bigger picture–how is our life in Arkansas affected by oceans, tides, floods, erosion?
• I want my students to see the scientific opportunities, jobs, and careers that are available to them! I want to help inspire future scientists!
• I want my girls to see women working in scientific fields!
• And… I love adventure, and exploring and learning about our beautiful world! I will not fear the unknown; I will learn and grow as I figure it out!

Whitaker Point, Hawksbill Crag Trail, Arkansas

On top of the world! I made my first visit to Whitaker Point in Arkansas this summer!

My mission this summer, from August 16 – September 5, will be a Hydrographic Survey aboard the NOAA Ship Rainier. NOAA is the National Oceanic and Atmospheric Administration. NOAA’s mission is to understand the Earth’s environment in order to conserve and care for marine (ocean) resources. The Rainier is “one of the most modern and productive survey platforms of its type in the world” and uses multibeam sonar systems to “cover large survey areas in a field season. The ship’s hydrographers acquire and process massive amounts of data and create high-resolution, three-dimensional terrain models of the ocean floor.”  Those models can then be used to identify obstructions and shoals along the bottom of the ocean that are dangerous for navigating ships.  (http://www.omao.noaa.gov/publications/ra_flier.pdf) Hydro ships, like the Rainier, map the ocean floor to help with safe navigation of the seas. Knowing the depth and make-up of the ocean floor surrounding Alaska will benefit all the vessels and ships, large and small, passing through the Gulf of Alaska. Activities onboard can include echosounding, tide gauge installation, shoreline surveying, verification, and mapping, and data processing.

 

NOAA ship Rainier, named for Mt. Rainier - a volcanic cone in Washington state that rises 14,410 feet above sea level.  Photo courtesy of NOAA.

NOAA ship Rainier, named for Mt. Rainier – a volcanic cone in Washington state that rises 14,410 feet above sea level. Photo courtesy of NOAA.

So what does all of that mean?? I am about to find out! NOAA’s Teacher at Sea program aims to provide me, the teacher, with real-world research experience through work with world-renowned scientists, to allow unique insights into oceanic and atmospheric research crucial to our world. To this end, I truly believe the best way to learn is by getting ones hands dirty and trying to figure things out. So, on August 16 I will head to Alaska and meet up the Rainier in Kodiak, AK. On August 18 we will depart from Kodiak and head toward Cold Bay to begin our hydrographic survey mission.

Right now, I have more questions than answers: What will it be like without land beneath my feet for three whole weeks? What hours will I work? How am I going to learn all the crew members’ names? Will I get sea sick? What is echosounding? Will I get to go out on a launch? What marine life am I going to see? Will I ever want to leave Alaska? I guess I am about to find out!

For My Students

Can you find out…..?

1. How can I track the distance and speed I am traveling at while on the Rainier? (What units would I use to measure and share this information with you?)

2. When I am on the Rainier, weather information will be shared in degrees Celsius. How can I convert that information to degrees Farenheit so all of my non-science friends can understand?

“Leave a Reply” at the very bottom of this page! I am looking forward to answering (or trying to answer) your questions and sharing this epic learning adventure with you!

And of course, as Will.I.Am wrote and sang, and I kareoked to my students all year, “Reach for the Stars” and you’re sure to end up in the “Hall of Fame!”

Mary Murrian: My First Days in Dutch Harbor, July 6, 2014

NOAA Teacher at Sea 

Mary Murrian

Aboard NOAA Ship Oscar Dyson

July 4 – 22, 2014

Mission: Annual Walleye Pollock Survey

Geographical Area of Cruise: Bering Sea North of Dutch Harbor

Date: Sunday, July 6th, 2014

Weather Data from the Bridge:

Wind Speed: 6 kts

Air Temperature: 8.6 degrees Celsius

Weather conditions: Hazy

Barometric Pressure: 1009.9

Latitude: 5923.6198  N

Longitude: 17030.6395  W

 

Science and Technology Log

Part One of the Survey Trawl: Getting Ready to Fish

This is a picture of a pollock from our first trawl.

This is a picture of a pollock from our first trawl.

Today is my second day aboard the Oscar Dyson.  We are anxiously waiting for the echosounder (more information on echosounder follows) to send us a visual indication that a large abundance of fish is ready to be caught.  The point of the survey is to measure the abundance of Walleye Pollock throughout specific regions in the Bering Sea and manage the fisheries that harvest these fish for commercial use to process and sell across the world.  The Walleye Pollock are one of the largest populations of fish.  It is important to manage their populations due to over-fishing could cause a substantial decrease the species.  This would be detrimental to our ecosystem.  The food web [interconnecting food chains; i.e. Sun, plants or producers (algae), primary consumers, animals that eat plants (zooplankton), secondary consumers, animals that eat other animals (pollock), and decomposers, plants or animals that break down dead matter (bacteria)] could be altered and would cause a negative effect on other producers and consumers that depend on the pollock for food or maintain their population.

The main food source for young pollock is copepods, a very small marine animal (it looks like a grain of rice with handle bars).  They also eat zooplankton (animals in the plankton), crustaceans, and other bottom dwelling sea life.  On the weird side of the species, adult pollock are known to eat smaller pollock.  That’s right, they eat each other, otherwise known as cannibalism.  Pollock is one of the main food sources for young fur seal pups and other marine life in Alaskan waters.  Without the pollock, the food web would be greatly altered and not in a positive way.

How do we track the pollock?

Pollock

Pollock

Tracking begins in the acoustics lab.  Acoustics is the branch of science concerned with the properties of sound.  The acoustics lab on board the Oscar Dyson, is the main work room where scientists can monitor life in the ocean using an echosounder which measures how many fish there are with sound to track the walleye pollock’s location in the ocean.  They also use the ships’s GPS (Global Positioning System), a navigation system, to track the location of the NOAA vessel and trawl path.

Echo Sounder

Sonar Screen

What is sonar and how does it work? 

Sonar (sound ranging & navigation;  it’s a product of World War II) allows scientists to “see” things in the ocean using sound by measuring the amount of sound bouncing off of objects in the water.  On this survey, sonar images are displayed as colors on several computer monitors, which are used to see when fish are present and their abundance.  Strong echoes show up as red, and weak echoes are shown as white.  The greater the amount of sound reported by the sonar as red signals, the greater the amount of fish.

Echo Sonar Screen Showing the patterns of echos from the ocean.

Echo Sonar Screen Showing the patterns of echos from the ocean.

How does it work?  There is a piece of equipment attached to the bottom of the ship called the echosounder.  It sends pings (sound pulses) to the bottom of the ocean and measures how much sound bounces back to track possible fish locations.   The echo from the ocean floor shows up as a very strong red signal.   When echoes appear before the sound hits the ocean floor, this represents the ping colliding with an object in the water such as a fish.

The scientists monitor the echosounder signal so they can convey to the ships’s bridge and commanding officer to release the nets so that they can identify the animals reflecting the sound.  The net catches anything in its path such as jellyfish, star fish, crabs, snails, clams, and a variety of other fish species. Years of experience allows the NOAA scientists the ability to distinguish between the colors represented on the computer monitor and determine which markings represent pollock versus krill or other sea life.  We also measure the echoes at different frequencies and can tell whether we have located fish such as pollock, or smaller aquatic life (zooplankton). The red color shown on the sonar screen is also an indicator of pollock, which form dense schools.  The greater amount of red color shown on the sonar monitor, the better opportunity to we have to catch a larger sample of pollock.

The Science Team Wonderful group of people.

Once we have located the pollock and the net is ready, it is time to fish.  It is not as easy as you think, although the deck hands and surveyors make it look simple.  In order to survey the pollock, we have to trawl the ocean.  Depending on the sonar location of the pollock, the trawl can gather fish from the bottom of floor, middle level and/or surface of the ocean covering preplanned locations or coordinates. Note: Not all the fish caught are pollock.

The preplanned survey path is called transect lines with head due north for a certain distance. When the path turns at a 90 degree angle west (called cross-transect lines) and turns around another 90 degree angle heading back south again.  This is repeated numerous times over the course of each leg in order to cover a greater area of the ocean floor.  In my case we are navigating the Bering Sea.  My voyage, on the Oscar Dyson is actually the second leg of the survey, in which, scientists are trawling for walleye pollock.  There are a total of three legs planned covering a distance of approximately 6,200nmi (nautical miles, that is).

Trawling is where we release a large net into the sea located on the stern (the back of the boat).  Trawling is similar to herding sheep.  The fish swim into the net as the boat continues to move forward, eventually moving to the smaller end of the net.  Once the sonar screen (located on a computer monitor) shows that we have collected a large enough sample of pollock, the deck hands reel the net back on board the boat.

 

The crew are beginning to release the trawl net.

The crew are beginning to release the trawl net.

This is the stern of the boat where the trawl net gets released into the ocean.

This is the stern of the boat where the trawl net gets released into the ocean.

We have caught the fish, now what?  Stay tuned for my exciting experience in the wet lab handling the pollock and other marine wild life.  It is most certainly an opportunity of a lifetime.

Personal Log

What an adventure!

I was lucky enough to spend a day exploring Dutch Harbor, Alaska before departing on the pollock survey across the Bering Sea. It took me three plane rides, several short lay-overs and and a car ride to get here, a total of 16 hours. There is a four hour time difference between Dutch Harbor and Dover, Delaware. It takes some getting used to, but definitely worth it. The sun sets shortly after 12:00 midnight and appears again around 5:00 in the morning. Going to sleep when it’s still daylight can be tricky. Thank goodness I have a curtain surrounding my bed. Speaking of the bed, it is extremely comfortable. It is one of those soft pillow top beds. Getting in and out of the top bunk can be challenging. I haven’t fallen yet.

My bed is the top bunk.

My bed is the top bunk.

During my tour through the small town of Dutch Harbor, I have encountered very friendly residents and fishermen from around the world.  I was fortunate to see the U.S. Coast Guard ship Healy docked at the harbor. What a beautiful vessel.  Dutch Harbor has one full grocery store (Safeway) just like we have in Delaware, with the exception of some of the local Alaska food products like Alaska BBQ potato chips. They have a merchant store that sells a variety of items ranging from food, souvenirs, clothing, and hardware. They have three local restaurants and a mom and pop fast food establishment. One of the restaurants is located in the only local Inn the Aleutian hotel, which also includes a gift shop. Dutch Harbor is home to several major fisheries. Dutch Harbor is rich in history and is home to the native Aleutian tribe. I took a tour of their local museum. It was filled with the history and journey of the Aleutian people. While driving through town, I got a chance to see their elementary and high school. They both looked relatively new. Dutch Harbor is also home to our nation’s first Russian Orthodox Church. Alaska is our 50th state and was purchased from Russia in 1867.

Me and the Oscar Dyson

Mary Murian in front of the Oscar Dyson

A very funny photo of me in my survival suit.

A very funny photo of me in my survival suit.

One of the coolest parts of my tour was walking around the area known as the “spit”. The “spit” is located directly behind the airport. I’m told it is called the “spit” because the land and water are spitting distance in length and width. We walked along the shoreline and discovered hundreds of small snails gathered around the rocks. We also found hermit crabs, starfish, sea anemones, jellyfish, and red algae. We saw red colored water, which is a bloom or a population explosion of tiny algae that get so thick that they change the color of the water.

One of numerous amazing views in Dutch Harbor

One of numerous amazing views in Dutch Harbor

tas 2014 day 1 and perboarding july 2-4th 089

Starfish

Another animal in abundance in Dutch Harbor is the bald eagle. There is practically one on every light post or tall structure. Often the bald eagles are perched in small groups. Watch out: if you walk too close to a nesting mother, she will come after you. They are massive, regal animals. I never get tired of watching them.

We had to watch our step, the snails were everywhere along the shoreline of the Spit.

We had to watch our step, the snails were everywhere along the shoreline of the Spit.

A bald eagle hoping to find some lunch.

A bald eagle hoping to find some lunch.

Russian Orthodox Church in Dutch Harbor, AK

Russian Orthodox Church in Dutch Harbor, AK

Did You Know?

Did you know that Alaska’s United States Coast Guard vessel has the ability to break through sea ice? 

This is especially helpful if you want to study northern areas, which are often ice covered, in the winter, and to assist a smaller boat if it gets trapped in the ice.

U.S. Coast Guard Ship Healy docked at the Spit.

U.S. Coast Guard Ship Healy docked at the Spit.

Did you know that scientists set time to Greenwich Mean Time (GMT) which is the time in a place in England?

This reduces confusion (e.g. related to daylight savings, time zones) when the measurements are analyzed.

Key Vocabulary:

Carnivore

Primary Consumer

Secondary Consumer

Nautical Miles

Trawling

Stern

Acoustics

Decomposers

Echosounder

Meet the Scientist:

Alex De Biologist

Alex De Robertis Chief Scientist

Leg II Chief Scientist Dr. Alex De Robertis

Title: NOAA Research Fishery Biologist (10 years)

Education:  UCLA Biology Undergraduate Degree

Scripps Institute Oceanography San Diego, CA PhD.

Newport, Oregon Post Doctorate work

Living Quarters:

Born in Argentina and moved to England when one-year old.

Lived in Switzerland and moved to Los Angeles,CA at the age of 13.

Currently lives in Seattle, Washington, and he has two kids aged one and five.

Job Responsibilities:

Responsible for acoustic trawl surveying at Alaska Fisheries Science Center

Was able to help with the Gulf of Mexico oil spill clean-up using the same echo sonar used on trawl surveys.

What is cool about his work:

He enjoys his work, especially the chance to travel to different geographic locations and meet new people.  “You never know what you are going to encounter; there is always a surprise or curve ball, when that occurs you adjust and just go with it”.

In the near future, he would love to see or be part of the design for an autonomous ocean robot that will simplify the surveying process.

He has been interested in oceans and biology since a small boy.  He remembers seeing two divers emerge from the sea and was amazed it was possible.

Melissa George: Do You Hear What I Hear? July 28, 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:  Sunday, July 28, 2013

Current Data From Today’s Cruise

Weather Data from the Bridge 
Sky Condition:  Cloudy
Temperature:  14° C
Wind Speed:  4 knots
Barometric Pressure:  1025.1 mb
Humidity:  90%

Sun and Moon Data 
Sunrise:  5:57 am
Sunset:  10:34 pm

Moonrise:  11:52 pm  (July 27, 2013)
Moonset:  2:35 pm

Geographic Coordinates at 

Latitude:  59° 53.3′ N
Longitude:  149° 00.0′ W

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

False Point on Kenai Peninsula (viewed this morning through the fog)

False Point on Kenai Peninsula (viewed this morning through the fog)

Science and Technology Log

How do scientists use acoustics to locate Pollock (and serendipitously other ocean creatures)?

Scientists aboard the NOAA Research Vessel Oscar Dyson use acoustic, specifically hydroacoustic data, to locate schools of fish before trawling.  The trawl data provide a sample from each school and allow the NOAA scientists to take a closer look by age, gender and species distribution.  Basically, the trawl data verify and validate the acoustics data.  The acoustics data, collected in the Gulf of Alaska in systematic paths called transects, combined with the validating biological data from the numerous individual trawls, give scientists a very good estimate for the entire Walleye pollock population in this location.

This screen is showing the echogram from the EK 60 echosounder during a trawl at 83.13 meters.  The red line in the middle of the screen is the ocean floor.  The colorful spikes above the red line indicate “backscatter” that is characteristic of capelin, a small fish that pollock feed on.

This screen is showing the echogram from the EK 60 echosounder during a trawl at 83.13 meters. The red line in the middle of the screen is the ocean floor. The colorful spikes above the red line indicate “backscatter” that is characteristic of capelin, a small fish that pollock feed on.

Hydroacoustics  (from Greek words: hydro meaning “water”  and  acoustics meaning “sound”) is the study of sound in water.  Sound is a form of energy that travels in pressure waves. In water, sound can travel great distances without losing strength and can travel fast, roughly 4.3 times faster in water than in air (depending on temperature and salinity of the water).

Click on this picture to see how sound travels from various ocean creatures through water. (Photo from sciencelearn.org)

Click on this picture to see how sound travels from various ocean creatures through water. (Photo from sciencelearn.org)

The Oscar Dyson has powerful, extremely sensitive, carefully calibrated, scientific acoustic instruments or “fish finders” including the five SIMRAD EK60 transducers located on the bottom of the centerboard, the SIMRAD ME70 multibeam transducer located on the hull, and a pair of SIMRAD ITI transducers on the trailing edge of the centerboard.

Image of acoustic instruments on the Oscar Dyson.  (Photo courtesy of NOAA Teacher at Sea Program)

Image of acoustic instruments on the Oscar Dyson. (Photo courtesy of NOAA Teacher at Sea Program)

This “fish-finder” technology works when transducers emit a sound wave at a particular frequency and detect the sound wave bouncing back (the echo) at the same frequency.  When the sound waves return from a school of fish, the strength of the returning echo helps determine how many fish are at that particular site.

The green ship’s transducer is sending out sound waves towards the fish.  The waves bounce back echoes towards the ship that are received by the transducer.  (Photo courtesy of Oracle Thinkquest)

The green ship’s transducer is sending out sound waves towards the fish. The waves bounce back echoes towards the ship that are received by the transducer. (Photo courtesy of Oracle Thinkquest)

Sound waves bounce or reflect off of fish and other creatures in the sea differently.  Most fish reflect sound energy sent from the transducers because of their swim bladders, organs that fish use to stay buoyant in the water column.  Since a swim bladder is filled with air, it reflects sound very well.   When the sound energy goes from one medium to another, there is a stronger reflection of that sound energy.  In most cases, the bigger the fish, the bigger the swim bladder; the bigger the swim bladder, the more sound is reflected and received by the transducer.  The characteristic reflection of sound is called target strength and can be used to detect the size of the fish. This is why fish that have air-filled swim bladders show up nicely on hydroacoustic data, while fish that lack swim bladders (like sharks) or that have oil or wax filled swim bladders (like Orange Roughy), have weak signals.

The above picture shows the location of the swim bladder.  (Photo courtesy of greatneck.k12.ny.us)

The above picture shows the location of the swim bladder. (Photo courtesy of greatneck.k12.ny.us)

These reflections of sound (echoes) are sent to computers which display the information in echograms.  The reflections showing up on the computer screen are called backscatter.  The backscatter is how we determine how dense the fish are in a particular school.  Scientists take the backscatter that we measure from the transducers and divide that by the target strength for an individual and that gives  the number of individuals that must be there to produce that amount of backscatter.  For example, a hundred fish produce 100x more echoes than a single fish.  This information can be used to estimate the pollock population in the Gulf of Alaska.

The above picture shows a computer screen with dense red “backscatter” characteristic of large amount of fish. The yellow lines above and below the backscatter show the location of the trawl lines.

The above picture shows a computer screen with dense red “backscatter” characteristic of large amount of fish, most likely pollock. The yellow lines above and below the backscatter show the location of the trawl lines.

Personal Log: 

Safety

Safety Announcements Don the Walls of the Oscar Dyson

Safety Announcements Don the Walls of the Oscar Dyson

Continuing with Maslow’s hierarchy of needs, I will continue up the pyramid  (see below) and discuss some ways that the basic need of safety is  met on the ship.  The safety and security of all staff (as well as sea animals we encounter) are top priority on the Oscar Dyson.   There are constant reminders of  this priority during ship life.

A Version of Maslow's Hierarchy of Needs

A Version of Maslow’s Hierarchy of Needs

Safety Drills

On the first day of our travel,  before the Oscar Dyson was far from port at Kodiak,  we had three drills.  The fire drill and man overboard drill required me to report to the conference room and meet up with the rest of the science team.  Patrick, the lead scientist, then reported that we (the scientist team) were all accounted for.  The crew had more complex tasks of deploying a small boat and retrieving “the man overboard”.

The other drill was the abandon ship drill.  On the ship, every person is assigned to a life boat (mine is Lifeboat 1).  When the drill commenced, I reported to my muster, the portside of the trawl deck, with survival gear:  jacket, hat, survival suit and life preserver.  We will have drills weekly at anytime.

Abandon Ship Crew Assignments

Abandon Ship Crew Assignments

Safety Gear
When working in the lab, the scientists wear orange slickers, boots, and gloves, not only to keep clean, but to protect us from anything that might be dangerous (fish spines, jellyfish tentacles, and so on).  When on deck, we must wear hardhats (to protect from falling objects from the crane or trawl) and life preservers like the rest of the crew.

Gloves, a Must in Fish Lab!

Gloves, a Must in Fish Lab!

Water Tight Doors
Watertight doors are special types of doors found on the ship which prevent the flow of water from one compartment to other during flooding or accidents. These doors are used onboard in areas, such as the engine room compartment,  science and acoustics labs, and control bridge, where chances of flooding are high.

Water Tight Door on Bridge

Water Tight Door on Bridge

These are just a few examples of how safety is emphasized on the ship.  There are reminders in one’s line of vision constantly.

Safety, Everyone's Responsibility

Safety, Everyone’s Responsibility

Did You Know?

There are various seafarer or crew positions on the Oscar Dyson.  A ship’s crew can generally be divided into three main categories: the deck department, the engineering department, and the steward department.  Rob and Greg are members of the deck department; both men hold Merchant Mariner Credentials as “Able Bodied Seamen” or ABS.  Rob is from Boston, Massachusetts and went to school for seamanship in Fairhaven, MA.  He considers his NOAA position as a good job with a good income, but his main profession is lobstering which he does on the open sea when he is not working for NOAA.  Rob says, “The ocean is in my blood” and always wanted to work on it.   Greg, on the other hand, chose to be a Merchant Mariner after a voyage at sea.  He moved to Texas from Louisiana in his 20’s, went fishing for the first time, and got seasick.  He considered battling seasickness a challenge, and thus pursing seamanship as a career.  In his free time he is a free-lance photographer and journalist.  Below are some pictures of Greg and Rob on the job.  Notice they are always wearing their safety gear.

Greg and Rob Bringing in the Trawling Net

Greg and Rob Bringing in the Trawling Net

Greg and Rob, Preparing for a Camera Drop

Greg and Rob, Preparing for a Camera Drop

Something to Think About: 

Since I will begin teaching Zoology later in August, I have decided to highlight some of the animals that the scientist team has found in our trawls.  Today’s feature will be one of the simplest multicellular animal families, the Porifera.  Porifera is a word formed from combining the Latin words porus which means “passage-way” and fera meaning “bearing.”  Porifera, commonly referred to as sponges, have tiny pores in their outer walls that filter water to get nutrients.  

Various Porifera (Sponges) from a Bottom Trawl

Various Porifera (Sponges) from a Bottom Trawl

Teacher (me) Demonstrating How Water Flows out the Osculum (opening) of a Poriferan

Teacher (me) Demonstrating How Water Flows out the Osculum (opening) of a Poriferan

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

Tree of Life:  Can you spot  the Poriferan?

Tree of Life: Can you spot the Poriferan?

Kathleen Harrison: Finding Fish, July 12, 2011

NOAA Teacher at Sea
Kathleen Harrison
Aboard NOAA Ship  Oscar Dyson
July 4 — 22, 2011

Location:  Gulf of Alaska
Mission:  Walleye Pollock Survey
Date: July 12, 2011

Weather Data from the Bridge
Air Temperature:  10.15° C, Sea Water Temperature:  7.6° C
True Wind Speed:  12.26 knots, True Wind Direction:  191.38°
Very foggy, visibility < 1/4 mile
Door open on bridge to hear other fog horns
Latitude:  56.07° N, Longitude:  158.08° W
Ship Heading:  24°, Ship Speed:  11.7 knots

Science and Technology Log:  Finding Fish

In a previous log, I talked about using nautical charts and trawling as 2 methods used in calculating the biomass of Walleye Pollock in the Gulf of Alaska.  Finding the fish to catch is tricky business in the ocean, they don’t usually come up to the surface and say hi.  The NOAA scientists working on the Walleye Pollock Survey spend a lot of time looking for fish, so that their trawling efforts won’t be wasted (that is the general idea, anyway).  How do you look for fish in the ocean?  With acoustics, of course, another method used in calculating biomass.

Acoustics is the use of sound, which will travel through the water, and bounce off of objects that it hits.  There is Simrad ER60 echosounder  that operates 5 transducers mounted on the center board under the ship, and it continuously sends out sound waves.

multibeam sonar mapping the ocean floor

The Simrad ER60 echosounder sends sound directly under the ship, finding fish anywhere in the water column.

In the Acoustics Lab of the Oscar Dyson, the data from the multi-beam echosounder is being studied all of the time.  The sound waves leave the device, travel down, hit the swim bladder in a fish (the fish doesn’t even know), and reflect back to the ship.  The time it takes for the sound to return is used to calculate the distance down, and a computer generated picture called an echogram is produced.

echogram shows surface, fish, and bottom

The echogram shows plankton at the surface in blue/green, fish near the bottom as red/brown spots, and the ocean floor as a red/brown line.

The echogram tells the scientists several things.  The surface of the water is shown, with surface dwelling organisms such as krill, phytoplankton, zooplankton, and juvenile fish.  The fish that are mid-water are shown as well, showing up as red or blue dashes or blobs.  This is where the Pollock usually are.  Some fish are bottom feeders, and the red and blue dashes on the bottom represent those.  The ocean floor is also shown, which is very important when choosing which type of trawl to use.   If the bottom is flat, the Poly Nor’Easter could be used to capture to fish on the bottom.  The Aleutian Wing Trawl might be used in mid water if the bottom is rocky and irregular.

Now, looking at the fish from the surface is nice, but wouldn’t it be better to see them close up?  Of course!  The scientists have another tool at their disposal, and no, it isn’t me diving down to the fish (brrr).  This tool is called a Drop Target Strength, or DTS.

echosounder can be dropped into water

The Drop Target Strength (DTS) can be lowered into the water, and get closer to the fish. The information is fed into the computer by a water proof cable.

About once a day, or every other day, the DTS is lowered over the side, and it starts sending out sound waves (3 pings/second), just like the echosounder mounted on the ship.  The advantage with the DTS, though, is that it is closer to the fish, giving a more detailed and accurate picture.  Individual fish can be sighted.  Taking a picture of a fish is kind of like taking a picture of a toddler, they don’t hold still very well.  So, a count of the fish on the echogram might not be exact.  Also, they might change the angle of their body, making the sound wave reflect off their swim bladder at a different angle.  The colors on the echogram are significant:  brown and red mean a strong signal, yellow is medium, and green and blue indicate a weak signal.

echogram shows individual fish

Studying the echogram from the DTS gives scientists a better picture of where the fish are. Each individual wavy line is probably a separate fish.

The scientists will study the echograms to determine where the fish are, and make a decision to fish or not.  Once fishing begins, they will move from the acoustics lab to the bridge, and study the echograms there.  An estimate of how many fish are in the net is made, and then the scientists will ask the crew to “haul back” the net.   (I am learning a whole new language!)  Then, things get very busy as we head to the fish lab to process the fish.

scientists at their desks in the acoustics lab

Here are the NOAA scientists that I am privileged to work with on the Oscar Dyson: (left to right) Darin Jones, Fish Biologist, Denise McKelvey, Fish Biologist, Neal Williamson, Chief Scientist.

New species seen:

Giant Pacific Octopus (juvenile, 1 cm)

Opalescent Squid

Chinook (King) Salmon

Egg yolk jelly fish

Sculpin (juvenile)

North Pacific sea nettle

Spud sponge

tiny squid, only 2 cm long

These are juvenile squid, about 2 cm long. They are nearly transparent.

giant pacific octopus, juvenile, only 1 cm

This is a juvenile Giant Pacific Octopus, only 1 cm wide, complete with 2 huge eyes, and 8 perfect legs.

Personal Log

My days have developed a routine now:  wake at 3:30 am (ugh), start my shift in the acoustics lab about 4:00, breakfast at 7:30, lunch at 11:30, end my shift at 4:00 pm, dinner at 5:30, shower, in bed by 8:00.

my window and life boats

See the orange life saving ring? My window is just to the right of the ring. The 3 white canisters on the back wall hold life rafts that inflate upon release of the canister.

In between these times, I work on my Teacher at Sea log, post pictures on Facebook, read and answer e-mail, visit the bridge and ask lots of questions, and of course, process fish whenever there is a trawl (very fun).  Today marks the halfway point of our cruise!  The ship is quieter than I thought, even though there are 35 people on board, the most that I ever see might be 10 during mealtimes.  There is constant background noise of the ship’s engines, waves hitting the bow of the ship, creaks and groans of the furniture as the ship rolls, but I am used to it now, and hardly notice it.  I am thankful for the calm weather that we have had so far.