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 EyesSalmon 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 rollPassing through the fog
Did you know? Fog is essentially a cloud on the ground’s surface.
NOAA Teacher at Sea
Staci DeSchryver Onboard NOAA Ship Oscar Dyson July 26 – August 12, 2011
Mission: Pollock Survey Geographical Area: Gulf of Alaska
Location: Kodiak, AK
Heading: back to the docks
Date: August 12, 2011
Weather Data From the Bridge: N/A
Science and Technology Log
My last night on the Oscar Dyson was a busy one! Because our trip was cut so short, we had to “break protocol” so to speak. Typically, nighttime operations consist of seafloor mapping (which I will get to in a minute), and do not consist of trawling for Pollock. For science students, you probably have a good idea why – running operations only in the daytime means that the experiment is controlled. Since Pollock behave differently in the night-time, it is important to only run operations when their behavior is consistent. However, because we were so short on time, we had to make a “run” for the shelf break that got us to the area well after dark. So we got to do one more trawl! This one was the best kind, in my humble opinion. We completed a bottom trawl, which means that the net went almost down to the bottom of the ocean – within a couple of meters. The reason why bottom trawls are so neat is because there are plenty of ocean critters down there that the average Joe doesn’t get to see on a daily basis. Of course, the scientists do their absolute best to catch only Pollock to minimize bycatch, but one or two fish of different species are difficult to avoid. On this trawl, we had a few jellies, two Pacific Ocean Perch, and a Herring. We finished late – right around one in the morning. At that time, we began our night-time operations.
Night time operations are run by Dr. Jodi Pirtle. Dr. Pirtle is a Post-Doctoral Research Associate at the University of New Hampshire Center for Coastal and Ocean Mapping. Her research is a collaborative effort between the UNH CCOM and the NOAA Alaska Fisheries Science Center. Even though Jodi is traveling all the way from New Hampshire, she is actually very close to home right now. She is quite connected to the Alaska fisheries – she grew up in Alaska, and has both family and friends who are involved in the commercial fishing industry. The fisheries hold a place very close to her heart, and her passion for her current line of work is well evident.
So, why, then, does Dr. Pirtle work in the cover of night?
Here, the scientists are working in the acoustics lab on daytime operations. As you can see, most of the electronic equipment is used during the day. At night, Dr. Pirtle gets the opportunity to chart her own path and select an area to map without interfering with the ship's primary operations.
At first I suspected it was some sort of secret service operation, but the reality is much more strange and explainable. Her line of work is a side project on the Oscar Dyson, which means that she can work when the ship is not working for its primary purposes. Hence, she works from 6pm until 6am. One focus of her research is to identify whether or not certain areas of the Gulf of Alaska are trawlable or untrawlable by the Alaska Fisheries Science Center bottom-trawl survey for groundfish. How is an area determined to be untrawlable? Let’s say, for example, there is a commercial fishing ship somewhere in the Gulf of Alaska. This ship decides to do a similar trawl as the one that I did earlier this evening, but they use a net that makes contact with the seafloor because they are fishing for groundfish species – say, Rockfish, for example. But, something happens. When the net comes up, it is all torn up – as though it got caught on a series of rocks or ledges. In order to warn other ships of the dangers of losing a very expensive net, the fisherman deems the area “untrawlable.” It’s kind of like putting caution tape around the area.
Untrawlable areas are problematic for scientists because every area deemed untrawlable is an area where they can’t sample with the bottom-trawl gear. For example, a large component of the groundfish fishery are several species of rockfish (Sebastes spp.) that associate with a rocky habitat. Rockfish are delicious with garlic and butter, but they are sneaky little guys because they like hanging out around rocks (who knew?). Many rockfish could be in areas that are untrawlable, but scientists would never know because it is inadvisable to tow a bottom-trawl net in the area to find out. In a sense, untrawlable areas are a source of error, or uncertainty in the population estimate for species of groundfish in those areas. This is where Dr. Pirtle’s research starts.
A few years ago, a group did research in an area called Snakehead Bank – a location previously deemed to be untrawlable. They wanted to tighten the definition of “untrawlable.” For example, there is a possibility that an untrawlable area is covered with steep cliffs, many sharp, large rocks, and impossibly tough relief. However, there is also the possiblity that the area is relatively flat and trawlable, but the fisherman was just unlucky enough to drag his or her net over a rogue boulder that found its way onto the vast, flat, continental shelf. So, the scientists decided to see what kind of “untrawlable” this particular area was. The group took the time to make a bathymetric profile of the area and couple that research with camera drops – video cameras that would make the trek to the bottom of the ocean and provide a second set of data for scientists to confirm what the bathymetric profile showed them. From the camera drops and the bathymetry, the scientists determined that Snakehead bank was not completely untrawlable – in fact, most areas could support trawl nets without the risk of tearing the nets. Dr. Pirtle is continuing with this important work.
One focus of the research is determining seafloor trawlability in the Gulf of Alaska using the same acoustic transducers that we use to catch fish in our daytime operations. The fishery that the survey is concerned about is groundfish – a general term that encompasses many species such as flatfish, cod, and rockfish. These sneaky guys enjoy habitats that are associated with rocky areas, so we are not getting the best estimate of populations in those areas. Dr. Pirtle is looking in to alternative methods to determine whether an areas of the seafloor is untrawlable or trawlable using the mulibeam sonar. Not only is she looking for areas that can now be considered trawlable, she’s also using the data she collects to determine certain seafloor characteristics. Hardness, roughness, and grain size are all data that can be collected using the acoustic transducers. This information will help her to determine the relative trawlability of an area, as well. Therefore, the groundfish survey benefits because she is either finding areas to be trawlable (thus, they can now sample there) or somewhat trawlable, which can tell them ahead of time that alternative sampling methods might be needed in a particular area.
Her research is also concerned with developing alternative sampling methods for untrawlable locations. These methods could involve a combination of acoustic seafloor mapping to characterize seafloor habitats for groundfish, acoustic midwater data (to observe the fish that like to hang out on tall pinnacles and rocky banks) and, the most fun method – dropping a camera to the ground to identify species and biomass assessment (which is a fancy term for seeing how many fish are in a particular area). Improved understanding of groundfish habitats can lead to better management models, and the work Dr. Pirtle is doing can also contribute to conservation of areas that are sensitive to fishing gear that touches the seafloor.
The area that Dr. Pirtle decided to survey this evening was an area that was deemed to be untrawlable surrounded by many trawlable areas. These areas are often good candidates for mapping and camera surveys because both untrawlable and trawlable seafloor types are likely to be encountered, so the area can more easily be compared against existing data. We began our transects – driving transects with the ship over the area while sending sound waves to the bottom of the ocean to figure out differing ocean depths and seafloor type. Transect lines are close together and driven in a pattern similar to mowing a lawn, which gives Dr. Pirtle 100% coverage of her targeted area. Dr. Pirtle selects a location to drop a CTD – Conductivity, Temperature, and Depth meter – usually in the middle of the mapped area. The CTD is used to estimate sound speed in the location she is mapping. This is important because ocean depth is measured by the amount of time it takes for a sound wave to leave the ship, bounce off the ocean floor, and return back to the ship.
This is a photograph of a halibut on the uncharted pinnacle discovered by Dr. Pirtle, similar to what I saw real-time on the camera late at night.
She then selects three to five areas to conduct camera drops. The camera travels to the bottom of the ocean where she can see if the area is untrawlable or trawlable based on what the camera shows her. I, on the other hand, get to see deep ocean critters in their habitats, which is also very cool. There are two types of camera drops – ones that record the information and then get played back later, and real-time camera drops where we can literally watch the camera make the trek to the bottom of the ocean in real-time. Dr. Pirtle uses the camera data to “groundtruth” or check the seafloor type against her acoustic map, to identify fish and other animals in the area, and to observe how species use the seafloor habitat.
As my shift was coming to a close, I could barely keep my eyes open, but I didn’t want to miss this. Tonight, we dropped the live camera into the depths. I stayed awake for the first drop so I could see what these operations looked like. Dr. Pirtle expertly maneuvered the camera into the deep using something that looked much like an old-school Atari controller.
This photograph shows Dr. Pirtle's work in combination - the area she surveyed is in the bottom right corner. The other three photos are snapshots of the surveyed area.
As the camera dropped, we saw a few pollock and some other unidentified neritic creatures, but the real fun started when we got to the bottom. It was intense as Dr. Pirtle relayed information back to the bridge about the direction in which to travel, holding the ship still in the waves and currents when she wanted to examine an area more closely, and communicate with the technicians on the hero deck to relay the height that she wanted the camera held at. We saw all sorts of interesting creatures on the ocean floor – some arrowtooth flounder, a halibut, and Pacific Ocean Perch. We also observed beautiful cold-water corals and sponges that form a living component of seafloor habitat for many marine animals, including our target – rockfish. We even saw a shark! It was completely worth getting to bed a little bit later to see this incredible work in real-time.
This is the unmapped pinnacle discovered by Dr. Pirtle and her colleague! Now, seafloor maps have been updated to include this potentially dangerous sea hazard.
On a side note, in a previous leg of the survey, Dr. Pirtle and her colleague from UNH CCOM, Glen Rice, found an underwater pinnacle that was later determined to be a navigational hazard! This pinnacle came so close to the surface of the water that in a “perfect storm” of low tide and a large enough ship with a deep enough hull, it could have unknowingly collided with this unmapped pinnacle – which could have potentially been disastrous. Glen, a NOAA hydrographer, was able to update the navigational charts in the area, alerting ships to the pinnacle’s presence. It just further supports the idea that the our oceans are so vastly unexplored – there is so much we don’t know about the feature that takes up the biggest portion of our Earth! I asked her if she named it because she discovered it – I quickly learned that just because you find something in the Ocean, it doesn’t mean you get to keep it. Apparently, you can’t name it, either. But I still called it Pirtle’s Pinnacle. I think it has a nice ring.
Personal Log
It was a sad day today watching the scientists pack up and box and tag the lab equipment and computers. As everyone bustled about, I spent some time hanging out for the last time on the bridge, in the galley, and in the fish lab thinking about my journey coming to its close. Although we spent the majority of it tied to the dock, I am so grateful for the opportunities we experienced that we otherwise would not have – it was a blessing in disguise, because we really got to experience all of Kodiak, and much of the bays and inlets around the island from the ship. The pictures will bring no justice to the beauty I’ve experienced in the last three weeks, whether it was walking along a beach with wild horses or staring in all directions to find nothing but water for as far as the eye could see. I spent an hour one night on the bridge watching the Leonids streak across the sky – a front row and first class seat, in my opinion. I never though that dodging whales would be an area of concern in my small life until we sailed through pods of them every day. If you would have told me three years ago I’d be petting an octopus three weeks ago, I would have called you a fool. If you would have told me three hours ago that this experience would be coming to a close three minutes from now, I would believe you even less. In the last three weeks, I have never laughed harder, worked more eagerly, or learned more with and from these incredible individuals who call this ship Home. As I quietly stood on the bridge watching the fast rescue boat dart off to the docks, I remembered the last time it was in the water watching carefully over us as we swam around the ship in our gumby suits. As we drove silently through the still waters to the city docks, we bade farewell to the animals that accompanied us on our trips – otters, eagles, puffins, and even sea lions gathered around to see us off to our homes and families. Or, they just so happened to be there looking for food and doing other instinctual things, but I do really think I saw an otter wave me goodbye.
Here is a whale "waving goodbye" with his fluke in the Gulf of Alaska - I will never forget the journey I had here!
Thank you so much to the crew and scientists of the Oscar Dyson – you fed my soul this summer and rejuvenated me in a way I never could have imagined. I am more revived today than I was on the first day of my second year of teaching (because, let’s face it, the first day of your first year you spend most of your time trying not to vomit) and I owe it completely to the Teacher at Sea Program and to all of the fine people I got to work with. To my partner in crime, Cat Fox – I’ll see you when we’re landlocked again! It was a total blast working with you. Thanks for always being there for a good laugh and for finding me so many salmon berries! If you are wondering whether or not you should apply for this program in the 2012 season – this is the advice I will give to you: JUST APPLY! It will change your life – promise.
Until our next adventure,
Staci DeSchryver
Did you know…
While I was working my night shift, I got the opportunity to help Dr. Pirtle “log the turns” of the ship as it was “mowing the lawn” in the zigzag pattern. This meant that I got to communicate with the bridge via radio every time they ended a transect and began turning in the opposite direction. I’m sure you may have predicted that this was most certainly a highlight of my work. It took great restraint on my part to behave myself with the radio, as everyone knows that radios can be a lot of fun. I did, however, let a few nautical words fly on the airwaves up to the bridge, one of them being “Roger, Willco.”
I had no clue where the origin of the word “Roger” came from. But now I do…
Roger, which starts with the letter R, means “Received”, which means, “I received your last transmission.” A long time ago, the radio alphabet (you know, Alpha, Bravo, Charlie, Foxtrot, Whiskey, etc.) used Roger to represent the letter R. It has since been changed to “Romeo.” Adding Willco to the end, means “I received your transmission, and I WILL COmply.” So saying that I received a message from the bridge and I was going to comply with it really made me look like a navigational moron – because they weren’t asking me to comply with anything. But I still had fun.
NOAA Teacher at Sea
Lindsay Knippenberg
Aboard NOAA Ship Oscar Dyson
September 4 – 16, 2011
Mission: Bering-Aleutian Salmon International Survey (BASIS) Geographical Area: Bering Sea Date: September 13, 2011
Weather Data from the Bridge Latitude: 56.91 N Longitude: -169.08 W Wind Speed: 10.07 kts Wave Height: 4 – 6 ft Surface Water Temperature: 6.5 C Air Temperature: 7.5 C
Science and Technology Log
The Oscar Dyson uses several different types of sonar to get the best image of what is beneath the ship.
Today I learned about acoustics with Paul. The Oscar Dyson is one of NOAA’s newer ships and has a hull-mounted sonar system which uses sound waves to “see” what is underneath the ship. The Oscar Dyson was also built to have a low acoustic signature and be “quiet” in the water. This is helpful to the scientists using acoustics to study fish onboard the Dyson because the fish don’t hear the ship and swim away. On our cruise the acoustics data is used to get a picture of where there is life in the entire water column. For the most part we have just been trawling on the surface, but the ocean is much deeper and there could be a lot more life underneath our nets that we will never catch. If we get very few fish in our nets, it could mean that the fish are just at a deeper depth and not that there are not any fish in that area. Since the scientists are getting a better picture of what is really going in that ecosystem, they can make more accurate stock assessments. All throughout the cruise I have been curious about the images displayed on the screens in the acoustics room and on the bridge. Today I would finally learn what they were all about.
Since the sonar is attached to the bottom of the boat, the top 14 meters aren't seen in the images. To solve that problem, a sonar transducer is lowered over the side to get the top 14 meters when we at station.
Basically how acoustics work is that a sound or ping is sent from the ship and it travels through the water. When it hits something in the water column or the bottom of the ocean it bounces back and the ship’s echosounder records the length of time that it took for the sound wave to travel there and back. Depending on the temperature and depth of the water, the pings are sent at different time intervals and pulses. The pings can also be sent at different frequencies to “see” different types of organisms. For instance zooplankton can be viewed best at one frequency and jellyfish can be viewed best at another frequency. As the sound waves are returning to the vessel, the computer translates the returning sound waves into images for the scientists to analyze.
A sonar image at dawn. The dark red line at the bottom of the screen is the ocean floor. Notice all the greens and blues at the top of the water column. Those are pollock.
On our cruise Paul is comparing the sonar signatures produced by the different organisms under the boat to what we are actually catching in the nets. The use of acoustics technologies for stock assessments is fairly new and individual species can’t be recognized by the sonar images, but Paul can use the images to detect if an area will have a greater density of organisms. We are also selecting several locations between stations to do mid-water trawls. Paul selects areas that have a high density of organisms underneath the depth that our surface trawl nets reach and we do a mid-water trawl. He then compares what we find in the trawl to the sonar signatures that he saw in the images to see if he can find any patterns between specific species and sonar signatures. It will be amazing if some day fisheries biologists will be able to assess the stock of fisheries by using sonar instead of net trawls which are a lot more work and often result in the death of the fish.
Personal Log
Today's weather after the two low pressure systems had entered the area. The weather was pretty crappy the last two days, but today it is beautiful.
We have had several lo- pressure systems blow through during our cruise and so far we have had two gale warnings. The first one occurred when we had only been out to sea for a day so it was easy to head back in to Dutch Harbor. The last one occurred a couple of days ago and we were too far out into the Bering Sea to turn back. We had no choice but to ride it out. Two low-pressure systems were colliding and the Bering Sea turned into a washing machine. There were consistent 10 – 13 ft waves coming from one direction, large 20ft swells coming from another direction, and the occasional 8 – 10 ft wave coming from a different direction. The ship just kind of bobbed from side to side and up and down and we were all along for the ride. Thank goodness I didn’t get sick, but I definitely didn’t sleep well.
Face to face with some angry seas.
I was also amused by how life went on for everyone onboard the ship. Dinner was hilarious as everyone held onto their dishes and your chair moved from side to side with the waves. Walking around was pretty funny too. There was no way that you could walk in a straight line. I would choose something to grab onto, walk another couple of steps, and then grab onto something else. As I tried to sleep at night I could hear the things that we had thought we had secured roll around the room. Who knew that a roll of paper towels could make so much noise? The curtain on my bed was making me crack up because it would roll open with one wave and close shut with another. It just kept opening and closing all night and there was nothing that I could do about it but laugh. Thankfully by today the seas had calmed down significantly and the sun is actually out.
Francesco was a lost shorebird who found his way to our ship in the middle of the Bering Sea.
There was one casualty though, and that was Francesco. Francesco was a shorebird, an American Pipit, that was blown way off course during the storm. He ended up cold and hungry on our back deck last night. We were able to catch him and we put him in a warm box with some dead flies, water, and crackers. He managed to eat and drink, but he was a juvenile and had very little body fat. He was pretty much skin and bones. He lasted until this afternoon and when we went to check on him, he was dead. We gave him a burial at sea and were reminded that the Bering Sea is a harsh, harsh environment.
NOAA Teacher at Sea
Lindsay Knippenberg
Aboard NOAA Ship Oscar Dyson
September 4 – 16, 2011
Mission: Bering-Aleutian Salmon International Survey (BASIS) Geographical Area: Bering Sea Date: September 4, 2011
Weather Data from the Bridge
Latitude: 54.13
Longitude: -166.41
Wind Speed: 24.10kts
Wave Height: 4-6 ft
Surface Water Temperature: 9.0°C
Air Temperature: 8.8°C
Science and Technology Log
The station grid for all of the proposed sampling sites.
Yeah! Today we left Dutch Harbor and began the second leg of the Bering-Aleutian Salmon International Survey (BASIS). The purpose of the BASIS Study is to assess the status of marine species in the Eastern Bering Sea and support the decision making process for commercially important fisheries. The scientists on my team are accomplishing this goal by combining their knowledge of fisheries, oceanography, and acoustics. While I am onboard I will be helping out the scientists in all these different areas to get a broad view of all the science going on during our cruise.
There are specific sampling locations called stations that we will be going to throughout the Eastern Bering Sea. The map on the left shows the locations of these stations. The green dots are the stations that we are sampling during leg 1 and leg 2 of the BASIS survey. Leg 1 is already complete and they sampled at all the stations east of Unalaska. We will be picking up where they left off and sampling at all of the remaining green stations. The black dots are stations that will be sampled by another vessel named the Bristol Explorer.
The trawl net being let out behind the ship.
For the first station I got to help out the fisheries team in the fish lab. We did a surface trawl by letting out a large net out the back of the boat with floats on it to keep it at the surface. By adjusting the floats and weights on the trawl, the fishermen can choose what depth they fish at. While the net is out, the OOD (Officer of the Deck) slowly motors the ship for about 30 minutes and the net catches the fish that are swimming in that area and depth. For this station we want to see the fish that are swimming within the top 30 meters of our sampling area. At later stations we might also do a mid level or deep trawl to see the fish that live at those depths.
We found some Salmon!
After the 30 minutes were up, the fishermen slowly brought in the net and we immediately saw salmon caught in the net. Yeah! We caught something! As more and more net was brought in the fish began to pile up on our sorting table. There were a lot more fish than I had expected and the majority of them were salmon. It was now our job to sort the fish by species and I will admit that I am pretty slow at identifying the species. They may all look like fish, but they each have identifiable features like the color of their gums (black for Chinook Salmon), type of gill rakers, or color patterns on their body or tails. At this station we were lucky enough to pull in four out of the five salmon species in Alaska. We caught Chinook, Sockeye, Chum, and Pink Salmon. We also caught several different species of jellyfish and some squid.
That is a lot of salmon to sort.
After we caught the fish, we had to process them. In order to learn about the fish and the health of their population, we took samples and collected data from the fish we caught. Here is a description of the data we collected and what the scientists can learn from that data.
Weight and Length – Weight and length are an index of fitness for the fish. The scientists multiply how fat the fish is by how long it is to determine its lipid (fat) content. In cold waters the fish tend to have a higher lipid content than in warmer waters where the fish have to use more energy to metabolize. Additionally, if a fish has a higher lipid content, it might also mean that it is healthy and finding prey easily.
Gill rakers (white hairs on top of the red gills) from two different salmon. Can you see the difference?
Axillary Process – We cut the axillary process off the fish we caught for genetic studies. The scientists know the baseline genetic sequence for the salmon that come from different regions of the world. By looking at the genetics of the fish we caught, we can tell where the fish came from and reconstruct their migration and distribution. For instance, the scientists have used the genetics from the axillary processes to determine that a large percentage of chum salmon caught in the Eastern Bering Sea are from Japan.
Sexual Maturity – By looking at the testes and ovaries of the fish, the scientists can determine if the fish were immature or mature and when they were going to spawn. Using this information along with the results from the axillary process genetics, the scientists can determine migration patterns and growth rates.
Determining the sex, stomach contents, and sexual maturity of the fish we caught.
Male vs. Female – The scientists also use the testes and ovaries to determine if the fish was a female or male. This is helpful in looking at the ratio of males to females in their population.
Stomach Contents – By removing the stomach of the fish and analyzing its stomach contents, the scientists can determine what the fish was eating. This is can be very helpful when comparing warm years to cold years and the effect that climate change can have on prey sources and the nutrition of the fish.
All of this information can then be extremely useful to fisheries managers who are assessing the stock of the fish that are important to commercial fishermen. One of the species that we hope to collect as we sample at other stations is Pollock. Pollock is the largest US fishery by volume. Each year around 2.9 Billion pounds of Pollock are harvested. To learn more about the Pollock fishery check out this link to NOAA FishWatch. The scientists on my team are assessing the health of the Pollock fishery by looking at the total lipid content of Age 0 Pollock in late summer. Their lipid content is important at this time of year because winter in coming and they will need lipids to survive the cold winter. By looking at the lipid content of the Age 0 Pollock that we collect, the scientists can predict how many Age 0 Pollock will survive to become Age 1 Pollock and eventually mature to become Age 3 or 4 Pollock that can be harvested.
Personal Log
The fluke of a whale as it dives.
Whales! I was hanging out on the bridge getting my last look at land for a couple of weeks when I thought I saw a whale out of the corner of my eye. I couple of minutes later a huge Humpback Whale breached right next to the ship. I have seen whales before, but it was just their dorsal fin of flukes. This was crazy. An entire whale was out of the water and it kept on breaching over and over again like it was playing. I wanted to take a picture, but I was too mesmerized to even take my eyes away from it for a moment. Then as I started to look farther out to sea, I saw even more whales. There were about a dozen whales flapping their tails and rolling on to their sides. It looked like they were having a good time playing on a beautiful day.
The weather forecast for September 4 - 6. It doesn't look good...
That beautiful day, however, did not last very long. We managed to sample at two different stations when the wind started to pick up and the waves began to get a little larger. The forecast was calling for a Gale Warning with gusts of up to 50kts and 20-24 ft seas. Those conditions are far too dangerous to fish in, so we turned around and headed back to Dutch Harbor. Hopefully the storm will pass quickly and we will only have to hide out a couple of days until it is safe to fish again.
NOAA Teacher at Sea
Staci DeSchryver Onboard NOAA Ship Oscar Dyson July 26 – August 12, 2011
Mission: Pollock Survey Geographical Area of Cruise: Gulf of Alaska Location: Barnabas Strait57 deg 22.630 N, 152 deg 24.910W Heading: 67.8 deg
Date: August 9, 2011
Weather Data From the Bridge Partly Cloudy Skies
Temp: 13.5 deg
Dewpoint: 6 deg
Barometric Pressure: 1020 mb, falling, then steady
Wind: 240 deg at 12kts
Seas: Calm stn model 08.11
Science and Technology Log
The start of my first official shift onboard the Oscar Dyson was an interesting one! We had lost some time (11 days) to some complications, so our cruise goals shifted a bit from the original plan. We had to focus on the most important aspects of the mission, and sacrifice carefully, as it wasn’t plausible to complete the entire mission in the time allotted. One of the major steps for completing the season was to do what is known as a calibration. In order to save time, we did the calibration on my first night out on the job!
Calibrations are typically done during the daytime because the fish are curious little beasts. During the day, they move lower in the water column, and therefore do not interfere with the calibration of the system, mainly because they are so far away they are oblivious to it. At night, however, they party at a shallower depth, and sometimes their acoustic signatures can mar the data collected during a calibration. It is critical to the scientists that they calibrate the acoustic system accurately, and if there is a school of fish swarming the calibration tools, well, it’s a big ‘ole mess. Given that we are on a shortened time schedule, it made practical sense to conduct the calibration overnight.
Marshmallow has been very helpful on the trip. Here he is counting krill. I don't have the heart to inform him that these krill have already been counted.
Why do we calibrate the acoustic transducer? Think of it like this. Have you ever baked cookies before and followed the directions to the letter, only to have them come out of the oven like crispy critters or balls of goo? Or, let’s say, you have a favorite recipe you use all the time, and you gave the recipe to a friend who makes the same cookies the same way, yet complains that they are overcooked? Well, one of the reasons that the recipe may have not turned out was because either your oven, or your friend’s oven was not properly calibrated. Let’s say, for example, the recipe calls to bake the cookies at 350 degrees for 15 minutes.
If you turn the dial to 350 degrees, it is reasonable to expect that the oven is, in fact, 350 degrees. But there is an equal possibility that the oven is actually only 325, or maybe even 400 degrees. How would you double check to see if your instrument is off its mark? One solution is to heat the oven to 350, and use a meat or candy thermometer that you know has an accurate readout and then put the thermometer in the oven. If the candy thermometer reads out at 350, you can be certain that your oven really is 350 when you turn it on. If the candy thermometer reads out at 375, then you can be certain there’s an error in the readout of your instrument. Calibration corrects for those errors.
Here you see Cat and I showing off the downrigger - the piece of equipment that holds the calibration spheres under the ship.
Calibration on this survey is important because scientists use information from the acoustic transducer to determine the types and abundance of organisms in the water column. If the instrument they use to make these predictions is off in any way, then all of the data they collect could be determined to be insufficient or unreliable. Calibration also ensures that acoustic measurements (and survey results) are comparable between different cruises, locations, and times.
Calibration is done much in the same way as an oven is calibrated. We take an object that has a known and reliable return rate on the acoustic transducer, and hang it below the ship. Then, the scientists will “ping” acoustic soundings off of the object and see how well the return matches up with the known return rate. If it’s off, then they can “tune” the transducers, much like a guitar is tuned.
Here, the chief scientist, Chris Wilson, double checks our superior downrigging work!
It is only necessary to calibrate the transducers twice per survey – once at the beginning of the survey (one was done in June) and one at the end of the survey (which was now). When the transducer is calibrating, the ship must be as close to stationary as possible. This is why the lead scientist chose to do the calibration at night – we can’t calibrate and conduct assessment surveys at the same time. Therefore, it’s a one-pony show when the transducer is calibrating. Almost all other scientific field work ceases while the calibration is completed.
There are two materials used for calibration for this particular transducer on the Oscar Dyson. The first is Tungsten Carbide, and the second is pure Copper. These small, spherical objects are quite cleverly hung below the ship off of three downriggers attached to the port and starboard rails. In order to hang the spheres, the strings on either side of the ship must connect. In a sense, we ask the Dyson to “jump rope” to get the calibration sphere underneath the ship in the correct position.
Calibration takes about six to eight hours to complete. I got to help with setting the downriggers up, changing out the calibration spheres, and breaking down the equipment. As it turns out, the transducer only needed minor adjustments this time, which is pretty typical for the ship. However, it’s important to double check so that if there is a problem, it can be detected early and corrected.
Personal Log
Today, the chief engineer of the ship, Jeff, gave us a tour of the engine room. Holy cow, was that impressive! I don’t know what I was thinking when I thought that the guts of this beast were contained in one small room. They most decidedly are not. There are two whole decks below the lowest level I know of – and they are filled with all kinds of interesting equipment. We got to see all of the engines (there are 4 diesel generators), where the water is purified for consumption, and all of the internal components of the winch system that lowers and raises our fishing nets. As if that weren’t enough, we popped open a floor hatch, climbed down the ladder two flights, and got to stand right on the “skin” of the boat. Translation: The only thing separating my feet and the big blue sea was a thin little piece of metal. It was so cool. The ship is designed to be “acoustically silent” – like a stealth fighter, except they don’t call it stealth and we aren’t fighting enemies – we are hunting fish. Because of this, many of the larger pieces of equipment are hoisted up on platforms that silence their working parts. The ship has diesel-electric propulsion.
Here is just ONE of the four massive engines on the ship!
This means that there are four diesel generators that make electricity, which then gets split into two different forms – one type is for propulsion, and the other is for our lights and other conveniences. It sounds really complicated, and much of what the engineers do on board is quite complicated, but everything onboard is smartly labeled to help the engineers get the job done. I also learned today what the funny numbers on all of the passage doors mean. See the caption for a description.
Here is one of the door signs on the ship, which act like a "you are here" sign on a map. The first number tells us what floor we are on. The second number tells us what area of the ship we are in. The third number tells us whether we are port, starboard, or in the center of the ship.
One thing that Cat and I were discussing this morning while searching through binoculars in Alitak Bay for interesting woodland creatures was that we can go pretty much wherever we want to go on this ship. Everyone who works and lives here is so friendly and welcoming. They answer any of our questions (even the silly ones) and they all have such cool life stories. What’s better is that everyone is willing to share what they’ve learned, experiences they’ve had, and accomplishments they’ve achieved to make it here. I am aboard a utopian city bursting with genuine people who love what they do. Now, please understand that it’s not that I ever expected the opposite for even a single second. The science and technology is definitely neat, but the people who live and work here are what is making this trip a once-in-a-lifetime experience.
Do you know….
Your Ship Superstitions?
1. Bananas on a boat are considered bad luck.
2. Black luggage for sailors is considered bad luck.
3. One should never whistle – especially on the bridge or in the wheelhouse – you may whistle up a storm.
4. To see a black cat before boarding is good luck.
5. Dolphins swimming along the ship are good luck.
6. Never sail on Friday – it’s unlucky.
7. Never sail on the first Monday in April – also unlucky.
8. Never say the word “Drown” on a ship, as it encourages the act.
9. Sailors should avoid flat-footed people – they are bad luck.
10. Never step onboard a ship with your left foot first.
