krill – Page 10 – NOAA Teacher at Sea Blog

August 12, 2009April 6, 2021

Justin Czarka, August 12, 2009

NOAA Teacher at Sea
Justin Czarka
Onboard NOAA Ship McArthur II (tracker)
August 10 – 19, 2009

Mission: Hydrographic and Plankton Survey
Geographical area of cruise: North Pacific Ocean from San Francisco, CA to Seattle, WA
Date: August 12, 2009

Weather Data from the Bridge

Sunrise: 06:25 a.m.
Sunset: 20:03 (8:03 p.m.)
Weather: isolated showers/patchy coastal fog
Sky: partly cloudy
Wind direction and speed: North 10-15 knots (kt)
Visibility: unrestricted to less than 1 nautical mile (nm) in fog
Waves: northwest 4-6 feet
Air Temperature: 17.3 °C
Water Temperature: 16.6 °C

Science and Technology Log

Justin Czarka collects water samples to use in nutrient and chlorophyll research. While on the deck during “ops” (operation) all personnel must wear a life jacket and hardhat.

This log discusses the purpose behind the scientific cruise aboard the McArthur II. The cruise is titled, “Hydrographic and Plankton Survey.” The cruise is part of a larger study by many scientists to, in the words of chief scientist, Bill Peterson, “understand the effects of climate variability and climate change on biological, chemical and physical parameters that affect plankton, krill, fish, bird and mammal populations in Pacific Northwest waters.” This specific cruise focuses on hydrology, harmful algal blooms, zooplankton, krill, fish eggs, fish larvae, and bird and mammal observations.

I will provide an overview of these aspects of the cruise. The McArthur II is set up with sensors for salinity, temperature, and fluorescence that provide a continuous monitoring of the ocean (hydrology) throughout the cruise. In addition at various points along the transect lines (see the dots on the diagram of the cruise route on page 2), the CTD is deployed into the water column at specific depths to determine salinity (via measuring conductivity), water temperature, and depth (via pressure), and collect water samples (which we use to measure chlorophyll and nutrient levels at specific depths). The transects (predetermined latitudes that forms a line of sampling stations) have been selected because they have been consistently monitored over time, some since the late 1980s. This provides a historical record to monitor changes in the ocean environment over time.

The dots represent planned sampling station. Due to sea conditions, these have been slightly modified.

One scientist, Morgaine McKibben from Oregon State University, is researching harmful algal blooms (HAB). HABs occur when certain algae (the small plants in the ocean that are the basis of the food web) produce toxins that concentrate in animals feeding on them. As these toxins move up the food web through different species, they cause harmful effects in those species, including humans. Bill Peterson (NOAA/ Northwest Fisheries Science Center) and Jay Peterson (OSU/Hatfield Marine Science Center) are studying copepod reproduction. They are collecting data on how many eggs are laid in a 24 hour period, as well as how the copepod eggs survive in hypoxic (low oxygen) conditions. Mike Force, the bird and marine mammal observer is keeping a log of all species spotted along the cruise route, which is utilized by scientists studying the species.

Personal Log

Tiny squid collected in a vertical net and viewed under microscope on Crescent City transect line at 41 deg 54 min North.

Who said you never find the end of the rainbow? All you have to do is go out to sea (or become a leprechaun!). We have been going through patches of fog today, putting the foghorn into action. When it clears out above, yet is foggy to the horizon, you get these white rainbows which arc down right to the ship. We have become the pot of gold at the end of the rainbow. Who knew it was the McArthur II! If you follow the entire rainbow, you will notice that it makes a complete 360° circle, half on top the ocean and half in the atmosphere near the horizon.

I enjoyed using the dissecting microscope today.

The water collected from the vertical net is stored in a cooler on the deck to be used in experiments. I was able to collect a sample of the water, which contained a diverse group of organisms, from tiny squids to copepods to euphausiids. These tiny organisms from the size of a pinhead to a centimeter long are critical to the diets of large fish populations, such as salmon. Under magnification, one can see so much spectacular detail. I have learned how essential it is to have an identification guide in order to identify the names of each copepod and euphausiid. On the other hand the scientists tend to specialize and become very adept at identifying the different species.

Animals Seen Today

Arrow worms (long clear, with bristles)
Shrimp Copepods
Tiny rockfish (indigo colored eyes)
Fish larvae

August 1, 2009April 6, 2021

Kathryn Lanouette, August 1, 2009

NOAA Teacher at Sea
Kathryn Lanouette
Onboard NOAA Ship Oscar Dyson
July 21-August 7, 2009

Mission: Summer Pollock Survey
Geographical area of cruise: Bering Sea, Alaska
Date: August 1, 2009

This sonar-generated image shows walleye pollock close to the sea floor. The red line at the bottom of the image is the sea floor. The blue specks at the top of the image are jellyfish floating close to the water’s surface.

Weather Data from the Ship’s Bridge
Visibility: 10+ nautical miles
Wind direction: variable
Wind speed: less than 5 knots, light
Sea wave height: 0 feet
Air temperature: 7.9˚C
Seawater temperature: 8.6˚C
Sea level pressure: 30.1 inches Hg
Cloud cover: 7/8, stratus

Science and Technology Log

In addition to the Aleutian wing trawl (which I explained in Day 5 NOAA ship log) and Methot (which I explained in Day 8 NOAA ship log), scientists also use a net called an 83-112 for bottom trawls. The 83-112 net is strong enough to drag along the sea floor, enabling it to catch a lot of the animals that live in, on, or near the sea floor. This afternoon, we conducted the first bottom trawl of our cruise. Bottom trawls are usually conducted in two situations: if the walleye pollock are too close to the sea floor to use an Aleutian wing trawl or if the scientists want to sample a small amount of fish (because the 83-112’s net opening is smaller than the Aleutian wing trawl’s net). From the looks of the sonar-generated images, it appeared that most of the walleye pollock were swimming very close to the bottom so the scientists decided it would be best to use the 83-112 net.

Here I am holding one of the skates that was caught in the bottom trawl

Once the fish were spotted, we changed our course to get ready to trawl. Usually the trawl is made into the wind for stability and net control. Once the ship reached trawling speed, the lead fisherman was given the “OK” to shoot the doors. Slowly, the net was lowered to 186 meters below the surface, the sea depth where we happened to be. The water temperature down there was about 1˚C (compared to 7˚C on the sea’s surface). I had heard from a previous Teacher At Sea that bottom trawls brought up a wide variety of animal species (compared to the relatively homogenous catches in mid-water trawls). And sure enough, when the net was brought up, I couldn’t believe my eyes!

All told, we sorted through over 7,000 animals, a total of 36 different species represented in the total catch. It took 4 of us over 4 hours to sort, measure, and weigh all these animals. There were over 350 walleye pollock in this catch as well as skates, octopi, crabs, snails, arrowtooth flounder, sea anemones, star fish, and dozens of other animals. Some of them were even walking themselves down the table.

During this catch, I also learned how to take the ear bones, or otoliths, out of a walleye pollock. Why ear bones you might ask? Using the ear bones from a walleye pollock, scientists are able to determine the exact age of the fish. Misha Stepanenko, one of the two Russian scientists on board the Oscar Dyson, showed me how to cut partially through the fish’s skull and take out two large ear bones. Once they were taken out, I put them in a solution to preserve them. Back in NOAA’s Seattle lab, the ear bones are stained, enabling scientists to count the different layers in each ear bone. For every year that the fish lives, a new layer of bone grows, similar to how trees add a layer for each year that they live. By learning the exact age of a fish, scientists are able to track age groups (called “cohorts”), allowing more precise modeling of the walleye pollock population life cycle.

A diagram of an otolith, or ear bone, of a fish. You can see that it’s a lot like looking at tree rings!

Personal Log

So far this trip, we have sailed within 15 miles of Cape Navarin (Russia) on at least two different occasions but fog and clouds prevented any glimpse of land both times. It was a frustrating feeling knowing that land was so close, yet impossible to see. After 12 days of looking at nothing but water and sky, seeing land would have been a welcome treat.

Despite not seeing land, I still felt like I was in Russia just from listening to different fishing vessels communicate with one another. On our first night in Russian waters, we sailed through a heavy fog, with 7 or 8 different boats fishing nearby. I was impressed with how Ensign Faith Opatrny, the Officer on Deck at the time, communicated with various vessels, using collision regulations (“the rules of the road”) to navigate safely. On a culinary note, I got my first chance to eat some of a catch. After most trawls, we discard remaining inedible specimens overboard. After our bottom trawl however, one of the scientists filleted some of the cod. The next day, the stewards cooked it up for lunch. It tasted great and it felt good to be eating some of the fish that we sampled.

A graph showing the adult walleye pollock biomass estimates from 1965 to 2008.

As the cruise starts to wind down, I also want to express my gratitude to all the NOAA scientists and Oscar Dyson crew. Everyone in the science group took time to explain their research, teach me scientific techniques, and answer my many questions. On numerous occasions, the deck crew explained the mechanics of fishing nets as well as the fishing process. The engineering crew gave me a tour of the engine rooms, describing how four diesel engines power the entire boat. The survey techs explained how different equipment is operated as well as the information it relays back to the scientists. The NOAA Corps officers showed me how to read weather maps, take coordinates, and explained ship navigation. The ship’s stewards described the art and science behind feeding 33 people at sea. And the USFWS bird observers patiently showed me how to identify numerous bird species. From each of them, I learned a tremendous amount about fisheries science, fishing, boats, sailing, birding, and life in the Bering Sea. Thank you!

Answer to July 28 (Tuesday) Log: How has the walleye pollock biomass changed over time?
In the past few years, the walleye pollock biomass has decreased (according to the acoustic-trawl survey, the survey that I joined.) It should be noted that there is a second complementary walleye pollock survey, the eastern Bering Sea bottom trawl survey. This survey studies walleye pollock living close to the sea floor. As walleye pollock age, they tend to live closer to the sea floor, thus the bottom trawl survey sometimes shows different biomass trends than the acoustic-trawl survey. Both surveys are used together to manage the walleye pollock stock.

An up-close look at one of the squid’s tentacles

Animals Seen
Auklet, Arrowtooth flounder, Basket star, Bering skate, Cod, Hermit crab, Fin whale, Fur seal, Octopus, Sculpin, Sea mouse, Sea slug, Shortfin eelpout, Snow crab, Squid, and Tanner crab.

New Vocabulary: Bottom trawl – fishing conducted on and near the bottom of the sea floor. Catch – fish brought up in a net. Shoot the doors – a fishing expression that means to lower the 2 metal panels that hold open the fishing nets in the water. Stewards – the name for cooks on a ship. Table – nickname for the conveyor belt where the fish are sorted for sampling. Vessels – another word for ships.

July 28, 2009April 6, 2021

Kathryn Lanouette, July 28, 2009

NOAA Teacher at Sea
Kathryn Lanouette
Onboard NOAA Ship Oscar Dyson
July 21-August 7, 2009

Here I am sorting different zooplankton species

Mission: Summer Pollock Survey
Geographical area of cruise: Bering Sea, Alaska
Date: July 28, 2009

Weather Data from the Ship’s Bridge
Visibility: 8 nautical miles
Wind direction: 015 degrees (N, NE)
Wind speed: 7 knots
Sea wave height: 1 foot
Air temperature: 7.6˚C
Seawater temperature: 7.3˚C
Sea level pressure: 29.8 inches Hg and falling
Cloud cover: 8/8, stratus

Science and Technology Log

In addition to studying walleye pollock, NOAA scientists are also interested in learning about the really tiny plants (phytoplankton) and animals (zooplankton) that live in the Bering Sea. Plankton is of interest for a two reasons. First, phytoplankton are the backbone of the entire marine food chain. Almost all life in the ocean is directly or indirectly dependent on it. By converting the sun’s energy into food, phytoplankton are the building blocks of the entire marine food web, becoming the food for zooplankton which in turn feed bigger animals like small fish, crustaceans, and marine mammals. Second, zooplankton and small fish are the primary food source for walleye pollock. By collecting, measuring, and weighing these tiny animals, scientists are able to learn more about the food available to walleye pollock. In addition, every time the scientists trawl for walleye pollock, the stomachs of 20 fish are cut out and preserved. Back at a NOAA lab in Seattle, the contents of these fish stomachs will be analyzed, giving scientists a direct connection between walleye pollocks’ diet and specific zooplankton populations found throughout the Bering Sea.

A simplified marine food chain (Note: A complete marine food web involves hundreds of different species.)

Two important zooplankton groups in the Bering Sea are copepods and euphausiids (commonly referred to as krill). Euphausiids are larger and form thick layers in the water column. In order to catch euphausiids and other zooplankton of a similar size, a special net called a Methot is lowered into the water. This fine meshed net is capable of catching animals as small as 1 millimeter. The same sonar generated images that show walleye pollock swimming below the water’s surface are also capable of showing layers of zooplankton. Using these images, the scientists and fishermen work together, lowering the net into the zooplankton layers.

The Methot net is the square shaped net in the background. It was just brought up and is filled with hundreds of zooplankton.

Once the Methot net is back onboard the boat, its contents are poured through fine sieves and rinsed. All species are identified. A smaller sub sample is weighed and counted. This information is applied to the entire catch so if there were 80 krill, 15 jellyfish, and 5 larval fish in a sub sample, then scientists would approximate that 80% of the entire catch was krill, 15% was jellyfish, and 5% was larval fish. Having only seen photos of some of these zooplanktons, it was interesting to hold them in my hands and look at them up close. They seemed better suited for space travel or a science fiction movie than the Bering Sea!

Personal Log

The day before, I caught my first glimpse of Dall’s porpoises. This pod of porpoises came swimming alongside the boat. It was awesome to see their bodies rise and fall in the water. I was surprised at how quickly they were swimming, darting in and out of the Oscar Dyson’s wake. Today, I also got my first glimpse of a whale! It was a fin whale, a type of baleen whale, about 20 meters from the boat. It was exciting to watch such a large mammal swimming in such a vast expanse of water. I’m hoping to see a few more marine mammal species before we return to port. The seas have been very calm for the last five days, at times as smooth as a mirror. I’m surprised that I’ve gotten used to falling asleep in the early morning hours and waking around midday. Now that I’ve adjusted to the 4pm to 4am shift, I’m wondering how strange it will be to return to my regular schedule back on the east coast.

Answer to July 25^th Question of the Day: Why are only some jellyfish species capable of stinging?
As I picked up my first jellyfish in the wet lab (asking at least twice “Are you sure this won’t sting?”), I wondered why some jellyfish don’t sting. So I did some reading and asked some of the scientists a few questions. Here is what I found out: All jellyfish (called “gelatinous animals” in the scientific world) have stinging cells (nematocysts) in their bodies. When a nematocyst is touched, a tiny barb inside fires out, injecting toxin into its prey. It seems that in some jellyfish, the barbs are either too small to pierce human skin or that nematocysts don’t fire when in contact with human skin.

One euphausiid and two different species of hyperiid amphipod (They are between 1-3 cm long) — One euphausiid and two different species of hyperiid amphipod

Animals Seen
Capelin, Dall’s porpoise, Euphausiid, Fin whale, Hyperiid amphipod, and Slaty-backed gull.

New Vocabulary: Baleen whale – a whale that has plates of baleen in the mouth for straining plankton from the water (includes rorqual, humpback, right, and gray whales). Methot net – a square framed, small meshed net used to sample larval fish and zooplankton. Phytoplankton – plankton consisting of microscopic plants. Plankton – small and microscopic plants and animals drifting or floating in the sea or fresh water. Trawl – to fish by dragging a net behind a boat. Zooplankton – plankton consisting of small animals and the immature stages of larger animals

Question of the Day: How has the walleye pollock biomass changed over time?

July 25, 2009April 6, 2021

Kathryn Lanouette, July 25, 2009

NOAA Teacher at Sea
Kathryn Lanouette
Onboard NOAA Ship Oscar Dyson
July 21-August 7, 2009

Mission: Summer Pollock Survey
Geographical area of cruise: Bering Sea, Alaska
Date: July 25, 2009

Weather Data from the Ship’s Bridge
Visibility: 10+ miles (to the horizon)
Wind direction: 030 degrees (NE)
Wind speed: 15 knots
Sea wave height: 4-6 feet
Air temperature: 6˚C
Seawater temperature: 6.4˚C
Sea level pressure: 29.85 inches Hg and rising
Cloud cover: 8/ 8, stratus

Science Log

Why study walleye pollock? Before even setting sail, I wondered why NOAA scientists were interested in studying walleye pollock. It turns out that walleye pollock is the largest fishery, by volume, in the USA. In one year, about 1 million metric tons of walleye pollock are fished, mostly from the waters of the Bering Sea. Given that walleye pollock accounts for such a large percentage of the total fish caught in the United States, I was curious why I had never seen it on restaurant menus or rarely seen it at supermarket fish counters. It is because walleye pollock is usually processed into other things – like fish sticks, imitation crabmeat, and McDonald’s fish fillet sandwiches. So it seems that walleye pollock is that mild white fish you often eat when you don’t know for sure what kind of fish you are eating.

Above is a map showing the 31 transect lines of the walleye pollock survey area. I have joined the cruise that is sailing along the 8 transect lines closest to Russia.

In addition to supporting a major multi-billion-dollar fishing industry, walleye pollock is a fundamental species in the Bering Sea food web. It is an important food source for Steller sea lions as well a variety of other marine mammals, birds, and fish. The population size, age composition, and geographic distribution of walleye pollock significantly affect the entire Bering Sea ecosystem. What do scientists hope to learn about walleye pollock? NOAA scientists are primarily interested in calculating the total biomass of walleye pollock. To estimate how many walleye pollock are in the Bering Sea, scientists sample the fish, recording their age, length, weight, male/female ratio, and geographic location. This information is used by North Pacific Fishery Management Council (NPFMC) to set sustainable fishing quotas for the following year. The NPFMC, whose membership comprises university, commercial, and government representatives, uses NOAA’s survey data, fishery observer program data, as well as catch statistics from the commercial fishing industry, to determine how much walleye pollock can be fished in the coming year.

An illustration of the Oscar Dyson sending down sound waves (in order to “see” the animals swimming below the water’s surface.)

Where do scientists study walleye pollock? Every year or two, a NOAA research ship (usually the Oscar Dyson) travels throughout the Bering Sea, following approximately 31 transect lines. These transect lines can be anywhere from 60 to 270 miles long. These lines were selected because they include areas where either walleye pollock spawn in the winter or feed in the summer. As the ship travels along these lines, its sonar system uses sound waves to locate fish and other animals living below the water’s surface. As the sound waves return to the ship, they create different images, depending on which animals are swimming in the water below. Using these images, the scientists decide whether or not they should lower the nets and sample the walleye pollock. They also continuously store digital data from the images, later using this information to estimate the total biomass of the fish species. On this 18 day research cruise, the scientists are hoping to travel the last 8 transect lines (over 1,500 nautical miles). Each transect line takes us into Russian waters. On Thursday, we reached our first transect line. Within hours of traveling along this first line, many schools of walleye pollock were spotted. After the fish net was brought up, I was amazed at the number of fish that came sliding down the conveyor belt into the science lab. I helped weigh and measure hundreds of fish, a quick introduction to the whole process!

Personal Log

We traveled into Russian waters today, crossing the International Date Line as we went. So technically, Saturday became Sunday this afternoon! But later in the evening, we completed the transect line, turned, and headed back into Saturday just as night fell. Luckily, the time never changes here on the boat. The scientists and crew live on Alaska Daylight Time (ADT), regardless of how far we travel to the north and west. I’ve see a few whales spouting but so far, I haven’t been able to identify any. In the coming days, I am hoping to get a glimpse of their backs or flukes (tails). It has been exciting seeing so many animals – some of which I never even knew existed. A few of these animals look a bit scary, like this Pacific lamprey. Its mouth forms a suction and then all those small yellow teeth go to town, letting it feed on the blood and tissue of its prey. Even the small tongue in the back of its mouth is toothed!

Animals Seen
Hyperiid amphipod Aequorea species, Chrysaora melanaster jellyfish, Euphausiids (aka krill), Pacific lamprey, and Short-tailed albatross.

New Vocabulary: Biomass – the total amount of a species, by weight Cruise – nautical trip, for science research or fun. Quotas – a limited or fixed number or amount of things. Sample – to study a small number of species from a bigger group. Transect Line – a straight line or narrow section of land or water, along which observations and measurements are made

Question of the Day
Why are only some jellyfish species capable of stinging?

Here I am holding up a Chrysaora melanaster jelly fish (Luckily this species doesn’t sting!) — Holding up a Chrysaora melanaster jelly fish (Luckily this species doesn’t sting!)

July 5, 2009April 5, 2021

Megan Woodward, July 5, 2009

NOAA Teacher at Sea
Megan Woodward
Onboard NOAA Ship Oscar Dyson
July 1 – 18, 2009

Mission: Bering Sea Acoustic Trawl Survey
Geographical Area: Bering Sea/Dutch Harbor
Date: Tuesday, July 5, 2009

Weather/Location
Position: N 58.37.239; W 171.05.968
Air Temp: 4.5-6.0 (deg C)
Water Temp: 4.94 (deg C)
Wind Speed: 16 knots
Weather: Overcast and rainy

This is the screen I use to get info about our ship’s location. The little white speck inside the red oval is our ship.

Science and Technology Log

We have been at sea now for almost five days in search of pollock. The fish had not been spotted on the lines we traveled on until today. We had the opportunity for our first pollock trawl around 02:00, and used the Methot net to bring in two zooplankton samples earlier in my shift. This was by far the most action yet. I was eager and ready to see what the fishing process was all about. This log will focus on the zooplankton samples.

The Methot net was put in the water and lowered to the desired depth determined by watching the location of the acoustic return. After twenty minutes the net was brought back up and the catch was unloaded. I was expecting a net full of euphausiids, but the critters were actually collected in a small container on the back end of the net. The catch was brought into the fish lab and dumped into a bucket so we could separate the other organisms caught in the net (9 jellyfish and 23 tiny pollock in this case). Once the other fish had been removed, we took a sample (a ••• cup scoop) to weigh and count the euphausiids in the sample (sample is shown above). The rest of the catch was also weighed.

There were 543 euphausiids in the scoop. The weight and number help estimate the amount of euphausiids in the entire catch. We repeated this process again a few hours later. The second sample had almost twice as many euphausiids, 13 jellyfish and fewer than 5 pollock.

The survey tech and skilled fishermen lower the Methot net into the water.

Personal Log

Until today, the fishing portion of this trip remained a mystery. However, I was feeling a little sea sick, okay very sea sick, so it was probably a good thing. We encountered some VERY rough seas with sustained winds ranging from 30-40 knots and swells averaging 17 ft. Some of the swells were much larger; one was rumored to be almost 35 ft. high. Apparently the rough seas are expected to return tonight and tomorrow. My sea legs are securely fastened, so I am ready to take on whatever the sea has to offer.

When we brought in the first haul of pollock last night, my eyes must have looked like they were going to roll out of my head. I couldn’t believe how many fish were coming across the conveyor belt. This was what I had been waiting for, so I got on my rain gear and started sorting the fish. Each species was placed into separate crates so a count of all fish caught could be taken. Of course, pollock made up the majority of the catch. In the next few weeks, I will become an expert member of the pollock survey team. Everyone on board, both scientists and crew, have been more than willing to answer my

A sample of zooplankton brought up in the Methot net. These are euphausiids, which are also referred to as krill.

Getting used to the 16:00-04:00 (4pm4am) shift has been trying. Today’s shift was the first that didn’t require a nap. Due to the odd shift hours, I’ve been waking up at 14:00 (2 pm) and going to bed around 05:00 (5 am). This makes mealtime tricky. Dinner is served first, then I eat some breakfast in the middle of the night. My body is thoroughly confused. The ship’s cooks are wonderful, and continually provide a stocked mess hall with loads of choices. I swear the dessert bar is continually whispering my name. I couldn’t ask for a more kind, welcoming group of people to work questions. One part of this adventure I’m looking forward to is getting to know the wide range of characters who make this important research possible.

It was certainly a thrill to see the first whale of the trip. The pod was spotted just off the bow of the ship andlater seen in the distance.

Animals Seen

Fin Whale
Jelly Fish
Flathead Sole
Northern Flathead Sole
Arrow tooth Flounder
Pollock
Yellow Irish Lord
Euphausiids

New Vocabulary

Zooplankton– A very small or microscopic animal organisms possessing little or no power of locomotion (can’t move themselves), leaving them to merely drift or float in the water.

Euphausiids (eu·phau·si·id) – A type of zooplankton, also known as krill, are tiny shrimp-like crustaceans that form an important part in the diet of many animals including whales, seals, fishes and birds. These are the main food source for pollock.

Methot Net – Methot is the name of the man who designed the style of plankton net we used to catch the euphausiids.

One of several jellyfish brought up in the nets. This guy is slimy and heavy, but not a stinger