Mission: Alaska Walleye Pollock Survey Geographical Area: Gulf of Alaska Date: July 11th, 2013
Location Data from the Bridge: Latitude: 56.56 N
Longitude: 152.74 W
Ship speed: 11.3 kn
Weather Data from the Bridge: Air temperature: 10.7 degrees Centigrade
Surface water temperature: 8.6 degrees Centigrade
Wind speed: 18 kn
Wind direction: 250 degrees
Barometric pressure: 1016 mb
Science and Technology Log:
So now that you know what we do with the fish after they are caught, let’s go back and see how the fishermen trawl. There are two large nets at the stern of the ship. Today we used both nets for the first time. The scientists, crew, and fishermen all work together to catch the fish. In the acoustics lab Paul is reviewing and scrutinizing the data he receives from the echo locators mounted on the hull of the ship. There are many factors he must evaluate in order to have a good trawl. There are places in our area that have been marked as “untrawlable”. This is usually due to a sea floor that is rocky. Trawling in these places may ruin the nets. We have completed at least one trawl a day since we have been out to sea. Today we completed two during my watch. The first was with a larger net and was not sent all the way to the bottom. The second trawl was sent to the bottom with a smaller net. The bottom trawl brought up the largest pollock I have seen so far. The longest pollock was 75 cm. We also brought up a salmon, cod, rock fish, and a whole lot of herring.
The nets are both on large spools and are released or returned with the help of a very large winch. Before the net is released into the water the CamTrawl is attached to it. This is a camera that takes pictures that help the scientists see at what point in the trawl fish were entering the net.
The time that the net is in the water depends on the information about the amount of fish coming from the acoustics lab. Scientists watch the echo information to determine how much time the net should be in the water to catch enough fish to sample. We must have at least 300 pollock to make a complete survey.
The fishermen bring the nets back to the trawl deck and wind them back onto the spools. They then will use a crane to lift the catch and dump it into a bin. From the fish lab we can lift this bin to dump the fish onto the conveyor belt.
On Monday, we had our weekly fire and abandon ship drills. After the drills I practiced putting on my survival suit. This suit is designed to keep you afloat and warm in the event that you have to go into the water.
On Tuesday, we surveyed up into Deadman’s Bay. It was a beautiful sun shiny day and the scenery was amazing. We were very close to the shore on both sides. I sat out on the trawl deck and scanned the hillsides with my binoculars. I was told that it is common to see bears here, but I did not see any.
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.
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:
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.
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.
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.
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.
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.
NOAA TEACHER AT SEA JASON MOELLER ONBOARD NOAA SHIP OSCAR DYSON JUNE 11-JUNE 30, 2011
NOAA Teacher at Sea: Jason Moeller Ship: Oscar Dyson Mission: Walleye Pollock Survey Geographic Location: Gulf of Alaska Date: June 23-24, 2011
Latitude: 54.86 N
Longitude: -161.68 W
Wind: 12.1 knots
Surface Water Temperature: 8.5 degrees C
Air Temperature: 9.1 degrees C
Relative Humidity: 95%
Depth: 52.43 m
As I mentioned in the last post, everything here has settled into a routine from a personal standpoint, and on that end there is not much to write about. However, there were three things that broke up the monotony. First, as always, the scenery was beautiful.
Second, I found out that even with all of the modern equipment on board, catching fish is still not guaranteed. We trawled three times last night on the 23rd and caught a total of 14 fish in all three trawls! Remember, a good sample size for one trawl is supposed to be 300 pollock, so this is the equivalent of fishing all day long and catching a minnow that just happened to swim into the fishing hook.
The first trawl caught absolutely nothing, as the fish dove underneath the net to escape the danger. The second trawl caught two pacific ocean perch and one pollock, and the third trawl caught eleven pollock. All in all, not the best fishing day.
Despite the poor fishing, we did bring up this neat little critter.
The third thing to break up the monotony was the Aleutian Islands earthquake. On the evening of June 23rd, a magnitude 7.2 earthquake shook the Aleutian Islands. According to ABC news, the earthquake was centered about 1,200 miles southwest of Anchorage. The quake spawned a brief tsunami warning that caused a large number of Dutch Harbor residents (Dutch Harbor is the home base of the show Deadliest Catch) to head for higher ground. We had been in the Aleutian Islands and Dutch Harbor area on our survey route, but had left two days before, so the Oscar Dysonwas completely unaffected by the earthquake.
Science and Technology Log
In order to obtain photos of all of this neat sealife, we first have to catch it! We catch fish by trawling for them. Some of you may not know exactly what I’m talking about, so let me explain. Trawling is a fishing method that pulls a long mesh net behind a boat in order to collect fish. Trawling is used to collect fish for both scientific purposes (like we’re doing) and also in commercial fishing operations. We have two types of fish trawls onboard the NOAA Ship Oscar Dyson — a mid-water trawl net and a bottom trawl net. We’ve used both types throughout our cruise, so let me tell you a little about each.
The mid-water trawl net is just as it sounds — it collects fish from the middle of the water column — not those that live on the seafloor, not those that live at the surface. The technical name for the net we have is an Aleutian Wing Trawl (AWT) — it’s commonly used by the commercial fishing industry.
The end of the net where the fish first enter has very large mesh, which is used to corral the fish and push them towards the bag at the end. The mesh gets progressively smaller and smaller the further into it you go, and at the very end (where the collecting bag is), the mesh size is 0.5 inches. The end (where the bag is, or where the fish are actually collected) is called the codend.
This is the kind of net we use when we want to collect a pollock sample, because pollock are found in the water column, as opposed to right on the seafloor (in other words, pollock aren’t benthic animals). Our particular net is also modified a little from a “normal” AWT. Our trawl has three codends (collecting bags) on it, each of which can be opened and closed with a switch that is controlled onboard the ship. The mechanism that opens and closes each of the 3 codends is called the Multiple Opening and Closing Codend (MOCC) device. Using the MOCC gives us the ability to obtain 3 discrete samples of fish, which can then be processed in the fish lab.
One other modification we have on our mid-water trawl net is the attachment of a video camera to the net, so we can actually see the fish that are going into the codends.
When we spot a school of fish on the acoustic displays, we then radio the bridge (where the captain is) and the deck (where the fishermen are) to let them know that we’d like to fish in a certain spot. The fishermen that are in charge of deploying the net can mechanically control how deep the net goes using hydraulic gears, and the depth that we fish at varies at each sampling location. Once the gear is deployed, it stays in the water for an amount of time determined by the amount of fish in the area, and then the fishermen begin to reel in the net. See the videos below to get an idea of how long the trawl nets are — they’re being reeled in the videos. Once all of the net (it’s VERY long — over 500 ft) is reeled back in, the fish in the codends are unloaded onto a big table on the deck using a crane. From there, the fish move into the lab and we begin processing them.
Videos of the net being reeled in and additional photos are below!
The other type of trawl gear that we use is a bottom trawl, and again, it’s just as it sounds. The bottom trawl is outfitted with roller-type wheels that sort of roll and/or bounce over the seafloor. We use this trawl to collect benthic organisms like rockfish, Pacific ocean perch, and invertebrates. There’s usually a random pollock or cod in there, too. The biggest problem with bottom trawls is that the net can sometimes get snagged on rocks on the bottom, resulting in a hole being ripped in the net. Obviously, we try to avoid bottom trawling in rocky areas, but we can never be 100% sure that there aren’t any rogue rocks sitting on the bottom 🙂
The first question for today comes from Rich, Wanda, and Ryan Ellis! Ryan is in the homeschool Tuesday class at the Zoo.
Q. We looked up what an anemone was and we found it was some kind of plant. Is that correct?
A. Great question! The answer is both yes and no. There is a type of flowering plant called the anemone. There are about 120 different species, and they are in the buttercup family. For one example of the plant, look below!
The sea anemone, however, is not actually a plant but an animal! Anemones are classified as cnidarians, which are animals that have specialized cells for capturing prey! In anemones, these are called nematocysts, which have toxin and a harpoon like structure to deliver the toxin. When the nematocysts are touched, the harpoon structure injects the toxin into the animal that touches it.
Cnidarians also have bodies consist of mesoglea, a non living jelly like substance. They generally have a mouth that is surrounded by the tentacles mentioned above.
The second question comes from my wife Olivia.
Q. What has surprised you most about this trip? Any unexpected or odd situations?
A. I think the thing that has surprised me the most is the amount of down time I have had. When I came on, I assumed that it would be physical and intense, like the show Deadliest Catch, where I would spend my whole time fishing and then working on the science. I figured that I would be absolutely toast by the end of my shift.
While I have worked hard and learned a lot, I have quite a bit of down time. Processing a catch takes about one hour, and we fish on average once or twice a night. That means I am processing fish for roughly two hours at most, and my shift is twelve hours. I have gotten a fair amount of extra work done, as well as a lot of pleasure reading and movie watching.
As for unexpected and odd situations, I didn’t really expect to get your camera killed by a wave. Fortunately, I have been allowed to use the scientist camera, and have been able to scavenge photos from other cameras, so I will still have plenty of pictures.
Another technological oddball that I didn’t think about beforehand was that certain headings (mainly if we are going north) will cut off the internet, which is normally fantastic. It is frustrating to have a photo 90% downloaded only to have the ship change vectors, head north, and cut off the download, forcing me to redownload the whole photo.
I also didn’t expect that the fish would be able to dodge the trawl net as effectively as they have. We have had four or five “misses” so far because the fish will not stay in one spot and let us catch them. While the use of sonar and acoustics has greatly improved our ability to catch fish, catching fish is by no means assured.
Perhaps the biggest “Are you kidding me?” moment though, comes from James and David Segrest asking me about sharks (June 17-18 post). An hour after I read the question, we trawled for the first time of the trip, and naturally the first thing we caught was the sleeper shark. Also naturally, I haven’t seen a shark since. Sometimes, you just get lucky.
NOAA Teacher at Sea: Tammy Orilio NOAA Ship Oscar Dyson Mission: Pollock Survey Geographical Area of Cruise: Gulf of Alaska Date: 24 June 2011
Weather Data from the Bridge:
Latitude: 54.14 N
Wind Speed: 9.73 knots
Surface Water Temp: 7.0 degrees C
Water Depth: 92.75 m
Air Temp: 7.2 degrees C
Relative Humidity: 101%
Science & Technology Log:
I’ve been talking a lot about trawling for fish, and I realize that some of you may not know exactly what I’m talking about, so let me explain. Trawling is a fishing method that pulls a long mesh net behind a boat in order to collect fish. Trawling is used to collect fish for both scientific purposes (like we’re doing) and also in commercial fishing operations. We have two types of fish trawls onboard the NOAA Ship Oscar Dyson– a mid-water trawl net and a bottom trawl net. We’ve used both types throughout our cruise, so let me tell you a little about each.
The mid-water trawl net is just as it sounds- it collects fish from the middle of the water column- not those that live on the seafloor, not those that live at the surface. The technical name for the net we have is an Aleutian Wing Trawl (AWT)- it’s commonly used by the commercial fishing industry. The end of the net where the fish first enter has very large mesh, which is used to corral the fish and push them towards the bag at the end. The mesh gets progressively smaller and smaller the further into it you go, and at the very end (where the collecting bag is), the mesh size is 0.5 inches. The end (where the bag is, or where the fish are actually collected) is called the codend. This is the kind of net we use when we want to collect a pollock sample, because pollock are found in the water column, as opposed to right on the seafloor (in other words, pollock aren’tbenthic animals). Our particular net is also modified a little from a “normal” AWT. Our trawl has three codends (collecting bags) on it- each of which can be opened and closed with a switch that is controlled onboard the ship. The mechanism that opens and closes each of the 3 codends is called the Multiple Opening and Closing Codend (MOCC) device. Using the MOCC gives us the ability to obtain 3 discrete samples of fish, which can then be processed in the fish lab. One other modification we have on our mid-water trawl net is the attachment of a video camera to the net, so we can actually see the fish that are going into the codends.
When we spot a school of fish on the acoustic displays, we then radio the bridge (where the captain is) and the deck (where the fishermen are) to let them know that we’d like to fish in a certain spot. The fishermen that are in charge of deploying the net can mechanically control how deep the net goes using hydraulic gears, and the depth that we fish at varies at each sampling location. Once the gear is deployed, it stays in the water for an amount of time determined by the amount of fish in the area, and then the fishermen begin to reel in the net. See the videos below to get an idea of how long the trawl nets are- they’re being reeled in in the videos. Once all of the net (it’s VERY long- over 500 ft) is reeled back in, the fish in the codends are unloaded onto a big table on the deck using a crane. From there, the fish move into the lab and we begin processing them.
The other type of trawl gear that we use is a bottom trawl, and again, it’s just as it sounds. The bottom trawl is outfitted with roller-type wheels that sort of roll and/or bounce over the seafloor. We use this trawl to collect benthic organisms like rockfish, Pacific ocean perch, and invertebrates. There’s usually a random pollock or cod in there, too. As I mentioned in my last post (“Today’s Catch”), the net can sometimes get snagged on rocks on the bottom, resulting in a hole being ripped in the net. Obviously, we try to avoid bottom trawling in rocky areas, but we can never be 100% sure that there aren’t any rogue rocks sitting on the bottom 🙂
It’s been a quiet couple of days. On Wednesday, we didn’t see any fish until late in my shift, then we did a mid-water trawl. We ended up actually busting the bag- that’s how many fish we ended up collecting!! Once the codends were opened, we immediately began processing- first separating the pollock from everything else we caught. After sorting, I got to work on sexing the fish- it’s a kind of gruesome job, because you have to take a scalpel and cut them open (while they’re still alive!), exposing their innards- definitely NOT like the preserved organisms we dissect in class. I’m not a huge fan of cutting them open, so I moved on to measuring the length of the male fish- there were so many males in our catch, I was the last one working! After I cleaned up, that was the end of my shift. We were near some islands at the end of my shift, and the bridge called down to the lab to tell us that there some whales off the starboard side of the ship. I grabbed my camera and ran up to the deck, scanning the water for whales. Finally, I spotted a pod waaaay off the starboard side- they were too far off to get a good picture, and I couldn’t even tell what kind they were, but I was able to see them spouting water out of their blowholes, and it looked like one of them breached. The officers up on the bridge said they thought they were minke whales.
Thursday we didn’t see any fish (well, not enough to put our gear in the water) all day, so no fishing for me. Right now, it’s about 9:30 a.m. on Friday, and we’re just cruising to begin our next set of transects. I just read that there was an earthquake in the western Aleutian Islands last night- magnitude 7.2! Holy moly, I was just there! Apparently, people felt the earthquake as far east as Dutch Harbor on the island of Unalaska, and they had a tsunami warning go off. It’s crazy to think that I was in that area a couple days ago!
Question of the Day:
Speaking of tsunamis…What would cause the East Coast of the U.S. to be hit by a megatsunami?
In the Bering Sea, pollock are so abundant that our mid-water trawls capture mostly pollock. However, there are a lot of other species in the Bering Sea that scientists are interested in. In addition to the Oscar Dyson, NOAA charters fishing boats (such as the Alaska Knightand the Aldebaron) to trawl on the ocean floor. This allows scientists to see more species in the Bering Sea. These ships trawl all day; sometimes up to 6 trawls a day. The GF boats cover the eastern Bering Sea shelf, extending up to the region around St. Lawrence Island (a wider area than the Oscar Dyson will cover). While the Oscar Dyson focuses on euphausiids and pollock, the ground fishing boats examine everything else found on the bottom.Who owns the water?
International laws provide countries with an Exclusive Economic Zone (EEZ) within 200 miles of their shoreline. The area we are studying in the Bering Sea can be fished solely by fishing boats operated in the United States. On the other side of the Sea, Russians fish in their own 200-mile zone. However, in the middle there is a “donut hole” which is considered “international waters”. This Donut Hole supported a large pollock fishery in the late 1980’s. Here is a diagram showing the Donut Hole (interesting note, it is also called the Donut Hole in Russia (or at least called Bubleek — the Russian word for a donut hole))
How do American scientists collaborate with scientists from other countries?
The United States works with other Pacific countries to conduct research on the Pacific Ocean and the Bering Sea. For example, theOscar Dyson, in addition to hosting two Teachers at Sea, is hosting two Russian scientists from the Pacific Research Institute of Fisheries and Oceanography (TINRO) in Vladivostok, Russia – Mikhail Stepanenko and Elena Gritsay. I had the opportunity to sit down with Mikhail the other night and asked him about his experience and how he ended up on the Oscar Dyson.
Born and raised in Primorye, Mikhail spent a great deal of time at the Ussuri River. He studied biology at The Far East State University in Vladivostok and began researching at sea soon after his graduation in 1968. After the first USA-USSR agreement regarding marine research, Mikhail visited the United States and worked out of La Jolla, CA starting in 1969. He has spent about 5-6 months at sea per year for the last 40 years, including the last 18 summers on the NOAA summer pollock survey (specifically on the Oscar Dyson and its predecessor the Miller Freeman).This wealth of experience has made Mikhail an expert and he is a well-respected member of the Pacific marine science community. Throughout the years, there have been numerous conferences between stakeholder countries and Mikhail has played an active role in recommending action for working together to maintain the populations of pollock and other fish.Mikhail has served on the Intergovernmental Consultative Committee (ICC) – a six-nation committee that meets biannually to discuss fishing polices in the “donut hole.” In addition, Mikhail worked as a Russian delegate during meetings which led to the creation of PICES (North Pacific Marine Science Organization), an “intergovernmental scientific organization, was established in 1992 to promote and coordinate marine research in the northern North Pacific and adjacent seas.” (Visit their website for more information). Mikhail was elected Chairman of the Fisheries Science Committee (FIS), a branch of PICES, in 2008 and is currently preparing for their next meeting in October.
Each organization is trying to find the best policies to help understand the organisms through reproduction, population dynamics, stock assessments and fishery management. Mikhail’s wealth of knowledge, collaborative scientific research and commitment to the sustainable fishing benefits all members of the international community and we are lucky to have such a science superstar in our midst.