Weather Data for Claremont, CA from National Weather Service:
Latitude: 34.1368º N
Longitude: 117.7076º W
Wind Speed: 12 mph
Wind Direction: SSW
Air Temperature: 29.4º Celsius
Well, NOAA Ship Oscar Dyson docked in Dutch Harbor on August 11th from the 19-day journey in the Eastern Bering Sea. During our time at sea, I learned so much and got to know both the NOAA scientists and the crew and officers on the ship. When I applied for the Teacher at Sea program, I knew that it would be an invaluable experience, but it far exceeded my expectations. I learned about the work of the NOAA scientists pretty much non-stop and any question I had was answered in detail, which allowed me to have a robust picture of the work the NOAA scientists do, the different types of scientific instruments they use and the underlying principles behind them as well as the day-to-day operations of a scientific vessel such as NOAA Ship Oscar Dyson. Additionally, I also ate the best food of my life made by the stewards; there was always amazing entrees and dessert at every meal!
After we came into port, I was able to explore the town of Dutch Harbor as well. Along with other NOAA Scientists and the ship’s medic, I explored the Museum of the Aleutians in town and learned about the native people of the island and their traditions as well as the military encampments that were built on Unalaska (the island where Dutch Harbor is) during WWII. The next day we went up Ballyhoo mountain and saw the ruins of one of the WWII bases. The view from there was amazing and we saw all around Unalaska. I was surprised in Dutch Harbor to see so many bald eagles everywhere! The next day I said goodbye to the many people I got to know aboard the Oscar Dyson, many of whom were staying aboard for the next leg or for a long time thereafter. I was surprised how easily I transitioned to life aboard the boat and it still feels a bit weird to not be moving all the time!
I had a chance to interview the chief scientist aboard NOAA Ship Oscar Dyson, Taina Honkalehto, and ask her about her career path to working at NOAA as well as recommendations she has for anyone interested in an ocean career.
Taina knew that she wanted to pursue a career in science ever since she was a child as she has always been interested in the outdoors and collecting and observing things. During college, she took an oceanography course as a junior and knew she wanted to work with the ocean. Her college advisor recommended that if she wanted to pursue science she needed to do a field program. As a junior, she was able to secure participation at a marine lab in the U.S. Virgin Islands, which inspired her choice to go to graduate school and study invertebrate zoology.
At NOAA, Taina really enjoys her colleagues and the field work, which includes the pollock counting work she is currently doing on NOAA Ship Oscar Dyson. She feels that her work at NOAA is an opportunity to contribute to the preservation of our planet. Additionally, she enjoys doing outreach at NOAA and talking to people about her work and answering questions about the ocean. Often, discussions with the public involve balancing what they have heard about fisheries and overfishing in the news versus the reality and experiences Taina has had in the field counting pollock in the Bering Sea and Gulf of Alaska.
The advice that Taina has for those wanting to work for NOAA is to get an internship. Students can find internship opportunities through the NOAA website and there are avenues into NOAA experience for students at the middle and high school level as well as college students. These internships are a great way to get hands-on experience (as I can attest!) and some of them are even paid if students apply for the Hollings scholarship. Taina also recommends reading some of the following books to get an idea about what it is like on a field placement: “The Log from the Sea of Cortez” by John Steinbeck, “Moby Duck” by Donovan Hohn, and “Cod” by Mark Kurlansky.
The wet lab aboard NOAA Ship Oscar Dyson is where most of the action happens during my shift. When a haul comes in, we are responsible for processing the catch and obtaining the needed measurements so that the MACE team can put together their report on the health of the pollock population. The catch is released from the trawling net onto a hydraulic table that can be dumped onto a conveyor belt. The first job to be done is to sort the catch, where all species that are not adult pollock are separated out.
The next task is to measure the length of a subsample of about 300 of the adult pollock in the catch. This helps the NOAA scientists to create histograms of pollock lengths to compare between hauls. Finally, about 30 pollock are separated to measure length, weight and to determine gender and maturity and another 30 have length and weight measured, otoliths taken, and ovaries weighed and collected if the pollock is a spawning female. During my shift, there are six of us in the fish lab and we are working like a well-oiled machine!
Length distributions from several hauls
Determining if a pollock is male or female
TAS Emily Cilli-Turner collecting otoliths from a pollock
Today we are starting the long transit back to Dutch Harbor. It is bittersweet since I feel like we have a nice routine down in the fish lab and I finally feel used to the motions of the ship. However, I am grateful for this opportunity and for all the great people that I have gotten to know during my time on NOAA Ship Oscar Dyson. Also, we finally saw some blue sky again and a rainbow even came out for a moment!
Did You Know?
The NOAA Ship Oscar Dyson was launched on October 17, 2003. It is named after Alaskan fisherman Oscar Dyson and there is a smaller boat on board named after his wife, Peggy Dyson.
While the techniques written about in the previous blog post ensure that when we use the trawling nets we mostly catch pollock, there is usually a small amount of by-catch in each haul. By-catch means ocean life other than pollock (the desired catch) that we bring up in a haul using the trawling net. This post will focus on some of the creatures that I have seen in the catches during my time on NOAA Ship Oscar Dyson.
Principal species of interest:
Pollock: The scientific name for these pollock (known as Alaska pollock or walleye pollock) is Gadus chalcogrammus. We often catch many different ages of pollock, from age 0 pollock up to large adult pollock and these range in length from a few centimeters up to about 62 centimeters. Pollock is most of what we catch, and they are easy to identify by their three dorsal fins and speckling. Pollock mainly eat euphausiids and copepods, but also sometimes eat the age 0 pollock.
Chum Salmon: Chum salmon (Oncorhynchus keta) is one of the five types of salmon and lives for about 6 years on average. Like all salmon, they are spawned in freshwater and then migrate out to the ocean. Once they return to the freshwater and spawn, they die about two weeks later. They mostly eat zooplankton and insects, but have been known to eat comb jellyfish as well.
Jellyfish: We see several types of jellyfish in each catch, but we mainly see the Northern Sea Nettle (Chrysaora melanaster). We have also seen Northern Sea Nettle swimming near the surface before sunrise when we are pole fishing for pollock. The word melanaster translates to “black star,” which you can identify in the pattern on the bell of this jellyfish. The bell diameter can reach up to 12 inches and the tentacles can grow as long as 10 feet. As climate change has warmed the surface temperatures of the Bering Sea, the population of Northern Sea Nettle is increasing. Northern Sea Nettles mostly eat zooplankton, but sometimes also eat pollock!
Smooth Lumpsucker: Smooth lumpsuckers (Cyclopterus lumpus) are named so because of an adhesive disc on their underside that helps them suction onto the ocean floor. These fish spend most of their time on the bottom of the ocean and are not particularly good swimmers. The roe (eggs) of the lumpsucker is a delicacy in Scandinavia.
TAS Emily Cilli-Turner holding a lumpsucker.
Flatfish: Alaska Plaice & Yellowfin Sole: We have also caught two types of flatfish during my time aboard the ship: yellowfin sole (Pleuronectes aspera) and Alaska Plaice (Pleuronectes quadrituberculatus). These peculiar looking fish can be identified by having both eyes on top of their head. When they are spawned, these fish have eyes on either side of their head, but as they get older the eyes migrate to be on the same side. These fish mainly reside on the ocean floor, where they eat polychaetes and amphipods, such as worms and mollusks.
Capelin: The capelin (Mallotus villosus) is a small fish in the smelt family reaching a length of about 10 inches. It feeds mainly on plankton and krill. The most interesting thing about capelin is their smell; if you put their scales close to your nose you will smell cucumbers!
While the weather since boarding the NOAA Ship Oscar Dyson has largely consisted of some high winds and big swells, there have been one or two nice days in the Bering Sea. On these days, we have taken the opportunity to go outside. On one particularly nice day where the sun was shining, there was a mini corn-hole tournament on the deck. After thinking that my time on the ship was the least amount of time spent outside during the summer, this was a nice way to spend the after-dinner time.
I am also grateful for NOAA scientists Mike Levine and Darin Jones, who have made me feel like an expert in the fish lab. At this point, I know more about pollock than I ever thought I would. In the fish lab, I primarily am responsible for measuring the length of the pollock sample. However, Mike and Darin have also taught me about pollock anatomy and how to tell if a pollock is male or female. I have also become good at extracting the otoliths, which involves a precise cut of the pollock. For a person with almost no experience working with biological specimens, much less fish, I finally feel like a useful part of the team.
Did You Know?
The Bering Sea is an extremely important fishing location and the United States catches over $1 billion of seafood here each year.
“When am I ever going to use this?” This is the query of many students who are required to take mathematics courses. However, scientists aboard the NOAA Ship Oscar Dyson use mathematics every day as part of their job. As discussed in a previous blog post, underwater acoustic data are collected as the NOAA Ship Oscar Dyson navigates along the transects. These backscatter data are relied upon to decide when to take trawling net samples as well as to estimate the number and biomass of pollock in the area.
How do these underwater acoustics work? The answer can be found in mathematics and physics. As previously discussed, echosounders affixed to a centerboard below the hull of the ship send an audible ping down into the water and measure how long it takes to bounce off of an object (like a pollock) and return to the surface. The echosounders know the transmitted signal power (denoted Pt) and measure the received signal power (denoted Pr). Measuring the time between the signal transmission and reception and multiplying by the speed of sound (approximately 1450 m/s, given local water salinity and temperature conditions) will allow the calculation of distance of an object below the surface (or range denoted r). Using acoustics properties combined with known properties of pollock, we can get the equation for backscattering strength at a point as , where β is a constant and C(r) is a constant that is dependent on range.
However, since sound is measured in decibels which are arranged on a log scale, 10 times the log of both sides of the backscattering strength equation is desired. Using logarithm rules, this becomes
The value on the left-hand side of this equation is commonly referred to as target strength (TS) and is an important value to complete the survey.
The target strength is the amount of energy returned from a fish of a certain length. Since the echosounders are transmitting through the water column below the ship, the TS values are converted to backscatter strength per volume unit of water, referred to in the literature as Sv. The Sv values are graphed on the EK60 scientific echosounder, giving a picture similar to the one below. Different colors in the output are matched to various ranges of Sv values. An experienced fisheries scientist, like the ones aboard the NOAA Ship Oscar Dyson, can use the echosign data to determine a possible picture of the ocean life below the ship. While the EK60 scientific echosounder can transmit at five different frequencies (18 kHz, 38 kHz, 70 kHz, 120 kHz, and 200 kHz), the 38-kilohertz transmission frequency is the best frequency to detect pollock. Other transmission frequencies are shown to help delineate adult pollock from baby pollock and from other types of fish and smaller crustaceans called euphausiids.
The target strength is related to the length of the fish. The age of pollock is strongly correlated to their length until they are about 4 years old, so length can help the scientists determine how many of each year class are in the ocean below. Once again, logarithms come in handy, as the equation that relates the fork length in centimeters, l, of the pollock to the recorded target strength is TS = 20 log l – 66. This allows the scientists to use the echosounder data to get an approximate measure of the fish below without having to catch them.
Today we will be going on a partial tour of NOAA Ship Oscar Dyson so you can see where I spend most of my time while aboard. The first stop is my stateroom, where I sleep and relax when not on shift. The top bunk is mine and the bottom bunk belongs to my roommate, NOAA scientist Abigail McCarthy. Our stateroom has one window where we can check on the weather and sea conditions. The picture below shows our view most of the time: cloudy!
Ocean from my window
Next stop is the mess hall where three meals a day are served. The stewards do a great job of cooking creative meals for everyone aboard. Before I boarded the ship, I bought a lot of snacks because I was worried about not getting enough to eat, but boy was I wrong. There is always plenty to eat at every meal, snacks that are out if you get hungry in between, and lots of dessert!
Finally, we come to the fish lab where the trawling net samples referred to in my last blog post are processed. Before processing, we go to the ready room and put on our gear. This includes work boots as well as waterproof coveralls and jacket. Measuring the length of the pollock can get messy so we have to have the right gear. Once in the fish lab, we grab our gloves and get to measuring!
The fish lab where samples from the trawling net and methot are processed.
Did You Know?
Scientists aboard the NOAA Ship Oscar Dyson are part of the National Marine Fisheries Service (NMFS), which is one of the six major line offices of NOAA.
Air Temperature: 10.1° C (Manual Reading from the Bridge)
Barometric Pressure: 992.7 mb
Visibility: 6 nautical miles
Sea Wave Height: 3 feet
How do the scientists aboard NOAA Ship Oscar Dyson estimate the number and biomass of pollock in the Eastern Bering Sea? By using the science of statistics, of course! When political strategists want to determine what percentage of voters support a specific candidate or issue, they take a sample from the population of all registered voters. Voters in this sample are then asked about their preferences and statistical techniques are employed to extrapolate the results from the sample to the entire population and measure the margin of error. Similar statistical techniques are employed by the scientists on NOAA Ship Oscar Dyson, but as you can imagine it is more difficult to sample pollock than voters that can be called on the phone!
Before each pollock survey begins, a set of transects is created for the Eastern Bering Sea. These transects are paths for the ship to follow along which the scientists sample the pollock. As you can see below, the transects for this survey are a fixed distance apart and cover the entire area of interest. Generally, the transects are straight lines created to be perpendicular to the ocean depth grade. This allows for the scientists to encounter a variety of species as well as different ages of pollock to gain a robust picture of the ocean life in the area.
The NOAA Ship Oscar Dyson follows the transects during daylight hours, continuously recording water column acoustic backscatter data using EK60 instruments mounted on the bottom of the centerboard. Scientists monitor the backscatter images, and when they observe sufficient pollock or other fish aggregations they use the trawling nets to take a random sample of the fish and other ocean life they observed. The trawling net is 140 m long with a vertical mouth opening of 25 m and horizontal mouth opening of 35 m. The net is deployed from the back of the ship and dragged at a fixed depth for an amount of time determine by the lead scientist to ensure a large enough sample. Once the trawling net is hauled in, the sample of marine fish and invertebrates is processed in the wet lab and entered into a database. Later the pollock numbers and weights by length are combined with recorded acoustic data to create a robust estimate of the pollock population in the Eastern Bering Sea.
View of trawling nets being hauled in from the bridge.
View of trawling nets being hauled in from the deck.
After the catch comes in, the first job in processing the sample is to sort the specimens from the trawling net. The first part of the net to come in is called the pocket net. This small net, also called a recapture net, has a fine mesh and is designed to capture small species such as krill, age 0 pollock and jellyfish which slip through the meshes of the large trawl. After the pocket net is processed, we process the codend, the closed end of the net and the main section where larger fish enter and are captured. The fish in the codend are sorted by species. The scientists can choose to measure the length of all the pollock in the haul or, if it is a particularly large catch, split the haul and measure length of a subsample of pollock. Other species are also identified and their length is measured for later estimates of the total biomass that pollock make up as compared to other species. Smaller species such as krill are weighed in aggregate instead of individually.
Sample analysis consists of measuring the lengths of approximately 200-400 adult pollock in the catch using the magnetic length board. This is just one of the numerous software and instruments created by the MACE (Midwater Assessment and Conservation Engineering) group at NOAA in Seattle to make analysis easier and more automated. The length distribution of the adult pollock helps scientists determine the approximate age distribution of pollock in the sample and it also helps them compare this distribution to other samples taken in the Eastern Bering Sea. A subsample of about 50 pollock from the haul is taken to get more in-depth measurements. From these pollock, we measure both the length and weight and a subsample from the 50 is taken to determine the gender, measure maturity (i.e. what stage in the life cycle the pollock is at), and collect the otolith (ear bone), which gives a more accurate measurement of the pollock’s age.
TAS Emily Cilli-Turner
measuring the length of pollock from a haul.
At this point, I am getting used to life at sea and have a nice routine. The beginning of my shift, from 4am to a little past 7am, starts at sunrise and during which we resume our path along the transect. No trawling operations are conducted at night, but there is still excitement. If the underwater acoustics show that the pollock are at an appropriate depth, we can go pole fishing off the boat. NOAA scientist Mike Levine is interested in post-capture mortality of pollock and the feasibility of tagging pollock. Thus, he would like to catch pollock using a fishing pole, which puts much less stress on the pollock and increases the chance of their survival after the catch, instead of the trawling nets.
As an instructor of mathematics, I have little knowledge of fish biology, but the scientists are great teachers! I have been given a crash course on fish anatomy using specimens from the catch and I have learned how to sex the fish as well as how to collect the ovaries and the otoliths (ear bones). If you asked me a week ago if I ever thought I would know so much about pollock after just a couple days on board, I would have laughed. It has been great being the student and being able to learn so much in such a short time with real hands-on experience!
Did You Know?
Most of the personnel that are responsible for piloting and maintaining the ship are part of NOAA Corps, which is one of the seven uniformed services of the United States.
Scientists aboard NOAA Ship Oscar Dyson are aiming to estimate the number and biomass of pollock in the Eastern Bering Sea, which, as you can imagine, is a big undertaking. In order to complete this job, they use a lot of sophisticated technology to determine where the fish are as well as statistical methods to extrapolate the total number of fish from the samples taken. This job is extremely important as it helps to determine the health and sustainability of the pollock population in the Bering Sea so that the government can model and forecast next year’s population numbers, and the North Pacific Fishery Management Council can set future catch quotas.
The first piece of technology used is the underwater acoustics. Echosounders send an audible ping down into the water and measure how long it takes to bounce off of an object (like a pollock) and return to the surface. Using the known value of the speed of sound, this technology can create a picture of where the fish are below the boat. While the acoustics only show that there is an object the length of a fish below, the scientists use their knowledge of the regions pollock normally occupy, the depth they regularly swim at, as well as the shape and size of pollock aggregations to determine when they are seeing pollock versus other types of fish.
Once it is determined that there is likely a large school of pollock in the area, then the trawling nets are deployed to catch pollock. Once the nets are hauled in, the total catch is weighed and then a smaller sample is pulled to collect length and weight data to determine the sizes of fish in the area. Other samples, such as the pollock ear bone (otolith) or ovaries may also be taken at this time. Using statistics, the number and length of pollock in the entire catch and then in the entire area is estimated.
The flight into Dutch Harbor was very exciting. Before boarding the plane, they weigh you and your carry-on baggage to make sure the plane will be balanced and that there is not too much weight. The airport at Dutch Harbor is not much more than a landing strip between two mountains. We came in for landing right over the water and for a second it looked like we might land on the water before the landing strip appeared. Once we reached the dock where we boarded the NOAA Ship Oscar Dyson, I saw a sea otter, but it disappeared before I could take a picture of it!
So far, I am adjusting to life at sea. The first day the boat was a little rough and I got a bit seasick, however after seeing the ship’s medic for some medication I am feeling much better. During our first full day at sea we had to practice safety drills, which are required within 24 hours of departing. Once they announce the drill, you have to grab your life jacket and survival suit from your stateroom and bring them to the assembly point on the deck. Then, we had to practice putting on the survival suit, which is sort of like a giant wet suit complete with a hood, lights and a manually-inflated flotation device.
The ship itself is like a small city; there are the residences, which are the staterooms where we sleep, the entertainment, which is the lounge where there is always a moving playing, and the restaurant, which is the mess hall where great food is served three times a day. However, this “city” runs and powers itself; all electricity and water must be made aboard the boat.
The hardest adjustment so far has been a temporal one. I am responsible for the 4am – 4pm shift in the fish lab, which means I must rise by 3:30am every day! I am normally not an early riser so this has been tough, but the rocking of the ship means that when I do go to bed I normally get a great night’s sleep!
Did You Know?
Scientists collect the ear bone, called the otolith, from pollock to determine their age. This bone grows in rings for each year, just like a tree!
Hello! My name is Emily Cilli-Turner and I will be aboard the NOAA Ship Oscar Dyson as a participant in the 2018 NOAA Teacher at Sea program. I am Assistant Professor of Mathematics at the University of La Verne in La Verne, California where I teach the entire undergraduate curriculum in mathematics. This will be my sixth year teaching full-time. My bachelor’s degree in mathematics is from Colorado State University and I received my doctorate from University of Illinois at Chicago, where I specialized in undergraduate mathematics education. I am especially interest in the transition students make when they enter a proof-based course and how to best acclimate them to the abstract and non-formulaic nature of proving.
I am passionate about math and science education and excited to use the data collected from my time on the ship to create real-world applications problems for my students. I will be teaching Calculus I and II next semester and I plan to use the data gained from my experience to teach my students about concepts such as rates of change and statistical techniques.
I have a strong love for the ocean and so I am excited to be on the water for so long. I am transitioning to California after living in Washington, where I co-owned a 23-foot sailboat with some friends. We often would sail to different islands and ports on Puget Sound, which was always a blast. When I am not teaching or sailing, I enjoy walking my dog, hiking and reading!
In about a week, I will fly to Dutch Harbor, Alaska to board the NOAA Ship Oscar Dyson and participate in the Alaska Pollock counting survey. Before receiving this placement, I have never really heard of Pollock, but after researching it I realized it is an amazing fish! Pollock can easily taste like other fish and is often used for imitation crab amongst other things.
I am also really excited to meet the scientists and the crew. The reason I know about the Teacher at Sea program is that I have a friend that works at NOAA in Seattle. I mentioned offhandedly that I would love to go out on a NOAA cruise and she said, “Well…they do have the Teacher at Sea program.” I was immediately intrigued and I wrote my application as soon as it was available. As a person who is passionate about education and the ocean, the Teacher at Sea program is a great fit for me and I know I will learn a lot that I can take back to my students. Hopefully, I can also inspire them to seek out a career with NOAA.