Erica Marlaine: Diving Down the pH Scale, July 13, 2019

NOAA Teacher at Sea

Erica Marlaine

Aboard NOAA Ship Oscar Dyson

June 22 – July 15, 2019


Mission: Pollock Acoustic-Trawl Survey

Geographic Area of Cruise: Gulf of Alaska

Date: July 13, 2019

Weather Data from the Bridge:

Latitude: 57º 09.61 N
Longitude: 152º 20.99W
Wind Speed: 15 knots
Wind Direction: 210 º
Air Temperature:  12º Celsius
Barometric Pressure: 1013 mb
Depth of water column 84 m
Surface Sea Temperature: 12º Celsius


Science and Technology Log

Are you wondering what it’s really like to live and work full-time on a NOAA research vessel? I asked Andrea Stoneman, the Senior Survey Technician on the NOAA Ship Oscar Dyson.

Andrea Stoneman
Senior Survey Technician Andrea Stoneman

Like everyone onboard the Oscar Dyson, Andrea is always working hard, but always has a smile on her face. Originally from Duluth, Minnesota, she has been employed by NOAA as a “wage mariner” for a year. A wage mariner means she is an at-sea civilian employee of NOAA. She began college at the University of Minnesota as a business major, but an internship as a freshwater mussel researcher changed her life and made her realize her true love: BIOLOGY! She earned a degree in Environmental Science, and then attended graduate school at Delaware State University, where NOAA funded her research on ocean acidification and its impact on fish.

Are you wondering what ocean acidification means?  

The amount of carbon in the ocean is rising due to an increase in the amount of carbon dioxide (CO2) in the air. Carbon dioxide acidifies the water, reducing its pH level.  The letters pH stands for the ‘potential of Hydrogen.’ The pH scale was invented in 1909 by a biochemist names S.P. Sorenson. The scale uses numbers from 1 to 14, with 1 being the most acidic, 14 being the least acidic (or more alkaline) and 7 as the middle (neutral) point.

For the past 300 million years, the average pH of the ocean was approximately 8.2. It is now closer to 8.1, a drop of 0.1 pH units.  Remember, the numbers go “in reverse” so a drop in pH means it is MORE acidic.  You may be thinking, but it’s only a drop of 0.1. That doesn’t sound like a lot. However, a drop of 0.1 represents a 25-percent increase in acidity.  That’s because the pH scale is a logarithmic scale, not a linear scale.  To understand a linear scale, think of a ruler. The difference between inches on a ruler stays constant. A 5-inch fish is one inch bigger than a 4-inch fish, and 2 inches bigger than a 3-inch fish. In contrast, the pH scale is a logarithmic scale in which two adjacent values increase or decrease by a factor of 10.  Therefore, a pH of 3 is ten times more acidic than a pH of 4, and 100 times more acidic than a pH of 5.

Studies indicate that many marine species may experience adverse effects on their health, growth, reproduction, and life span due to ocean acidification. That means fish could develop diseases, have fewer babies, or die younger.

You and I need calcium to build strong bones. We get calcium through milk, cheese, green leafy vegetables, and many other sources. Marine species also need calcium carbonate to build their bones or shells. Ocean acidification causes carbonate ions to be less abundant in the ocean, which makes it harder for marine species to build strong bones and shells. This is especially bad for oysters, clams, sea urchins, corals, and mussels, the very species that made Andrea fall in love with science!

After graduate school, Andrea worked as a fisheries observer on commercial fishing vessels. (I met quite a few people on-board the ship who are or were observers.) To a non-fisheries person, an “observer” SOUNDS like someone who stands around watching others, but it is actually very hard work! Observers document compliance (making sure that things are being done the correct way). They take samples of the catch and collect data regarding the size of the catch and the species caught.  The data goes into the same service model that NOAA data does, which is vital for ensuring sustainable fishing for the future. 

Through her work as an observer in Alaska, Andrea met people at NOAA, took a tour of a NOAA ship, and decided to apply for a job with NOAA.  (Hmmm… When I interviewed Ensign Andonian for an earlier blog, she also mentioned visiting a NOAA ship as the thing that made her decide to choose a career with NOAA. That gives you an idea of just how amazing NOAA ships are!)

So what does a Senior Survey Technician do?

She runs and maintains all of the scientific sensors on the ship (including the meteorological and oceanographic sensors). She also runs the CTD, a device which measures the conductivity, temperature, depth, salinity, and other oceanographic parameters of the water. 

CTD
The CTD device

In addition, she is involved in setting and retrieving the fishing nets and is an expert at processing the catch in the fish lab. Andrea ensures that the data collected onboard is sound and accurate, and “packages” the data so that it is presentable and accessible to NOAA thus becoming accessible to the public whom NOAA serves.

Asked if she recommends a NOAA life, Andrea says it’s great for college graduates who have an interest in science and a love of the ocean. Some perks (especially for new college graduates) include living rent-free onboard, having delicious meals cooked for you three times a day, and getting to see the world while being involved in interesting, and sometimes ground-breaking, scientific research. An added perk is that working for the federal government can “erase” some of your student loans!

Andrea enjoys being the Senior Survey Technician onboard the NOAA Ship Oscar Dyson, and has fallen in love with Alaska, which she now considers her home.

Click below to watch a 2-minute video by NOAA about ocean acidification:



Personal Log

While I cannot describe what it is like to live full-time on a NOAA ship, I can tell you what it’s like as a Teacher at Sea for 26 days. Like everyone onboard, I “work” a 12-hour shift.  The science team works shifts starting at either 4 a.m. or 4 p.m.  I was assigned the 4 p.m. to 4 a.m. shift. That means I wake up most days between 2:30 and 3:00 in the afternoon.  On days that I am “good” I head down to the gym. On other days, I grab a light “breakfast” before heading to the chem lab to start my shift.

Often we start our shift processing fish by 4:30. First I suit up in steel-toed boots, a waterproof jacket and overalls, and elbow-high rubber gloves. 

Erica ready for the fish lab
I am ready to work in the fish lab!

Then we process the haul, which means sorting approximately 1000 pounds of fish and jellyfish by species.

haul
An average-sized haul

We weigh them, measure them, and dissect some to collect otoliths (ear bones) or ovaries.  All of this can take 2-3 hours. Then we clean.  The fish lab gets COVERED in fish slime, scales, and jellyfish goo.

Jellyfish "goo"
Jellyfish “goo”

There are high-powered waters sprayers hanging from the ceiling, and we blast every surface in the room with saltwater for at least 10 minutes after every haul. Imagine cleaning your kitchen with a fire engine hose! It’s definitely the most fun I have ever had cleaning!  

cleaning the fish room
One of the many high power saltwater sprayers

At the end of the cruise, I will join Andrea the Survey Technician and the science team for 2-3 hours of meticulously scrubbing and spraying the fish lab so that it is clean and ready for the next group that comes aboard a few days after we leave.

Since the scientists onboard often want to do “pair trawls” (fishing in the same area using the “old” AWT net and the “newer” LFS net in order to align the catch data with the acoustics data),  I am often back in the fish lab an hour later to process another haul, and again clean the fish lab.

After that, depending upon the time, I might have a snack, or do research and write blogs, or spend time in the chem lab with my co-workers, Matthew Phillips (the Fish Lab Lead) and volunteer biologist Nathan Battey, discussing the haul or what is coming up for the rest of the shift. At about 11 p.m., the sun sets, and sometimes it is spectacular, so I try to pop out onto the deck for a quick photo. 

The sun setting near Mitrofania
The sun setting near Mitrofania

At midnight, we start getting ready to do the drop camera to determine which areas are trawlable. We usually do at least 4 camera drops, from approximately 1 p.m. to 4 p.m. This time of night often involves the science team consuming caffeine, ice cream, red vines, sour patch kids, or all of the above. At 4 a.m., the next shift starts, and my roommate, Jamie Giganti, comes into the chem lab. Jamie is a field coordinator for AIS. She works as an observer part of the time, but also provides support and training for new observers, and acts as a liaison between boat captains and observers.

Jamie Giganti
My roommate Jamie Giganti

Jamie’s arrival in the chem lab means it is my turn to go to “our” room.  Although we are roommates, we are never actually in the room at the same time. The goal is that you stay out of the room for the 12 hours your roommate is off-shift, allowing them to sleep or relax.  That means that every time I am on shift I need to make sure that I take everything I might need for the day.

The first few days onboard, I was in bed and asleep 15 minutes after my shift ended. Now that I am accustomed to the schedule, or perhaps due to the caffeine or sugar, I am often up until 5 or 5:30 a.m. That means I go to sleep just as the sun rises.

My stateroom has a bathroom and shower, a desk, a few shelves, lockers that act as a closet, and bunkbeds.  (I was so happy when Jamie asked if she could have the top bunk!)

My state room
My state room

The large window has both magnificent views of Alaska and also blackout curtains that block the sun so that people on my shift can sleep.

The shower area in the bathroom has a slightly raised border, but since the boat moves while you are showering, so does the shower curtain.

shower
Shower

Perhaps other people have figured out how to get the water to stay IN the shower.  I am still working on that. On the upside, the bathroom floor gets cleaned every day! (I am told that one trick is to use zip ties to “lengthen” the shower curtain.  (Next time?)

Processing a haul seems easy now, but it was overwhelming the first few days! As a non-scientist, I was unfamiliar with fish and jellyfish species, perplexed by the computer program used to enter data, and kept confusing which fish to measure, which fish to weigh, and which fish to measure and weigh.  I am so grateful for the patience of everyone around me!

Amazingly, I never got seasick. I wore a scopolamine patch for the first part of the trip, and then one day decided to take it off and learned that I had in fact “gotten my sea legs.” Now I barely feel the boat moving during the day and enjoy the light rocking at night.

I am writing this during my last few days onboard.  While we have occasionally been near land, during much of our time onboard, the view was the incredibly beautiful Gulf of Alaska.  Yesterday, when I saw land in the distance, I was sad to learn that it was Kodiak.  That means my time on the NOAA Ship Oscar Dyson is almost over. 


Lacee Sherman: Teacher With Fish Scales in Her Hair, June 22, 2018

NOAA Teacher at Sea

Lacee Sherman

Aboard NOAA Ship Oscar Dyson

June 6 – 28, 2018

Mission: Eastern Bering Sea Pollock Acoustic Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date:  June 22, 2018

rain gear

TAS Lacee Sherman getting in rain gear to process a haul

Weather Data from the Bridge at 19:00 on 6/24

Latitude: 56° 0.7 N

Longitude: 169° 34.5 W

Sea Wave Height: 3-4 ft

Wind Speed: 16 knots

Wind Direction:107° (E)

Visibility: 10 nmi

Air Temperature: 8.1°C

Water Temperature: 7.7° C

Sky: Overcast

Science and Technology Log

With this blog, I will be focusing on the biodiversity in the Eastern Bering Sea. Biodiversity includes all of the different types of plant and animal species in a given environment. All of the species that I will be discussing I’ve seen come up in the trawl net, or have seen from the ship.

Adult Walleye Pollock

Adult Walleye Pollock

Common Name: Walleye Pollock

Scientific Name: Gadus chalcogrammus

Identifying Features: 3 Dorsal Fins, large eyes

Ecological Importance: Polllock influence the euphausiid populations and are food to many larger marine species, and humans.

Interesting Facts:  Walleye pollock produces the largest catch by volume of any single species inhabiting the 200-mile U.S. Exclusive Economic Zone.

 

 

Common Name: Krill

Scientific Name:  Euphausiidae (Family)

Identifying Features:  1-2 centimeters in length on average.  They look similar to very small shrimp, and often swim in schools.

Ecological Importance:  Krill are a very important food source for many fish and also larger marine mammals such as whales.

Interesting Facts:  They are filter feeders and eat zooplankton and phytoplankton, which makes them omnivores.

Chrysaora melanaster

Chrysaora melanaster

Common Name:  Northern Sea Nettle, Brown Jellyfish

Scientific Name: Chrysaora melanaster

Identifying Features: 16 lines from the center of the bell to the outer edges of the bell.  Large range in sizes, from very small to very large.

Interesting Facts:  Jellyfish may become a problem for the Bering Sea in the future because they reproduce in large numbers and they can dominate an entire environment easily.

Pacific Ocean Perch

Pacific Ocean Perch

Common Name: Pacific Ocean Perch

Scientific Name: Sebastes alutus

Identifying Features: Bright to light red with brown blotches dorsally near fins, large spines on dorsal and anal fins, knob on lower jaw

Ecological Importance: delicious

Interesting Facts: Pacific Ocean Perch are a type of Rockfish.  Pacific Ocean Perch have a swim bladder similar to that of pollock, so they reflect similar acoustic signals and can sometimes be acoustically confused for pollock if no sample is taken in a specific area.

Yellowfin Sole

Yellowfin Sole

Common Name: Yellowfin Sole

Scientific Name: Limanda aspera

Identifying Features: Black line between body and dorsal and ventral fins, fins may appear yellow in color

Ecological Importance: Yellowfin sole are benthic (live and feed on the ocean floor).

Interesting Facts: Yellowfin sole grow slowly and may be 10.5 years old by the time they reach 30 cm in length.

Magister Armhook Squid

Magister Armhook Squid

Common Name: Magister Armhook Squid

Scientific Name: Berryteuthis magister

Identifying Features: 8 tentacles and two larger feeding arms, dark red in color, but white when damaged

Ecological Importance: Prey on fishes and other squid

Interesting Facts: These are the most abundant squid found in the waters of Alaska.

Chum Salmon

Chum Salmon on the conveyer belt with pollock

Common Name: Chum Salmon

Scientific Name: Oncorhynchus keta

Identifying Features: Metallic dark blue on the top and silvery on the sides

Ecological Importance:  Chum Salmon have adapted to live in saltwater and freshwater.  They mainly eat copepods, fishes, squid, mollusks and tunicates.

Interesting Facts:  Chum salmon eggs are hatched in freshwater rivers and streams.  They then travel downstream to live most of their life in the ocean.  When it is time, Chum Salmon spawn (reproduce) in the same freshwater stream they hatched in.  Once a salmon spawns, they die.

Pacific Herring

Pacific Herring

Common Name:  Pacific Herring

Scientific Name:  Clupea pallasii

Identifying Features: Large scales that are shiny silver along the sides and shiny blue along the top of the fish.  Tail has a fork and there is only one dorsal fin.

Ecological Importance: Eat phytoplankton and zooplankton.  Herring and their eggs are eaten by fish, birds, marine mammals, and humans.

Interesting Facts: Herring eggs (roe) are considered a traditional delicacy in Japan called kazunoko.

Yellow Irish Lord

Yellow Irish Lord

Common Name: Yellow Irish Lord

Scientific NameHemilepidotus jordani

Identifying Features: Yellowish tan to dark brown, white to yellow bottom, and yellow gill membranes

Ecological Importance: Since they are usually found close the ocean floor, they regularly eat things like fish eggs, isopods and amphipods, worms, and small fishes.

Interesting Facts: There is another species of Sculpin that is similar called a Red Irish Lord.

Fish Lab Gloves

A photo of our fish lab gloves

 

Personal Log

During our hauls, a member of the science team is needed on the bridge to watch for the presence of marine mammals and endangered bird species.  I am one of the people that gets to do this, and I must admit, there is a slight conflict of interest.  I, of course, want to see all of the marine mammals possible, but if they are nearby during a haul, we are required to give them space until they pass so that they are not injured in any way by the ship.  This can definitely slow down the process of hauling if we see them, but of course I don’t mind it if I get to see more whales.  Most of the time I don’t see any marine mammals and just end up enjoying a beautiful view of the open ocean.

I am definitely feeling more comfortable and at home on the ship now. Constant motion from the swells is the new normal, and the creaks and sounds of the ship are a new soundtrack to listen to (on repeat). Sometimes I like to push the limits and see how far forward or backward I can lean during larger swells to maintain balance and have a few superhero moments as I pretend to defy the laws of physics.

I’m getting to know more about the other people on the ship every day and it’s nice to get into a rhythm and start to really work well together and have a good flow, especially in the fish lab. If we are motivated to finish before meal times, we can process a good haul of Pollock in around 45 minutes. That is much quicker than we started at, and it’s because we have really learned how to capitalize on each other’s strengths and just being willing to do whatever job is needed in the lab, even if it is not our favorite task.

Scientists in the Fish Lab

Some of the science team in the fish lab. (left to right) TAS Lacee Sherman, Darin Jones, Sarah Stienessen, Denise McKelvey, Matthew Phillips, and Mike Levine

I have claimed a workspace in “the cave” (acoustics lab) that is perfectly in the way of the phone when it rings, but it’s usually quiet in there and I can focus on these blogs, reading, or planning for next school year. I’ve also been reading the transcripts to a ton of TED talks when we don’t have access to the internet.

Did You Know?

In Alaska, during the summer, they experience what is called “the midnight sun”. It is rarely ever dark enough to see the stars during the summer.  This happens because of how far north it is!

Midnight Sun

This photo was taken just after midnight on 6/21/18 (summer solstice).

 

Bonus!  Cool Photo time!

Cam Trawl image

Cam Trawl image of pollock and pacific ocean perch. Can you tell the difference?

Bird on the fish table

This bird flew into the table where the fish are held before being processed. It was just hoping for a free meal, but ended up getting stuck. After realizing it couldn’t get out on its own, a survey technician helped to get it out and back on its way.

Watertight door

The black bars on the sides of the doors hold it shut and are controlled by the black lever on the left of the photo. Talk about a tough door!

 

 

References:

Alaska Fisheries Science Center. “Yellowfin Sole Research.” NOAA Fisheries, 25 Oct. 2004, http://www.afsc.noaa.gov/species/yellowfin_sole.php.
“Crustaceans.” Crustaceans , Marine Education Society of Austrailasia, 2015, http://www.mesa.edu.au/crustaceans/crustaceans07.asp.
“Facts.” Facts | Pacific Herring, http://www.pacificherring.org/facts.
Jorgensen, Elaina M. Field Guide to Squids and Octopods of the Eastern North Pacific and Bering Sea. Alaska Sea Grant College Program, University of Alaska Fairbanks, 2009.
Mecklenburg, Catherine W., et al. Fishes of Alaska. American Fisheries Society, 2002.
NOAA. “Chum Salmon (Oncorhynchus Keta).” NOAA Fisheries, 21 Jan. 2015, http://www.nmfs.noaa.gov/pr/species/fish/chum-salmon.html.
TenBrink, Todd & W Buckley, Troy. (2013). Life-History Aspects of the Yellow Irish Lord ( Hemilepidotus jordani ) in the Eastern Bering Sea and Aleutian Islands. Northwestern Naturalist. 94. 126-136. 10.1898/12-33.1.

Lindsay Knippenberg: A Tour of the Oscar Dyson, September 8, 2011

NOAA Teacher at Sea
Lindsay Knippenberg
Aboard NOAA Ship Oscar Dyson
September 4 – 16, 2011

Mission: Bering-Aleutian Salmon International Survey (BASIS)
Geographical Area: Bering Sea
Date: September 8, 2011

Weather Data from the Bridge
Latitude: 54.14 N
Longitude: -166.57 W
Wind Speed: 27.33kts
Wave Height: up to 17 ft
Surface Water Temperature: 8.4 °C
Air Temperature: 7.7 °C

While hiding from the storm in Dutch Harbor for the past two days, I had plenty of time to explore my new home onboard the Oscar Dyson. The Dyson is 209 ft in length and is like a small city. Everything that I would need during my two-week cruise, including a laundry room, would be available to me onboard. To show you what life is like onboard a ship, I decided to go on a little tour of the Dyson and take some pictures of the different areas of the ship. If you are interested in  more in-depth specifications of the ship, check out the Oscar Dyson’s website.

Science and Technology Log

Let’s start in the scientific areas of the ship. I have been spending most of my time working with the fisheries team in the fish lab. When we are done trawling and the fishermen bring in the net, they dump our catch onto a large conveyor belt. As the conveyor belt slowly moves, we sort our catch by species. Once we are done sorting, we also process the catch by weighing, measuring, and taking samples of the organisms. To learn more about this process, see my blog post from September 4th.

The Fish Lab. This is where the fish are brought in and processed.

The Fish Lab. This is where the fish are brought in and processed.

Next to the fish lab is a wet lab. A lot goes on in the wet lab. Some scientists are identifying plankton under microscopes, other scientists are dissecting fish stomachs to see what the fish are eating, and some scientists are filtering water from different depths of the ocean looking for chlorophyll.

The Wet Lab. Scientists study the ocean water, use microscopes, and dissect fish stomachs in this lab.

The Wet Lab. Scientists study the ocean water, use microscopes, and dissect fish stomachs in this lab.

When you pass through yet another door, you end up in another lab called the dry lab. There are several computers and other pieces of machinery that control the instruments that are lowered over the side of the ship at our sampling stations. This room is where a lot of the oceanography data is collected. I will talk about what they do and the data that they are collecting in another blog.

The Dry Lab. Jeanette is watching the data come in from one of the instruments.

The Dry Lab. Jeanette is watching the data come in from one of the instruments.

The last lab is across the hall and it is called the acoustics lab. This room is mostly composed of computers and lots of large screens to track where the fish are underneath the boat. Stay tuned for more on acoustics later.

The Acoustics Lab. Paul is using acoustics to watch the fish swim under the boat.

The Acoustics Lab. Paul is using acoustics to watch the fish swim under the boat.

Personal Log

I know that many of you have been wondering…Where do I sleep? What do I eat? What do I do when I am not playing with fish? And do I get to take a shower after playing with fish all day? Hopefully these pictures will help you to get a better idea of what life is like on the ship. It is no cruise ship, but I’m not “roughing it” by any means.

Let’s start with my room. The rooms are actually a lot larger than I thought that they would be. Everyone has a roommate and I am sharing a room with the Chief Scientist, Ellen Martinson. Each room has two bunks, a desk with an internet connection, two lockers for storing gear, a refrigerator, drawers for more storage, and a bathroom.

Mine and Ellen's room.

Mine and Ellen's room.

Ahh…the bathroom. Each room has its own bathroom with a sink, shower, and toilet. Before I got here I had imagined having one large bathroom for each floor or group of rooms, so this was a pleasant surprise. Even better was that it was much larger than any bathroom I have ever seen on a boat. The shower even has a bar to hold onto when you are trying to shower in rough seas, which I have found quite useful.

My Bathroom...it's so huge for a boat.

My Bathroom...it's so huge for a boat.

So what do I eat? It is more like what have I not eaten. The food has been excellent and there is always a variety of choices to choose from. Breakfast is from 07:00 – 8:00 and consists of eggs, bacon, sausage, pancakes or french toast, oatmeal, and today there was even quiche. I’m not a big breakfast person so I have been eating cereal and fruit for most breakfasts. Lunch is from 11:00 – 12:00 and is my favorite meal of the day. The cook makes amazing soups and there is usually a good sandwich to pair it with. If you don’t want soup and sandwich, there is usually burgers, quesadillas, or chicken fingers to choose from. If you don’t think that you can make it until 17:00 (or 5pm) when dinner is served again, don’t worry. There are usually fresh-baked cookies in the galley at around 15:00. If you still are hungry at dinner time, then you are in for a treat. So far for dinner I have had pork chops, spaghetti, leg of lamb, steak, and chicken ala king. Of course you would have to finish dinner with dessert and coffee. How about homemade chocolate cake and a scoop of ice cream? And you can’t just serve a regular cup of coffee. How about a mocha latte made from the espresso machine in the galley?

The Galley. Lots of good food can be found here.

The Galley. Lots of good food can be found here.

What happens if you eat too much and get sick? Don’t worry, the ship has a medical officer and infirmary if you need medicine. We have had some pretty rough seas during our cruise so it is nice to know that there is somewhere that I can go if I am feeling sick or if I need more medicine.

Not feeling well. Don't worry, the ship has a medical officer and infirmary.

Not feeling well? Don't worry, the ship has a medical officer and infirmary.

What do I do when I’m not playing with fish in the fish lab? Well, there are lots of things to do to keep yourself busy. You could workout in one of two workout rooms. You could choose from over 500 movies to watch in the lounge. You could clean your fish-smelling clothes in the laundry room. My personal favorite is to go up to the bridge and check out what is going on outside. From here you can see for miles and there are usually lots of seabirds to see and if you are lucky you can even see a whale or porpoise passing by.

Wash your dirty clothes at the ship's laundry room.

Wash your dirty clothes at the ship's laundry room.

Relax in the lounge and watch a movie.

Relax in the lounge and watch a movie.

Eat too many cookies today? Work off those extra calories in one of the ships two workout rooms.

Eat too many cookies today? Work off those extra calories in one of the ships two workout rooms.

Check out the bridge to look for sea birds and whales.

Check out the bridge to look for sea birds and whales.

Tammy Orilio, Trawling for Krill, June 29, 2011

NOAA Teacher at Sea: Tammy Orilio
NOAA Ship Oscar Dyson
Mission: Pollock Survey
Geographical Area of Cruise: Gulf of Alaska
Date: 29 June 2011

Weather Data from the Bridge:

Latitude: 58.01 N
Longitude: -152.50 W
Wind: 23.95 knots
Surface Water Temperature: 9.4 degrees C
Air Temperature: 10.8 degrees C
Relative Humidity: 71%
Depth: 177.72 m



Science & Technology Log:
What are krill, you ask? They’re animals in the Phylum Arthropoda, which means they’re related to insects, spiders, crabs, lobsters, etc. They have jointed legs and an exoskeleton, are usually a couple centimeters in length, and are reddish/orange-ish in color. They can often be found in dense schools near the surface of the water, and play an important role in the ecosystem as a source of food for lots of larger animals (like fish, whales, & penguins).

I’ve mentioned the two types of trawl gear that we use to catch fish, but if we want to catch smaller things like plankton, the mesh on those nets is way too small. Therefore, we use a third type of trawl called the Methot which has very fine mesh to corral the plankton down into a collection container at the end of the net. In addition to having a hard container at the end- as opposed to just a bag/codend that you see in the fish trawls- the Methot trawl also has a large metal frame at the beginning of the net. Check out the photos below.

The Methot trawl being taken out of the water. Note the square frame.

The Methot trawl being taken out of the water. Note the square frame.

The container that collects all of the plankton in the net.

The container that collects all of the plankton in the net.

After the net is brought back on deck, one of the fishermen or deckhands brings the container of krill into the fish lab. The first thing we do is dump the container into a sieve or a bucket and start picking out everything that isn’tkrill. The two most common things that are collected (besides krill) are gelatinous animals (like jellyfish & salps) and larval fish. The fish get weighed (as one big unit, not individually) and then frozen for someone to look at later on.

The larval fish that we separated from one plankton tow.

The larval fish that we separated from one plankton tow.

After sorting the catch, we’re left with a big pile of krill, which gets weighed. We then take a small subsample from the big pile of krill (it’s a totally random amount- depends on how much we scoop out!) and then weigh the subsample. Then the fun begins, as I’m the one that does this job- I get to count every single individual krill in the subsample. Tedious work. All of the data is then entered into the computer system, and the krill and anything else that we’ve caught (besides the larval fish) are thrown back into the water.

Sorting through the big pile of krill.

Sorting through the big pile of krill.

How many individual krill are in this picture? You get a prize if you're the closest without going over :)

How many individual krill are in this picture? You get a prize if you’re the closest without going over 🙂

Personal Log:
I mentioned that once we’re done with the krill, we throw it back into the water- that was until I came aboard! My eel (Ms. Oreelio for those of you that don’t know!) eats dried krill, and I’m going to run out soon, so I figured I’d take these krill home with me! I got a gallon-size baggie from the galley (kitchen) and filled it up with krill, and holy cow, it’s a lot!! I stuck it in our freezer- which is at -22 degrees C (or 7.6 degrees F) so now I have a big frozen block of krill to take back home with me. What a great souvenir.