Lesley Urasky: Do You See What the Pisces “Hears”?, June 22, 2012

NOAA Teacher at Sea
Lesley Urasky
Aboard the NOAA ship Pisces
June 16 – June 29, 2012

Mission:  SEAMAP Caribbean Reef Fish Survey
Geographical area of cruise: St. Croix, U.S. Virgin Islands
Date: June 22, 2012

Location:
Latitude: 18.5472
Longitude: -65.1325

Weather Data from the Bridge:

Air Temperature: 28.6°C (83.5°F)
Wind Speed:  9 knots (10.5 mph), Beaufort scale: 3
Wind Direction: from SE
Relative Humidity: 77%
Barometric Pressure: 1,014.80  mb
Surface Water Temperature: 28.1°C (82.6°F)

Science and Technology Log

Another aspect (much more technical) of the scientific research conducted on this cruise is the collection of acoustic data.  This field is continually evolving as the detection resolution improves allowing scientists to more precisely identify fish.  This has been used with more success in fisheries farther north because the schools of fish are more likely to be monospecific (a single species).  However, the technique still needs improvement in warmer waters where the fish assemblages tend to be multi-specific (having a much greater variety of fish).

General idea behind an acoustic sounder being used to detect fish. (Source: www.biosonicinc.com)

This field of study is called Hydroacoustics (hydro- means water, and acoustics refers to sound).   It is the science of  how sound moves through water. Leonardo da Vinci noticed how sound travels through water in 1490.  He noticed that, “If you cause your ship to stop and place the head of a long tube in the water and place the outer extremity to your ear, you will hear ships at a great distance from you.” (Urick, Robert J. Principles of Underwater Sound, 3rd Edition. New York. McGraw-Hill, 1983.)  World War I helped promote innovation in the field, especially with the need for anti-submarine detection devices (Wood, A. B., From the Board of Invention and Research to the Royal Naval Scientific Service, Journal of the Royal Naval Scientific Service Vol 20, No 4, pp 1-100 (185-284)).

Hydroacoustic instruments utilize SOund Navigation and Ranging, more commonly referred to as SONAR.  The ship Pisces is equipped with a system located on the center board; this is a flat structure that can be raised/lowered through the water column beneath the center of the ship.

Line drawing of the NOAA ship Pisces showing the location of the center board.

The system used is a sonar beam that is split into quadrants.  This instrument is used to assist in determining fish abundance and distribution.  The premise is relatively simple: an echo sounder transmits a pulse of energy waves (sound), when the pulse strikes an object, it is reflected (bounced) back to the transducer.  The echo sounder is then processed and sent to a video display.  This is the same general process behind the recreationally available fishfinder.

Acoustic beam split into quadrants (Source: http://www.htisonar.com

A short burst of energy is focused into a narrow beam.  When this beam encounters an object such as a fish, a school of fish, plankton, or other object, some of the energy bounces back up through the water to the transducer.   It is the detection of these reflections that allow scientists to determine location, size, and abundance of fish.  These reflections show up on our video monitor.  These measurements are combined with groundtruthed data (for example, fish collected in the field, camera images).

One of the difficulties in data interpretation is that often, the signals that appear on the computer monitor have false readings.  This is a result of the sound wave bouncing multiple times.  It travels to the bottom from the transducer, strikes an object, returns to the ship, bounces off the ship back toward the bottom, strikes another object, and is detected yet again.

Real-time annotated echogram at sampling site.

The Pisces is actually home to one of six multi-beam acoustic instruments in the world.  Of the six in existence, NOAA has five of them.  The benefit of running a multi-beam instrument is that each beam can be set to measure a different frequency (kHz), thus enabling detection of many more features (different species of fish, etc.)

Scientific multibeam echo sounder (Source: www. simrad.com)

Personal Log

Last night the crew of the Pisces carried out a task that they don’t normally perform.  The Pisces was created for fisheries research projects – it focuses on collecting fish samples either by bandit reel, longline, or trawling.  This particular operation was to deploy the anchor for a buoy that will be attached at a later date.  When the buoy is ready to be attached, another vessel will bring it out to the site and divers will go down to the anchor to make the final attachment.

The anchor consists of a huge rebar-reinforced concrete block with a very long chain that has marker floats attached at the end.  Logistically, this took some planning; the A-frame had to be raised and the anchor lifted with the Gilson winch with a 1″ spectra line (has an enormous tensile strength).  The gate to the ship’s ramp was lowered and the A-frame (or as the deck hands call it, the “Tuna Tower”)  repositioned so the anchor was hanging over the water.  The rope holding the anchor, chain, and float was cut through, and the anchor plunged to the ocean bottom.  Again, the crew made the operation go smoothly and demonstrated their ability to complete unexpectedly assigned tasks.

Today was a slow fishing day – no fish at all.  Without any fish to “work up” (collect samples from), the day goes more slowly and we have more down time.  With the extra time, I had a chance to interview Kevin Rademacher, the Chief Scientist on the cruise.

LU: What is your official job title and what are your job duties?

KR: I’m a Research Fisheries Biologist.  I work for the Reef Fish Unit at the NOAA Fisheries Lab in Pascagoula, MS.  I am the Senior Tape Reader/Reviewer, in charge of the readers that analyze  the video data we collect from Reef Fish Surveys.  I also help plan, organize, and run the surveys.  Additionally, I participate in trawl surveys and anything else the lab needs done.

LU: When did you first become interested in the ocean and marine sciences?

KR: I guess that would have been when I was really young.  There is a photo from the Panama City, Florida newspaper, two weeks after I was born with my parents pulling me in a homemade wagon along the beach!  I knew in junior high school that I wanted to be a cross between Jacques Cousteau and Marlin Perkins of Mutual of Omaha’s Wild Kingdom.

LU: It’s such a broad field; how did you narrow your focus down to what you’re currently doing?

KR: I got lucky and kind of fell into reading underwater videos at the initial stages of the project and fell in love with being the proverbial “fly on the wall”! It has allowed me to see the fish in their natural  habitat, different color phases, behavior, etc.

LU: If you were to go into another area of ocean research, what would it be?

KR: Marine Mammal Studies.  After college I trained dolphins and sea lions and put on shows with them for a local Oceanarium on the Mississippi Gulf Coast.

LU: What is the biggest challenge in your job?

KR: Communicating with people and writing papers.

Ariane Frappier and Kevin Rademacher reviewing a dichotomous key in order to determine the species of a fish we caught.

LU: What do you think is the biggest issue of contention in your field?

KR: The impression that commercial fishermen have regarding the work we do to regulate the fisheries they work in.

LU: What are some effects of climate change that you’ve witnessed during your career in fisheries research?

KR: The decline of coral reefs and overfishing of some species.

LU: In what areas of marine science do you foresee a lot of career paths and job opportunities?

KR: Ecosystem management and data modelers.  There has also been a decline in taxonomists over the past few decades.

LU: How would you explain your work to a layperson?

KR: I use underwater cameras to help assess populations of reef fish, especially snappers and groupers.  The data collected is used to manage those fisheries.

LU: If a high school student wanted to go into your field of study/marine science in general, what kinds of courses would you recommend they take?

KR: Math, Biology, Chemistry, and any other science courses available.

LU: Do you recommend students interested in your field pursue original research as high school students or undergraduates?  If so, what kind?

KR: Most definitely! Whatever they are interested in would be beneficial.

Well, only two more days left with the scientists before we pull into San Juan, Puerto Rico.  We have 17 more daytime sites to sample and then this survey will be over.  The scientific crew will be flying home on the 25th, and once home, their work will really begin.  Back in the lab, they will be analyzing the data and reviewing the video.  Some of them will be going back out on other cruises.  Kevin Rademacher will be going out on another reef fish survey in the eastern Gulf of Mexico.  It is currently delayed because of the potential formation of tropical storm Debby.  Joey Salisbury has a couple more; he will be going on a longline cruise and then another reef fish survey, both of which will be in the Gulf of Mexico.  Arian Frappier will be heading off to begin a masters program in marine systems and coastal studies at Texas A&M Corpus Christi.

After a day’s shore leave in San Juan, I’ll continue on to Mayport on the Pisces.  During this time, I’ll focus on the crew members and their jobs.  The cruise will definitely take on a different feel at this point, but it will give me an opportunity to explore other ocean related careers.

Robert Oddo, July 25, 2009

NOAA Teacher at Sea
Robert Oddo
Onboard NOAA Ship Ronald H. Brown 
July 11 – August 10, 2009 

Mission: PIRATA (Prediction and Research Moored Array in the Atlantic)
Geographical area of cruise: Tropical Atlantic
Date: July 25, 2009

The Brown seen from a small boat

The Brown seen from a small boat

Weather Data from the Bridge 
Outside Temperature 26.94oC
Relative Humidity 81.85%
Sea Temperature 27.84oC
Barometric Pressure 1013.74 inches
Latitude 13o 07.114N Longitude 23o 00.000W

Science and Technology Log 

I have continued to help out on the 11:30 am to 11:30 pm watch with CTDs and XBTs. Why do so many CTDs and XBTs? The scientists on board are developing a subsurface profile of the water temperature, salinity and density. Based on these data, models can be constructed and refined that can help us better understand what is happening in the Tropical Atlantic.

 Removal of radiometer and anemometer from buoy

Removal of radiometer and anemometer from buoy

The Brown arrived at the second buoy that needed to be serviced on July 24th. I was lucky enough to get on the small boat sent out to take some equipment off the buoy before it was pulled up on the boat. Once at the buoy, the radiometer and the anemometer were removed.  An acoustic message is then sent from the Brown to release the anchor on the buoy. The buoy is then attached to a rope from the Brown and pulled up onto the fantail. All the instrumentation and sensors below the buoy are pulled up on the Brown and exchanged. I attached a picture of the buoy to the right so you get an idea of all the instrumentation that is attached to these buoys. I could not believe all the fish that were around the buoy.  Apparently, the buoy creates a small  ecosystem, where all kinds of marine organism congregate.  Algae and small crustaceans attach to the buoy and some of the cables that are underneath. Small fish eat the algae and crustaceans, larger fish eat the smaller fish and before you know it you have a food web.  Some of the fish are huge. Yellow fin tuna, triggerfish and mahi mahi.  This actually causes a big problem.  Fishermen come out to these buoys and damage the buoy instrumentation when they are fishing and we end up losing valuable data.

This figure shows all the instrumentation attached to the buoy.

This figure shows all the instrumentation attached to the buoy.

Personal Log 

Once the buoy is pulled up onto the ship, the fish that were around it looked for a place to go. Sometimes they come under the ship. We threw a few fishing lines in after the buoy was pulled up on the fantail and the tuna were biting like crazy. We caught a few that afternoon and had them for lunch the next day!!

 

 

 

 

Got one!  It’s tuna for lunch!

Got one! It’s tuna for lunch!

Research cruise plan

Research cruise plan

Robert Oddo, July 23, 2009

NOAA Teacher at Sea
Robert Oddo
Onboard NOAA Ship Ronald H. Brown 
July 11 – August 10, 2009 

Mission: PIRATA (Prediction and Research Moored Array in the Atlantic)
Geographical area of cruise: Tropical Atlantic
Date: July 23, 2009

Weather Data from the Bridge  
Outside Temperature 26.77oC
Relative Humidity 74.89%
Sea Temperature 27.64 oC
Barometric Pressure 1013.98 inches
Latitude 07o 59.993 N Longitude 22o 59.767W

Science and Technology Log 

We arrived at the first buoy two days ago and exchanged the “package” which is kind of like the brains of the buoy. Four people went out with a small boat and exchanged the package.  This is not an easy task since you have to climb off the small boat onto the buoy in what can be pretty rough seas and change instruments. We also deployed the “CTD” for the first time.  After the deployment, we collected seawater from various depths for salinity and dissolved oxygen analysis.  We also are deploying XBTs every 10 nautical miles on a 24 hours schedule as the ship steams along its course.  There are two shifts. I am on the 12 noon to 12 midnight shift.  The XBT (Expendable Bathythermograph) is dropped from a ship and measures the temperature as it falls through the water. Two very small wires transmit the temperature data to the ship.  When it gets to about 1500 meters, the small wire is cut and the operation is over. By plotting temperature as a function of depth, the scientists can get a picture of the temperature profile of the ocean at a particular place.

Preparing to service a buoy (left) and recovered buoy on deck (right)

Preparing to service a buoy (left) and recovered buoy on deck (right)

Yesterday, we got to the second buoy and had to pretty much exchange it with a new package, sensors and an anchor. This took over 8 hours to do and takes a lot of manpower.  The buoy is actually pulled up on the deck as well as the instrumentation below the buoy and then new instruments, buoy and an anchor are deployed. If this is not done exactly right, everything can be destroyed.

Personal Log 

Wow, there is a lot of action right now on the ship.  The atmospheric scientists are releasing sondes, collecting dust and smoke samples, and measuring incoming solar radiation at different wavelengths. There are people getting instrumentation ready for the next buoys we are steaming towards. People are deploying CTDs, XBTs, and drifters.  Behinds the scenes the crew lends all kinds of support, from preparing food, working the winches and cranes, navigating through the ocean and working in the engine room It is really teamwork that makes this all work and not any one person could do all of this work. There are a lot of very dedicated people onboard this ship and all their hard work make this work!!

Here I am deploying an XBT (left) and collecting seawater samples from the CTD (right)

Here I am deploying an XBT (left) and collecting seawater samples from the CTD (right)

Research cruise plan

Research cruise plan

Robert Oddo, July 14, 2009

NOAA Teacher at Sea
Robert Oddo
Onboard NOAA Ship Ronald H. Brown 
July 11 – August 10, 2009 

Mission: PIRATA (Prediction and Research Moored Array in the Atlantic)
Geographical area of cruise: Tropical Atlantic
Date: July 14, 2009

Deploying a radiosonde

Deploying a radiosonde

Weather Data from the Bridge 
Outside Temperature 26.01oC
Relative Humidity 89.26
Sea Surface Temperature 28.3oC
Barometric Pressure 1015.9 inches
Latitude 8o 53.96 N Longitude 48o 05.43 W

Science and Technology Log 

We released our first radiosonde this morning.  These balloons have instruments attached to them that will measure atmospheric pressure, temperature and relative humidity as they go up into the atmosphere.  As the balloon rises, it expands as the atmospheric pressure outside the balloon decreases. After about 2 hours the balloon bursts and falls back into the ocean. Four of this particular type of radiosonde will be released every day.  This data is used as input for weather prediction models, weather and climate change research, input for air pollution models and ground truth for satellite data.

Radiosonde is off!

Radiosonde is off!

We also deployed our first global drifter this afternoon. A surface drifter consists of a buoy and a sea anchor. The drifters have sensors that can measure sea surface temperature and the ocean current.  Information is collected by the sensors and uploaded to a passing satellite and then transmitted back to Earth where all the information from all the drifters give us a better picture of what is happening out in the ocean. Drifters are deployed from hurricane hunter aircraft so we can better predict and understand hurricanes. Data from drifters was used to determine where floating debris would be found shortly after the disappearance of Air France flight 447 on May 31, 2009.  For more information on the NOAA Global Drifter Program, visit their website.  

Personal Log 

The drifter buoy is deployed.

The drifter buoy is deployed.

I have received a couple of emails asking about the food on the ship.  We have three meals a day and there is quite a selection. For breakfast, you can have pancakes, eggs, sausage, oatmeal, fresh fruit or a selection of dry cereal.  For lunch, it really varies; today there was a salad, hot dogs, hamburgers and french fries.  Dinner also varies, but so far we have had fish, ribs, chicken and a salad. There is also a veggie option for each meal.  Coffee, tea and other beverages as well as some snack items are pretty much available 24 hours.

Our dining hall

Our dining hall

Tracking the cruise plan

Tracking the cruise plan

Robert Oddo, July 13, 2009

NOAA Teacher at Sea
Robert Oddo
Onboard NOAA Ship Ronald H. Brown 
July 11 – August 10, 2009 

Mission: PIRATA (Prediction and Research Moored Array in the Atlantic)
Geographical area of cruise: Tropical Atlantic
Date: July 13, 2009

Weather Data from the Bridge 
Outside Temperature 27.7oC
Relative Humidity 80.16
Sea Temperature 28.2oC
Barometric Pressure 1013.76 inches
Latitude 10o 21.11 N Longitude 52o 13.67 W

The replacement PIRATA Buoy

The replacement PIRATA Buoy

Science and Technology Log 

We have been steaming at full speed towards our first buoy. To the right you can see a picture of the replacement buoy that is on the back of the ship.  This buoy will be lowered into the water using cranes on the ship and then anchored in place. These buoys are anchored on the bottom of the ocean, which is very deep here in the Tropical Atlantic.  The ocean here right under this ship is 4,990 meters or 16,371 feet deep. That’s a lot of chain to attach to the anchor!!  A picture of the buoy instruments that will be redeployed are on the right.  There are other instruments that extend down into the ocean.

Personal Log 

Anchors for the buoys ATLAS buoy instruments that will be redeployed

Anchors for the buoys

I was wondering how we were going to deal with time as we traveled to the East.  A notice was put up yesterday telling us that we should change our clocks from 4 hours ahead of Greenwich Mean Time to 3 hours ahead of Greenwich Mean Time.  This ship has things going on 24 hours, so it is really easy to lose track of time and the day.

All in all, it is pretty comfortable on board and the people are very friendly. If you need to take a break from your work you can watch a video, read in the library, or sit out on the back deck of the ship.

Anchors for the ATLAS buoy instruments that to redeploy

Anchors for the ATLAS buoy instruments to redeploy

Cruise ship plan

Cruise ship plan

We change our clocks as we move east

We change our clocks as we move east

Robert Oddo, July 15-20, 2009

NOAA Teacher at Sea
Robert Oddo
Onboard NOAA Ship Ronald H. Brown 
July 11 – August 10, 2009 

Mission: PIRATA (Prediction and Research Moored Array in the Atlantic)
Geographical area of cruise: Tropical Atlantic
Date: July 15-20, 2009

Weather Data from the Bridge 
Outside Temperature 24.19 oC
Relative Humidity 78.87
Sea Temperature 24.28 oC
Barometric Pressure 1016.0 inches
Latitude 00o 12.5 N Longitude 23o 37.28W

The CTD

The CTD

Science and Technology Log 

We have been steaming at around 10 knots(approx 11.5 mph) 24 hours a day to our first buoy. The scientists on board are preparing equipment for the work that awaits them once we arrive at our first stop, 0 degrees 01.0 South latitude, 22 degrees 59.9 West.  Replacement tubes for the buoys are being readied and the “CTD” is being prepared for deployment.  The “CTD” is the name for a package of instruments that is lowered in the water that includes sensors that measure conductivity, temperature and the depth of the seawater. Conductivity and temperature are important since salinity can be derived from these values.  The CTD is connected to the ship by means of a cable through which real-time data can be sent back to scientists on the ship as the winch lowers and raises the CTD through the water. The metal frame around the CTD has a number of bottles attached to it that collect seawater samples at various depths.  This water then can be analyzed back in the laboratory when the CTD is brought back on board. 

We have deployed a number of drifters as we are making our way to the first stop.  For the last couple of days, we have not been allowed to collect any data as we traveled through the territorial waters of Brazil. On the night of July 19th we launched an ozonesonde. An ozonesonde transmits information to a ground receiving station information on ozone and standard meteorological quantities such as pressure, temperature and humidity. The balloon ascends to altitudes of about 115,000 feet (35 km) before it bursts.

Deployment of the ozonesonde

Deployment of the ozonesonde

Personal Log 

A few days ago, I toured the bridge of the ship. There is always one officer on the bridge and also a person on watch. Unfortunately there is not a big wheel like I imagined up there to steer the ship (I always wanted my picture at one of those big wheels). But there are a number of thrusters that you maneuver the ship with.  There are also a number of radar screens that enable one to see surrounding objects and well as computers that allow the ship to run on different auto pilot modes. Before a radiosonde or a buoy is launched, one needs to inform the bridge and the operation is logged in. You really get a unique perspective of the ship from up on the bridge.

I have spent hours on deck watching for signs of life out in the ocean. We did have a pod of dolphins of our bow one day, flying fish seem to be out there all the time and one day we believe we saw a pod of false killer whales (maybe).  I expected to see some birds, but so far not one.

Here I am at the helm of the Brown.

Here I am at the helm of the Brown.

Research cruise plan

Research cruise plan