CTD – Page 2 – NOAA Teacher at Sea Blog

July 23, 2025July 23, 2025

Sinh Nguyen: Big Ocean, Big Mission, July 21, 2025

NOAA Teacher at Sea

Sinh Nguyen

Aboard NOAA Ship Pisces

July 7, 2025 – July 24, 2025

Mission: Larval Bluefin Tuna Slope Survey

Geographic Area of Cruise: North Atlantic Ocean, Slope Sea

Date: 7/21/2025

Weather Data:

4:27 PM Eastern Time

screenshot from the "Windy" app, showing a map of wind direction and speed in the eastern United States and Atlantic Ocean. A white dot near the continental shelf east of Delaware marks Sinh's current location. The colors and wind marks indicate a storm over the ocean to the east. — Information source: Windy app

The current temperature is 26°C (°79F).

The wind speed is 270 knots (21mph). Source: Windy app.

Science Log

Mighty Primary scholars: Our mission has officially started! NOAA Ship Pisces sailed to an area of the ocean called Slope Sea. Slope Sea is what scientists use to describe a part of ocean here on the East Coast.

topographic and bathymetric map of the North Atlantic Ocean, including the Northeast Atlantic Coast, up through Canada, and part of Greenland. — *The Slope Sea is a region, or area, of the Northwest Atlantic Ocean. Photo credit: NOAA*

map of the northeast Atlantic Ocean color coded to show ocean temperatures. "Slope Sea" is identified offshore, east of Delaware and New Jersey. — *We’ve been sailing to areas with the best conditions for larval bluefin tuna to spawn, where larval bluefin tuna are born.* Each color represents water temperature. On the scale (right), from blue to red represents colder to hotter water temperature.

a man stands at the front of the mess hall (we can see the tables with condiment baskets) next to a large screen mounted on the wall, displaying a slide (version 1) — Chief Scientist Dave gave a presentation on the goals of our mission.

Activity: Let’s explore Slope Sea on Google Earth!

Click on this link: https://earth.google.com/web/@40,-68,7.90643423a,629.4080939d,35y,0h,0t,0r/data=CgRCAggBQgIIAEoNCP___________wEQAA?authuser=0
Search these coordinates: 40°N, 68°W
Click the “Ocean” option if you want to see more!

Remember, our mission is to survey (catch and identify) larval bluefin fish. Since one of our science members focuses on surveying seabirds, there are 8 of us left for work. We are divided into two equal teams for the shifts, or watches.

Sunset Crew

This team works from the 3PM to 3AM watch. They get to see the sunset!

a man standing at a work table in the wet lab — Chief Scientist Dave

close up view of a woman flipping through a book — Autumn

a woman sitting at a desk with multiple computer monitors — Betsy

Sinh, in his Teacher at Sea t shirt and a backwards baseball cap, holds up a small sample vial and smiles for the camera — Myself

Sunrise Crew

This team works from the 3AM to 3PM watch. They get to see the sunrise!

group photo of four women in matching light-blue t shirts on deck (Version 1) — Sunrise crew is representing! Photo credit: Allison Black

group photo of four women in matching light-blue t shirts on deck (Version 2) — Sunrise crew is representing! Photo credit: Allison Black

a woman poses for a photo with a safety skills dummy in the wet lab — Kristen

a woman kneeling on the deck next to a piece of scientific equipment looks up and smiles for a photo — Amanda

a woman in a hard hat and life vest crouches next to a suspended larval fish trap and a drifter, on the aft deck at night — Sarah

a woman rinses down a plankton net into a sieve in the wet lab — Chrissy

a woman stands at the rail on the flying bridge of NOAA Ship Pisces. She looks through a camera with a large, long lense. Words on top of the image read: "Seabird Crew. Allison surveys seabirds on the flying bridge, the highest point of NOAA Ship Pisces! She then identifies them for research."

Seabird Crew

Allison surveys seabirds on the flying bridge, the highest point of NOAA Ship Pisces! She then identifies them for research.

With Allison, watching for seabirds or marine animals!

Sinh stands at the alidade, an instrument mounted on a pillar on an upper deck of NOAA Ship Pisces. The sky and ocean are a bright blue, and there is a low line of clouds at the horizon. (version 1) — This tool is like binoculars.

Mighty Primary scholars: Here’s a math connection. How many hours are there in one shift? If we combine both shifts, what is the total number of hours?

hands use a squeeze bottle to fill a small sample vial; we see a microscope on the table in front of this person. Words on top of the imeage read: "We've all been coordinating (working together) for these four tasks to be done:"

We’ve all been coordinating (working together) for these four tasks to be done:

Computer for CTD and Data

a woman sits at a computer desk with multiple monitors; she looks up at one of the higher monitors, which is displaying four outdoor camera feeds

We look at CTD data. We use walkie-talkies to coordinate with deck crew and NOAA Corps Officers so that it is dropped into the sea. When it’s returned, we record data.

We then print out CTD information (remember conductivity, temperature, and depth) to label our bottles of samples.

Sinh sits at a computer desk next to a woman in a blue sweatshirt. they both look up at the computer monitors displaying video and data feeds. — Recording CTD data

Sinh sits at a computer desk next to a woman in a blue sweatshirt. Sinh looks ahead at a lower computer monitor. — Recording CTD data

We make sure all the data is saved and then backed up, or stored, so that other scientists can use them for more research.

Washing Bongo Nets

two crewmembers in hard hats and life vests stand around the retrieved bongo nets, which are splayed out on deck. It is nighttime. Words on top the image read: "After catching planktons (tiny fish and other small creatures), we wash the nets carefully, so we don’t lose any samples."

After catching planktons (tiny fish and other small creatures), we wash the nets carefully, so we don’t lose any samples.

Bongo nets return to deck.

Chrissy washed down plankton into a tray.

Preserving samples

close up view of a sample jar in someone's hands containing plankton suspended in solution; it is a bit out of focus. Words on top of the image read: We wash and store planktons in jars to keep them safe.

We wash and store planktons in jars to keep them safe.

Dave carefully washed plankton down to be preserved and then observed.

a woman wearing large orange overalls stands at a metal table in the wet lab, an empty sample jar in her hands. — Amanda stored collected plankton into jars, which are then studied and then saved for later research.

These bottles are stored in ethanol, which helps preserve (protect) the DNA of planktons.

fingers smooth out a printed label affixed to the white lid of a sample jar — We print CTD information from the computer to label collected samples.

Identification (ID)

We look closely and carefully at planktons’ physical properties to identify them.

a woman adjusts the lenses of a microscope at a lab bench — We use a **microscope** for this.

What is a microscope?

A microscope is a tool that allows small creatures or objects to be seen. Almost like looking through binoculars or a camera to zoom in.

view over a woman's shoulder as she flips through a guidebook. her phone is on the table next to the book, displaying an image of a plankton. — Autumn was observing and identifying what kinds of planktons we saw on the microscope.

view through a microscope of several types of fish larvae on a petri dish — Autumn was observing and identifying what kinds of planktons we saw on the microscope.

Sinh looks through a microscope on a bench. his Teacher at Sea hat is backwards so the rim stays out of the way. there is a pair of tweezers on the bench in front of him. — I had to pay close attention! I had to move the planktons around a lot using a tweezer (can you locate it in the picture?)

Sinh, in the foreground, leans over a tray holding tweezers in his right hand and a light cord in his left hand. in the background, Dave points at a guidebook laying open on a table next to a microscope, and speaks with another person who is mostly obscured by Sinh. — Pouring the samples into a tray helped us pick out certain plankton to observe. The light and the tweezer definitely helped!

Can you guess what we were looking at?

in the wet lab, Dave holds up a sample jar for two other science team members to look at. we see two additional people in the background, facing away from the camera. — Sometimes, when a scientist is really good at one task, he or she would stick to it throughout the entire shift.

You’ve learned about NOAA Corps Officers who work in the bridge and support our science missions. We’ve also been working closely with the deck crew to make our surveying possible.

close up view of a bulletin board. a nautical chart forms the background. five images have been posted to this section, labeled "Deck Dept." Their captions read: Chief Boatswain James "Boats" Walker, AB Brandon Wang, Freeman, AB Rodney English, and AB-F Todd Fatkin. — The deck crew helps the ship work safely. They make sure everything on deck working right.
Photo credit: NOAA Ship Pisces

view of the bongo nets lying folded flat on the aft deck of NOAA Ship Pisces; beyond, we can see the CTD rosette. the sky and water are bright blue. — Nets on deck

at night, three crewmembers wearing life vests lean over the railing. one holds a purple line (rope) attached to buoys and feeds it over the rail. — Nets on deck

view over multiple decks of the Pisces while it is in port; possibly over a small boat covered and in storage — They do things like drive small boats to and from the ship.

a pile of ropes on the gangway leading up to NOAA Ship Pisce — They do things like drive small boats to and from the ship.

A video of deck crew members making sure ropes were tied to the dock.

Personal Log

Right now, I’m writing to you from the flying deck, or the very top part of the ship.

The flying deck is a wide, open area where scientists can get a great view of the ocean, sky, and marine life.

This is part of an anemometer that measures wind speed and direction.

Allison gets very excited when she sees fish or seabirds! If we’re not with her on the flying bridge, she sends photos and videos:

A brown booby bird flying around NOAA Ship Pisces. Video credit: Allison Black

a dolphin leaping entirely above the water — Photo Credit: Allison Black, NOAA

a seabird grasps a piece of something (a fish?) in its bill as it swims along the ocean surface — Photo Credit: Allison Black, NOAA

a group of people on deck surrounded by life jackets and bagged survival suits; the drill has not begun yet — We spent more time practicing safety drills. It’s important that all crew members know about safety equipment.

We went over how to evacuate our staterooms in case there’s a fire and lots of smoke. This included hands-on practice. We were blindfolded to make it feel real!
Was scientist Allison able to evacuate safely?

view of the buffet bar in the mess hall; a line of people work on fixing their plates — Good healthy food is super important on a ship! We eat three meals a day in the mess (kitchen). There are continental foods, fruits, and drinks we can enjoy all day and night. Do you recognize some of the food here? What is something you’d like to eat aboard?

Right now, because of my shift, I sleep in so I miss breakfast. I make it up by having a big lunch instead. Throughout the afternoon and night, I snack on lots of vegetables and fruits.

The stewards in our mission cook and prepare all the delicious food for everyone. They make sure the scientists and crew stay strong and healthy by serving breakfast, lunch, and dinner. They work in the kitchen (remember: called the galley or mess).

Our Chief Steward Jean and Steward Mo.
Enjoying an ice cream social.
Crew members hang out in the galley, or kitchen.
Jean and Mo preparing our dinner, listening to awesome music.
Crew members lining up for lunch.
A riddle on screen while we wait in line. Can you solve it?
My colorful meal!
Can’t forget the hot sauce.

Did you know?

There are 15 different types, or species, of tuna that live in all the oceans of the world! Some are tiny… and some are giants (as you know)!

Here are just a few types of tuna!

Bluefin Tuna

The biggest! They can weigh over 1,000 pounds. Found in the Atlantic and Pacific Oceans

Yellowfin Tuna

Named for its bright yellow fins. Super fast swimmers. Popular in sushi!

Skipjack Tuna

Small but speedy. Most common in canned tun. Has stripes on its belly

Albacore Tuna

Known as “white tuna.” Has long fins. Also used in canned tuna

Bigeye Tuna

Got its name from its large eyes. Loves deep, cooler waters. Fished for sushi and sashimi

Now, if you’d like, try this activity: Compare and contrast two different types of tuna fish!

empty venn diagram circles, titled Venn Diagram Sorting — *Pick two types of tuna. Name them on each circle. Write or draw the differences (outside) or similarities (overlap, inside). Resource credit: Sinh Nguyen*

July 18, 2025July 23, 2025

Sinh Nguyen: What’s the Water Telling Us? July 15, 2025

NOAA Teacher at Sea

Sinh Nguyen

Aboard NOAA Ship Pisces

July 7, 2025 – July 24, 2025

Mission: Larval Bluefin Tuna Slope Survey

Geographic Area of Cruise: North Atlantic Ocean, Slope Sea

Date: July 15, 2025

Weather Data:

6:29 PM Eastern Time

screenshot of an app on a phone showing a map of the coastline around the mouth of the Chesapeake Bay, with white lines indicating direction and speed of wind. temperatures are listed for the following cities on the map: Virginia Beach (82 degrees), Norfolk (82), Newport News (80), Poquoson (80), Cape Charles (80) — The current temperature is 27°C (80°F).
The wind speed is 6 knots. Source: Windy app.

Science Log

Uplift Education, Mighty Primary students: Ahoy from the sea! We’ve set sail this morning to Newport, Rhode Island. There’s a port there that our ship will dock at. NOAA Ship Pisces has been sailing smoothly, or without any issues.

distant view of a lighthouse surrounded by water, seen from the deck of NOAA Ship Pisces. the sky is mostly cloudy and the water is calm. — We spotted a lighthouse! Did you know that lighthouses were made to help ships travel safely? They shine bright light at night to warn sailors about dangerous rocks, reefs, or shorelines. They’re almost like traffic signals for boats.

Sinh, wearing a long-sleeve shirt and shorts, poses for a photo on the aft deck of NOAA Ship Pisces. We see upper decks and empty trawl net spools behind him. He clutches a laptop under one arm. — It’s colder inside the Lab Room to make sure the computers don’t overheat. I’m typing this post on one of the deck tables. It feels amazing with the ocean view and breeze.

Today, I’m introducing you to a special instrument, or tool, that helps us learn about sea water. It’s called a CTD instrument.

CTD stands for Conductivity-Temperature-Depth. Video credit: NOAA

The CTD is very important for science missions at sea. Do you remember the goal, or purpose, of our mission? Here’s a hint….

magnified image of a larval bluefin tuna. it is mostly white, with a large eye and just some patches of yellow and blue coloring. — Photo Credit: Chrissy Hernandez (one of our scientists), Woods Hole Oceanographic Institution

Yes, that’s right. We’re surveying, which means collecting and studying, baby bluefin tuna (larvae). The CTD will help us learn about the sea water where we find the larvae. Like how warm the water is and what it’s made of.

Conductivity tells us what’s in the water, like salt. Salt helps electricity move through water. If the water has more salt, that means it has higher conductivity.

Temperature tells us how warm or cold the water is. Some sea animals like warm water and some like cold water.

a bluefin tuna swimming underwater — Bluefin tuna larvae like warmer water, so that means grown-up bluefin tuna swim a long way to find warm water to lay eggs. The area where they lay eggs in are called spawning areas. Photo credit: NOAA

annotated illustration of the life stages of a bluefin tuna chasing their preferred foods. 1) Egg and Larva: 48 to 72 hours, droplet of oil. 2) Larva: 14 days, copepods and cladocerans (marine plankton). 3) Larva: 20 to 25 days, piscivore: larvae of tuna and other species. 4) Juvenile: from 25 days on, fish and cephalopods. 5) Adult: 4 to 6 years, fish and cephalopods — The life cycle of bluefin tuna. Photo credit: Planet Tuna

Depth tells us how deep the water is. The deeper you go, the darker and colder it gets, so we have find the depth where temperature and conductivity are just right for bluefin tuna larvae.

school of bluefin tuna underwater, as seen from underneath — This information helps scientists learn the physical properties of water where bluefin tuna larvae are found. This is important because larvae need just the right kind of living conditions to grow and survive. Photo credit: Discover Wildlife

By using the CTD, scientists can figure out where the best places are for them to live. This helps protect their habitat and make sure their population can last a long time. It also helps us find them next time, knowing where to come back to find them.

view of a scientific apparatus containing a probe and a ring of water sampling bottles as it is lowered by a winch over the side of a research vessel — During this mission, we’ll be using the CTD to sample, or study, the water. This requires a big crane like what you see at a construction site! Photo credit: NOAA

The CTD is connected to computers in our Dry Lab. This means we can see water information live, or real-time.
The CTD (Conductivity, Temperature, and Depth) apparatus.

Sinh, wearing his Teacher at Sea baseball cap backward, sits at a computer desk containing five monitors and several keyboards. He faces a computer screen. — **Learning how to read data, or information, from the CTD!**

Personal Log

There’s been plenty of time to review, practice, and set up equipment for our mission. Here are some updates.

Do you remember the drifters from our last post? Well, they’re finished! Look at the photos below. These traps will be attached to the drifters. The drifters will be thrown into the ocean. The light will attract bluefin tuna larvae and then trap them in the net. Each drifter also has a GPS so we know where they are always. Here, scientist Kristen was making sure the nets stay in place.

Kristen adjusts a trap
Larval fish trap
Two larval fish traps
Discussing the trap design

Two women sit on opposite sides of a wooden table on an outer deck of NOAA Ship Pisces. There is a canvas shade cover overhead. The table contains a laptop, a book, some sweaters, and some rope. The sky is blue with some clouds, and the water seems very still. Black barrels line the edge of the deck. — Scientists Chrissy and Sarah were helping me review this blog post. I wanted to make sure I can explain everything to you correctly. All scientists have been helpful. They’ve been explaining a lot of scientific words and information that I don’t know.

view of the isolated conductivity, temperature, and depth probe resting on deck (with two hands reaching in from the right side of the photo) near the bundled up netting from the bongo nets. — Scientist Betsy was working on a part of the CTD (right). Bongo nets (left) are also in this picture. They are shaped like a pair of bongo drums and used to catch very small sea creatures.

close up view of a cloth-bound book titled Development of Fishes of the Mid-Atlantic Bight: An Atlas of Egg, Larval, and Juvenile Stages, Volume V, Chaetodontidae through Ophidiidae. U.S. Fish and Wildlife Service, U.S. Department of the Interior. — Scientists were walking me through books that scientists have created to identify sea animals.

close up view of a page in a book showing rows of illustrations of larval bluefin tuna at successive stages — Here’s scientific information about Atlantic bluefin tuna larvae. They’re called Thunnus thynnus.

Scientists Amanda and Allison were observing birds.

view of a lounge room from one of the reclining chairs. a woman sits with a laptop in a different reclining chair. there is a TV mounted on the wall above a sound system. — In the lounge room with Autumn, one of the scientists who will be on 3PM – 3 AM duty with me once we begin our survey. Here, crew members can watch TV, read books, or work on their laptops during free time.

Tomorrow, there’s a full day of practicing emergency drills. I’m about to sleep early to rest and to feel better from sea sickness. The ship’s been rocking back and forth so it’s time to turn off my laptop for the day!

Did you know?

Dave stands next to a drifter comprising a tall metal pole and four small canvas sails. He ties a line onto the central pole. Small round floats are visible on the deck nearby. — Chief Scientist Dave was tying each drifter to a float.

a close up view of hands tying a purple rope to a small round orange float, about the size of a cantaloupe — To make sure each drifter is tied securely to a float, we tied a special knot called the bowline knot.

a woman bends down to tie a purple rope to a small round orange float; we can see the spool for the rope resting on the deck nearby — People have been using this knot for a very long time. It was confusing for me, so Dave and Kristen gave me plenty of chances to practice!

two orange buoys tied to purple ropes with bowline knots — Can you find some rope and try to tie a bowline knot?

Here’s a helpful video! Video credit: Youtuber NightHawkInLight

Here’s a fun way to memorize it!

“The rabbit comes out of the hole,
Goes around the tree,
And back down the hole.”

June 25, 2025June 25, 2025

Jenna Cloninger: CTDs and Cephalopod Central, June 20, 2025

NOAA Teacher at Sea

Jenna Cloninger

Aboard Bell M. Shimada

June 11 – June 26, 2025

Mission: Integrated West Coast Pelagics Survey (Leg 1)

Geographic Area of Cruise: Pacific Ocean, California Coast

Today’s Date: June 20, 2025

Track the Ship: Bell M. Shimada

Weather Data Snapshot: 9:54am, Pacific Daylight Time

Currently, the air temperature is 58°F (14°C) with a wind speed of 23 knots and a wave height of 9 feet. Not only are the seas rough offshore, but the wind is making it very chilly to work outside. Luckily, we have some gear that keeps us warm for times when we need to be outside for extended periods. The sky is clear, and the sun is shining, so I am counting my blessings despite the cooler temperatures.

two women bundled up for outdoor work in large red "float coats" and beanies - they are striking somewhat silly poses for the camera. Jenna (left) is wearing a Teacher at Sea beanie. — Melissa (left) and myself (right) preparing to go outside for UCTD deployment.

Science and Technology Log

It’s been an exciting week regarding technology! I had the opportunity to help prepare a CTD (a piece of equipment mentioned in a previous blog post) for deployment as well as the opportunity to observe a UCTD being deployed. A CTD (Conductivity, Temperature, Depth) is a tool that measures how salty and warm the water is at certain depths . For larger CTDs, the ship comes to a stop, scientists then lower the CTD using a cable, and it collects data as it goes down. A UCTD (Underway CTD), however, is a smaller version that can be used while the ship is moving. It’s dropped into the water and pulled behind the ship, collecting data as it sinks. This allows scientists to gather information more quickly and without stopping the ship. Both tools are important for helping scientists understand seawater conditions and how they change based on depth, time of day, season, location, etc.

Elias stands, and Jenna kneels, near a large apparatus consisting of a white metal frame, a ring of gray water sampling bottles, and a scientific probe. Jenna is wearing a hard hat and doing something (stringing a wire?) on the CTD as Elias looks on. — Elias and myself preparing the CTD for deployment.

Jenna, wearing a red float coat and Teacher at Sea beanie, stands on deck and holds what appears to be a metal tube in both hands for a photo. — Photo of me with UCTD equipment.

In other news, we have run into several different cephalopods this week. Cephalopods are part of a group of marine invertebrates that includes octopus, squid, cuttlefish, and nautilus. They are known for having large heads, arms or tentacles, and relatively high intelligence when compared to other invertebrates. In our case, we caught a few different kinds of squid, a few small octopus, and a nautilus in our trawling net. I was particularly excited to see the nautilus, because I had never seen one in person before!

close up view of a paper nautilus against a white background; we can see the curved shell with sawtooth bumps, and the eye of the nautilus peeking out the opening of the shell — Paper Nautilus

a squid in a green plastic basket — Robust Clubhook Squid

smaller squid photographed against a plastic blue background — Market Squid

close-up view of a small octopus — Tuberculate Pelagic Octopus

three octopus in messy piles in a green plastic basket — A group of three (3) Seven-Armed Octopus.

As you can see, cephalopods come in many different varieties. I enjoy teaching about them in the classroom because of their unique evolutionary features, like chromatophores, which are specialized cells that enable cephalopods like squid, cuttlefish, and octopuses to rapidly change color. It should also be noted that cephalopods are part of the phylum Mollusca, just like the abalone that I discussed in a previous blog post. In general, I really love teaching about mollusks in the classroom because of the amount of diversity that we see within the phylum.

Personal Log

Speaking of squid, I tried calamari (fried squid) for lunch yesterday. I typically do not eat seafood of any kind, but when you’re on a ship, the food options may not always be what you want them to be. (That’s not to say that the food isn’t amazing, because it is. I am simply a picky eater.) Let’s just say that I will not be eating any more squid any time soon. (But I will still pose for pictures with them!)

a gloved hand holds out a very round squid for a close-up photo — Me, holding a Sandpaper Squid.

I also got to photograph a sunrise on the Pacific! The mornings have typically been hazy, or the boat has been facing the wrong direction for me to view the sun properly, but I finally managed to catch the sunrise while out on the back deck after processing our last catch of the night. Seeing the sunrise and sunset on the Pacific are two goals that I had when I started this journey. Unfortunately, because of my night shift hours, I do not think I will be able to catch a sunset any time soon. Perhaps on the last night of the cruise, I will stay up past my “bedtime” and wait for the sunset!

view through the A-frame on the aft deck of the sun rising over the ocean. seabirds trail the boat, silhouetted against the sun. to the right of the deck, a group of four crewmembers wearing personal flotation devices and hard hats work to untangle a trawl net. — Sunrise on the Pacific ocean from the fishing deck of NOAA ship Bell M. Shimada.

On another note, it has been 10 days since I left Georgia and arrived on the west coast, and I am starting to feel the effects of working such long days. I miss my family, and I miss the comfort of home. That is not to say that I am not enjoying this learning experience, because I am. But I want people to know that individuals who conduct research on scientific vessels like NOAA ship Bell M. Shimada are some of the most hard-working people I have ever met. I get to go home after 16 days and return to my own house with my own bed and other creature comforts. Some people are on this ship for several legs between now and September, and if they’re not at sea, they’re at their respective places of everyday work, such as an office or science center. It’s quite admirable, and humbling, to see how dedicated these people are to marine science and to the well-being of our oceans. It makes me want to be a better teacher so that we have people in the future who love and care for the ocean and are interested in preserving it as well.

view through a porthole window of a churning ocean — A view of the rough seas from my stateroom.

Did You Know?

Let’s talk about butterfish! Off the Atlantic coast, there is a commercial fishery for Atlantic butterfish. There’s another species of butterfish known as the Pacific butterfish that is quite common off the coast of California even though it’s not fished commercially in this region. I have decided that butterfish are the cutest fish that we have caught in our net so far! I love them so much that my teammates toss me all the butterfish when we are sorting our catch, and I make excited noises when I find them buried amongst our anchovies, mackerels, and sardines. In honor of the humble butterfish, I dedicate this Did You Know? section to them!

a hand holds a fish up to a laminated photo of a group of fish (labeled Peprilus simillimus, Pacific butterfish) mounted on a metal wall — A Pacific butterfish from our catch being compared to an image of the species.

According to NOAA, butterfish are small, round fish that are bluish on top with silvery sides and belly. They have small mouths, blunt noses, and grow to about 6–9 inches long, though some can reach 12 inches and weigh up to 1.25 pounds. Butterfish grow quickly but don’t live long; most only live about 3 years and can reproduce by age 1. They spawn in the summer (June and July) and swim in loose groups, feeding on small invertebrates. Why do we care about butterfish? Many animals, like bigger fish, marine mammals, and seabirds, eat butterfish. That means that they are a humble yet important piece of a healthy and balanced ocean ecosystem.

an orange-gloved hand holds three fish by their tails, splayed out like flowers, above a pile of smaller fish (probably anchovy) — A bouquet of butterfish, my new favorite fish.

June 20, 2025June 20, 2025

Jenna Cloninger: Anchovy Expert and Pyrosome Party Time, June 15, 2025

NOAA Teacher at Sea

Jenna Cloninger

Aboard Bell M. Shimada

June 11 – June 26, 2025

Mission: Integrated West Coast Pelagics Survey (Leg 1)

Geographic Area of Cruise: Pacific Ocean, California Coast

Today’s Date: June 15, 2025

Track the Ship: Bell M. Shimada

Weather Data Snapshot: 12:23pm, Pacific Daylight Time

Currently, the air temperature is 65°F (18°C) with a wind speed of 10 knots and a wave height of 5 feet. I was finally able to witness a sunrise this morning during my working hours, thanks to clear skies, and I am staying up a little bit past my “bedtime” to enjoy today’s sunshine.

Science and Technology Log

Trawling operations are in full swing here on the ship! Please enjoy this image of me in front of our two trawling nets, which we pull behind the boat at different depths to target different species of fish.

A woman in bright orange overalls and rubber boots poses for a photo in front of two massive spools mounted horizontally above the aft deck, such that they can be wound or unwound. The spools contain teal and yellow netting. One trawl net is partially unrolled, with buoys attached at different points. — Photo of me with our fishing nets, which we use for surface and midwater trawling.

In these first few days, we are seeing many anchovy! I have quickly become an expert at identifying the differences between anchovy and other fishes that may be brought up with our net. In addition to fish species, we see quite a few small squid and some other invertebrates known as pyrosomes in our net. (See the Did You Know? section below for more information.)

close up view of the corner of a plastic teal basket filled with small narrow fish, each about 3-4 inches long. a hand wearing a black glove holds a single fish out for display above the pile. — Photo of a basket of anchovy, with one being held by someone’s hand for a size reference.

After sorting our catch, we measure and weigh a certain number of the target species (sardine, anchovy, and mackerel) to collect data that helps us characterize their species and size distributions. In addition, some specimens are selected for dissection, where we determine the fish’s sex, reproductive stage, and health; collect tissue samples for genetic analysis; and extract otoliths for estimating age.(For more about otoliths, which are also known as ear stones or ear bones, click here.) This information helps scientists monitor fish health through their life history stages. It’s not possible to catch every fish in the ocean, so scientists study a smaller representative group instead, like we are doing aboard NOAA Ship Bell M. Shimada. This age data, along with other information like length, weight, and sex, is used to create computer-generated models of the fish population. When combined with acoustic data, these models help estimate how many fish are in the wild and predict what might happen if people keep fishing.

A woman wearing heavy-duty orange overalls and black gloves stands at a measuring board on a metal table in the wet lab. With her right hand, she uses a tool to measure a small fish placed along the board. She looks down, absorbed in her work. — Photo of me measuring a very small fish with a digital tool called an Ichythystick.

In the picture above, you can see that I am using a special tool called an Ichthystick to digitally measure the length of each fish in a specific subset from our catch. I have discovered that, although I do not normally consider myself squeamish when it comes to science, I am not a fan of dissecting fish for otoliths. Instead, I do a lot of the measuring and weighing of the fish, as well as additional tasks to support my teammates while they work on extracting otoliths.

In addition to trawling for fish, NOAA Ship Bell M. Shimada has a special piece of technology known as a CTD. A CTD is a scientific instrument used in marine science to study the properties of seawater. CTD stands for Conductivity, Temperature, and Depth. These three measurements help scientists understand what the ocean is like at different levels. The CTD device is usually attached to a metal frame and lowered into the ocean from a research ship. As it goes down, it collects data about the water’s temperature, how salty it is (measured by conductivity), and how deep it is. This information helps scientists learn about ocean currents, climate, and marine life. CTDs can also carry bottles that collect water samples from specific depths. Scientists use these samples to test for oxygen, nutrients, or tiny organisms. CTD data is very important for studying how the ocean changes over time. (I have not yet seen the CTD in action, but I pass by it every day on the side deck and am hoping that it will be deployed sometime soon during my working hours.)

Jenna, wearing a Teacher at Sea beanie and a Teacher at Sea t-shirt under heavy orange overalls, stands next to the CTD rosette - a large metal apparatus that hosts both the CTD probe and a ring of gray water sampling bottles. — Photo of me next to a CTD (Conductivity, Temperature, Depth) device for size reference.

Personal Log

Adjusting to life at sea is an ongoing process. I experienced a bit of seasickness yesterday right after lunch, but I was able to go to my stateroom at noon (which is the end of my night shift) and sleep it off until my next shift began at midnight. As a person who traditionally struggles with sleep, I am so exhausted after each shift that I am sleeping much better on the ship than I do at home, which I did not expect! In addition, I am eating much better on the ship than I do at home, thanks to our amazing Chief Steward who has been cooking fabulous meals for us. I have learned that mealtimes are very important on the ship, because sitting with your colleagues while enjoying good food is a boost for team morale and helps everyone stay energized.

Did You Know?

A lot of different animals can become caught in a trawling net while fishing, but pyrosomes are some of the most common animals we see during night trawls (aside from our target species of anchovy, mackerel, and sardine). What are pyrosomes? NOAA’s website tells us that pyrosomes are pelagic tunicates, which are part of the phylum Chordata. In other words, pyrosomes are tough, bumpy, gelatinous tube-like animals that gather in large clusters at the ocean’s surface. Like many jelly-like animals in the ocean, we still don’t know a lot about pyrosomes and how they live. This makes it hard to understand how they might be affecting ocean ecosystems. For example, pyrosomes can grow quickly and filter large amounts of water, which could have a big effect on phytoplankton blooms. Before this experience, I had never even heard of a pyrosome, and now, I feel like I am part of a pyrosome party every night!

top down view of a green plastic basket filled mostly with pyrosomes (which look like pink gelatinous tubes) with some various fish mixed in. — A basket full of pyrosomes (the pink gelatinous tubes) mixed with fish.

September 10, 2024September 10, 2024

Lisa Werner: eDNA Studies, September 6, 2024

NOAA Teacher at Sea

Lisa Werner

Aboard NOAA Ship Bell M. Shimada

August 29-September 13, 2024

Mission: EXPRESS Project

Geographic Area of Cruise: Pacific Coast, near Northern California

Date: September 6, 2024

Weather Data from the Bridge (Mendocino Ridge Essential Fish Habitat Conservation Area):

Latitude: 40º18.178’ N

Longitude: 124º48.470’W

Wind Speed: 5.87 knots

Air Temperature: 14.3ºC/57.74ºF

Conditions: Foggy

Science and Technology Log

There are many methods of studying the ecosystem of the ocean on the mission that I am on, and another method we are utilizing is that of Environmental DNA (referred to as eDNA). Every living organism in the ocean leaves behind traces of its existence. Much like humans shed skin cells and hair, and cats and dogs shed fur, ocean organisms leave behind skin, scales, and waste products. These artifacts contain DNA, and can last in the water for anywhere from 7 to 21 days. Scientists have ways of collecting eDNA using the CTD (Conductivity, Temperature, and Depth) rosette.

view up the starboard deck of the ship as a large apparatus - a circle of gray cylinders contained in a metal frame - is hoisted above the ocean surface by a davit arm. four crewmembers wearing hard hats and life vests stand on deck watching. the sky is gray clouds, and the ocean is calm. — *Deploying the CTD*

top down view of the CTD rosette as it is lowered into the water — *CTD off the side of the ship.*

A CTD rosette is a device that is routinely lowered off of the ship to monitor the temperature and conductivity of the water at measured depths in the water column. NOAA Ship Bell M. Shimada’s rosette has 12 containers, called Niskin bottles, that are opened before deployment, and then triggered at different depths one at a time as the rosette ascends, trapping the water from that depth inside. Separate from these collections, sensors analyze the temperature, salinity (salt levels), pressure, dissolved oxygen, turbidity (cloudiness), and other useful information. The data collected from the CTD shows up instantaneously on a computer screen aboard the ship.

photo of a computer screen showing two side by side graphs. we can see different colored lines on the graphs - which have depth as the y axis - but it is hard to make out details on the graphs. — *Data coming in from the CTD dive*

To collect eDNA, the scientists look at where the biggest temperature changes happen (called the thermocline). Once the CTD is back aboard the ship’s deck, the scientists pump the water collected in the Niskin bottles triggered at the depths surrounding the thermocline through a filter. The eDNA material is collected and strained into this filter, where it is preserved to be sent to a lab for further analysis. Once the eDNA gets to the lab, scientists look at the DNA “fingerprints” left behind by organisms and match them to a database of known DNA. The scientists then have knowledge of what organisms were present in that location in the ocean at the depths those samples were collected from.

fairly close-up view of a woman wearing an orange hard hat, a purple jacket, and purple latex gloves, crouching near the CTD rosette and the net-covered rail of the ship's deck. she grasps a sort of hose in her left hand and uses her right to point to a small filter attached to the hose. — *Scientist Alice Kojima-Clarke pointing out the eDNA filter*

This goes hand in hand with the work I blogged about last on the MultiNet. The identification of the plankton that Jenn is doing is part of the work that goes into the database helping scientists identify DNA from the eDNA samples.

Personal Log

I’ve gotten a lot of questions about what the food is like on the ship, and anyone who knows me knows that food is a big part of my life! The ship’s cook, Ronnie, is amazing. He cooks the food from scratch, and it is not uncommon to see meatballs being rolled out for the next meal, or other prep taking place. The meals are served buffet-style, and there is no shortage of food. Even the pickiest eater would be happily satisfied here.

view of a computer screen reading: MENU SEPT 4, and listing the food options available at breakfast, lunch, and dinner. dinner options include chicken schnitzel, pork chops, vegetable couscous. — *The menu from a few days ago*

top down view of a metal food service bar, with labels pointing out roasted lamb, fried rockfish, garlic potatoes, etc. — *Dinner from tonight*

For Labor Day, we got to have a cookout on the ship’s back deck. It was quite the feast, featuring all of the grilled meat and fixings you could want.

a man stands at a grill flipping chicken patties as the fire leaps up from the coals. — *Grilling steaks for Labor Day*

Also, if at any meal you ‘forget’ to take dessert, Ed, the steward, will remind you. He’s always looking out for your best interest! He also always has the best jazz music playing in the kitchen.

view into the galley of a man standing at a metal sink washing dishes; in the background another man carries metal trays to a counter. — *Ed always has the biggest smile on his face – you can tell he takes great pride in his job! Ronnie is in the background, and his food is spoiling us!*

Finally, I have to take a minute to wish my Dad a happy birthday! I had some cake to celebrate you today, Dad!!!

close-up view of a large piece of red velvet cake on a serving plate; the cake is iced with white frosting and topped with chocolate curls. — *I saved you a piece of Red Velvet Cake!*

Music Connections

In looking at how the eDNA analysis works, I’m going to compare it to listening to an audio recording of a high school band. When a person listens to a recording of the band, they can tell what instruments are represented in the recording. For example, you may notice that there are flutes, oboes, clarinets, and saxophones, but perhaps the band is missing a bassoonist. If the group does a really good job of section playing, you would have a very tough time picking out HOW MANY flutists are in the recording. You may be able to hear that there are a lot of them, based on the depth of sound you hear throughout the dynamics being played, but you could not say with any confidence whether there are 7, 8, or 9 flutists. You also would not know whether one of the high school students was absent that day, or whether a guest was playing on the recording as well. The process of eDNA analysis is the same way – scientists can tell what was present in that one snapshot of time, based on the DNA present in the sample. They cannot tell you how many of each organism is present, or whether those organisms live there or were merely just migrating through the area.

For today’s audio clip, I recorded the ship’s horn being blown as a result of the reduced visibility from the fog. I learned that there are several different patterns for the horn to blow, and the example I have for you here is the long fog horn blast followed by two short blasts, signaling that we are unable to change course (in this case, due to the fact that we are acoustically tethered to the AUV that was in the water at the time)

The ship’s fog horn

Student Questions

Students asked me to be on the lookout for dolphins. On our third day at sea, we saw a whole pod of dolphins right next to the ship! Here’s a very short video to watch them all, and I am not zoomed in at all with my phone!

Pod of dolphins swimming past NOAA Ship Bell M. Shimada