Mission: Walleye Pollock Survey Geographical Area of Cruise: Gulf of Alaska Date: 8/8/13
Weather Data from the Bridge (as of 17:00 Alaska Time): Wind Speed: 15.72 knots
Temperature: 13.4 C
Barometric Pressure: 1012.1 mb
Science and Technology Log:
We came. We fished. We measured, counted and weighed. Now What? We completed one last trawl on Tuesday night (August 6th). When we finished we had caught over 65,000 walleye pollock and a whole lot of POP (Pacific ocean perch) on this leg of the survey.
The scientists now process and analyze the data.
Darin and Patrick will present at a public meeting when we are back in Kodiak on Friday. They will discuss what was seen and preliminary findings of the walleye pollock survey. Back in Seattle the MACE team will further evaluate the data along with data from the bottom trawl survey and determine the walleye pollock biomass for the Gulf of Alaska. This will then be taken under advisement by the North Pacific Fishery Management Council.
There is also the lab to clean. Even though we cleaned the lab after each trawl, it needed a good scrub down. There were scales and slime hidden everywhere. Just when you thought you were done, more scales were discovered.
Did You Know?
The note on the white board stated that there will be beam seas tonight. What does that really mean? It means the waves are moving in a direction roughly 90° from our heading. So the water will be hitting us at a right angle to our keel. It will be a rocking boat tonight.
Darin took a sample of the salmon shark’s fin when we caught it. It will be sent to a scientist in Juneau who works at Auke Bay Laboratories (where Jodi works). The sample will be used to examine the population genetics of the salmon shark and other species such as the Pacific sleeper shark.
In my first blog, I wrote about a childhood dream of becoming an oceanographer. After my third year of teaching in the Peace Corps, I decided education was my new direction. I was excited to taste that bygone dream aboard the Oscar Dyson. How do I feel now? I jokingly sent an email to my assistant principal telling her to look for a new science teacher because I love life at sea. I love collecting data in the field. Although I was not responsible for analyzing the data and I do miss my boys, I had an awesome cruise. So where does that leave me?
It leaves me back in the classroom with an amazing sea voyage experience to share with my students. I will always long for that oceanographic career that could have been. But perhaps after my experience, I will inspire future oceanographers and fisheries scientists. And I would do Teacher at Sea again in a heartbeat. I will follow up with the outcomes and biomass estimates from MACE (Mid-Water Assessment & Conservation Engineering) and I will most definitely follow Jodi’s research on the use of multibeam sonar for seafloor mapping.
I want to say thank you to everyone who made my experience one of the best of my life and definitely the best professional development of my career. Thank you to Jennifer Hammond, Elizabeth McMahon, Jennifer Annetta, Emily Susko and Robert Ostheimer for the opportunity to participate in the NOAA Teacher at Sea Program. Thank you to NOAA for developing a practical and realistic opportunity to connect my students to ocean science. Thank you to the science team (Chief Scientist Patrick Ressler, Darin Jones, Paul Walline, Jodi Pirtle, Kirsten Simonsen, and Abigale McCarthy) aboard the Oscar Dyson for their willingness to train me, answer all of my questions, preview my blogs, and to allow me have a glimpse of their lives as scientists. Thank you to Patrick Ressler and XO Chris Skapin for promptly providing feedback on my blogs. And a special thanks to the night shift crew (Jodi, Paul and Darin). I was very nervous about adjusting to my work hours (4 pm to 4 am) especially after falling asleep that first night, but I am very grateful for colleagues who were fascinating and night-time enjoyable. Chats with everyone aboard the Oscar Dyson from fishermen to NOAA Corps to engineers to stewards to scientists were educational and pleasant. I met lots of people from all over the U.S. and some just from Newport (2 hours from Eugene).
WOW. How fortunate was I to be chosen? I am nearly speechless about what I saw and what I did. What a mind blowing three weeks. Thank You! Thank You! Thank You!
Now I begin the transition of living during daylight hours.
I hope everyone was able to sample a little of my adventure. I appreciate everyone who followed my blog especially Camas Country Mill folks.
Mission: Walleye Pollock Survey Geographical Area of Cruise: Gulf of Alaska Date: 8/7/13
Weather Data from the Bridge (as of 21:00 Alaska Time): Wind Speed: 10.42 knots
Temperature: 13.6 C
Barometric Pressure: 1012.4 mb
Current Weather: A high pressure system is building in the east and the swells will increase to 8 ft tonight.
Science and Technology Log:
Before I begin, I must thank Paul for educating me on the calibration process. Because calibration occurred during the day shift, I was not awake for some of it.
The EK60 is a critical instrument for the pollock survey. The calculations from the acoustic backscatter are what determines when and where the scientists will fish. Also these measurements of backscatter are what are used, along with the estimates of size and species composition from the trawling, to estimate fish biomass in this survey. If the instruments are not calibrated then the data collected would possibly be unreliable.
Calibration of the transducers is done twice during the summer survey. It was done before leg one in June, which began out of Dutch Harbor, and again now near Yakutat as we end leg three and wrap up the 2013 survey.
As we entered Monti Bay last night, Paul observed lots of fish in the echosounder. This could pose a problem during calibrations. The backscatter from the fish would interfere with the returns from the spheres. Fortunately fish tend to migrate lower in the water column during the day when calibrations were scheduled.
This morning the Oscar Dyson moved from Monti Bay, where we stopped last night, into Sea Otter Bay and anchored up. The boat needs to be as still as possible for the calibrations to be successful.
Calibration involves using small metal spheres made either of copper or tungsten carbide.
The spheres are placed in the water under transducers. The sphere is attached to the boat in three places so that the sphere can be adjusted for depth and location. The sphere is moved throughout the beam area and pings are reflected. This backscatter (return) is recorded. The scientists know what the strength of the echo should be for this known metal. If there is a significant difference, then data will need to be processed for this difference.
The 38 khz transducer is the important one for identifying pollock. A tungsten carbide sphere was used for its calibration. Below shows the backscatter during calibration, an excellent backscatter plot.
The return for this sphere was expected to be -42.2 decibels at the temperature, salinity and depth of the calibration The actual return was -42.6 decibels. This was good news for the scientists. This difference was deemed to be insignificant.
Calibration took all of the day and we finally departed at 4:30 pm. The views were breathtaking. My camera doesn’t do it justice. Paul and Darin got some truly magnificent shots.
As we left Yakutat Bay, I finally saw a handful of sea otters. They were never close enough for a good shot. They would also dive when we would get close. As we were leaving, we were able to approach Hubbard Glacier, another breathtaking sight. Despite the chill in the air, we stayed on top getting picture after picture. I think hundreds of photos were snapped this evening.
Did You Know?
According to the National Park Service, Hubbard Glacier is the largest tidewater glacier in North America. At the terminal face it is 600 feet tall. This terminal face that we saw was about 450 years old. Amazing!
Mission: Walleye Pollock Survey Geographical Area of Cruise: Gulf of Alaska Date: 8/5/13
Weather Data from the Bridge (as of 17:00 Alaska Time): Wind Speed: 9.54 knots
Temperature: 15.7 C
Humidity: 83 %
Barometric Pressure: 1017.9 mb
Current Weather: The winds have decreased and we are not moving as much. The weather report calls for an increase to the winds with 7 ft swells on Wednesday. But maybe it will die down before it reaches us.
Science and Technology Log:
We only will fish during daylight hours. The sun is now setting before 10:00 pm and rising around 5:30 am. And even though we are not fishing between sunset and sunrise, science continues. At nightfall, we break transect and Jodi begins her data collection.
The Sustainable Fisheries Act mandates an assessment of essential fish habitat. This is in conjunction with stock assessments of groundfish. Jodi’s research involves integrating multibeam accoustic technology to characterize trawlable and untrawlable seafloor types and habitat for managed species.
A bottom trawl survey is conducted every other year in the Gulf of Alaska. The goal is to better identify seafloor types using multibeam acoustics. This would help improve groundfish assessment, and limit damage to habitat and trawling gear.
The Gulf of Alaska survey area is divided into square grids.
On this cruise we are conducting multibeam mapping in trawlable and untrawlable grid cells. A grid cell is divided into 3 equidistant transects for a multibeam survey. Jodi directs the ship to follow these smaller transect lines. While the ship is following the transects lines, the multibeam sonar is active and data is collected.
The SIMRAD ME70 is the multibeam sonar that Jodi is using for her research. There are 6 transducers on the ship that will send out a fan of 31beams of varying frequencies. The strength of their return (backscatter) can be analyzed for sea floor type. Looking at the diagram below, you can see the differences in backscatter clearly in the range of 30 to 50 degrees (away from straight down).
Silts will have a very weak backscatter and rock will have a strong backscatter.
After the transects are completed, Jodi and Darin complete 1 – 3 camera drops to record visually how the seafloor appears. This camera below will be lowered to the ocean floor and video footage will stream to the computer for 10 minutes. Then the camera is brought up.
An example of an untrawlable area. Photo courtesy of Jodi Pirtle.
Last night, Darin gave me the opportunity to operate the camera drop. After a bit of instruction, it was showtime. I am very grateful for the chance to explore the seafloor.
Here is what I saw at 190 meters.
For more photos of my drop camera experience, see the end of this blog.
CTD (conductivity, temperature, depth) drops are conducted in the grid as well. Data that are gathered are used to correct for the speed of sound under varying conditions of the ocean.
The next day, Jodi processes the data from the ME70. The bottom detection algorithm (a series of calculations) removes backscatter from the water column (from fish).
Each frame product represents 5 minutes of seafloor. The following are outcomes from the algorithm and represent angle dependent data. The images below, show backscatter on the left and bathymetry on the right.
Then Jodi takes into account a number of factors such as results from the CTD, motion of the boat (offset, attitude, pitch, roll), and tides. These uncertainties are applied.
Then she mosaics the data.
The color image above represents the depth and the bottom image provides information on seafloor substrate.
The footage from the camera drops is also reviewed for more evidence of the seafloor substrate and to look for objects that would snag trawl nets.
I really appreciate Jodi taking the time to educate me on her research. Her passion for her work is evident. I look forward to seeing where her research leads.
So who actually works the night shift (4pm to 4 am) in the “cave”. Jodi Pirtle, Paul Walline and Darin Jones are the three scientists I have been lucky to work with during my cruise.
I discussed Jodi’s work on the ship in the science section. She has an extensive educational background. She earned a BS in Biology from Western Washington University in Bellingham and then a MS in Environmental Science from Washington State University in Vancouver. Then she earned a Ph.D in Fisheries from the University of Alaska at Fairbanks. Her thesis was on ground fish habitat on rocky banks along the US west coast. And her dissertation was based on red king crab nursery habitat. She just finished her postdoc at the University of New Hampshire Center for Coastal and Ocean Mapping where her work applied multibeam acoustics to study trawlable and untrawlable seafloor types and groundfish habitat in the Gulf of Alaska. She is now working on groundfish habitat suitability modeling after she was selected to be a National Research Council NOAA postdoc at the Alaska Fisheries Science Center Auke Bay Lab in Juneau. Jodi continues to integrate multibeam acoustics in her research at ABL.
Jodi was born and raised in Cordova, Alaska which we came near when we were in Prince William Sound. I have enjoyed listening to her speak of growing up in Alaska. There are no roads out of Cordova, so imagine traveling with a sports team in high school? I will not forget how she described the Exxon Valdez oil spill to me from the eyes of herself at 11 years old.
I have greatly appreciated her knowledge of the creatures we bring up in the nets. She has an eye for finding the hidden gems like the chaetognath (arrow worm).
Jodi enjoys cross country skiing, snow boarding, berry picking, hiking and yoga. She introduced me to beautiful ripe salmon berries back on Kodiak.
Darin is a MACE (Midwater Assessment & Conservation Engineering) scientist who earned his BS in Marine Biology from the University of North Carolina at Wilmington and then his MS in Fisheries Resources form the University of Idaho at Moscow. His master’s work involved disease resistance in bull trout. He spent 5 years collecting fishing data as an observer aboard commercial fishing boats in Alaska. He also tagged cod on George’s Bank and worked at several conservation fish hatcheries before moving to Seattle to work for MACE. Darin is part of the team to assess the biomass of the walleye pollock in the Gulf of Alaska.
I have heard that Darin played in a band with some MACE colleagues but they broke up because one of them moved. Maybe there will be a reunion tour.
He is a surfer and has surfed on Kodiak but his favorite surf spot so far was in Costa Rica. Darin is an easy-going guy who I often call Scott because he reminds me so much of a colleague at school. Darin has patiently explained my tasks to me and helped me learn what I am really doing. And he supported me as I did my first camera drop.
Paul is a native of Washington state and completed his academics there as well. He earned a BS in Oceanography and a Ph.D in Fisheries Oceanography from the University of Washington. For 20 years he worked at the Israel Limnological and Oceanographic Institute. He was involved in managing the water quality in Lake Kinneret. His role was to estimate the number of fish to determine their affect on water quality. Paul accomplished this by developing acoustics surveys of fish stocks in Israel. Lake Kinneret, also known as the Sea of Galilee, provides Israel with 40% of its drinking water.
In 2000, Paul moved back to Seattle and is working as a fisheries biologist for MACE.
I have been fortunate to see photographs that Paul has taken both on this trip and elsewhere. He has an incredible talent for finding beauty.
I am writing this as we are tossing and turning in ten foot swells. According to Paul, it doesn’t matter if the swells get any bigger because the effect is the same. His calmness, knowledge and expertise remind me a lot of my dad.
As you can see, I worked with amazing, brilliant individuals. The night shift rules. We had awesome teamwork when a haul needed to be processed.
And then we slept through the fog and awoke to beautiful sunsets (on some days).
Did You Know?
Glacial runoff changes the color of the ocean. Compare the two photos. The one at the bottom is near a glacier.
Animals Seen Today:
The bottom trawl that was brought up right when I began work, contained three types of sharks. The smaller ones were spiny dogfish and spotted spiny dogfish. The big one was a salmon shark. Check out the video.
To read more about salmon sharks and to monitor their migration pattern, check out the content on Tagging of Pacific Predators website. Click here: TOPP
Mission: Walleye Pollock Survey Geographical Area of Cruise: Gulf of Alaska Date: August 3, 2013
Weather Data from the Bridge (as of 00:00 Alaska Time): Wind Speed: 26.5 knots
Temperature: 13.6 C
Barometric Pressure: 1014.6 mb
Weather Update: A low pressure system is in the north Pacific and we are having increase winds and swells.
Science and Technology Log:
We listened. We fished. Now what?
Before reporting to the fish lab, I must gear up. Slime gear keeps the scales and goo off of my clothes.
Fish are emptied out of the net and onto the table outside the fish lab.
We can control how many fish land on the conveyor belt by raising the table and opening the door.
The fish on the conveyor belt are separated by species.
In this blog we will focus on the pollock that were caught.
Pollock are gathered into baskets and weighed.
We group the pollock into 3 groups; age 1, age 2 and age 3+. Each group as an entirety is weighed. Each age group has a somewhat different protocol for processing. Fifty specimens that are age 1 will be measured with the ichthystick and 10 will also be weighed.
Fish that are age 2 are processed as age 1 but are also sexed.
When measuring a pollock on an icthystick, one measures from the head to the fork in the tail. The icthystick (a magnetic board for measuring fish) is connected to a computer that automatically records the data.
The larger pollock are grouped by sex. To do this, we cut open their abdomen and look for ovaries or testes.
Then all of the fish (or at least 300) are measured on the icthystick. Forty will be measured and weighed and set aside for otolith removal.
Otoliths are made of calcium carbonate and are located directly behind the brain of bony fishes.
They are involved in the detection of sound and the process of hearing. The age of the fish can be established by counting the annuli much like one does when counting tree rings.
This age data allows scientists to estimate growth rates, maximum age, age at maturity, and trends of future generations. This data is vital for age based stock assessment models. These fish are weighed and measured. Otoliths are removed and placed in jars with glycerol thymol.
The jars have bar codes on the side so that the otoliths are linked to the fish’ weight, length and sex.
The otoliths are sent to Seattle for more detailed analysis of age. These results will be used to correspond length to age in the stock assessment report.
Sometimes, ovaries are removed and sent to other scientists for further histological study.
Other organisms that are caught alongside the pollock are counted and measured as well. The catch might include Pacific ocean perch, salmon, herring, viper fish, lantern fish, jellyfish, squid, and capelin. Below are a few of the normal finds and the rest can be found in my personal blog account “the beautiful, the odd and the interesting”.
The beautiful, the odd and the interesting
This trip is not just about pollock. When we bring any of the nets in there is the possibility of weirdness and other things that catch my eye. Jodi is always filling me in on the uniqueness of our discoveries. And Darin lets me save organisms for photographing later.
My favorite find so far is the lumpsucker. As Jodi says, they have gentle brown eyes and they do. They also have suckers on the bottom that allow it to stick to substrate.
The Methot trawl went close to the bottom and picked up a handful of brittle stars. At first, when they were mixed with all of the krill, it looked like a bunch of worms.
Pollock do eat young pollock. We found evidence of this when Darin opened the stomach of an adult and discovered partially digested age 1 pollock.
Lanternfish (Myctophids) make up a huge amount of the deep sea biomass. They have photophores along their sides for producing light.
The adult Pacific sandfish bury themselves in the sand with only their mouths protuding.
Prowfish lack pelvic fins. They have continuous teeth to feed on jellyfish.
When I think of deep ocean fish I think of the viperfish with its needle sharp teeth.
This cute mud star came up with the brittle stars. It was also referred to as the cookie cutter starfish because it resembles a shortbread cookie.
Salmon are good swimmers and usually escape the net. A few are caught at the surface.
When we were in Kodiak, I would watch the moon jellies drift by. Now we are catching several different species of jellyfish like this sunrise jelly.
Jodi always has a keen eye for finding nearly invisible creatures. The arrow worm is a voracious predator. They immobilize their prey with neurotoxins.
I had never heard of a sea mouse before this cruise. Now I have. Except it is not a rodent. It is a carnivorous worm that feeds on hermit crabs and other worms. It is also a scavenger like a vulture.
Some isopods are parasitic and will feed off of the blood of fish in the gill chamber. I prefer their cousins the pill bugs.
Did You Know?
When we are all measuring and weighing away in the lab, it sounds like a video game. Each machine has it’s own unique sound effects. This allows scientists to have confidence that their data was recorded.
Mission: Walleye Pollock Survey Geographical Area of Cruise: Gulf of Alaska Date: 8/1/13
Weather Data from the Bridge (as of 00:00 Alaska Time): Wind Speed: 12 knots
Temperature: 13 C
Humidity: 97 %
Barometric Pressure: 1021 mb
Science and Technology Log:
The main goal of Leg 3 of this mission is to use acoustics and trawling to survey the mid-water portion of the pollock population along the Gulf of Alaska starting near Kodiak to Yakutat Bay.
Pollock live in the an area between the middle of the water column and the seafloor. Sometimes we sample the mid-water and sometimes we will sample the bottom.
The Oscar Dyson carries three different types of trawling nets for capturing fish as part of the mid-water survey: the Aleutian Wing Trawl (AWT), a mid-water trawl net, the Poly Nor’Eastern (PNE), for bottom trawls and the Methot, which is for gathering samples of very small ocean creatures such as krill. I will focus on the AWT, although some of the video footage is from a bottom trawl.
When the net is deployed from the ship, the first part of the net to hit the water is called the codend. This is where most of the fish end up after the trawl. The mesh size of the net is smallest at the codend (about 1 cm) and gets larger as it approaches the doors (about 1 m).
A Cam Trawl goes in the water next. This is a pair of cameras that help scientists identify and measure the fish that are caught in the net. This technology can also be used to help scientists validate their biomass estimate from trawling sampling counts. This piece of equipment has to be clipped into loops on the trawl each time.
The next piece of the net to hit the water is the “kite” which is secured to the head rope. Here, a series of sensors is attached to help the scientists gather data about the condition of the net including depth, size, and shape underwater. The major acoustic sensor, called the “turtle,” can tell if the fish are actually going into the net.
Once the kite is deployed, a pair of tom weights (each weighing 250 lbs), are attached to the bridal cables to help separate the head rope from the foot rope and ensure the mouth of the net will open. Then, after a good length of cable is let out, the crew transfers the net from the net reel to the two tuna towers and attach the doors. The doors create drag to ensure the net mouth opens wide.
The scientists use acoustic data to determine at what depth they should fish, then the OOD (Officer on Deck) uses a scope table to determine how much cable to let out in order to reach our target depth. Adjustments to the depth of the head rope can be made by adjusting speed and/or adjusting the length of cable released.
The scientists use the acoustic data sent from the “turtle” to determine when enough fish are caught to have a scientifically viable sample size, then the entire net is hauled in.
Once on board, the crew uses a crane to lift the cod end over to the lift-table. The lift-table then dumps the catch into the fish lab where the fish get sorted on a conveyor belt.
The Oscar Dyson needed to pick up materials for a net repair so we headed into Prince William Sound towards Valdez. The area was spectacular.
The sun was out and the skies were blue for most of the day. Although we have had very calm seas, we have been under clouds for most of the last few days.
The absolute highlight of the day was spotting Dall porpoises and filming them bow surfing.
Here are snapshots of the day. The area was so impressive that I have several hundred pictures. Here are just a few:
I am reminded of the Exxon Valdez oil spill devastation.
Did You Know?
The Exxon Valdez (oil tanker) ran aground on Bligh Reef in Prince William Sound, Alaska on March 24, 1989.
The amount of oil spilled into this pristine environment exceeded 11 million gallons of crude oil and affected over 1300 miles of shoreline. According to OCEANA, as many as 2,800 sea otters, 300 harbor seals, 900 bald eagles and 250,000 seabirds died in the days following the disaster.
Jodi, who works the night shift with me, grew up in Cordova, Alaska and as a child remembers the smell of the disaster and the fears in her town (many were fishermen).
Has the area recovered? Part of the settlement with Exxon established a fund to support research. Read more.
Mission: Walleye Pollock Survey Geographical Area of Cruise: Gulf of Alaska Date: 7/28/13
Weather Data from the Bridge (as of 18:00 Alaska Time): Wind Speed: 15.61 knots
Temperature: 13.71 C
Barometric Pressure: 1023 mb
Science and Technology Log:
How do scientists use acoustics to locate pollock and other organisms?
Scientists aboard the NOAA Research Vessel Oscar Dyson use acoustics, to locate schools of fish before trawling. The Oscar Dyson has powerful, extremely sensitive, carefully calibrated, scientific acoustic instruments or “fish finders” including the five SIMRAD EK60 transducers located on the bottom of the centerboard.
This “fish-finder” technology works when transducers emit a sound wave at a particular frequency and detect the sound wave bouncing back (the echo) at the same frequency. When the sound waves return from a school of fish, the strength of the returning echo helps determine how many fish are at that particular site.
Sound waves bounce or reflect off of fish and other creatures in the sea differently. Most fish reflect sound energy sent from the transducers because of their swim bladder<s, organs that fish use to stay buoyant in the water column.
These reflections of sound (echoes) are sent to computers which display the information in echograms. The reflections showing up on the computer screen are called backscatter. The backscatter is how we determine how dense the fish are in a particular school. Scientists take the backscatter that we measure from the transducers and divide that by the target strength for an individual and that gives the number of individuals that must be there to produce that amount of backscatter. For example, a hundred fish produce 100x more echo than a single fish. This information can be used to estimate the pollock population in the Gulf of Alaska.
The trawl data provide a sample from each school and allow the NOAA scientists to take a closer look by age, gender and species distribution. Basically, the trawl data verifies and validates the acoustics data. The acoustics data, combined with the validating biological data from the numerous individual trawls give scientists a very good estimate for the entire walleye pollock population in this location.
How I spent my shift on Saturday, July 27th?
When I arrived at work at 4 pm, a decision was made to trawl for krill. A methot trawl is used to collect krill.
Then we set to work processing the catch. First we have to suit up in slime gear because the lab will get messy. My previous blog mentioned not wanting to count all of the krill in the Gulf of Alaska. But in this case we needed to count the krill and other species that were collected by the methot trawl.
How many krill do you think we collected?
Patrick, the lead scientist, put a few specimens under the microscope so we could see the different types of krill.
The collection of krill was preserved in formaldehyde and sea water. It will be sent to Poland for further species diagnosis.
As the ship continued back on transect, I wandered in to see what Jodi and Darin were doing with the data collected last night. Jodi was processing data from the multibeam sonar and Darin was surveying the images from the drop camera. Jodi was very patient explaining what the data means. I will write more about that later. But I did feel quite accomplished as I realized my understanding was increasing.
A decision was made to do another methot trawl. This time we had a huge sample.
In an approximately 50 gram sample we counted 602 individual krill. Compare this to the 1728 individuals in a 50 gram sample from the first trawl. They were much bigger this time. The total weight of the entire sample of krill was 3.584 kilograms.
How many individuals were collected in the second trawl? (Check your answer at the end of the blog)
Around midnight, Paul decided to verify an echogram by trawling.
We collected data from the trawl net and the pocket net.
The pocket net catches the smaller organisms that escape through the trawl net.
It was after 2 am by the time we had processed catch and washed down the lab. The internet was not available for the rest of my shift due to the ship’s position so I organized my growing collection of videos and pictures.
I wasn’t sure how I would handle my night shift (4 pm to 4 am) after I dozed off during the first night. Now that I have adjusted, I really enjoy the night shift. The night science team of Paul, Darin and Jodi are awesome.
Did You Know?
People who are on the Oscar Dyson live throughout the United States. They fly to meet the boat when they are assigned a cruise. Jodi is from Juneau, Alaska. Paul is from Seattle, Washington. And Darin is from Seattle/North Carolina. There are a number who are based out of Newport, Oregon.
Something to Think About:
When we are fishing, a number of birds gather behind the boat. What different sea birds are observable this time of the year in our survey area?
Mission: Walleye Pollock Survey Geographical Area of Cruise: Gulf of Alaska Date: 7/27/13
Weather Data from the Bridge (at 1:00 am Alaskan time):
Wind Speed = 3.52 knots
Air Temperature = 13.6 C
Humidity = 94%
Barometric Pressure = 1025.5 mb
Science and Technology Log:
How can you determine the population size of species?
You could count every member of the population. This would be the most accurate but what if the population moves around a lot? What if the population is enormous and requires too much time to count each and every one? Would you want to count all of the krill in the Gulf of Alaska?
You could mark and recapture. In this method you catch individuals from the population and tag them. Data are compiled from the recaptures and the population is mathematically calculated. Halibut and many other populations are monitored this way and require fishermen to report any recaptures.
Another method is sampling. The organisms in a small area are counted and then the overall population in the entire area is calculated.
This picture above illustrates the use of a transect line. On various increments along the transect line, samples of populations are taken. Imagine the Oscar Dyson’s path as the measuring tape and the trawl net as the sampling square.
The overall survey area of the pollock study this summer is the northern Gulf of Alaska between the shore and the continental break. Within this area transect lines were established. These are pathways that the Oscar Dyson will travel along and periodically take samples of the fish.
The current set of transects are 25 nautical miles (1 nautical mile is equal to 1 minute of latitude) apart and are parallel but transects in other areas may be 2 or 5 miles apart. Transects that we are following now are located on the shelf and are perpendicular to the coastline. Transects in inlets and bays may run differently and may even zigzag.
If fish are located through acoustics, the ship will break transect (a mark is made on the map) and the ship will circle around and a sample of the population is taken by trawling. The population of pollock can then be mathematical calculated. After trawling, the ship will return to the break and continue along the transect line.
This afternoon, we were working smaller transect lines near Amatuli Trench that were 6 miles apart. It is an area that has had good pollock catches. Just when we were going to fish, a pod of fin whales was spotted in the area. So we moved to another area and hauled in quite the catch of Pacific Ocean perch.
It is hopeful that the Oscar Dyson will finish a transect line by nightfall and then the ship can be at the next transect by sunrise. This maximizes the time looking for fish and trawling.
I am settling into life on the Oscar Dyson and have established a routine that will support my night shift (4 pm to 4 am). So how do I spend 24 hours on the ship?
I wake up around 11:45 in the morning to be able to eat lunch that is served only between 11:00 and 12:00. Because of the shift schedules, some people are bound to miss one or more of the meals. I miss breakfast because I am sleeping. We are able to request a plate of food be saved for later.
Between the end of lunch and the start of my shift, there are several things that I can do. The weather has been very nice and so I often go on deck to soak up the sun and whale watch.
I may need to do laundry as my clothes start to smell fishy.
I will also workout in one of the two gyms. The gym at the back of the boat can’t be used when trawling because of the high noise level. There is a rower, two exercise bikes, two treadmills, a cross trainer, mats and weights. I got lucky and someone installed a makeshift pull up bar.
There is also a lounge where I can read or watch DVDs. Some of the movies are still in theaters.
An hour before my shift starts, I read and take a short nap. Then, I grab a cup of coffee at 4 pm as my shift starts. I listen as the day shift fills in the evening shift about the happenings of the last 12 hours.
During my shift, there are several things that I may do. If we have fished, there will be pollock and other organisms to process.
After processing, we need to clean up the fish lab which involves spraying down everything include ourselves with water to remove scales and slime.
I also keep an eye on the acoustic monitors, to see what I can recognize. Paul and Darin are always willing to answer my questions (even the ones I already asked).
I may look at trawl camera footage or observe camera drops. Drop Camera
I also have time to work on my blog.
Dinner is served at 5 pm but the mess is always open and is filled with snacks such as sandwich fixings, ice cream, yoghurt, a salad bar and pop tarts.
Whenever I get hungry at night, I just head for the mess. It is a time that I am able to chat with the crew and NOAA Corps as they come in for snacks too.
At 4 am, I make it a point to head directly to my stateroom and go to sleep. The room has a window but I can close the curtains on the portlight (window) and around my bed.
There are no weekends out here. Everyone works 7 days a week for the duration of the cruise.
Did You Know?
Usually fin whales show only their back as they surface for air. Check out my video clip and see if you can spot the whale. It wasn’t too close.
Mission: Walleye Pollock Survey Geographical Area of Cruise: Gulf of Alaska Date: July 22, 2013
Weather Data from the Bridge: (7/23/13 at 11 pm) Wind Speed = 13 knots
Air Temperature = 12.7 C
Humidity = 93%
Barometric Pressure = 1017 mb
Science and Technology Log:
There is a great deal of hope to complete the survey, which is supposed to end near Yakutat in the southeast of Alaska. It began near the islands of Four Mountains during leg 1. We are on leg 3, the final leg this summer. Leg 3 began in Kodiak. Three Legs of the Survey
The purpose of this cruise is to survey the walleye pollock (Theragra chalcogramma)in the Gulf of Alaska. Pollock is a significant fishery in the United States as well as the world. Pollock is processed into fish sticks, fish patties and imitation crab. Last year, about 3 million tons of pollock were caught in North Pacific. The scientists on board will collect data to determine the pollock biomass and age structure. These data are used with results from other independent surveys to establish the total allowable pollock catch.
According to the Alaska Fisheries Science Center, pollock can grow to about 3 ½ feet and weigh about 13 lbs. More typically the pollock are approximately 50 cm (20 in) and weigh .75 kg (1.7 lbs). They live in the water column and feed on krill, zooplankton and other crustaceans. As they age they will eat juvenile pollock and other small fishes such as capelin, eulachon and herring as well. Sexual maturity is reached around age 4. Spawning and fertilization occurs in the water column in early spring. The eggs stay in the water column and once hatched are part of the zooplankton until they are free swimming.
The general process used to catch the pollock involves multiple parts. I will break down those steps in a series of blogs. But basically, acoustics are used to locate fish in the water column. Once the scientists have located the fish along the transect (transects are the paths that the ship will travel on so the scientists can collect data), the Oscar Dyson sets out a trawl equipped with a camera. The trawl is brought in and data from the catch is documented. And then the ship continues on.
Trawling is usually completed only during daylight hours. Fortunately the sun does not set here in Alaska right now until after 10 pm. When it is dark, work aboard the Oscar Dyson continues. Jodi is documenting the sea floor with a drop camera. She is looking at life that is there as well as potential threats to the trawl nets for the bottom trawl surveys.
How do scientists use acoustics to locate pollock?
How are the transects locations determined?
How are pollock and the rest of the catch processed?
What information is retrieved from the trawl camera?
What is a bottom trawl and how is it different from a mid-water trawl?
We left Kodiak at 1 pm on July 22 heading southwest.
We had 8 hours of travel time before we would reach our first transect. But before we got too far away from Kodiak, we needed to practice the three drills for the safety of everyone. The fire drill and man overboard drill required me to report to the conference room and meet up with the rest of the science team. Patrick, the lead scientist, then reported that we were all accounted for. The crew had more complex tasks of deploying a small boat and retrieving “the man overboard”.
The other drill was the abandon ship drill. We are assigned to a lifeboat and I reported to my muster on the portside of the trawl deck with my survival suit, long sleeve shirt, hat and life preserver. We will have drills weekly at anytime.
For the last two days I have been becoming oriented to the ship and to my responsibilities to the science team. Jodi, a post doctorate from Juneau gave us a tour of the boat on the first day we arrived in Kodiak. I then practiced finding all of the key parts of the ship I will need to access. I now am confident that I can find my stateroom, the mess, laundry room, both exercise spaces, acoustics lab, and fish lab. For other sites, I wander around for a while until I locate it.
My first shift began at 4 pm on Monday. There are two shifts for scientists. Some work 4 am to 4 pm and the others work 4 pm to 4 am. I work the night shift. I never drink coffee but today I realized that I needed it. My shift includes scientists Paul, Jodi and Darin as well as a survey tech named Vince. We all share staterooms with people who work the opposite shift.
The ocean is very calm but most of us took Bonine (a seasickness medication) anyway to acclimate to the movement. Hopefully we will be adjusted to the motion before the seas get very rough if it does. The rocking of the boat does make one very sleepy.
Did You Know?
The requirements for joining the NOAA Corps include a bachelor’s degree in science, math or engineering and a 5 month program at the US Coast Guard Academy in New London, CT. This is Abby’s second cruise with the NOAA Corps. She has a bachelor’s degree in chemistry and just completed her NOAA officer basictraining.
Something to Think About:
What is a day in the life aboard the Oscar Dyson like?
Mission: Alaska Walleye Pollock Survey
Geographical Area: Gulf of Alaska
Date: July 18, 2013
My name is Julia Harvey and I currently teach biology and environmental science at South Eugene High School in Eugene, Oregon. Eugene is at the southern end of the Willamette Valley and just a short drive from the Pacific Ocean. I have taken many trips over the coastal range to Florence and the beautiful Oregon Coast.
And while the weather is not always cooperative, the ocean is always gorgeous. This last spring I took a group of students on a short marine discovery cruise out of Newport, where NOAA (National Oceanic and Atmospheric Administration) has based their Marine Operations Center for the Pacific.
It was my dream since 2nd grade to become a marine biologist. Mrs. Hellwege inspired me to learn more about the ocean as we studied marine mammals. My career path remained unchanged as I attended Occidental College and spent time on the college’s boat the Vantuna. I put my academic education on hold after graduating to serve in the Peace Corps. My passion for the sea continued while I was stationed in the South Pacific on an island in the Kingdom of Tonga. But as I became a teacher, I realized the perfect career would combine my love for biology and my new love of teaching. 22 years later, I now have to opportunity to revisit my childhood dream.
I learned about the NOAA Teacher at Sea program as I was taking an Oceanic Studies course. I decided to apply last October because I wished to connect my students directly with current research that is impacting our ocean environment. I also wanted to learn first hand how oceanic data was being collected since I have been out of the lab setting for quite some time. I was ecstatic when I learned in February that I was selected to sail. I am truly honored and appreciate the opportunity to involve my students in oceanic research and to present to them potential oceanic careers.
I will be sailing in the Gulf of Alaska aboard the Oscar Dyson and participating in a Walleye pollock fish population survey. Walleye pollock is the largest fisheries in the United States and one of the largest in the world. These fish become fish sticks, fish sandwiches and imitation crab. I am looking forward to learning more about the science involved in assessing a fish population. What makes fisheries healthy and sustainable?
My bags are packed with clothes, cameras, workouts, books and lots of enthusiasm. I am excited beyond description. I will be blogging several times a week and I hope you will continue to follow my journey at sea.