walleye pollock – Page 4 – NOAA Teacher at Sea Blog

August 3, 2012August 11, 2021

Allan Phipps: Show Me the Data! August 2, 2012

NOAA Teacher at Sea
Allan Phipps
Aboard NOAA Ship Oscar Dyson
July 23 – August 11, 2012

Mission: Alaskan Pollock Mid-water Acoustic Survey
Geographical Area: Bering Sea
Date: August 2, 2012

Location Data
Latitude: 61°12’61” N
Longitude: 178°27’175″ W
Ship speed: 11.6 knots (13.3 mph)

Weather Data from the Bridge
Wind Speed: 11 knots (12.7 mph)
Wind Direction: 193°
Wave Height: 2-4 ft (0.6 – 1.2 m)
Surface Water Temperature: 8.3°C ( 47°F)
Air Temperature: 8.5°C (47.3°F)
Barometric Pressure: 999.98 millibars (0.99 atm)

Science and Technology Log

At the end of last blog, I asked the question, “What do you do with all these fish data?”

The easy answer is… try and determine how many fish are in the sea. That way, you can establish sustainable fishing limits. But there is a little more to the story…

Historically, all fisheries data were based on length. It is a lot easier to measure the length of a fish than to accurately determine its weight on a ship at sea. To accurately measure weight on a ship, you have to have special scales that account for the changes in weight due to the up and down motion of the ship. Similar to riding a roller coaster, at the crest of a wave (or top of a hill on a roller coaster), the fish would appear to weigh less as it experiences less gravitational force. At the trough of a wave (or bottom of a hill on a roller coaster), the fish would experience more gravitational force and appear to weigh more. Motion compensating scales are a more recent invention, so, historically, it was easier to just measure lengths.

For fisheries management purposes, however, you want to be able to determine the mass of each fish in your sample and inevitably the biomass of the entire fishery in order to decide on quotas to determine a sustainable fishing rate. So, you need to be able to use length data to estimate mass. Here is where science and math come to the rescue! By taking a random sample that is large enough to be statistically significant, and by using the actual length and weight data from that sample, you can create a model to represent the entire population. In doing so, you can use the model for estimating weights even if all you know is the lengths of the fish that you sample. Then you can extrapolate that data (using the analysis of your acoustic data – more on this later) to determine the entire size of the pollock biomass in the Bering Sea.

How do they do that? First, you analyze and plot the actual lengths vs. weights of your random sample and your result is a scatter-plot diagram that appears to be an exponential curve.

Then you create a linear model by log-transforming the data. This gives you a straight line.

linear-regression — Linear regression of the Walleye pollock length and weight data.

Next, you back-transform the data into linear space (instead of log space) and you will have created a model for estimating weight of pollock if all you know are the lengths of the fish. This is close to a cubic expansion which makes sense because you are going from a one-dimensional measurement (length) to a 3-dimensional measurement (volume).

observed vs predicted — Observed weight and length data showing the model for predicting weight if all you know are lengths.

Scientists can now use this line to predict weights from all of their fish samples and then extrapolate to determine the entire biomass of Walleye pollock population in the Bering Sea (when combined with acoustic data… coming up in the next blog!) when the majority of the data collected is only fish lengths.

Another interesting question… How does length change with age? Fish get bigger as they get older, all the way until they die, which is different from mammals and birds. However, some individual fish grow faster than others, so the relationship between age and length gets a little complicated. How do you determine the age distribution of an entire population when all you are collecting are lengths?

Just like weight, you can determine the age from a subset of fish and apply your results to the rest. This works great with young fish that are one year old. The problem is… once you get beyond a one-year-old fish, using lengths alone to determine age becomes a little sketchy. Different fish may have had a better life than others (environmental/ecological effects) and had plenty to eat, great growing conditions, etc and be big for their age relative to the rest of the population. Some may have had less to eat and/or unfavorable conditions such as high parasite loads leading them to be smaller… There are also other things to consider such as genetics that affect length and growth rate of individuals. Here is where the collection of otoliths becomes important. By collecting the otoliths with the lengths, weights, and gender data, the scientists can look at the age distributions within the population. The graph below shows that if a pollock is 15 cm long, it is clearly a 1 year old fish. If a pollock is 30 cm long, it might be a 2 year old, a 3 year old, or a 4 year old fish, but about 90% of fish at this length will be 3 years old. If a fish is 55 cm long, it could be anywhere from 6 to 10+ years old!

length-age relationship — Graph showing age proportions of the Walleye pollock population when compared to length data.

Collection of otoliths is the only way to accurately determine the age of the fish in the random sample and be able to extrapolate that data to determine the estimated age of all the pollock in the fishery. Here is a photo comparing otolith size of Walleye pollock with their lengths.

A comparison of otolith sizes. These otoliths were taken from fish that were 12.5cm, 24.5cm, 30.5cm, 39.0cm, 55.5cm, and 70.0cm counter clockwise from top, respectively.

If we wanted to find out exactly how old each of these fish were, we would need to break the otoliths in half to look at a cross section. Below is what a prepared otolith looks like (courtesy of Alaska Fisheries Science Center). You can try counting rings yourself at their interactive otolith activity found here.

pollock otolith cross section — Cross section of Walleye pollock otolith after being prepared (courtesy of the Alaska Fisheries Science Center).

All of these data go into a much more complicated model (including the acoustic-trawl survey walleye pollock population estimates) to accurately estimate the total size of the fishery and set the quotas for the pollock fishing industry so that the fishery is maintained in a sustainable manner.

Next blog, we will learn about how the various ways acoustic data fit into this equation to create the pollock fishery model!

Personal Blog

Ok, so here is a long overdue look at the NOAA Ship Oscar Dyson that I am calling home for three weeks. I was pleasantly surprised when I saw my state room. It is bigger than I thought it would be and came with its own bathroom. I was also pleasantly surprised to learn I would be sharing my state room with Kresimir Williams, one of the NOAA scientists and an old college friend of mine! Here is a picture of our room.

The room has a set of bunk beds. Thankfully, my bed is on the bottom. I do not know how I would have gotten in and out of bed in the rough seas we had over the last couple of days. If I do fall out of bed, at least I will not have far to fall. Last year, the ship rocked so hard in rough seas that one of the scientists fell head first out of the top bunk! The room also had two lockers that serve as closets, a desk and chair, and our immersion suits (the red gumby suits). The bathroom is small and the shower is tiny! Notice the handles on the wall. These are really handy when trying to shower in rough seas!

Next, we have the Galley or Mess Hall. This is where we have all of our meals prepared by Tim and Adam. Notice that all of the chairs have tennis balls on the legs and that each chair has a bungee cord securing it to the floor! There are also bungee cords over the plates and bowls. Everything has to be secured for rough seas.

The Mess Hall also has a salad bar, cereal bar, sandwich fixings, soup, snacks like cookies, and ice cream available 24 hours a day. No one on board is going hungry. The food has been excellent! We have had steaks, ribs, hamburgers and fish that Tim has grilled right out on deck. Here is a picture of my “surf and turf” with a double-baked potato.

Most of my work here on board (other than processing fish) has been in the acoustics lab, also known as “The Cave” since it has no windows. This is where the NOAA scientists are collecting acoustic data on the schools of fish and comparing the acoustic data with the biological samples we process in the fish lab.

I also spend some time up on the Bridge. From the Bridge, you can see 10 to 12+ nautical miles on a clear day. This morning, we saw a couple of humpback whales blowing (surfacing to breathe) about 1/4 mile off our starboard side! A couple of days ago (before the weather turned foul), we spotted an American trawler.

Today, we got close enough to see the Russian coastline! Here is a picture of a small tanker ship with the Russian coastline in the background!

Here are some pictures of the helm and some of the technology we have onboard to help navigate the ship.

I have also spent some time in the lounge. This is where you can go to watch movies, play darts (yea, right! on a ship in rough weather???), or just relax. The couch and chairs are so very comfy!

When you have 30 people on board and in close quarters, you better have a place to do laundry! Here is a picture of our very own laundromat.

All for now. Next time, I will share more about life at sea!

August 2, 2012August 11, 2021

Johanna Mendillo: From Russia with Love… August 1, 2012

NOAA Teacher at Sea
Johanna Mendillo
Aboard NOAA Ship Oscar Dyson
July 23 – August 10, 2012

Mission: Pollock Survey
Geographical area of the cruise: Bering Sea
Date: Wednesday, August 1, 2012

Location Data from the Bridge:
Latitude: 62^○ 18’ N
Longitude: 178^○ 51’ W
Ship speed: 2.5 knots (2.9 mph)

Weather Data from the Bridge:
Air temperature: 9.5^○C (49.1ºF)
Surface water temperature: 8.5^○C (47.3ºF)
Wind speed: 9.1 knots (10.5 mph)
Wind direction: 270^○T
Barometric pressure: 1001 millibar (0.99 atm)

Science and Technology Log:

In the last few days, we have crossed into the Russian Exclusive Economic Zone, sampled, and are now back on the U.S. side! Unfortunately, students, there was no way for my passport to get stamped. There was no formal ceremony, and we will cross back and forth many times in the next two weeks as we do our science transects, collecting Pollock, but the science team took a moment to celebrate— and I snapped a quick picture of the computer screen.

Crossing into Russia! — Crossing into the Russian Exclusive Economic Zone!

I would now like to introduce you to one of the most simple and valuable tools we use on board to measure a sample of Pollock- the Ichthystick.

The one... the only... Icthystick! — The one… the only… Ichthystick!

First, some background. Each day we “go fishing” 2-4 times with our mid-water and bottom trawls. “Trawling” simply means dragging a large net through the water to collect fish (and you will learn more about the different types of nets we use quite soon). After the trawl, we bring the net back on board and see what we have caught!

There are many types of data we collect from each catch- first and foremost, the total weight of the catch and the numbers and masses of any species we catch in addition to pollock. So far, we have collected salmon, herring, cod, lumpsuckers, rock sole, arrowtooth flounder, Greenland turbot, and jellyfish on my shifts! Our focus, though, of course, is pollock. For pollock-specific data, we keep a sub-sample of the catch, usually 300-500 fish, for further analysis, and we release the rest back into the ocean.

From this sub-sample, I help the scientists collect gender and length data. As I mentioned in my last post, we also collect otoliths from the sub-samples so that the age structure of the population can be studied back in Seattle. The most straightforward and obvious data, though, is simply measuring the length of the fish, which takes us back to the wonderful contraption known as the Ichthystick!

Now, scientists cannot determines the age of a pollock simply from measuring its length- there are many factors that determine how fast a fish can grow, such as access to food, space, its overall health, environmental conditions, etc. But, by collecting length data and combining it with age data from otoliths, scientists can begin to see the length ranges at each age class and the overall “big picture” for the population emerges.

And again, once the age structure and population size of pollock in the Bering Sea are determined for a certain year, management decisions can be made, commercial fish quotas are set for the upcoming fishing season, and there will still be a suitable population of fish left in the ocean to reproduce and keep the stocks at sustainable levels for upcoming years.

The Ichthystick logo… designed by scientist Kresimir!

So, it clearly does not make much sense to measure pollock with a ruler, paper, and pencil. To measure hundreds of fish at a time, the NOAA team has developed a simple yet ingenious measuring tool, powered by magnets, and transmitted electronically back to their computers for easy analysis- the Ichthystick!

The Ichthystick may simply look like a large ruler, but it consists of a sensor and electronic processing board mounted in a protective (& waterproof!) container. Inside, the sensor processes, formats and transmits the measurement values of each fish to an external computer that collects and stores the data.

Here I am...measuring away! — Here I am…measuring away!

Interestingly, the board works with magnets and makes use of the property of magnetostriction.

With magnetostriction, magnetic materials change shape when exposed to a magnetic field. Magnetostrictive sensors can use this property to measure distances by calculating the “time of flight” for a sonic pulse generated in a magnetic filament when a measurement magnet is placed close to the sensor. Here, in the picture, I am placing the fish along the sensor and holding the measurement magnet in my right hand.

Do you see stylus in my right hand? — Do you see stylus (containing the magnet) in my right hand?

To determine the distance to the measurement magnet, the elapsed time between when I touch the magnet to the board to generate the ultrasonic pulse and when the pulse is detected by the sensor is recorded– and that time is converted to a distance (using the speed of sound in that material), which is equal to the fish’s length!

Now, the “measurement magnet” is referred to as the “stylus”, and it is a little white plastic piece, the size of a magic marker cap, which contains the magnet embedded into the bottom. You simply strap the stylus onto your index finger with velcro (so that the north pole of the magnet is facing down toward the sensor) and are ready to begin measuring! The magnet inside is a small neodymium magnet, chosen because it has a very strong magnetic field. Each time a measurement is recorded, a chime sounds, and I know I can go on to measuring my next fish! At this point, I have measured a few thousand fish!

Personal Log:

Let’s continue our tour aboard the Oscar Dyson! I think it is fair to say that scientific research makes one hungry! I have enjoyed meeting Tim and Adam, the stewards (chefs) onboard the Dyson, devouring their delicious meals, and spending time talking with the officers and crew in the galley (kitchen) and mess (dining hall). As you can see from my picture, the first thing you notice are the tennis balls on the bottoms of the chairs! Why do you think they are there?

Look on the floor... — Look on the floor…

As in most things related to ship design, planning for rough seas is paramount! So, in addition to tennis balls, which stop the chairs from sliding around, there are bungee cords that attach the chairs to the floor. The dishes are also strapped down and most items are in boxes, bins, or behind closed doors. But do not let that fool you— there is a LOT of food in there! I have enjoyed many a midnight snack- fruit, yogurt, ice cream bars, cereal bars, cookies, and soup to name just a few. In addition, there is a salad bar and a selection of leftover dinner items available to reheat each night. Since I am on the 4pm-4am shift, I have been missing breakfast, and I have been told I must have at least one hot cooked-to-order meal before I depart!

Don't be late... or you will go hungry! — Don’t be late… or you will go hungry!

I was a little surprised to see a mini-Starbucks on board too! It is quite a setup, complete with pictures and directions on how to make each concoction:

Dennis, one of the Survey Technicians who works on the overnight shift with me, promised to make me a hazelnut latte if I could correctly predict the number of pollock in a trawl, Price-Is-Right style. I finally won a few nights ago….

Interestingly, there are no mechanisms in place to help the stewards cook in rough seas, but Adam assured me that he has never had a dinner for thirty slide off the grill and onto the floor! Adam has been working in the NOAA fleet for over 10 yrs., including 7 yrs on the Miller Freeman, the precursor to the Oscar Dyson. He has been onboard the Dyson for almost a year. Tim has just joined the Dyson on this cruise and was previously in our home state— aboard the Delaware out of Woods Hole, Massachusetts! Before joining NOAA, he worked on several supply ships that sailed across the world. Each has been quite friendly and helpful as I learn to navigate my way around both the ship and my new schedule. One of our frequent conversations is menu planning and the all-important-dessert on the schedule for each night. So far, I have enjoyed apple cobbler, pineapple upside down cake, snickers cake, carrot cake, brownie sundaes, oatmeal raisin cookies, and… Boston cream pie!

Tim and Adam's domain... the Galley! — Tim and Adam’s domain… the Galley!

One last Q: How many dozens of eggs do you think Tim and Adam will go through on our 19-day cruise with 30 people on board? Write your guess in the comment section and I will announce the answer in my next post…

August 1, 2012August 11, 2021

Allan Phipps: Fish heads, fish heads, rolly polly fish heads…. July 31, 2012

NOAA Teacher at Sea
Allan Phipps
Aboard NOAA Ship Oscar Dyson
July 23 – August 11, 2012

Mission: Alaskan Pollock Mid-water Acoustic Survey
Geographical Area: Bering Sea
Date: July 31, 2012

Location Data
Latitude: N 61°39’29”
Longitude: W 117°55’90”
Ship speed: 11.7 knots (13.5mph)

Weather Data from the Bridge
Wind Speed: 26 knots (30mph)
Wind Direction: 044°
Wave Height: 4 meters (12 ft)
Surface Water Temperature: 8.2°C ( 46.8°F)
Air Temperature: 7.4°C (45°F)
Barometric Pressure: 994 millibar (0.98 atm)

Science and Technology Log:

Last blog, we learned about the different trawl nets and how the NOAA scientists are comparing those nets while conducting the mid-water acoustic pollock survey. We left off with the fish being released from the codend onto the lift table and entering the fish lab. Here is where the biological data is collected.

The fish lab is where the catch is sorted, weighed, counted, measured, sexed, and biological samples such as the otoliths, or earbones, are taken (more about otoliths later in this post). First, the fish come down a conveyor belt where they are sorted by species (see video above). Typically, the most numerous species (in our case pollock) stay on the conveyor and any other species (jellyfish and/or herring, but sometimes a salmon or two, or maybe even something unique like a lumpsucker!), are put into separate baskets to weigh and include in the inventory count. In the commercial fishing industry, these species would be considered bycatch, but since we are doing an inventory survey, we document all species caught. Here are some pictures of others species caught and included in the midwater survey.

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The goal of each trawl is to randomly select a sample of 300 pollock to measure as a good representation of the population (remember your statistics! Larger sample sizes will give you a better approximation of the real population). If more than 300 pollock are caught, the remainder are weighed in baskets and quickly sent back to sea. All of the catch is weighed so the scientists can use the length and gender data taken from the sample to extrapolate for the entire catch. This data is combined with the acoustics data to estimate the size of the entire fishery (more on acoustic data in a future post). Weights are entered via touch screen into a program (Catch Logger for Acoustic Midwater Surveys – CLAMS) developed by the NOAA scientists onboard.

The 300 pollock are sexed to determine the male/female ratio of this randomly selected portion of the population. Gender is determined by making an incision along the ventral side from posterior to anterior beginning near the vent. This exposes the internal organs so that either ovaries or testes can be seen. Sometimes determining gender is tricky since the gonads look very different as fish pass through pre-spawning, spawning, or post-spawning stages. When we determine gender, the fish are put into two separate hoppers, the one for females is labeled “Sheilas” and the hopper for males is labeled “Blokes.”

We use an Ichthystick to then measure the males and females separately to collect length data for this randomly selected sample. Designed by NOAA Scientists Rick and Kresimir, the Ichthystick very quickly measures lengths by using a magnet placed at the fork of the fish’s tail (when measuring fork-length). This sends a signal to the computer to record the individual fish’s length data immediately into a spreadsheet and the software creates a population length distribution histogram in real-time as you enter data.

icthystick — The Ichthystick with fingertip magnet used to quickly measure and enter length data into CLAMS.

A randomly selected subset of 40 pollock get individually weighed, length measured, sexed, evaluated for gonadal maturity and have the otoliths removed. Otoliths (oto = ear, lithos = bone) are calciferous bony structures in the fish’s inner ear. These are used to determine age when examined via cross-section under a dissecting scope. The number of rings corresponds to the age of the pollock, similar to rings seen in trees. The otoliths are taken by holding the fish at the operculum and making an incision across the top of the head to expose the brain and utricle of the inner ear. The otolith is found inside the utricle. Forceps are used to extract the otoliths, which are then washed and put in individual bar-coded vials with glycerol-thymol solution to preserve them for analysis back at the Alaska Fisheries Science Center.

Watch this short video to see what the entire process of data collection looks like.

So… why collect all of this data? How is this data analyzed and used? Stay tuned to my next blog!

Personal Log:

Well, I can officially say… the honeymoon is over. The Bering Sea had been so extremely kind to us with several days of great weather while we had a high pressure system over us. We enjoyed spectacular sunrises and sunsets, cloudless days and calm seas.

Now… we have a low pressure system on top of us. Last night, we experienced 35 knot winds and 12 foot seas. I have spent a lot of time in my room in the past 24 hours… Late this morning, the sun came out and the winds calmed down, but the barometric pressure was still very low (around 990 mbars) which basically meant we were in the center of the low pressure system (similar to the eye of a hurricane, but not as strong… thank goodness!). We had a few hours relief, but we are back to pounding through the waves as the wind picks back up. It will be another long and sleepless night for this landlubber…

On a positive note, we did see two Laysan Albatrosses (Phoebastria immutabilis) from the Bridge as the winds began to kick up. They seemed to really enjoy the high winds as they soared effortlessly around the ship. The Officer on Deck (OOD) also said he saw a humpback breaching, but by the time I got up to the Bridge, it had moved on…

Next blog, I will share pictures of my room, the galley, “the cave,” the Bridge, etc. Right now, I am just trying to hold on to my mattress and my stomach…

July 29, 2012August 11, 2021

Allan Phipps: Let the Fishing Begin! July 28, 2012

NOAA Teacher at Sea
Allan Phipps
Aboard NOAA Ship Oscar Dyson
July 23 – August 11, 2012

Mission: Alaskan Pollock Survey
Geographical Area: Bering Sea
Date: July 28, 2012

Location Data
Latitude: 61°24’39″N
Longitude: 177°07’68″W
Ship speed: 3.8 knots (4.4 mph) currently fishing

Weather Data from the Bridge
Wind Speed: 6.9 knots (7.9 mph)
Wind Direction: 30°T
Wave Height: 2ft with 2-4ft swells
Surface Water Temperature: 8.7°C ( 47.7°F)
Air Temperature: 7.9°C ( 46.2°F)
Barometric pressure: 1005.8 millibar (0.99 atm)

Science and Technology Log:

Since the main goal of this voyage is the acoustic-trawl survey of the mid-water portion of the Alaskan pollock population, I thought I would start by telling you how we go fishing to catch pollock! This isn’t the type of fishing I’m used to… Alaskan pollock is a semi-demersal species, which means it inhabits from the middle of the water column (mid-water) downward to the seafloor. This mid-water survey is typically carried out once every two years. Another NOAA Fisheries survey, the bottom trawl survey, surveys the bottom-dwelling or demersal portion of the pollock population every year. I will begin by describing how we are fishing for pollock on this acoustic-trawl survey.

The Oscar Dyson carries two different types of trawling nets for capturing fish as part of the mid-water survey, the AWT (Aleutian Wing Trawl which is a mid-water trawl net) and the 83-112 (a bottom-trawl net that is named for the length of its 83 foot long head rope that is at the top of the mouth of the net and the 112 foot long weighted foot rope at the bottom of the mouth of the net). One of the research projects on board the Oscar Dyson is a feasibility study that involves a comparison of the AWT and using the 83-112 bottom-trawl net as if it were a mid-water net. The 83-112 is much smaller than the AWT, so there is concern with the fish avoiding this net and thus causing a reduction in catch. While the bottom trawl survey acquires good information on the bottom-dwelling pollock using the 83-112 bottom trawl, if they also used this net to sample in mid-water they could help “fill in” estimates of mid-water dwelling pollock in years when the acoustic mid-water trawl survey does not occur.

AWT model commented — Scale model of the Aleutian Wing Trawl (AWT) net courtesy of NOAA Scientist Kresimir Williams

When the net is deployed from the ship, the first part of the net in the water is called the cod end. This is where the caught fish end up. The mesh size of the net gets smaller and smaller until the mesh size at the cod end is only ½ inch (The mesh size at the mouth of the net is over 3 meters!).

The AWT is also outfitted with a Cam-Trawl, which is the next major part that hits the water. This is a pair of cameras that help scientists identify and measure the fish that are caught in the net. Eventually, this technology might be used to allow scientists to gather data on fish biomass without having to actually collect any fish (more on this technology later). This piece of equipment has to be “sewn” into the side of the net each time the crew is instructed to deploy the AWT. The crew uses a special type of knot called a “zipper” knot, which allows them to untie the entire length of knots with one pull on the end much like yarn from a sweater comes unraveled.

Along the head rope, there is a piece of net called the “kite” where a series of sensors are attached to help the scientists gather data about the depth of the net, the shape of the net underwater, how large the net opening is, determine if the net is tangled, how far the net is off the bottom, and see an acoustic signal if fish are actually going into the net (more on these sensors later, although the major acoustic sensor is affectionately called the “turtle”).

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 act as hydrofoils and create drag to ensure the net mouth opens wide. Our AWT net usually has a 25 meter opening from head rope to foot rope and a 35 meter opening from side to side.

IMAG0775 — This picture shows the A-frame with the two tuna towers on either side. The AWT is being deployed down the trawl ramp on the stern of the ship.

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 more 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. More on acoustics and what happens in the fish lab in my next blog!

Personal Log:

WOW! What an adventure!!! So I must get you caught up on some of the happenings thus far. After a mix-up where my reservation was cancelled on the Saturday afternoon flight from Anchorage to Dutch Harbor and the threat of being stranded in Anchorage for another day, I finally made it to Dutch. The weather cooperated (which is not the case more often than not), and we landed on Dutch Harbor after a quick refueling stop in King Salmon. Since we landed after 8pm, we went straight to one of the few restaurants in Dutch Harbor and had a late dinner before heading to the Oscar Dyson for the night.

IMAG0751 — My flight after landing in Dutch Harbor, Alaska!

Sunday morning, we went with several of the scientists out to Alaska Ship Supply to get some gear. I picked up my obligatory “Deadliest Catch” shirt and hat as all tourists do here in Dutch Harbor. We made three trips to the airport throughout the day to see if some of the science gear and luggage came, but came back disappointed. On one of our trips to the airport, we had lunch at the airport restaurant. I had Vietnamese Pho, which is a beef noodle soup, but it wasn’t nearly as good as the Pho my wife makes. 🙂 We also drove up the “Tsunami Evacuation Route” to an overlook where we could see all of Dutch Harbor and the town of Unalaska. Later, we drove around Unalaska and stopped to check out some tidal pools on our way back to the Oscar Dyson. In the afternoon, we checked out the World War II museum that was absolutely fascinating! I did not know Dutch Harbor was bombed by the Japanese and that so many American soldiers were stationed in the bunkers surrounding the harbor. For dinner, I had black cod (sablefish) at the Grand Aleutian Hotel. Yummy!

Monday we embarked on our adventure shortly after noon. We had to leave the dock because another ship was scheduled to offload there in the afternoon. The scientists’ equipment arrived on a late Monday morning cargo flight, but they didn’t make it to the ship on time!!! We couldn’t go to sea without them, so we deployed the “Peggy D” to go pick them up and bring them aboard!

IMAG0759 — The Peggy D brings our scientists Rick and Kresimir with their long-awaited research equipment to the Oscar Dyson so we may head out to the Bering Sea!

Once we had our missing scientists, we left the safety of Dutch Harbor and ventured into open water. On our way, we saw dozens of humpback whales! None of the whales breached (jumped out of the water), but several of them fluked (dove and put their tail out of the water).

We started our day and a half journey to get to the starting point of our survey transects (the end point of last month’s survey). On our trip out, we experienced 6 to 10 ft seas and a 25 knot wind. It was a “gentle” welcome to the Bering Sea, but I struggled to get my sea legs underneath me. Meclizine is great motion sickness medication, but it sure knocked me out. I feel better now that I am not taking anything and am used to the rocking deck. While we made our way to our first transect, we had a couple of emergency drills. Here I am with fellow Teacher at Sea, Johanna, in our immersion suits as we completed our abandon ship drill.

On Wednesday morning, we began our first transect and did our first trawl along the transect (more on that later). I learned how to work in the fish lab collecting biological data on the catch we brought on board. I have been struggling to adjust to both my shift, which is 4am to 4pm, and the fact that the sun sets around 1am and rises at about 7am.

Thursday morning I woke on time and observed the survey scientists and crew deploying the CTD (Conductivity, Temperature, Depth) rosette from the hero deck (on the starboard side).

IMAG0828 — Skilled Fisherman Jim is assisting with deploying the CTD.

We also had beautiful clear skies and I was able to see Venus and Jupiter. At sunrise, I saw the GREEN FLASH!!! It was a beautiful start to the day.

We processed one mid-water AWT (Aleutian Wing Trawl) trawl that was all pollock, then switched to the 83-112 bottom trawl net (83 foot long head-rope and 112 foot long foot-rope) and pulled up a lot of jellyfish with our pollock.

Last night, I finally got a really good night sleep! This morning (Friday), I watched the CTD deployment again and learned more about the data being collected (more on this later). No spectacular sunrise this morning as it was the typical gray, foggy weather. I went up and spent some time on the bridge and Chelsea, our navigator/medic, taught me a lot about the instrumentation used for navigating the ship. There sure is a lot of technology on board!!!

From the bridge, we saw a pod of Dall’s Porpoise feeding, splashing around, and moving fast! We processed another AWT trawl of pollock that had quite a few herring mixed in. We traveled further into Russian waters than originally anticipated as we tried to identify the northern boundaries of the pollock population to get the best picture of the entire pollock range. We spotted a huge Russian trawler from the bridge!

We then headed south again towards American waters, but needed to do a quick water column profile test. Since we did not want to stop to drop the CTD again, I got to deploy a XBT (Expendable Bathythermograph)! After all the talk about safety briefings, the use of ballistics, and outfitting me with every piece of safety gear we could muster, I got ready to fire the XBT!!! Turns out, when you pull the firing pin, the XBT just slides out of the tube… no fireworks, no big bang… just a small kurplunk as the XBT enters the water. We all had a good laugh at my expense. See, scientists know how to have fun!

WOW! So I have just scratched the surface of our voyage thus far! Next time, I will give you a snapshot of what life was like aboard the ship.

June 20, 2012August 11, 2021

Amanda Peretich: Get to Know Me, June 20, 2012

NOAA Teacher at Sea
Amanda Peretich
(Almost) Onboard NOAA Ship Oscar Dyson
June 29 – July 17, 2012

Mission: Pollock Survey
Geographical area of cruise: eastern Bering Sea
Date: June 20, 2012

That's me and one of my loves: the periodic table! — That’s me and one of my loves: the periodic table!

PERSONAL LOG
My first post is supposed to be an introduction to me and what I’ll be doing for three weeks in the middle of the Bering Sea so here goes nothing! My name is Amanda Peretich, and I have been teaching biology, chemistry, and criminal science investigations (get it? CSI) at Karns High School in Knoxville, TN for the past four years. My route to teaching high school was probably not really traditional, but it’s provided me with plenty of adventures along the way, and if you know me, you know I love a good adventure!

I am so excited to arrive on the NOAA ship Oscar Dyson to participate in walleye pollock research in an acoustic trawl survey in the eastern Bering Sea (similar to this one from last summer) in a little over a week. You’ll hear plenty more about this research in the weeks to come. How am I able to do this? Well, NOAA (which is an acronym for National Oceanic and Atmospheric Administration) has a Teacher at Sea program that I had never heard of before last fall when I randomly found it in a Google search for summer teacher-y programs. Ahh, the wonders of the internet and technology! So I applied to the program (really kind of at the last-minute, which also hits on my procrastination problems), wrote some pretty good essays, had some amazing recommendations from people (shout out to Theresa Nixon and Anne Hudnall for what I can only imagine were the best letters ever!), and later found out I’d been selected as one of 25 teachers from across the U.S. for this amazing opportunity!

FUN FACT: Did you know that the Discovery show Deadliest Catch is filmed in the Bering Sea and that the operations base for the fishing fleet is in Dutch Harbor, Alaska where I will be leaving from? However, I think those rough seas on the show are due to filming during the fall and winter seasons, not summer. I’m sure I will update you in a later post about how crazy the waters are during July, but I will have to remember that it could be much more treacherous.

Not that I’ll be able to have so many photos in all of my blogs (being on a ship in the middle of the ocean = sporadic and slow internet access, thus less photos), but this little slideshow will hopefully tell you a little more about myself in picture form:

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Each of my posts (which are limited to about every other day or every 3 days) aboard the ship will include a science & technology log and then a personal log, but we are also able to add additional sections as well. Help me choose which ones to add below! (sidenote: I chose the “sunset” background for the poll because of the birds in it – I hear there are plenty of birds in Alaska – now the palm trees and sun, you’ll want to replace with other trees and clouds)

Did I forget to mention that this experience is also the beginning of a new chapter in my life? My wonderful husband Michael finished his PhD in chemistry at the University of Tennessee and accepted a civilian chemist position in the fuels lab with NAVAIR in Patuxent River, Maryland. I finished out the school year and sold our house in Knoxville while he has been training and traveling to fun places like Pensacola, Florida, but I will officially move up to Maryland the day before I get on a plane for Alaska! Didn’t I say how much I love adventures and the unknown?