Staci DeSchryver: Things We Deliberately Throw Overboard Part Deux: The Ocean Noise Sensor July 20, 2017

NOAA Teacher At Sea

Staci DeSchryver

Aboard Oscar Elton Sette

July 6 – Aug 2

Mission:  HICEAS Cetacean Study

Geographic Area:  Northwest Hawaiian Island Chain, Just past Mokumanamana (Necker Island)

Date:  July 20, 2017

Weather Data from the Bridge:

Science and Technology Log:

As promised in Blog Post #3, I mentioned that “Thing number four we deliberately throw overboard” would have a dedicated blog post because it was so involved.  Well, grab some popcorn, because the time has arrived!

Thing number 4 we deliberately throw over the side of a ship does not get thrown overboard very often, but when it does, it causes much hubbub and hullaballoo on the ship.  I had the unique opportunity to witness one of only ten ocean noise sensors that are deployed in US waters come aboard the ship and get redeployed.  These sensors are found all over US waters – from Alaska to the Atlantic.  One is located in the Catalina Marine Sanctuary, and still others are hanging out in the Gulf of Mexico, and we are going to be sailing right past one!  To see more about the Ocean Noise Sensors, visit the HICEAS website “other projects” tab, or just click here.  To see where the Ocean Noise Recorders are, click here.

The Ocean Noise Sensor system is a group of 10 microphones placed in the “SOFAR” channel all over US waters.  Once deployed, they collect data for two years in order to track the level of ocean noise over time.  It’s no secret that our oceans are getting louder.  Shipping routes, oil and gas exploration, and even natural sources of noise like earthquakes all contribute to the underwater noise that our cetacean friends must chatter through.  Imagine sitting at far ends of the table at a dinner party with a friend you have not caught up with in a while.  While other guests chat away, you and the friend must raise your voices slightly to remain in contact.  As the night progresses on, plates start clanging, glasses are clinking, servers are asking questions, and music is playing in the background.  The frustration of trying to communicate over the din is tolerable, but not insurmountable.  Now imagine the host turning on the Super Bowl at full volume for entertainment.  Now the noise in the room is incorrigible, and you and your friend have lost all hope of even hearing a simple greeting, let alone have a conversation.  In fact, you can hardly get anyone’s attention to get them to pass you the potatoes.  This is similar to the noise levels in our world’s ocean.  As time goes on, more noise is being added to the system.  This could potentially interfere with multiple species and their communications abilities.  Calling out to find a mate, forage for food, or simply find a group to associate with must now be done in the equivalent din of a ticker-tape parade, complete with bands, floats, and fire engines blaring their horns.  This is what the Ocean Noise Sensor is hoping to get a handle on.   By placing sensors in the ocean to passively collect ambient noise, we can answer two important questions:  How have the noise levels changed over time?  To what extent are these changes in noise levels impacting marine life?   

Many smaller isolated studies have been done on ocean noise levels in the past, but a few years ago, scientists from Cornell partnered with NOAA and the Pacific Islands Fisheries Science Center (PIFSC) and the Pacific Marine Environmental Lab to streamline this study in order to get a unified, global data source of ocean noise levels.  The Pacific Marine Environmental Lab built a unified sound recording system for all groups involved in the study, and undertook the deployments of the hydrophones.  They also took on the task of processing the data once it is recovered.  The HICEAS team is in a timely and geographical position to assist in recovery of the data box and redeploying the hydrophone.   This was how we spent the day.

The recovery and re-deployment of the buoy started just before dawn, and ended just before dinner.

 Our standard effort of marine mammal observation was put on hold so that we could recover and re-deploy the hydrophone.  It was an exciting day for a few reasons – one, it was definitely a novel way to spend the day.  There was much to do on the part of the crew, and much to watch on the part of those who didn’t have the know-how to assist.  (This was the category I fell in to.)

At dawn, an underwater acoustic command was sent to the depths to release a buoy held underwater attached to the hydrophone.  While the hydrophone is only 1000m below the surface seated nice and squarely in the SOFAR channel, the entire system is anchored to the ocean floor at a depth of 4000m.  Once the buoy was released, crew members stationed themselves around the ship on the Big Eyes and with binoculars to watch for the buoy to surface.  It took approximately 45 minutes before the buoy was spotted just off our port side.  The sighting award goes to CDR Stephanie Koes, our fearless CO.  A crewmember pointed out the advancement in our technologies in the following way:  “We can use GPS to find a buried hydrophone in the middle of the ocean…and then send a signal…down 4000m…to a buoy anchored to the ocean floor…cut the buoy loose remotely, and then actually have the buoy come up to the surface near enough to the ship where we can find it.”  Pretty impressive if you think about it.

The buoy was tied to the line that is attached to the hydrophone, so once the buoy surfaced, “all” we had to do was send a fast rescue boat out to retrieve it, bring the buoy and line back to the ship, bring the crew safely back aboard the ship, hook the line up through a pulley overhead and back to a deck wench, pull the line through, take off the hydrophone, pull the rest of the line up, unspool the line on the wench to re-set the line, re-spool the winch, and then reverse the whole process.

Watching the crew work on this process was impressive at least, and a fully orchestrated symphony at best.  There were many tyings of knots and transfers of lines, and all crew members worked like the well-seasoned deck crew that they are.  Chief Bos’n Chris Kaanaana is no stranger to hauling in and maintaining buoys, so his deck crew were well prepared to take on this monumental task.

Much of the day went exactly according to plan.  The buoy was safely retrieved, the hydrophone brought on board, the lines pulled in, re-spooled, and all sent back out again.  But I am here to tell you that 4000m of line to haul in and pay back out takes. A Long. Time.  We worked through a rainstorm spooling the line off the winch to reset it, through the glare of the tropical sun and the gentle and steadfast breeze of the trade winds.  By dinner time, all was back in place, the buoy safely submerged deep in the ocean waters, waiting to be released again in another two years to repeat the process all over again.  With any luck, the noise levels in the ocean will have improved.  Many commercial vessels have committed to adopting “quiet ship” technology to assist in the reduction of noise levels.  If this continues to improve, our cetacean friends just might be able to hear one another again at dinner.

 

Personal Log

So, I guess it’s pretty fair to say that once you’re a teacher, you’re always a teacher.  I could not fully escape my August to May duties onboard, despite my best efforts.  This week, I found myself on the bridge, doing a science experiment with the Wardroom (These are what all of the officers onboard as a group are called).   How is this even happening, you ask?  (Trust me, I asked myself the same thing when I was in the middle of it, running around to different “lab groups” just like in class.)  Our CO, CDR Koes, is committed to ensuring that her crew is always learning on the ship.

 If her staff do not know the answer to a question, she will guide them through the process of seeking out the correct answer so that all  officers learn as much as they can when it comes to being underway –  steering the ship, preparing for emergencies, and working with engineers, scientists, and crew.  For example, I found out that while I was off “small-boating” near Pilot Whales, the Wardroom was busy working on maneuvering the ship in practice of man overboard scenarios.  She is committed to ensuring that all of her staff knows all parts of this moving city, or at a minimum know how to find the answers to any questions they may have.  It’s become clear just how much the crew and the entire ship have a deep respect and admiration for CDR Koes.  I knew she was going to be great when we were at training and word got out that she would be the CO of this Leg on Sette and everyone had a range of positive emotions from elated to relieved to ecstatic.

As part of this training, she gives regular “quizzes” to her staff each day – many of them in good fun with questions for scientists, crew, engineers, and I.  Some questions are nautical “things” that the Wardroom should know or are nice to know (for example, knowing the locations of Material Safety Data Sheets or calculating dew point temperatures), some questions are about the scientific work done onboard, while others are questions about personal lives of onboard members.

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The Chief Medical Officer, “Doc” gives a lesson on water quality testing.

 It has been a lot of fun watching the Wardroom and Crew seek out others and ask them where they live while showing them their “whale dance” to encourage sightings.  It has exponentially increased the interactions between everyone onboard in a positive and productive way.

The other teaching element that CDR Koes has implemented is a daily lesson each day from Monday to Friday just after lunch.  All NOAA Officers meet on the bridge, while one officer takes the lead to teach a quick, fifteen minute lesson on any topic of their choosing.  It could be to refresh scientific knowledge, general ship operations, nautical concepts, or anything else that would be considered “good to know.”

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The Chief Engineer gives a rundown on the various ship emergency alarms.

 This sharing of knowledge builds trust among the Wardroom because it honors each officer’s strong suits and reminds us that we all have something to contribute while onboard.

I started attending these lunchtime sessions and volunteered to take on a lesson.  So, this past Tuesday, I rounded up some supplies and did what I know best – we all participated in the Cloud in a Bottle Lesson!

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Here I am learning to use a sextant for navigation.

The Wardroom had fun (I think?) making bottle clouds, talking about the three conditions for cloud formation, and refreshing their memories on adiabatic heating and cooling.  It was a little nerve wracking for me as a teacher because two of the officers are meteorologists by trade, but I think I passed the bar.  (I hope I did!)

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Teaching about adiabatic cooling with the the Cloud in a Bottle Demo with the Wardroom!

It was fun to slide back into the role of teacher, if only for a brief while, and served as a reminder that I’m on my way back to work in a few weeks!  Thanks to the Wardroom  for calling on me to dust up my teacher skills for the upcoming first weeks of school!

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ENS Holland and ENS Frederick working hard making clouds.

 

 

 

 

 

 

 

 

 

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Facebook Asks, DeSchryver Answers

I polled all of my Facebook friends, fishing (ha ha, see what I did there?) for questions about the ship, and here are some of the questions and my answers!

 

Q:   LC asks, “What has been your most exciting moment on the ship?”

It’s hard to pick just one, so I’ll tell you the times I was held at a little tear:  a) Any sighting of a new species is a solid winner, especially the rare ones  b) The first time I heard Sperm Whales on the acoustic detector c) The first time we took the small boat out for UAS operations….annnndddd d) The first time I was on Independent Observation and we had a sighting!

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A group of Melon-Headed Whales, or PEPs, cruise along with the ship.

Q:  JK asks, “What are your thoughts on the breakoff of Larsen C?  And have there been any effects from the Alaskan quake and tsunami?”

We’re actually pretty isolated on board!  Limited internet makes it hard to hear of all the current events.  I had only briefly heard about Larsen C, and just that it broke, not anything else.  I had no clue there was a quake and tsunami!  But!  I will tell a cool sort of related story.  On Ford Island, right where Sette is docked, the parking lot is holding three pretty banged up boats.  If you look closely, they all have Japanese markings on them.  Turns out they washed up on Oahu after the Japan Tsunami.  They tracked down the owners, and they came out to confirm those boats were theirs, but left them with NOAA as a donation.  So?  There’s tsunami debris on Oahu and I saw it.

 

Q:  NG asks, “Any aha moments when it comes to being on the ocean?  And anything to bring back to Earth Science class?”

So many aha moments, but one in particular that comes to mind is just how difficult it is to spot cetaceans and how talented the marine mammal observers are! They can quite literally spot animals from miles away!  There are a lot of measures put in place to help the marine mammal observers, but at the end of the day, there are some species that are just tougher than nails to spot, or to spot and keep an eye on since their behaviors are all so different.  And as far as anything to bring back to our class?  Tons.  I got a cool trick to make a range finder using a pencil.  I think we should use it!

 

Q:  MJB asks, “Have you had some peaceful moments to process and just take it all in?”

Yes.  At night between the sonobuoy launches, I get two miles of transit time out on the back deck to just absorb the day and be thankful for the opportunities.  The area of Hawai’i we are in right now is considered sacred ground, so it’s very powerful to just be here and be here.

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These sunsets will give Colorado sunsets a run for their money.  No green flash in Colorado = point awarded to Hawai’i.

 

Q:  SC asks, “What souvenir are you bringing me?”

Well, we saw a glass fishing float, and we tried to catch it for you, but it got away.

Q:  LC asks, “What’s the most disgusting ocean creature?”

Boy that’s a loaded question because I guarantee if I name a creature, someone out there studies it for a living.  But! I will tell you the most delicious ocean creature.  That would be Ono.  In sashimi form.  Also, there is a bird called a Great Frigate bird – it feeds via something called Klepto-parasitism, which is exactly how it sounds.  It basically finds other birds, harasses them until they give up whatever they just caught or in some cases until it pukes, and then it steals their food.  So, yeah.  I’d say that’s pretty gross.  But everyone’s gotta eat, right?

Q:  KI asks, “Have you eaten all that ginger?”

I’m about two weeks in and I’m pretty sure I’ve eaten about a pound. I’m still working on it!

Q:  HC asks, ”Have you seen or heard any species outside of their normal ocean territory?”

Sort of.  Yesterday we saw Orca!  They are tropical Orca, so they are found in this area, but they aren’t very common.  The scientific team was thinking we’d maybe see one or two out of the entire seven legs of the trip, and we saw some yesterday!  (I can’t say how many, and you’ll find out why in an upcoming post.)  We have also seen a little bird that wasn’t really technically out of his territory, but the poor fella sure was a little far from home.

Q:  JPK asks, “What kinds of data have you accumulated to use in a cross-curricular experience for math?”

We can do abundance estimates with a reasonably simplified equation.  It’s pretty neat how we can take everything that we see from this study, and use those numbers to extrapolate how many of each species is estimated to be “out there.”

Q: AP asks, “What has surprised you about this trip?”

Many, many things, but I’ll mention a couple fun ones.  The ship has an enormous movie collection – even of movies that aren’t out on DVD yet because they get them ahead of time!  Also? The food on the ship is amazing.  We’re halfway through the trip and the lettuce is still green.  I have to find out the chef’s secret!  And the desserts are to die for.  It’s a wonder I haven’t put on twenty pounds.  The crew does a lot of little things to celebrate and keep morale up, like birthday parties, and music at dinner, and shave ice once a week.  Lots of people take turns barbecuing and cooking traditional foods and desserts special to them from home and they share with everyone.  They are always in really high spirits and don’t let morale drop to begin with, so it’s always fun.

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Celebrating Engineer Jerry’s Birthday.

Q:  TS asks, “What’s the most exciting thing you’ve done?”

I’ve done lots of exciting things, but the one thing that comes to mind is launching on the small boat to go take photos of the pilot whales.  Such a cool experience, and I hope we get good enough weather to do it again while we’re out here!  Everything about ship life is brand new to me, so I like to help out as much as I can.  Any time someone says, “Will you help with this?” I get excited, because I  know I’m about to learn something new and also lend a hand. 

 

Staci DeSchryver: Listening with Your Eyes – How the Acoustics Team “Sees” in Sound, July 10, 2017

NOAA Teacher at Sea

Staci DeSchryver

Aboard NOAA Ship Oscar Elton Sette

July 6 – August 2, 2017

Mission:  HICEAS Cetacean Study

Geographic Area:  Kona Coast, Hawaii

Date:  July 10, 2017

Weather Data from the Bridge:

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Location and Weather Data

 

Science Log

While the visual team is working hard on the flying bridge, scanning the waters for our elusive cetacean friends, acoustics is down in the lab listening for any clues that there might be “something” out there.

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The hydrophone array is a long microphone pulled behind the ship

At any given time, two acousticians are listening to the sounds of the ocean via a hydrophone array. This array is a long microphone pulled behind the ship as she cuts through the water.  When the acousticians hear a click or a whistle, a special computer program localizes (or determines the distance to) the whistle or the click.

But it’s not quite as simple as that. There’s a lot of noise in the ocean.  The array will pick up other ship noise, cavitation (or bubbles from the propeller) on our ship, or anything it “thinks” might be a cetacean.  The acoustics team must determine which sounds are noise and which sounds belong to a mammal.  What the acousticians are looking for is something called a “click train.” These are sound produced by dolphins when they are foraging or socializing and are a good indicator of a nearby cetacean. On the computer screen, any ambient noise shows up as a plotted point on an on-screen graph.  When the plotted points show up in a fixed or predictable pattern, then it could be a nearby cetacean.

The acousticians are also listening to the sounds on headphones.  When they hear a whistle or a click, they can find the sound they’ve heard on the plotted graph.  On the graphical representation of the sounds coming in to the hydrophone, the x-axis of the graph is time, and the y-axis is a “bearing” angle.  It will tell which angle off the ship from the front the noise is coming from.  For example, if the animal is right in front of the bow of the ship, the reading would be 0 degrees.  If it were directly behind the ship, then the plotted point would come in at 180 degrees.  With these two pieces of information, acousticians can narrow the location of the animal in question down to two spots on either side of the ship.  When they think they have a significant sound, the acousticians will use the information from the graph to localize the sound and plot it on a map.  Often times they can identify the sound directly to the species, which is an extraordinary skill.

Here’s where things go a little “Fight Club.”  (First rule of fight club?  Don’t talk about fight club.)  Once the acousticians localize an animal, they must determine if it is ahead of the ship or behind it.   Let’s say for example an acoustician hears a Pilot Whale.  He or she will draw a line on a computerized map to determine the distance the whale is to the ship using the data from the graph.

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This is a “clean” localization of a marine mammal. Notice the two spots where the lines cross – those are the two possible locations of the mammal we are tracking. The ship is the red dot, the blue dots are the hydrophone as it is towed behind the ship.

Because the hydrophones are in a line, the location provided from the array shows on the left and the right sides.  So, the map plots both of those potential spots.  The two straight lines from the ship to the animal make a “V” shape.  As the ship passes the animal, the angle of the V opens up until it becomes a straight line, much like opening a book to lay it flat on the table and viewing how the pages change from the side.  As long as the animal or animal group is ahead of the ship, the acousticians will alert no one except the lead scientist, and especially not the marine observers.  If a crew member or another scientist who is not observing mammals just so happens to be in the acoustics lab when the localization happens, we are sworn to secrecy, as well.  Sometimes an acoustician will send a runner to get the lead scientist to discreetly tell her that there is something out there.

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The screenshot on the left shows a series of spotted dolphin “click trains.” Notice the marks all in a line along the graph. The right photo shows the various localizations that the acoustics team has picked up from the click train graph. The red dot is the ship, the gray line is the “track line”, and the two blue dots behind the ship are the hydrophone arrays. Notice the V shape gradually goes to a straight line and then turns in the opposite direction.

 

This way, the lead scientist can begin the planning stages for a chase on the mammals to do a biopsy, or send the UAS out to get photos with the Hexacopter.  (More on this later.)

As the mammals “pass the beam” (the signal is perfectly on either side of the ship, and starting to make an upside down V from the ship), the acousticians can alert the visual team of the sighting.  As soon as everyone is aware the mammals are out there, either by sight or sound, the whole scientific group goes “off effort,” meaning we funnel our energy in to counting and sighting the mammals we have found.  When this happens, communication is “open” between the acoustics team and the visual team.  The visual team can direct the bridge to head in any direction, and as long as it’s safe to do so, the bridge will aid in the pursuit of the mammals to put us in the best position to get close enough to hopefully identify the species.  Today, one mammal observer had a sighting almost 6 miles away from the ship, and she could identify the species from that distance, as well!  Even cooler is that it was a beaked whale, which is an elusive whale that isn’t often sighted.   They have the capability of diving to 1000m to forage for food!

When the visual team has a sighting, the three visual observers who are on shift have the responsibility to estimate the group size.

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Chris captures photos of Melon Headed Whales for Photo ID.

 

Here we go with Fight Club again – no one can talk to one another about the group sizes.  Each mammal observer keeps their totals to themselves.  This is so that no one can sway any other person’s opinion on group size and adds an extra element of control to the study.  It is off limits to talk about group sizes among one another even after the sighting is over. We must always be vigilant of not reviewing counts with one another, even after the day is done.  The scientific team really holds solid to this protocol.

Once the sighting is over, all parties resume “on effort” sightings, and the whole process starts all over again.

Now, you might be thinking, “Why don’t they just wait until acoustics has an animal localized before sending the mammal team up to look for it?

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Ernesto on the “Big Eyes” during a Melon Headed Whale Visual Chase

Surely if acoustics isn’t hearing anything, then there must not be anything out there.”  As I am writing this post, the visual team is closing in on a spotted dolphin sighting about 6.5 miles away.  The acoustics did not pick up any vocalizations from this group.

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Shannon and Jen in the acoustics lab “seeing” the sounds of the ocean.

This also happened this morning with the beaked whale.  Both teams really do need one another in this process of documenting cetaceans.  Further, the acoustics team in some cases can’t determine group sizes from the vocals alone.  They need the visual team to do that.  Each group relies on and complements one another with their own talents and abilities to conduct a completely comprehensive search.  When adding in the hexacopter drone to do aerial photography, we now have three components working in tandem – a group that uses their eyes to see the surface, a group that uses the ocean to “see” the sounds, and a group that uses the air to capture identifying photographs.  It truly is an interconnected effort.

 

Personal Log

I haven’t gotten the chance to discuss just how beautiful Hawai’i is.  I would think that it is generally understood that Hawai’i is beautiful – it’s a famed tourist destination in an exotic corner of the Pacific Ocean. But you have to see it to believe it.

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Melon-Headed Whales take an evening ride alongside the starboard side of Sette.

I’ve been lucky enough to see the islands from a unique perspective as an observer from the outside looking inland, and I just can’t let the beauty of this place pass without mention and homage to its stunning features.

Hawai’i truly is her own artist.  Her geologic features create the rain that builds her famed rainbows, which in turn gives her the full color palate she uses to create her own landscape.  The ocean surrounding the shores of Hawai’i are not just blue – they are cerulean with notes of turquoise, royal, and sage.  She will not forget to add her contrasting crimson and scarlet in the hibiscus and bromeliads that dot the landscape. At night when the moon shines on the waters, the ocean turns to gunmetal and ink, with wide swaths of brass and silver tracing the way back up to the moon that lights our path to the sea.  With time, all of her colors come out to dance along the landscape – including the sharp titanium white foam that crashes against the black cliffs along Kona.  And if a hue is errantly missed in her construction of the landscape, early morning showers sprout wide rainbows as a sign of good fortune, and as a reminder that she forgets no tones of color as she creates.

It is our responsibility to protect these waters, this landscape – this perfect artistry.  It is critically important to protect the animals that live in the ocean’s depths and the ones that cling to the island surface in their own corner of paradise.  I like to think that this study takes on this exact work.  By giving each of these species a name and identifying them to each individual group, we share with the world that these cetaceans are a family of their own with a habitat and a purpose.  When we “re-sight” whales that the team has seen in past studies, we further solidify that those animals have families and a home amongst themselves.   The photo identification team counts every new scar, marking, and change in these animals to piece together the story of their lives since they last met with the scientists.  Everyone on Oscar Elton Sette  talks about the new calves as if we were at the hospital with them on the day of their birth, celebrating the new life they’ve brought forth to continue their generations.  I like to think we all make a little room in the corner of our hearts for them as a part of our family, as well.

Did you know?

The Frigate bird has a Hawaiian name, “Iwa”, which means “thief.”  They call this bird “thief” because they steal prey right from the mouths of other birds!

 

“Spyhopping” is the act of a whale poking his head out of the water and bobbing along the surface.

 

It is legal for research ships to fish off the ship, so long as we eat what we catch while underway.  This led to the shared consumption of some delicious mahi mahi, fresh from the depths for lunch today.  Yes.  It was as good as it sounds.

 

Oscar Elton Sette knows how to celebrate!  Yesterday was Adam’s birthday, a marine mammal observer.  They decorated the mess in birthday theme, cranked up the dinnertime music, and the stewards made Adam his favorite – blueberry cheesecake for dessert!

 

Much of the crew likes to pitch in with food preparation.  The on ship doctor, “Doc”, makes authentic eastern dishes, and the crew made barbeque for everyone a few nights ago at dinner.

Dawn White: Pinging for Populations, June 29, 2017

 

NOAA Teacher at Sea

 Dawn White

Aboard NOAA Ship the Reuben Lasker

June 19 – July 1, 2017

 

Mission: West Coast Sardine Survey

Geographic Area of Cruise: Pacific Ocean; U.S. West Coast

Date: June 29, 2017

 

Weather Data from the Bridge

Date: June 29, 2017                                                         Wind Speed: 7.7 kts

Time: 6:15 p.m.                                                                 Latitude: 4805.5N

Temperature: 12.7oC                                                      Longitude: 12520.07W

 

Science and Technology Log

The technology present on this ship is amazing and at the same time quite overwhelming.  These systems allow for data to be collected on a wide range of variables both continuously and simultaneously.  Below are a couple of photos of the acoustics room where multiple sensors are monitoring the feedback from sonar systems placed below the ship’s hull.  One of the acoustic probes sends out sound waves in a cone-like formation directly below the ship.  Another unit emits sound waves in a horizontal pattern.  The ship was designed to run as quietly as possible so as to not disturb the marine life present in the waters as the ship passes by and also to reduce the interference of the ship’s sounds with the acoustics feedback.

 

 

Acoustics technician Dan Palance managing the multiple computers that are constantly collecting data.

Multiple programs help to eliminate the “noise” received by the probes until all that remains are images that represent schools of fish and their location relative to the ocean floor.

 

The images above were taken from a poster on board the Reuben Lasker. They illustrate the range of the water column surveyed by the various acoustic systems.

 

The “soundings” are received by the ship, processed and “cleaned up” using a series of program algorithms. The image below shows the feedback received from one of the systems.

Displays of feedback from an acoustics system

Once the background “noise” has been eliminated, the resulting image will show locations of fish, school size, and the depth (y axis) at which they can be found.

Graph of acoustic feedback, with background “noise” eliminated, depicting depth and size of fish schools

 

Extension question for my students reading this:  Approximately how deep are the schools of fish being picked up by the sonar at this location?

Acoustics aren’t the only tools used to try pinpoint the locations of the fish schools.  As I wrote about on an earlier blog, the CUFES egg sampler is used to monitor the presence of fish eggs in the waters that the ship passes over.  Water samples are analyzed every half hour.  If egg samples appear in an area where there is also a strong acoustics signal, then that may be a location the ship will return to for the night’s trawl.  The main focus of this trip is to monitor the anchovy and sardine populations, so extra attention is paid to the locations where those eggs appear in the samples.

Personal Log:

Each time we drop the net for an evening trawl it is always retrieved with a bit of suspense:  What’s going to be in the net this time?  How big is the haul?  Will we capture any of the key species or haul in something completely different?

I can honestly say that while on board there were no two hauls exactly the same.  We continued to capture large quantities of pyrosomes – unbelievable amounts.  Check out the net-tearing load we encountered one night.  We literally had to weigh them by the basketful!

Here I am getting ready to help unload this large catch.

TAS Dawn White prepares to help unload large catch

 

Net-tearing load of pyrosomes!

Above is the codend of the net filled with pyrosomes and fish.  A 5-basket sample was pulled aside for analysis.  The remainder was simply classified and massed.

While I was certainly don’t need to see another pyrosome any time soon, there were plenty of other times when some very unique species made an appearance!

Pacific Jack Mackerel
Solitary Common Salp
TAS Dawn White holds a Blue Shark
Dogfish Shark

Did you know?

The dogfish shark (pictured above) was one of about 50 or so that were caught in the same haul.  We had trawled through a school that was feeding on the small fish found at the ocean surface during the evening hours.  This is the same species of shark that is commonly provided to students for dissection.  Use the search terms “dogfish shark dissection” and see what you find!

Nikki Durkan: The sound of…fishes! June 17, 2015

NOAA Teacher at Sea
Nikki Durkan
Aboard NOAA Ship Oscar Dyson
June 11 – 30, 2015

Mission: Midwater Assessment Conservation Survey
Geographical area of cruise: Gulf of Alaska
Date: Wednesday, June 17, 2015

Weather Data from the Bridge:
Wind speed (knots):  13.47
Sea Temp (deg C):  8.55
Air Temp (deg C):  9

Science and Technology Log

The sound of fishes.

What are we doing here off the coast of the Aleutian Islands? Listening…sort of.  We are collecting data used to estimate biomass (total amount of living matter in a given habitat) and to project population estimates for the Walleye Pollock Gadus chalcogrammus fishery.

Transects we fish are the lines somewhat perpendicular to the islands.
Transects we fish are perpendicular to the islands.

How do we do this? In order to understand the instruments we are utilizing, I’ll attempt a simple but not completely accurate analogy: if I bounce a basketball on a cement driveway – it could bounce back with enough energy to hit me in the face (I’m not saying this has happened to me); however, if instead, I bounce the ball down onto a grassy lawn, the ball will barely bounce back up.   Different materials reflect energy back with different frequencies and the picture this information translates to on a computer monitor is called an echogram:

Red - seafloor Bluish dots above - fishes!
Red – seafloor
Bluish dots above – fishes!

The Oscar Dyson has several scientific echosounders (EK60, EK80, and ME70) with transducers attached to our hull that send out energy at various frequencies. As we travel along the transects (mostly perpendicular to the island chain) we are collecting these acoustic data. The fish species produce a different pattern on the echogram and the swimbladder (full of air) makes them show up clearly; scientists have been studying the Walleye Pollock for a while now and have a pretty good idea of what Walleye Pollock “look” like on an echogram.  Sometimes the scientists observe an echogram that they are not certain about or want to verify characteristics such as length, weight, and age for an area – this means we get to fish!

 

Me learning to measure the length of a Pollock.  Photo Credit:  Patrick Ressler
Me learning to measure the length of a ~3 yr Pollock. Photo Credit: Patrick Ressler

Personal Log

The process began with a bit of dancing to Macklemore and Gangnam Style (thanks, Alyssa Pourmonir for providing the playlist!).  Music makes every task more enjoyable! I learned how to sex a fish and cut its skull open to pull out the otoliths (calcium carbonate structures located behind the brain that can be used to estimate age and growth rate) – more on this process to come! Given that I spent the majority of my childhood as a vegetarian and maintained aspirations of becoming a veterinarian and saving the lives of animals, today was a gigantic step in another direction. I could not help but feel remorse as I sliced into the bellies of the fish and splayed them open to reveal the ovaries or testis.  As a newbie, I was quite a bit slower than my coworkers, but after about 30 fish, I started to hesitate less often and verify the gonads more quickly. If any of you have spent time fishing with me, you’ll know that I enjoy the chase, but avoid handling the fish once they are on board, I’ve even been known to utter an impulsive “uh oh” when I catch a fish. I am pretty sure that after this trip, I’ll be comfortable filleting…no guarantees on my casting skills.

We unintentionally caught a salmon shark but the crew was able to return it safely!
We unintentionally caught a salmon shark but the crew was able to return it to the ocean safely!

Did you know?  Killer whales are the most widely distributed marine mammal and live in matriarchal societies.  I’ve been enjoying watching these whales from the bridge!

 

Tom Savage: In Search of Whales, June 11, 2015

NOAA Teacher at Sea
Tom Savage
On Board NOAA Ship Henry B. Bigelow
June 10 – 19, 2015

Mission: Cetacean and Turtle Research
Geographic area of Cruise: North Atlantic
Date: June 11, 2015

Weather Data from the Bridge
Air temperature: 15 C
Wind speed: 22 knots
Wind direction: coming from south-east
Relative humidity: 95%
Barometer: 1010 millibars

Personal Log

My first day at sea began at the bow of the ship searching for Sei and Beaked Whales. What a privilege it is to wake up and walk to the front of a research vessel to start your work day. The early morning hours were ideal for sighting whales as we experienced sunny skies and calm seas. The weather conditions deteriorated into the afternoon and made sightings very challenging.  To accurately record the distance from the ship to the marine animals, the observer needs to see the visual horizon. This wind speed also increased during the day causing the ship to move in all directions impacting our accuracy.

IMG_0383
Using the “Big Eyes”

Preparing for a complex research mission is not easy and takes months of planning. Due to the complexity of this mission, we were delayed three days to ensure that all scientific equipment and gear was properly working. During this delay, the mission’s chief scientist, Dr. Danielle Cholewiak, has been exceptional in welcoming me. I took her advice and stayed in Falmouth, Massachusetts, which is near Woods Hole. Woods Hole is home to NOAA’s Northeast Fisheries Science Center. Woods Hole is a village in the town of Falmouth with a strong science contingent including Woods Hole Marine Biological Laboratory and the Woods Hole Oceanographic Institute which are private research institutions not directly affiliated with NOAA.

During this time, I had the privilege of meeting other scientists who are participating on this mission, Mike and Lorenzo. Mike will be collecting data on sea birds and Lorenzo is an acoustics (sound) specialist from Scotland.

Everyone on board NOAA’s research vessel Henry B. Bigelow has been exceptionally welcoming and nice which made my transition to life at sea smooth.

The food on board the ship is amazing; my Teacher at Sea colleagues were correct.

Science and Technology Log

Although visual whale sightings were difficult today, this did not prevent the scientists from using other technologies to detect the animals. Today, a Sonobouy was deployed for the purpose of detecting a “call” from Sei Whales. Like a human voice, whales produce sounds for communication. Each species of whale has  unique vocalizations with distinctive frequency range and timing characteristics, and the sonobouy is used to detect these sounds and to track their location. The sonobouy contains a single omni-directional hydrophone, particle motion sensors and a magnetic compass.

 

Sonobouy
Preparing the Sonobouy

This device is deployed from stern of the ship. The sonobuoy is configured to drift at a depth of 90 feet and send back acoustic signals to the vessel by VHF radio, where the data are processed using computer software.  The hydrophone is connected to the sonobouy by 90 feet of thin wire. This technology is relatively new in detecting whales for NOAA, but have been used extensively by the Navy for locating submarines. Today, the sonobouy did detect sounds from Sei whales (called “downsweeps”). The acoustics team plan on launching another sonobouy tonight and depending on this outcome will determine our travel plans for tomorrow.

Until next time, happy sailing!

~ Tom