Emily Cilli-Turner: Back on Land, August 13, 2018

NOAA Teacher at Sea

Emily Cilli-Turner

Aboard NOAA Ship Oscar Dyson

July 24 – August 11, 2018

 

Mission: Pollock Acoustic-Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date: August 13, 2018

 

Weather Data for Claremont, CA from National Weather Service:

Latitude:  34.1368º N

Longitude:  117.7076º W

Wind Speed: 12 mph

Wind Direction: SSW

Air Temperature:  29.4º Celsius

Humidity: 36%

Personal Log 

Well, NOAA Ship Oscar Dyson docked in Dutch Harbor on August 11th from the 19-day journey in the Eastern Bering Sea.  During our time at sea, I learned so much and got to know both the NOAA scientists and the crew and officers on the ship.  When I applied for the Teacher at Sea program, I knew that it would be an invaluable experience, but it far exceeded my expectations.  I learned about the work of the NOAA scientists pretty much non-stop and any question I had was answered in detail, which allowed me to have a robust picture of the work the NOAA scientists do, the different types of scientific instruments they use and the underlying principles behind them as well as the day-to-day operations of a scientific vessel such as NOAA Ship Oscar Dyson.  Additionally, I also ate the best food of my life made by the stewards; there was always amazing entrees and dessert at every meal!

NOAA Ship Oscar Dyson

NOAA Ship Oscar Dyson in Dutch Harbor, Alaska

After we came into port, I was able to explore the town of Dutch Harbor as well.  Along with other NOAA Scientists and the ship’s medic, I explored the Museum of the Aleutians in town and learned about the native people of the island and their traditions as well as the military encampments that were built on Unalaska (the island where Dutch Harbor is) during WWII.  The next day we went up Ballyhoo mountain and saw the ruins of one of the WWII bases.  The view from there was amazing and we saw all around Unalaska.  I was surprised in Dutch Harbor to see so many bald eagles everywhere!  The next day I said goodbye to the many people I got to know aboard the Oscar Dyson, many of whom were staying aboard for the next leg or for a long time thereafter.  I was surprised how easily I transitioned to life aboard the boat and it still feels a bit weird to not be moving all the time!

 

Emily Cilli-Turner: Journey’s Coming to an End, August 9, 2018

NOAA Teacher at Sea

Emily Cilli-Turner

Aboard NOAA Ship Oscar Dyson

July 24 – August 11, 2018

 

Mission: Pollock Acoustic-Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date: August 9, 2018

 

Weather Data from the Bridge:

Latitude: 60º28.02 N

Longitude: 175º25.19 W

Wind Speed: 8.77 knots

Wind Direction:  236.54º (SW)

Air Temperature:  8.8º Celsius

Barometric Pressure: 1010.7 mb

Sea Wave Height: 2-3 feet

Visibility: less than 1 nautical mile

 

Science Log

I had a chance to interview the chief scientist aboard NOAA Ship Oscar Dyson, Taina Honkalehto, and ask her about her career path to working at NOAA as well as recommendations she has for anyone interested in an ocean career.

Taina knew that she wanted to pursue a career in science ever since she was a child as she has always been interested in the outdoors and collecting and observing things.  During college, she took an oceanography course as a junior and knew she wanted to work with the ocean.  Her college advisor recommended that if she wanted to pursue science she needed to do a field program.  As a junior, she was able to secure participation at a marine lab in the U.S. Virgin Islands, which inspired her choice to go to graduate school and study invertebrate zoology.

At NOAA, Taina really enjoys her colleagues and the field work, which includes the pollock counting work she is currently doing on NOAA Ship Oscar Dyson.  She feels that her work at NOAA is an opportunity to contribute to the preservation of our planet.  Additionally, she enjoys doing outreach at NOAA and talking to people about her work and answering questions about the ocean.  Often, discussions with the public involve balancing what they have heard about fisheries and overfishing in the news versus the reality and experiences Taina has had in the field counting pollock in the Bering Sea and Gulf of Alaska.

The advice that Taina has for those wanting to work for NOAA is to get an internship.  Students can find internship opportunities through the NOAA website and there are avenues into NOAA experience for students at the middle and high school level as well as college students.  These internships are a great way to get hands-on experience (as I can attest!) and some of them are even paid if students apply for the Hollings scholarship. Taina also recommends reading some of the following books to get an idea about what it is like on a field placement: “The Log from the Sea of Cortez” by John Steinbeck, “Moby Duck” by Donovan Hohn, and “Cod” by Mark Kurlansky.

Taina Honkalehto

Chief Scientist aboard NOAA Ship Oscar Dyson, Taina Honkalehto

 

Personal Log

The wet lab aboard NOAA Ship Oscar Dyson is where most of the action happens during my shift.  When a haul comes in, we are responsible for processing the catch and obtaining the needed measurements so that the MACE team can put together their report on the health of the pollock population.  The catch is released from the trawling net onto a hydraulic table that can be dumped onto a conveyor belt.  The first job to be done is to sort the catch, where all species that are not adult pollock are separated out.

Pollock on belt

Adult pollock from a haul on the sorting belt

The next task is to measure the length of a subsample of about 300 of the adult pollock in the catch.  This helps the NOAA scientists to create histograms of pollock lengths to compare between hauls.  Finally, about 30 pollock are separated to measure length, weight and to determine gender and maturity and another 30 have length and weight measured, otoliths taken, and ovaries weighed and collected if the pollock is a spawning female.  During my shift, there are six of us in the fish lab and we are working like a well-oiled machine!

Today we are starting the long transit back to Dutch Harbor.  It is bittersweet since I feel like we have a nice routine down in the fish lab and I finally feel used to the motions of the ship.  However, I am grateful for this opportunity and for all the great people that I have gotten to know during my time on NOAA Ship Oscar Dyson.  Also, we finally saw some blue sky again and a rainbow even came out for a moment!

rainbow

A small rainbow over the Bering Sea

 

Did You Know?

The NOAA Ship Oscar Dyson was launched on October 17, 2003. It is named after Alaskan fisherman Oscar Dyson and there is a smaller boat on board named after his wife, Peggy Dyson.

Emily Cilli-Turner: Plenty of Fish in the (Bering) Sea, August 6, 2018

 

NOAA Teacher at Sea

Emily Cilli-Turner

Aboard NOAA Ship Oscar Dyson

July 24 – August 11, 2018

 

Mission: Pollock Acoustic-Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date: August 6, 2018

 

Weather Data from the Bridge:

Latitude: 58 04.81 N

Longitude: 174 06.88 W

Wind Speed: 6.88 knots

Wind Direction: 275.19 (NW)

Air Temperature: 10.0 C

Barometric Pressure: 1013.2 mb

Visibility: 6 nautical miles

Sea Wave Height: 4 feet

Sky: Overcast

 

Science Log

While the techniques written about in the previous blog post ensure that when we use the trawling nets we mostly catch pollock, there is usually a small amount of by-catch in each haul.  By-catch means ocean life other than pollock (the desired catch) that we bring up in a haul using the trawling net.  This post will focus on some of the creatures that I have seen in the catches during my time on NOAA Ship Oscar Dyson.

 

Principal species of interest:

Pollock: The scientific name for these pollock (known as Alaska pollock or walleye pollock) is Gadus chalcogrammus.  We often catch many different ages of pollock, from age 0 pollock up to large adult pollock and these range in length from a few centimeters up to about 62 centimeters. Pollock is most of what we catch, and they are easy to identify by their three dorsal fins and speckling.  Pollock mainly eat euphausiids and copepods, but also sometimes eat the age 0 pollock.

Adult pollock

Adult pollock

 

By-catch species:

Chum Salmon: Chum salmon (Oncorhynchus keta) is one of the five types of salmon and lives for about 6 years on average.  Like all salmon, they are spawned in freshwater and then migrate out to the ocean.  Once they return to the freshwater and spawn, they die about two weeks later. They mostly eat zooplankton and insects, but have been known to eat comb jellyfish as well.

chum salmon

Student intern Liz Allyn with a chum salmon from a haul.

 

Jellyfish: We see several types of jellyfish in each catch, but we mainly see the Northern Sea Nettle (Chrysaora melanaster).  We have also seen Northern Sea Nettle swimming near the surface before sunrise when we are pole fishing for pollock.  The word melanaster translates to “black star,” which you can identify in the pattern on the bell of this jellyfish. The bell diameter can reach up to 12 inches and the tentacles can grow as long as 10 feet. As climate change has warmed the surface temperatures of the Bering Sea, the population of Northern Sea Nettle is increasing.  Northern Sea Nettles mostly eat zooplankton, but sometimes also eat pollock!

Chrysaora melanster

Chrysaora melanster

Smooth Lumpsucker: Smooth lumpsuckers (Cyclopterus lumpus) are named so because of an adhesive disc on their underside that helps them suction onto the ocean floor.  These fish spend most of their time on the bottom of the ocean and are not particularly good swimmers. The roe (eggs) of the lumpsucker is a delicacy in Scandinavia.

Flatfish: Alaska Plaice & Yellowfin Sole: We have also caught two types of flatfish during my time aboard the ship: yellowfin sole (Pleuronectes aspera) and Alaska Plaice (Pleuronectes quadrituberculatus). These peculiar looking fish can be identified by having both eyes on top of their head.  When they are spawned, these fish have eyes on either side of their head, but as they get older the eyes migrate to be on the same side. These fish mainly reside on the ocean floor, where they eat polychaetes and amphipods, such as worms and mollusks.

Capelin: The capelin (Mallotus villosus) is a small fish in the smelt family reaching a length of about 10 inches.  It feeds mainly on plankton and krill.  The most interesting thing about capelin is their smell; if you put their scales close to your nose you will smell cucumbers!

Capelin

Capelin

 

Personal Log

While the weather since boarding the NOAA Ship Oscar Dyson has largely consisted of some high winds and big swells, there have been one or two nice days in the Bering Sea. On these days, we have taken the opportunity to go outside.  On one particularly nice day where the sun was shining, there was a mini corn-hole tournament on the deck.  After thinking that my time on the ship was the least amount of time spent outside during the summer, this was a nice way to spend the after-dinner time.

corn hole

Operations officer LT Carl Noblitt and student intern Grace Workman playing corn-hole on the deck.

I am also grateful for NOAA scientists Mike Levine and Darin Jones, who have made me feel like an expert in the fish lab.  At this point, I know more about pollock than I ever thought I would.  In the fish lab, I primarily am responsible for measuring the length of the pollock sample.  However, Mike and Darin have also taught me about pollock anatomy and how to tell if a pollock is male or female.  I have also become good at extracting the otoliths, which involves a precise cut of the pollock.  For a person with almost no experience working with biological specimens, much less fish, I finally feel like a useful part of the team.

Did You Know?

The Bering Sea is an extremely important fishing location and the United States catches over $1 billion of seafood here each year.

Emily Cilli-Turner: One Fish, Two Fish….Pollock Counting Techniques July 29, 2018

NOAA Teacher at Sea

Emily Cilli-Turner

Aboard NOAA Ship Oscar Dyson

July 24 – August 11, 2018

 

Mission: Pollock Acoustic-Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date: July 29, 2018

 

Weather Data from the Bridge:

Latitude: 57° 10.46 N

Longitude: 171° 58.29 W

Wind Speed: 11.16 knots

Wind Direction: 77.54° (NW)

Air Temperature: 10.1° C (Manual Reading from the Bridge)

Barometric Pressure: 992.7 mb

Visibility: 6 nautical miles

Sea Wave Height: 3 feet

Sky: Overcast

 

Science Log:

How do the scientists aboard NOAA Ship Oscar Dyson estimate the number and biomass of pollock in the Eastern Bering Sea? By using the science of statistics, of course! When political strategists want to determine what percentage of voters support a specific candidate or issue, they take a sample from the population of all registered voters. Voters in this sample are then asked about their preferences and statistical techniques are employed to extrapolate the results from the sample to the entire population and measure the margin of error.  Similar statistical techniques are employed by the scientists on NOAA Ship Oscar Dyson, but as you can imagine it is more difficult to sample pollock than voters that can be called on the phone!

Before each pollock survey begins, a set of transects is created for the Eastern Bering Sea.  These transects are paths for the ship to follow along which the scientists sample the pollock.  As you can see below, the transects for this survey are a fixed distance apart and cover the entire area of interest.  Generally, the transects are straight lines created to be perpendicular to the ocean depth grade. This allows for the scientists to encounter a variety of species as well as different ages of pollock to gain a robust picture of the ocean life in the area.

transect

The transects for this survey leg can be seen as the straight lines. The other markings are places where the trawls have been done and other scientific instruments have been deployed.

The NOAA Ship Oscar Dyson follows the transects during daylight hours, continuously recording water column acoustic backscatter data using EK60 instruments mounted on the bottom of the centerboard.  Scientists monitor the backscatter images, and when they observe sufficient pollock or other fish aggregations they  use the trawling nets to take a random sample of the fish and other ocean life they observed.  The trawling net is 140 m long with a vertical mouth opening of 25 m and horizontal mouth opening of 35 m. The net is deployed from the back of the ship and dragged at a fixed depth for an amount of time determine by the lead scientist to ensure a large enough sample. Once the trawling net is hauled in, the sample of marine fish and invertebrates is processed in the wet lab and entered into a database. Later the pollock numbers and weights by length are combined with  recorded acoustic data to create a robust estimate of the pollock population in the Eastern Bering Sea.

After the catch comes in, the first job in processing the sample is to sort the specimens from the trawling net.  The first part of the net to come in is called the pocket net. This small net, also called a recapture net,  has a fine mesh and is designed to capture small species such as krill, age 0 pollock and jellyfish which slip through the meshes of the large trawl.  After the pocket net is processed, we process the codend, the closed end of the net and the main section where larger fish enter and are captured.  The fish in the codend are sorted by species.  The scientists can choose to measure the length of all the pollock in the haul or, if it is a particularly large catch, split the haul and measure length of a subsample of pollock.  Other species are also identified and their length is measured for later estimates of the total biomass that pollock make up as compared to other species.  Smaller species such as krill are weighed in aggregate instead of individually.

codend

The codend of the trawling net.

Sample analysis consists of measuring the lengths of approximately 200-400 adult pollock in the catch using the magnetic length board.  This is just one of the numerous software and instruments created by the MACE (Midwater Assessment and Conservation Engineering) group at NOAA in Seattle to make analysis easier and more automated.  The length distribution of the adult pollock helps scientists determine the approximate age distribution of pollock in the sample and it also helps them compare this distribution to other samples taken in the Eastern Bering Sea.  A subsample of about 50 pollock from the haul is taken to get more in-depth measurements. From these pollock, we measure both the length and weight and a subsample from the 50 is taken to determine the gender, measure maturity (i.e. what stage in the life cycle the pollock is at), and collect the otolith (ear bone), which gives a more accurate measurement of the pollock’s age.

Personal Log:

At this point, I am getting used to life at sea and have a nice routine.  The beginning of my shift, from 4am to a little past 7am, starts at sunrise and during which we resume our path along the transect.  No trawling operations are conducted at night, but there is still excitement.  If the underwater acoustics show that the pollock are at an appropriate depth, we can go pole fishing off the boat.  NOAA scientist Mike Levine is interested in post-capture mortality of pollock and the feasibility of tagging pollock.  Thus, he would like to catch pollock using a fishing pole, which puts much less stress on the pollock and increases the chance of their survival after the catch, instead of the trawling nets.

fishing

NOAA scientist Mike Levine with a pollock caught with a fishing pole.

As an instructor of mathematics, I have little knowledge of fish biology, but the scientists are great teachers!  I have been given a crash course on fish anatomy using specimens from the catch and I have learned how to sex the fish as well as how to collect the ovaries and the otoliths (ear bones).  If you asked me a week ago if I ever thought I would know so much about pollock after just a couple days on board, I would have laughed.  It has been great being the student and being able to learn so much in such a short time with real hands-on experience!

Did You Know?

Most of the personnel that are responsible for piloting and maintaining the ship are part of NOAA Corps, which is one of the seven uniformed services of the United States.

Lee Teevan: The Unexpected Happens, July 13, 2018

NOAA Teacher at Sea

Lee Teevan

Aboard NOAA Ship Oscar Dyson

July 1-10, 2018

Mission: Acoustic Pollock-Trawl

Geographic Area of Cruise: eastern Bering Sea

Date: 13 July 2018

View of the Oscar Dyson on our last morning in Dutch Harbor, AK

View of the Oscar Dyson on our last morning in Dutch Harbor, AK

 

Weather Data from Norfolk, VA

Latitude: 36.8508° N

Longitude: 76.2859° W

Tide Heights: 2.76 ft & 3.35 ft

Wind Speed: 19 km/h

Wind Direction: NE

Air Temperature: 28°C, 82°F

Barometric Pressure: 1028.1 mb

Sky: Clear

Humidity: 76%

“If you’re awake at 6:00 a.m., you’ll get to see the Oculus as I prepare it to glide around in the Bering Sea!”  With this promise from Dr. Chris Bassett, I made sure I was ready at the appointed time on our last day on the ship.

Dr. Chris Bassett preparing the Oculus.

Dr. Chris Bassett preparing the Oculus.

The launching of the Oculus was not on Chris’ schedule for that day beforehand; our expedition was ending earlier than expected.  That setback, however, did not diminish the drive to pursue science.  The resilience and perseverance of the science team to readjust was apparent.  Through the mist of  disappointment, the scientists continued to do as much as possible to continue our mission of the pollock survey.

 

Science and Technology Log

Developed at Pacific Marine Environmental Laboratory in partnership with the University of Washington’s Joint Institute for the Study of the Atmosphere and Ocean and the University of Washington Seaglider Fabrication Lab, the Oculus is an ocean glider which samples abiotic factors in the ocean such as temperature, salinity and dissolved oxygen at different depths.

Inner component of the Oculus which regulates buoyancy.

Inner component of the Oculus which regulates buoyancy.

After setting the Oculus upright, Chris connected it via the Internet to a computer operated by a scientist at the University of Washington.  This scientist is going to be sending coordinates to the Oculus and guiding it at various depths in the Bering Sea.  Chris explained that the Oculus has the ability to adjust its buoyancy quickly and is able to carry out a more reliable survey than other gliders.  Through the data remotely sent by the Oculus, scientists can gather a more accurate picture of ocean dynamics such as water column layers and ocean mixing.

Unfortunately, I was not able to observe the launch of the Oculus as I had to leave for the airport.

Personal Log

View from dock in Dutch Harbor, AK.

View from dock in Dutch Harbor, AK.

The week I spent on the ship was a whirlwind of experiences. I was just hitting my stride being completely awake for my 4:00 a.m. to 4:00 p.m. work shift and efficiently measuring the length of the pollock in each trawl.

Pollock and jellyfish in trawl.

Pollock and jellyfish in trawl.

At the end of the last trawl, I held a pollock, out of its element of water. Its dense, streamlined body shimmered with iridescence.  One eye stared, unfocused on the strange surroundings.   I too would be out of my element were it not for the 208.6 ft. boat on which I was standing.  Being on the boat was a constant reminder that my species is alien to this ocean habitat and that to explore it, we have to use technology such as the Oculus, underwater cameras, and acoustic technology as well as physical trawls.  Together, these different means of exploring combine information so that we can evaluate our interactions with the ocean and its inhabitants.

The view of the horizon from the deck of the Oscar Dyson.

The view of the horizon from the deck of the Oscar Dyson.

At times, the ocean had a disorienting effect.  When on the deck, I looked out from all directions and saw nothing but ocean capped by a dome of stratus clouds.  Under this lid of heavy clouds, the sun gave no clue to discern our direction or time of day.

Marine Careers

Karla Martinez, Junior Unlicensed Engineer, on duty on the Oscar Dyson.

Karla Martinez, Junior Unlicensed Engineer, on duty on the Oscar Dyson.

With her philosophy of focusing on the positive, Karla Martinez enjoys her time on and off duty on the Oscar Dyson.  As a Junior Engineer, Karla is responsible for ship upkeep and repairs.  On our last day of the trip, I spoke to her as she changed air filters in all of the staterooms.  Karla began working as a NOAA Junior Engineer three years ago after seven years in the U.S. Navy.  Since working for NOAA, she has traveled extensively and makes sure she visits each place the Oscar Dyson docks.  Karla is on the ship for at least 7-8 months of the year, and she makes the ship feel like home by getting to know people.

Karla Martinez, Tourist, off duty in field of flowers, Unalaska, AK.

Karla Martinez, Tourist, off duty in field of flowers, Unalaska, AK.

For young people who are interested in a career like Karla’s, she advises asking many questions and studying technology as much as possible. In high school, students should take the ASVAP test before entering the military.  Once admitted to the military, students should get trained. Karla states that students should talk to their counselors and find out all they can.

Joan Shea-Rogers: Do You See What We See, July 10, 2018

NOAA Teacher at Sea

Joan Shea-Rogers

Aboard NOAA Ship Oscar Dyson

July 1-22, 2018

 

Mission: Walleye Pollock Acoustic Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date: July 10, 2018

 

Weather Data from the Bridge

Latitude: 53ºN

Longitude: 166ºW

Sea Wave Height: 1.5 feet

Wind Speed: 25 knots

Wind Direction: SW

Visibility: 15 Miles

Air Temperature: 52º F

Barometric Pressure: 1010.61mb

Sky: Overcast

Biological Trawl Data:

Letting the Net Out to Sea

Letting the Net Out to Sea

Trawl hauls are how fishing is conducted. A large net is dropped into the water for a specific amount of time. By catching exactly what is in the ocean, the acoustic backscatter can be identified (what the various colored pixels on the echograms represent). Below is an echogram on the screen, the black line is the path of the trawl through the backscatter, the little red circle indicated where the camera was, and the picture at left is pollock passing by the camera and into the back of the net at that point.

Echogram

Screenshot of an echogram. The black line is the path of the trawl through the backscatter, the little red circle indicates where the camera was, and the picture at left is pollock passing by the camera and into the back of the net at that point.

Samples of pollock and other organisms can be studied and other biological data collected. By counting, measuring, and weighing the pollock and other animals caught in each haul, calculations can estimate the amount of fish in a given area. Acoustic data can be used to determine the number of fish by dividing the measured backscatter by the backscattered energy from one fish (target strength, discussed in the last blog). That gives the number of fish:

To get the backscatter from one fish for the above calculation, we need to know the size and species of the fishes. The trawl provides that information. In the fish lab, species including pollock are identified, lengths are taken, and the number of fish at each length is entered in the computer. Also, the animals including pollock are weighed and a mean weight is determined. The number of fish computed from the acoustic and trawl data multiplied by the mean weight of a fish equals the biomass of the fish (total weight of the population in a given area).

The fisheries biologists developed the software used for all these calculations. This information coupled with the echograms can answer those earlier questions…Where are the pollock in the Bering Sea? How many are there? How big are they? How many adult pollock are there (fish that can be caught) and how many young pollock are present (providing information about future availability and how healthy the population is)?

When I first boarded the ship, I asked the fisheries biologists how they would describe what they do. They responded that they count fish, it’s not rocket science. But you know what? It kind of is!

 

At Work in the Fish Lab

TAS Joan Shea-Rogers at work in the Fish Lab

 

What is this information used for?

This information is used to manage the Pollock fishery. Numerical data is given to the entities that set the fishing quotas for the Bering Sea area. Quotas are then divided up between the commercial and individual fishing companies/boats. Once fishermen reach these quotas they must stop fishing. This protects the fishery to ensure that this food source will be healthy and strong for years to come. A similar example from my home state is that of the Illinois is the Department of Conservation. One of their responsibilities is to manage the deer population. Then they can determine how many deer can be harvested each season that still allows for the deer population to thrive.

 

Personal Blog:

In my last blog post, I talked about preparing for and “weathering the storm”. As with most things at sea and on land, things don’t always turn out as we plan. The stormy weather began with wave heights between 8-10 feet. The ship continually rocked back and forth making walking and everything else difficult. You can tell the experienced sailors because they were much more graceful than I was. I held on to every railing and bolted down piece of furniture that I could. And even then, I would forget and place a pen on the table, which immediately rolled off. While eating I held onto my glass and silverware because as I ate and placed my knife on my plate it rolled off. Dressing was a balancing act, which I was not good at. I finally figured out it was better if I sat in a chair. Luckily for me, my patch for seasickness worked.

While I was sitting in the mess hall (dining room) an alarm rang. The engineers got up read the screen and left. The decision was made by the acting CO (Commanding Officer) that we would have to go back to Dutch Harbor. And now, as I write this, we are docked in Dutch Harbor waiting for word about the status of our voyage. Out here in Dutch Harbor, everything must be shipped in. We wait until parts and people are flown in. The fisheries biologists also have to determine the validity of the data collected on such a short voyage. They also must decide in a timely matter, can this data collection continue after returning to port?

For me, I am holding out hope that all these factors are resolved so that we can go back out to sea. Since November when I turned in my application, this voyage has been such a focal point of my life. If it doesn’t work out (I’ll try not to cry), I will still have had the adventure and learning experience of a lifetime. So here’s hoping……

NOAA Ship Oscar Dyson at Port in Dutch Harbor, AK

NOAA Ship Oscar Dyson at Port in Dutch Harbor, AK

 

Joan Shea-Rogers: Do You Hear What They Hear, July 8, 2018

NOAA Teacher at Sea

Joan Shea-Rogers

Aboard NOAA Ship Oscar Dyson

July 1-22, 2018

Mission: Walleye Pollock Acoustic Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date: July 8, 2018

Weather Data from the Bridge

Latitude: 53º N

Longitude: 166ºW

Sea Wave Height: 1.5 feet

Wind Speed: 25 Knots

Wind Direction: SW

Visibility: 15 miles

Air Temperature: 52ºF

Water Temperature: 46º F

Barometric Pressure: 1010.61mb

Sky: Overcast

Science and Technology Log

What kinds of fish live in the Bering Sea? How many pollock are in the Bering Sea? Where are the pollock in the Bering Sea? How big are the pollock in the Bering Sea?

Those are just a few of the questions that the fisheries biologists on NOAA Ship Oscar Dyson work to answer during each voyage. In my last blog, I talked about the need to manage the pollock fishery in order to protect this important ocean resource because it provides food for people all over the world. It is important, then, to be able to answer the above questions, in order to make sure that this food source is available each year.

How do they do it? There are two main sources of information used in the Acoustics-Trawl (or Echo Integration Trawl) survey to determine the abundance and distribution of pollock in a targeted area of the Bering Sea. One is acoustics data, and the other is biological-trawl data.

Acoustics:

Acoustic data is continuously collected along a series of parallel transects with a Simrad EK60 scientific echo integration system incorporating five centerboard-mounted transducers (18-, 38-, 70-, 120-, and 200- kHz). In other words: There are 5 sound wave producers (transducers) attached to the bottom of the ship, each one emitting sound waves at different frequencies. This allows scientists to look at different organisms in the water column. Different types of organisms reflect different amounts of energy at different frequencies. The amount of acoustic energy reflected by an individual animal is called the target strength, and is related to the size and anatomy of the species. For example, a fish with a swimbladder (like pollock) reflects more energy than a fish without a swimbladder because its properties are very different from the surrounding water. Some ocean dwelling organisms don’t have swim bladders. Flatfish stay on the bottom so they don’t need the buoyancy. Floating organisms like jellyfish don’t have them. These organisms will look differently than pollock on an echogram because they have a smaller target strength.

Transducer

Transducer

Transducers convert mechanical waves (sound waves) into an electrical signal and vice versa (like both a loudspeaker and a microphone combined). They contain piezoelectric materials sensitive to electricity and pressure: if a voltage is applied to them, they make a pressure or sound wave (transmit), and when a sound wave passes over them, it produces a voltage (receive). When a sound wave (echo from a fish) is received, electoral signal is sent to a computer, which displays the signals as pixels of varying colors as the ship moves along (depth changes up and down on the left of the image, and time and location changes along the bottom of the image). This datum is used to estimate the number and type of fish in the water column, and to determine where the ship should fish next.

The size and colors on the images (called echograms) represent the backscatter at different depths and is related to the density of fish and their target strength. But, since they are dots on a screen, specific identification is not possible. The scientists assume certain strong signals are pollock based on the information they have but, those dots could be other fish. To determine what kind of fish are in the water column at this location, how many are there, and how big they are, other data must be obtained. Biological Trawl Data provides that additional information. More about that in my next blog post……I bet you can’t wait!

Personal Log

The Calm Before the Storm:

So far my trip has been smooth sailing, literally. As NOAA Ship Oscar Dyson sails across the Bering Sea there is a bit of rocking the ship experiences at all times. This is easy enough for one to get used to and sometimes it even becomes comforting, like being rocked to sleep as a child. You adjust to the motion. Over the past couple of days I have been hearing talk of a storm coming our way. On a ship, there are many preparations that occur in order to get ready for a storm. Many items are always secured, such as shelves that have a wall in front so that things don’t fall off. There are “handle bars” in showers and next to toilets (think about that). Along hallways and stairways there are handrails on each side. Mini refrigerators in staterooms are bolted to walls. In fact most things are bolted to walls or stored in containers that are bolted to the wall. In the mess hall (dining room) condiments on tables are in a box so they can’t slide off.

Why do you think this coffee mug is shaped like this (wider at the bottom than the top)?

 

At-Sea Coffee Mug

At-Sea Coffee Mug

Ans. The wider bottom of the mug above prevents it from sliding as the ship rocks.

Our bulletin board reminds us to secure for bad weather. This morning, I put small items in drawers, stowed books on shelves and packed my equipment (phone, laptop, camera, chargers and small items in a backpack that can be safely secured in my locker (the “closet” in my stateroom).

In talking to my shipmates with at sea experience, I am getting lots of helpful hints about storm preparations and strategies to use during the storm. Here are some of those suggestions:

*always hold on to railings with both hands when walking or going up steps. At all other times, remember to keep one hand for you (to do whatever you are doing) and one hand for the ship (to hold on).

*keep something in your stomach at all times, even if you are not feeling well

*eat saltines

*drink lots of water

*when sleeping in your bunk, place pillows between you and the edge so as not to roll off (I will definitely follow this one, as I am on the top bunk) It also depends upon which direction the ship is rolling. Pillows may need to be put between your head and the wall to prevent head bumps

*go to the lower parts of the ship because the top part will sway more with the waves

I also have been wearing patches to prevent seasickness. Hopefully they will continue to help. Only time will tell how we weather the storm (pun intended). Let’s hope it moves through quickly.