Richard Chewning, June 15th, 2010

NOAA Teacher at Sea
Richard Chewning
Onboard NOAA Ship Oscar Dyson
June 4 – 24, 2010

NOAA Ship Oscar Dyson
Mission: Pollock Survey
Geographical area of cruise: Gulf of Alaska (Kodiak) to eastern Bering Sea (Dutch Harbor)
Date: June 15th, 2010

Weather Data from the Bridge

Position: eastern Bering Sea
Time: 1530
Latitude: N 55 47.020
Longitude: W 165 24.970
Cloud Cover: overcast
Wind: 14 knots
Temperature: 6.4 C
Barometric Pressure: 1003.7 mbar

Science and Technology Log

In addition to researchers on the lookout for seabirds, the Oscar Dyson is also hosting researchers hoping to catch a glimpse of some the world’s largest animals: marine mammals. Either ocean dwelling or relying on the ocean for food, marine mammals include cetaceans (whales, porpoises, and dolphins), manatees, sea lions, sea otters, walrus, and polar bears. Although marine mammals can be enormous in size (the largest blue whale ever recorded by National Marine Mammal Laboratory scientists was 98 feet long or almost the length of a ten story building laid on its side!), studying marine mammals at sea can be challenging as they spend only a short time at the surface. Joining the Dyson from the NMML on this cruise are Suzanne Yin, Paula Olson, and Ernesto Vazquez. As a full time observer, Yin spends most of the year on assignment on various vessels sailing on one body of water or another and only occasionally is to be found transitioning through her home of San Francisco, California. Paula calls San Diego, California home and spends most of her time when not observing at sea working on a photo identification database of blue and killer whales. Ernesto is a contract biologist from La Paz, Mexico and has been working on and off with NOAA for several years. Ernesto has worked with several projects for the Mexican government including ecological management of the Gulf of California Islands.

Yin keeping warm from the cold

Ernesto keeping sharp lookout for marine mammals

Paula keeping an eye on the horizon

Yin, Paula, and Ernesto undoubtedly have the best view on the Oscar Dyson. Working as a three member team, they search for their illusive quarry from the flying bridge. The flying bridge is the open air platform above the bridge where the ship’s radar, communication equipment, and weather sensors are located. One observer is positioned both on the front left and front right corners of the flying bridge. Each observer is responsible for scanning the water directly in front to a line perpendicular to the ship forming a right angle. Two powerful BIG EYE binoculars are used to scan this to scan this 90 degree arc. These binoculars are so powerful they can spot a ship on the horizon at over ten miles (even before the Dyson’s radar can detect the vessel!). The third person is stationed in the middle of the flying bridge and is responsible for surveying directly ahead of the ship and for scanning the blind spot just in front of the ship that is too close for the BIG EYES to see. This person is also responsible for entering sightings into a computer database via a lap top computer. The three observers rotate positions every thirty minutes and take a thirty minute break after one full rotation. One complete shift lasts two hours. Yin, Paula, and Ernesto start soon after breakfast and will continue observing until 9:30 at night if conditions allow.

Dall’s porpoise

Weather can produce many challenges for marine mammal observers as they are exposed to the elements for hours at a time. Fortunately, Yin, Paula, and Ernesto are well prepared. Covered from head to toe wearing insulated Mustang suits (the name come from the manufacturer), they are pretty well protected from light spray, wind, and cold. Although a certain amount of the face is always exposed, a shoulder high wind shield helps deflect most of the spray and wind. In addition to wind chill and wind burn, a strong wind can also produce large rolling waves called swells that make viewing through the BIG EYES next to impossible. Sometimes reducing visibility so much that the bow can barely be seen the bridge, fog is undoubtedly a marine mammal observer’s greatest adversary.

Humpback whales through the Big Eyes

Salmon fishing operation through the Big Eyes

So far during the cruise, Yin, Paula, and Ernesto have spotted many blows on the horizon and have identified several species of marine mammals. A common sighting is the Dall’s porpoise. Your eyes are easily drawn towards these fun marine mammals as they produce characteristic white splashes by repeatedly breaking the water’s surface exposing a white stripe on their side. Blows from fin whales have also been regularly observed. Other sightings include killer whales, humpback whales, Pacific white sided dolphins, and a rare sighting of a Baird’s beaked whale.

Personal Log

Life aboard a constantly moving platform can take a little getting used to! I imagine if a person doesn’t live in an area frequented by earthquakes, one will easily take for granted the fact that the ground usually remains stable and firm underfoot (I know I did!). Over the last view days, steady winds from the south have conspired to create conditions ideal for rolling seas. Large swells (waves created by winds far away) make the Dyson very animated as we push forward on our survey transects. In addition to making deployments of gear more difficult, routine personal tasks soon assume a challenging nature as well. Whether you are simply getting dressed in the morning, trying to make your way to your seat with lunch in hand, or taking a shower in the evening, a constantly pitching and rolling deck will make even a seasoned deckhand wobble and stumble from time to time.

Building seas

A piece of advice I have often heard during these conditions calls for “one hand for you and one for the ship”. Maintaining three points of contact with ship, especially when moving between decks, can save you from being tossed off balance. The crew is very considerate of these conditions and allows even more understanding than customary when you bump into shipmates. I have also learned the importance of securing any loose equipment and personal items after usage during rough seas as they might not be in the same place when you return. In addition to waking several times during the night and having a restless sleep, these conditions will also leave you feeling stiff and fatigued in the morning after a bumpy night of being tossed around in your rack. Once you muster the strength to get moving, your legs become surprisingly tired as you constantly try to keep your balance. Along with the rest of the crew, the Dyson also feels the effects of jogging through rough seas as you constantly hear the rhythmic sounds of the bow plowing though the next wave and of the ship’s superstructure groaning under the strain.

Measuring the Dyson’s roll

Passing through the fog

Did you know? Fog is essentially a cloud on the ground’s surface.

Kathleen Harrison: First Trawl, July 7, 2011

NOAA Teacher at Sea
Kathleen Harrison
Aboard NOAA Ship  Oscar Dyson
  July 6– 17, 2011

Location:  Gulf of Alaska
Mission:  Walleye Pollock Survey
Date: July 7, 2011

Weather Data from the Bridge
True Wind Speed:  18.7 knots
True Wind direction:  145.55°
Sea Temperature:  8.12° C
Air Temperature:  9.65° C
Air Pressure:  1013.2 mb
Ship’s Heading:  299°, Ship’s Speed:  11.8 knots
Latitude:  54.59°N, Longitude:  145.55°W

Science and Technology Log
The primary mission of the Oscar Dyson Walleye Pollock Survey is to estimate the biomass (mass of the living fish) of the Pollock in the Gulf of Alaska.  Read about why Pollock are important here:  Pollock    Now, you can’t exactly go swimming through the Gulf of Alaska (brrrr) and weigh all of the fish, so the NOAA scientists on board use indirect methods of measuring the fish to come up with an estimate (a very accurate estimate).  Two of these methods include using nautical charts, and trawling.

Nautical charts are used for navigation, and location.  The Oscar Dyson has several systems of charts, including electronic and paper.  Each chart contains latitude, longitude, and ocean depth, as well as lands masses and islands.  A chart that shows ocean depth is called a bathymetric chart.

bathymetric map

Here is a bathymetric map for part of the Gulf of Alaska. The change in color from green to blue shows the edge of the continental shelf.

These need updating continually, because the sea floor may change due to volcanic eruption or earthquakes.  The Officer of the Deck (OOD, responsible for conning and navigating the ship) needs to know how deep the ship sits in the water, and study the bathymetric charts, so that the ship does not go into shallow water and run aground.  The lines on the bathymetric chart are called contour lines, depth is shown by the numbers on the lines.  Sometimes every line will have a number, sometimes every 5th line will have a number.   A steep slope is indicated by lines that are close together, a flat area would have lines that are very far apart.  The OOD also need to know where seamounts (underwater volcanoes) and trenches (very deep cracks in the ocean floor) are because these may affect local currents.  GPS receivers are great technology for location, but just in case the units fail, and the ship’s technology specialist is sick, the OOD needs to know how to use a paper chart.  He or she would calculate the ship’s position based on ship’s speed, wind speed, known surface currents, visible land masses, and maybe even use star positions.  Here in Alaska, star position is helpful in the winter, but not in summer.  (Do any of my readers know why?)

The Oscar Dyson’s charted course follows a series of parallel straight lines around the coast of Kodiak Island, and other Aleutian Islands.  These are called transects, and allows the scientists to collect data over a representative piece of the area, because no one has the money to pay for mapping and fishing every square inch.

The Chief Scientist on the Oscar Dyson is always checking our location on the electronic chart at his desk.  It looks something like this:

map of transects, Gulf of Alaska

This chart shows some of the transects for the Oscar Dyson in the Gulf of Alaska.

Several things are indicated on this chart with different symbols:  the transect lines that the ship is traveling (the straight, parallel lines), where the ship has fished (green fish), where an instrument was dropped into the water to measure temperature and salinity (yellow stars), and various other ship activities.  It also shows the ocean depth.  This electronic version is great because the scientists can use the computer to examine a small area in more detail, or look at the whole journey on one screen.

They can also put predicted activities on the map, and then record actual activities.  The scientists also use several systems for the same thing;  recording the ship’s path and activities in the computer, as well as making notes by hand in a notebook.

When the scientists want to catch fish, they ask the crew to put a trawling net into the water.  The basic design of the trawl is a huge net attached to 2 massive doors.

otter trawl

This is the basic design for a trawl net, showing the doors that hold the net open, and the pointed end, where the fish are guided, called the cod end.

The doors hold the net open, as it is dragged behind the boat.  There are 2 different trawling nets aboard the Oscar Dyson:  one that trawls on the bottom called the PNE (Poly Nor’Easter), and one that trawls midway in the water column called the AWT (Aleutian Wing Trawl).  Another net called the METHOT can be used to collect plankton and small fish that are less than 1 year old.  The scientists determine the preferred depth of the net based on the location of fish in the water column; the OOD gets the net to this requested depth and keeps it there by adjusting the ship’s speed and the amount of trawl warp (wire attached to the net).
A trawl typically lasts 15 – 20 minutes, depending on how many fish the scientists estimate are in the water at that point (more about this later).  Today, a bottom trawl was performed, and 2 tons of fish were caught!  The net itself weighs 600 pounds, and is handled by a large crane on the deck at the stern (back) of the ship.  Operating the trawl requires about 6 people, 3 on the deck, and 3 on the bridge at the controls.  When the scientists judge that there are the right amount of fish in the net, it is hauled back onto the deck, weighed, and is emptied into a large table.

poly nor'easter

Here is the PNE being weighed with the cod end full of fish.

Then the scientists (and me) go to work:  sorting the fish by species into baskets, counting the fish, and measuring the length of some of them.  NOAA technology specialists have designed a unique data collection system, complete with touch screens.  A fish is placed on a measuring board, and the length is marked by a  magnetic stylus that is worn on the finger.  The length is automatically recorded by the computer, and displayed on a screen beside the board.  I measured the length of about 50 Atka Mackerel after the first trawl.

using the measuring board

In the fish lab, this mackerel is having his length measured. The data goes directly into the computer, and shows up on the screen in front of me.

By sampling the fish that come up in the trawl net, the scientists can estimate the size of the population.  Using the length, and gender distribution, they can calculate the biomass.

Personal Log
Some great things about living on the Oscar Dyson:  the friendly and helpful people, the awesome food, the view from the bridge.

Some challenging things about living on the Oscar Dyson:  taking a shower, putting on mascara, staying in bed while the ship rolls.

I started my 12-hour shifts, working from 4 am to 4 pm.  Well, maybe working is not the right word, I actually worked about 3 hours, and asked a lot of questions during my first shift.  The scientists are very patient, and explain everything very well.  We did one trawl today, and it was a good one.  I enjoyed sorting and counting the fish, and then measuring the length of them.  I will probably take a shower, eat dinner, and read for a short time before climbing into bed.  I have the top bunk, and it is plenty of room, except I can’t sit up straight.  Here is a picture of the stateroom.  After my shift, I will probably take a shower, eat dinner, watch a movie and fall asleep around 8:30.

view of my room

Standing at the door, this is the view into my stateroom. The bunks are on the right, the desk and closets are on the left. There is a tiny bathroom, as well as a small refrigerator.

The weather today has been windy, so there are 6 – 8 foot swells, and the ship is rolling a bit.  I have not been seasick yet – yippee!  The wind is supposed to calm down tomorrow, so hopefully we will have a smoother ride tomorrow night.

I learned the difference between pitch, roll, and heave:  pitch is the rocking motion of the ship from bow to stern (front to back), roll is the motion from side to side, and heave is the motion up and down.  The Oscar Dyson is never still, demonstrating all 3 motions, in no particular pattern.  Imagine standing in a giant rocking chair, and someone else (that you can’t see) is pushing it.

Here is a view from the bridge:

from the aft deck

View from the deck in front of the bridge, showing a gyrorepeater (the white column on the right), and a windbird (anemometer and wind vane) on top of the forward mast. You can also see a horizontal black bar in the center of the picture - that is the provisions crane.

Species seen today:
Northern Rockfish
Dusky Rockfish
Walleye Pollock
Pacific Ocean Perch
Kelp Greenling
Atka Mackerel
Pacific Cod
Fanellia compresson (octocoral)
Sea Urchin
Kelp