Anne Mortimer: The Oscar Dyson is like a floating city, July 18, 2011

NOAA Teacher at Sea
Anne Mortimer
Onboard NOAA Ship Oscar Dyson
July 4 — 22, 2011 

Mission: Pollock Survey
Geographical area of cruise: Gulf of Alaska
Date: July 18, 2011

Weather Data from the Bridge
Monday, July 18, 2011—sunny and breezy
Air Temperature: 11.2 ⁰C
Sea Temperature: 10.7 ⁰C
Wind direction: 219⁰
Wind speed:  7.06 knots

Science and Technology Log

Yesterday I took a tour of the engine room and all of the behind the scenes areas that allow 30+ people to live comfortably at sea. One of the engineers, Terry, agreed to show me around, and now I understand that the Oscar Dyson is like a floating city.

First, this city needs power – power to drive the boat, power to run all of the computers and lab equipment for scientists, power to cook food, power to do laundry, and power to watch movies! This power comes from 4 diesel engines that run generators. The generators create electricity, and that electricity is shared throughout the boat to whatever needs it, including 2 electric motors that turn the propeller, pushing the ship ahead. All those engines create a lot of heat, but a seawater cooling system helps counteract that.

An amazing fact: the Oscar Dyson can hold 107, 000 gallons of fuel, and the last fill up was a top-off of only 37,000 gallons! At $3.86 per gallon of diesel, that was a hefty chunk of change – about $142,820!  The Oscar Dyson isn’t exactly fuel efficient, either. According to Jerry, the 1st Assistant Engineer, depending on the speed and fishing operations (fishing requires much slower speeds), the Oscar Dyson uses around 100 gallons per hour. We usually average about 10 knots per hour, that equals around 0.1 knots/gallon (and remember that 1 nautical mile = 1.2 miles). Wow! Because the fuel is so vital to all of the functions on the ship, the diesel is run through a purifier system that spins out any residuals and ensures the engines receive pure fuel. The fuel is stored in compartments throughout the ship, and is routinely monitored and moved using a series of valves to ensure the ship is balanced. All of the engines and electric motors are run by computers, and monitored by the engineers.

Diesel engine and generator number 2.
These computer monitors tell the engineers about the diesel engines, generators and motors.

I talked to Jeff, the Chief Engineer about the water and waste on the Oscar Dyson. A floating city must also use lots of fresh water, about 50 gallons per person per day to use in the sinks, showers, toilets, and kitchen.  The Oscar Dyson takes sea water in and converts it to freshwater by boiling the water at very high altitude in two water-makers. Once the water is used (gray water from sinks and drains, sewage from toilets) it goes to a water purifier that uses aerobic bacteria to break it down and then chlorine to kill any remaining bacteria in the effluent before it is released to the ocean. This is a similar to a septic system without the leach-field.  International codes require ships to dump waste water at least 3 miles from the shoreline. On the Oscar Dyson, the engineering crew will calculate when the holding tank’s volume is high enough to warrant releasing the waste — anywhere from 1000-6000 gallons. According to Terry, my tour guide, you could drink the treated water, but he wouldn’t do it! Terry also showed me the vacuum system that pulls the waste/water from toilets through the water treatment system, rather than a regular plumbing system using gravity. Much like an airplane toilet, they have a very auspicious “suck.”

Waste and gray water purifier.

Another necessary part of a floating city is a means to dispose of waste – and thankfully it’s not over the side! All solid waste, except for metals, compostables (food waste) and hazardous materials are burned in an incinerator. All metals used by the engineering department are retained and recycled in port. Aluminum cans are also collected and taken ashore to a recycling facility. Hazardous materials such as fluorescent lights and batteries are collected and taken to hazardous material collection facilities, also in port. The Chief Engineer, Jeff Hokkanen, told me that ship is attempting to change out hazardous fluorescent bulbs with l.e.d. lights in an attempt to reduce hazardous waste and to make the “hotel load” (every thing on the ship needed for living) more energy efficient, reducing the limits of the power supply.

The final part of the floating city are the crew that keep it running smoothly so the scientists can do the research they plan for. The ship’s crew is made of several groups – the NOAA Corps officers, deck crew, electronics crew, engineers, survey crew and stewards. The NOAA Corps officers (one of the seven uniformed services of the United States)  are responsible for managing all operations and departments on the ship, including navigation. The deck crew are the people who make fishing and other research operations happen. Some specialize in fishing, others are general deck crew and assist in deploying equipment. As I stated before, the engines and motors are all run by computers and monitored by the engineers. The engineers are a vital part of the crew — if anything on the ship is not working properly or is broken, the engineers can fix it. There is also an electrical crew – on this cruise only one person – who manages and maintains all of the communication and electronics. The survey crew play a key role in assisting the deck crew and scientists. These people have a degree in science, participate in all the research operations, and monitor information and data that the ship’s systems generate. The final group, the stewards, are also important for the ship to run smoothly – the cooks! Without these two, there would be many hungry crew members! The stewards cook breakfast, lunch, and dinner, and also retain food in several refrigerators for folks on the night shift that need more than a midnight snack.

Check out the Oscar Dyson on NOAA ship tracker to see where this floating city is now!

Personal Log

Well, I am in my last week as a Teacher at Sea. This has been quite a trip. I am really enjoying the Shelikof Strait– there have been calm seas, sunny days, lots of whales, good fishing and beautiful sunsets.  I was really happy to get a tour of the lower decks of the ship, it really is impressive to see and hear it all. I got a nice pair of ear plugs for going into the engine room that replaced the ones that I’ve lost while sleeping these past weeks (since I go to sleep when the next crew comes on, sometimes fishing happens early and it can be noisy when they bring the doors back on board!).  Terry did assure me that the engine room wasn’t as loud or as damaging to my ears as a rock concert. We have about 3 more days of fishing and then we head in. I’m starting to transition my sleep schedule but getting up earlier and earlier everyday, which is hard because I can’t seem to get to bed any earlier.

There was is a small chance to see auroras on the 19th and 20th, I’ll be up during those hours so you can bet I’ll be looking!

Species List

WHALES! humpbacks and fin whales — I saw at least 7 blows at one time, far off in the distance. Fulmars, tufted puffins, sea gulls, cormorants

Anne Mortimer: Shelikof Strait, July 16, 2011

NOAA Teacher at Sea
Anne Mortimer
Onboard NOAA Ship Oscar Dyson
July 4 — 22, 2011 

Mission: Pollock Survey
Geographical area of cruise: Gulf of Alaska
Date: July 16, 2011

Weather Data from the Bridge
Sat. July 16, 2011—sunny and windy
Air Temperature:  10.8⁰C
Sea Temperature: 9.3 ⁰C
Wind direction: 208.9⁰C
Wind speed: 23 knots

Science and Technology Log

Everyday on the ship there are many other research projects that are occurring, in addition to the pollock survey. Other scientists (currently not on this leg) are collecting data from a multiple beam system to look at the characteristics of the ocean floor, such as roughness or sound reflectivity, using 30 sound beams (of various frequencies between 100 and 115kHz) in a fan-shaped configuration. For this project, the researchers use several devices. First, they need updated temperature and depth data, which allows them to calculate the speed of sound and the attenuation coefficient (how easily a fish is penetrated by a beam – a large attenuation coefficient means that the beam is quickly weakened as it goes through the fish), which vary as a function of temperature and salinity. To do this, they have chosen select locations to release an expendable bathythermograph, or “XBT.”

This chart shows locations for XBT drops. The yellow and blue stars show where on the transect the XBT should be released.

This torpedo-shaped device is launched overboard with a gun-like dispenser. It has a long coil of fine, copper wire that begins spinning out when it’s released and the wire transmits temperature data back to the ship through the cable in the launch dispenser, and then to the database in the lab. The depth is calculated based on the assumed descent rate of the torpedo.

Getting Ready to Launch
Getting Ready to Launch

Link to Graph of XBT data

In order to confirm the suspected bottom composition from the multi-beam measurements, a drop camera is deployed at specific locations. The drop camera is usually performed off the side of the ship at night, so it doesn’t interfere with operations that can only happen during the day.  The deck crew will deploy the drop-camera using a hydraulic winch, where it is lowered to the bottom. The camera then records for 5 minutes of time at the bottom. Several camera drops are usually completed in an area.

Another operation that happens mostly at night, is using the “Drop TS” or Drop Target Strength echo-sounder. The DTS is used to get a stronger signal at closer range to fish. This helps the scientists differentiate the signals, or echo, that individual fish may give. Many fish have swim bladders (or air bladders) that allow them to regulate their buoyancy in the water. There is a large difference in the sound velocity in air and in water, so this swim bladder causes fish to give strong echo returns.  The DTS can give them a better idea of fish counts when looking at the echograms, but they aren’t perfect. No fish will remain still or perfectly straight. Just like the echograms from the single source mounted on the hull of the ship, the colors red and brown show strong signals, yellow is medium, and blue and green are weak.

This echogram was created with data from the DTS. Each wavy line is probably a separate fish.

Shelikof Strait

We are now traveling south through Shelikof Strait. This body of water runs northeast to southwest along the Alaska Peninsula on the east side of the Kodiak Archipelago. It extends about 150 miles and is dominated by many glaciers, cliffs, and both active and dormant volcanoes. The Alaska Peninsula and Aleutian Islands are part of the Pacific “Ring of Fire.” This is a seismically active area because the Pacific plate is subducting below the North American plate. This has been occurring for millions of years, also giving glaciers time to scour away at the mountains, creating U-shaped valleys and sharp peaks. We’ve had particularly good weather the past few days and caught a great sunset behind the island-volcano Augustine.

Sunset on Augustine
Raspberry Island

Personal Log

So far we are on day 2 (3?) of fair weather and partly sunny skies and I love it. Shelikof Strait is just amazing–there are volcanoes every direction you look and we’ve had beautiful sunset after beautiful sunset. The transect lines we are running in these waters run east-west so we are very close to shore every few hours which means lots of time for pictures. Tonight I went to the flying bridge with Kathleen, the other teacher, so we could whale watch. She had been up earlier (she works the day shift!) and saw a fin whale not too far from the shore and boat. We saw lots of whale blows far off in many directions, but none again that close.

Later after the sun went down and I had started my laundry and next blog entry. The net was in the water for another trawl. Luckily it wasn’t a big catch (I was tired and not ready to slice open tons of fish), but a very little one — literally! We caught mostly juvenile pollock and some smelt fish called eulachon and capelin. We also got our token salmon — we seem to catch one with every trawl — and some squid and jellies. We had some technical difficulties with the catch-processing program, so we were a little delayed in getting started and we had a team of two rather than three. Needless to say, we didn’t finish until after 2 am. Just in time to have some Cheerios for dinner.

The highlight of the night was Dall’s porpoises, which were following the boat to four different drop-camera sights! They were darting everywhere — it was fantastic!

Species Observed

Humpback whales, seagulls, storm petrel, northern fulmar, Dall’s porpoises, juvenile pollock, eulachon, capelin, squid, adult pollock, chum salmon

Anne Mortimer: Cam-trawl, July 14, 2011

NOAA Teacher at Sea
Anne Mortimer
Onboard NOAA Ship Oscar Dyson
July 4 — 22, 2011 

Mission: Pollock Survey
Geographical area of cruise: Gulf of Alaska
Date: July 14, 2011

Weather Data from the Bridge
Conditions: sunny and windy
Air Temperature: 10.1 ⁰C
Sea Temperature: 7.6 ⁰C
Wind direction: 237 ⁰C
Wind speed: 20 knots
Wave height: 2-3 ft.
Swell height: 5-6 ft.

Science and Technology Log

My last blog I said that I would talk more about the cam-trawl. This technology was created by scientists working on the pollock survey. The purpose behind the cam-trawl is to be able to put a net in the water with an open cod-end (basically a net with an opening at the end), and have images of the number, species, and size of fish that went through the net. Of course, sometimes some fish would have to be brought on deck so the otoliths and stomachs could be taken back to the lab in Seattle. Overall, this could eliminate taking so many research-based fish and/or invertebrate samples. When cam-trawl is used on acoustic-trawl surveys, the echograms can be matched up with the stereo-camera  images which can provide more data about the distribution of fish or other marine organisms in the water.

How the cam-trawl works: it is a stereo-camera system that takes snapshots of whatever comes through the net. These images allow the research team (including me on this leg) to determine the approximate number, species (some, not all), and size of fish that go through the net.

cam-trawl image
This still image from the cam-trawl shows a salmon and pollock against a black “curtain.”

The pictures are taken at the same time, but because of the slight difference in camera position, they look similar but not identical. You can mimic this with your eyes by looking at an object with only your right eye, then switching to looking with only your left eye. Did you see the same object but from a slightly different perspective? This is called disparity, or parallax (astronomers often use parallax to estimate the distance of far-away stars or other celestial objects). The program that was written for the cam-trawl (also by this research team) can then calculate the approximate size of the fish based on their relative positions.

In this photo, I’m using the cam-trawl measuring program to measure a sample of fish.
This screen shot shows the stereo-images and the yellow measurements that I’ve added. Using the lengths that I’ve chosen for the program, it calculates the approximate length (in meters) of the fish.

Personal Log

After several windy days with lots of swell, I’m happy to be in calmer waters. I’ve been working on the computer for some of the time which doesn’t go well with swell. I have also found it to be very tiring and tense on my body to be in constant motion and prepared to grab whatever I can to stay upright. I can’t tell you how hard it is to use a treadmill or take a shower in rough seas! BUT, for the time being, it’s calm and I just watched a great sunset over Kodiak island with a few humpback whale blows in the distance. If you are still wondering about the salmon in the picture above, it’s a chum!

Species Observed
humpback whales
northern fulmars
tufted puffins
black-footed albatross
storm petrels
porpoises (yesterday)

Anne Mortimer: Otoliths and more otoliths…, July 8, 2011

NOAA Teacher at Sea
Anne Mortimer
Onboard NOAA Ship Oscar Dyson
July 4 — 22, 2011 

Mission: Pollock Survey
Geographical area of cruise: Gulf of Alaska
Date: July 8, 2011

Weather Data from the Bridge
Air temperature: Sunny, 10°C
Sea temperature: 9.1°C
Wind direction: SW; 318 degrees
Wind Speed: 24.1 knots
Barometric pressure: 1012.12 mbar

Science and Technology Log

On my last 12 hour shift, a beautiful, sunny day, we started by pulling in, sorting, counting, and weighing fish caught in a mid-water trawl.  The scientists were also testing out a new “critter cam” that was attached to the net. The trawl net has a special device called a M.O.C.C. which stands for Multiple Opening and Closing Cod-ends. The net has three separate nets that can be opened and closed by the M.O.C.C. when the scientists reach the desired depth or location for catching, this keeps the catches from different targeted depths from mixing together. The three separate nets are called cod-ends. Each cod-end catch is processed separately. In this trawl, we saw multiple jellies, juvenile pollock, krill, juvenile squid, juvenile Pacific sandlance, capelin, juvenile flatfish, and juvenile cod.

Capelin from our trawl covered the deck of the boat.
MOCC entering the water
The Multiple Opening and Closing Cod-end, or MOCC, and net being released to the water for a mid-water tow.

Later, we trawled a 2nd time for about an hour. The trawl net used is called the AWT or Aleutian Wing Trawl because the sides of the net are like wings. After the net is in the water, two large steel doors are dropped in the water and help to pull the net open wide. You can see them in the picture above, they are the giant blue steel plates attached to the very stern (end) of the ship. During this trawl, only one cod-end was opened, and the catch was several hundred pounds of Pollock, with some eulachon, capelin, squid and jellies also.

Because pollock are the target fish of this survey, each was sexed and counted, and a smaller number were measured for length and weight, and the stomachs and otoliths were removed. The stomachs are being preserved for another research project back in Seattle, and as I mentioned previously about otoliths, they tell the age of the fish.

Personal Log

Today I was happy to have beautiful sunshine and 2 trawls to sort through. The skies and surrounding islands were absolutely stunning. I can understand why people are drawn to this place. It’s wild and rugged and looks like it probably did hundreds of years ago.

Scenery of the Shumigan Islands.
Dusk in the Shumigan Islands.

Species List

humpback whale (just one today!)


tufted puffin


arrowtooth flounder




Pacific sandlance


juvenile flatfish

juvenile cod

sea gulls


Thought for the day… if I was a blubbery whale, I would live in the Gulf of Alaska. If I was a pollock, I’d try not to get into a net, they can give you a splitting headache.

Anne Mortimer: Fishing, July 7, 2011

NOAA Teacher at Sea
Anne Mortimer
Onboard NOAA Ship Oscar Dyson
July 4 — 22, 2011 

Mission: Pollock Survey
Geographical area of cruise: Gulf of Alaska
Date: July 7, 2011

Weather Data from the Bridge
Air temperature: 9.53 C, Foggy
Sea temperature: 8.19 C
Wind direction: 145
Wind Speed: 18.73 knots
Barometric pressure: 1013.22 mbar

Science and Technology Log

Last night, we attempted a bottom trawl for walleye pollock. The way scientists know that fish are present is by using acoustic sampling. The centerboard of the ship is set-up with sound emitting and recording devices. When a sound wave is emitted toward the bottom, it will eventually be returned when it hits a fish or the ocean bottom. This is called echo-sounding and has been used by sport & commercial fisherman and researchers for many decades. The sound waves are sent down in pulses every 1.35 seconds and each returned wave is recorded. Each data point shows up in one pixel of color that is dependent on the density of the object hit. So a tightly packed group of fish will show as a red or red & yellow blob on the screen. When scientists see this, they fish!

This echogram shows scientists where fish can be found.

The scientists use this acoustic technology to identify when to put the net in the water, so they can collect data from the fish that are caught. The researchers that I am working with are specifically looking at pollock, a mid-water fish. The entire catch will be weighed, and then each species will be weighed separately. The pollock will all be individually weighed, measured, sexed, and the otolith removed to determine the age of the fish. Similar to the rings on a tree, the otolith can show the age of a fish, as well as the species.

pollock otolith
A pollock otolith.
Pollock otolith in my hand

These scientists aren’t the only ones that rely on technology, the ships navigation systems is computerized and always monitored by the ship’s crew. For scientific survey’s like these, there are designated routes the ship must follow called transects.

globe chart
This chart shows the transects, or route, that the ship will follow.
This chart shows the route (white line) of the ship once fish were spotted. When scientists find a spot that they want to fish (green fish symbol), they call up to the bridge and the ship returns to that area. As the ship is returning, the deckhands are preparing the net and gear for a trawl.

Personal Log

I think that I must have good sea legs. So far, I haven’t felt sick at all, although it is very challenging to walk straight most times! I’ve enjoyed talking with lots of different folks working on the ship, of all ages and from all different places. Without all of the crew on board, the scientists couldn’t do their research. I’ve been working the night shift and although we’ve completed a bottom trawl and Methot trawl, we haven’t had a lot of fish to sort through. My biggest challenge is staying awake until 3 or 4 am!

Did you know?

That nautical charts show depths in fathoms.  A fathom is a unit of measurement that originated from the distance from tip to tip of a man’s outstretched arms. A fathom is 2 yards, or 6 feet.

Species list for today:

Humpback Whale

Northern Fulmar

Tufted Puffin

Stormy Petrel

Fish biologist Kresimir found this petrel in the fish lab; attracted to the lights it flew inside by accident. The petrel is in the group of birds called the tube-nosed sea birds. They have one or two "tubes" on their beak that helps them excrete the excess salt in their bodies that they accumulate from a life spent at sea.

In the Methot net:

Multiple crab species including tanner crabs

Multiple sea star species, including rose star


Juvenile fish

Brittle stars


Multiple shrimp species including candy striped shrimp

shrimp variety
These are some of the shrimp types that we found in our Methot net tow.

Anne Mortimer: Life at Sea, July 5, 2011

NOAA Teacher at Sea
Anne Mortimer
Onboard NOAA Ship Oscar Dyson
July 4 — 22, 2011

Mission: Pollock Survey
Geographical area of cruise: Gulf of Alaska
Date: Tuesday, July 5, 2011

Weather data from the bridge
Air Temperature: 8.8 C
Sea Temperature: 9.3 C
Wind Speed: 16.42 knots
Wind Direction: 210.11 degrees
Barometric Pressure: 1018.31 mbar

Personal Log
We’ve been at sea for almost 24 hours now, and so far, it’s been smooth sailing. We’re headed southwest to the area where the last leg of the cruise left off, which means lots of sailing and no trawling yet. Yesterday, before the ship left port, we participated in a  man-over-board drill and fire drill. These drills are required,  and we are also required to don the life suit for practice.

Anne Moritmer in life suit
Here I am, donning the life-suit.

My shift will be from 4pm to 4am, so I’m trying to adjust myself to that schedule, which last night led me to the bridge. The bridge is where the Commanding Officer and others navigate the ship and control several of the fishing operations. The bridge has windows all around, so even at 11pm, when the sun is close to setting it is still filled with daylight. Yesterday evening, I spent most of my time on the bridge watching Humpback whales with binoculars. Then, just as the sun was presenting a spectacular sunset, we saw multiple whale flukes and spouts on the horizon in the glow of the sun’s rays.

Humpbacks, July 4
We had a spectacular July 4th show at sunset from Humpback whales. Photo by Paul Walline, NOAA scientist.

Species list at Sea (biggest to smallest!):

Humpback whale
Sea lion
Black-footed Albatross
Northern Fullmar
Tufted Puffin