CTD – Page 2 – NOAA Teacher at Sea Blog

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

August 23, 2024August 27, 2024

Tonya Prentice: NOAA’s CTD and Carousel, August 20, 2024

NOAA Teacher at Sea

Tonya Prentice

Aboard NOAA Ship Henry B. Bigelow

August 8 – August 24, 2024

Mission: Northeast Ecosystem Monitoring Survey

Geographic Area of Cruise: Northwest Atlantic Ocean

Date: August 20, 2024

Weather Data from the Bridge
Latitude: 42.2212 º N
Longitude: 70.29659º W
Wind Speed: NW at 12 mph
Air Temperature: 19.8° Celsius (67.64° F)
Sea Temperature: 19.3 Celsius (66.74° F)

Science and Technology Log

Monitoring Ocean Parameters with NOAA’s CTD and Carousel Bottle Sampler

The CTD and Carousel Sampler are essential tools NOAA uses to monitor ocean conditions. “CTD” stands for Conductivity, Temperature, and Depth, the primary parameters this device measures. By running profiles of the water column from the surface to the bottom, the CTD helps us understand key ocean characteristics. The Carousel Sampler paired with the CTD allows collection of water samples at depth for laboratory analysis.

What Does the CTD Measure?

Conductivity: Helps determine the salinity of the water.
Temperature: Measures the thermal profile of the water column.
Depth: Tracks how deep the CTD is during data collection.

Together, these measurements give us a detailed profile of the water column, helping scientists monitor what we call “the Big Four” parameters.

Carousel: Collecting Water Samples

The CTD and Carousel is equipped with twelve Niskin bottles, which are used to collect discrete water samples from specific depths. The bottles are numbered 1-12, and are “fired” (closed) at different depths to capture water samples.

For example, bottle 1 might be fired near the bottom (a few meters above the seafloor), bottle 2 at 10 meters, bottle 3 at the determined chlorophyll maximum (C Max), and bottle 4 couple just below the surface. Multiple bottles are often fired at each depth to collect additional water. These samples provide critical data about the ocean’s chemical properties at various levels.

view of the carousel sampler resting on the deck of NOAA Ship Henry B Bigelow at night. A white cylindrical metal frame holds twelve gray cylindrical bottles in a round. The bottles have opened stoppers connected at the top and bottom. the CTD probe, at the center of the round, is not visible. Tonya has added yellow text boxes to label the following: carousel, Niskin bottles, top stopper, valves, bottom stopper. — CTD Carousel Bottle Sampler

Preparing the CTD Carousel Bottle Sampler

Before deployment, we ensure that all the stopper valves at the top and bottom of each Niskin bottle are closed. We also hook the wires at the top and bottom to prepare the bottles to open at the designated depths. Once the CTD is ready, it is carefully lowered into the water, beginning its descent through the water column.

Analyzing the Key Parameters

Once the water samples are retrieved, we focus on analyzing these key parameters:

Dissolved Inorganic Carbon (DIC)
pH
Total Alkalinity (TA)
Nutrients
Chlorophyll

view of a large scientific instrument, a cylindrical metal frame containing a round of tall dark gray sample bottles, suspended over the rail of a ship. The sky and the water are both a dark blue, fading into one another at the horizon. — Lowering the CTD into the water.

photo of a computer monitor displaying a graph; the graph itself is not really readable — Lowering the CTD into the water.

Storing the Samples

After processing, the nutrient and chlorophyll samples are stored in a freezer kept at -80°C (-112°F) to preserve them for further analysis. Mercuric chloride is added to the DIC, pH, and TA samples to preserve them until they are measured in the laboratory. These samples provide invaluable insights into ocean health. The DIC, TA and pH samples help us monitor the effects effects of ocean acidification— which occurs when carbon dioxide dissolves into the ocean. The chlorophyll samples measure the amount of phytoplankton living in the water. Like plants on land, microscopic phytoplankton carry out photosynthesis, produce oxygen, and are at the base of the marine food web.

Understanding these parameters allows us to monitor the ocean’s health and better predict how it may change in the future. For more information on ocean acidification, check out this resource: NOAA Ocean Acidification.

By closely monitoring DIC, TA and pH we can track important changes in our oceans, providing critical data for research and conservation efforts.

Personal Log

Life on a 12-Hour Work Shift at Sea

Working a 12-hour shift at sea might sound intense, but there’s often some downtime between stations and even a few hours after the work is done. The time you get can vary depending on how far apart each station is. Sometimes it’s just enough to process samples before heading to the next station, while other times you have several hours to relax and recharge.

So, how do you spend that free time on a ship? There’s no shortage of options. You could enjoy a movie in the lounge area, dive into a good book, play a board or card game with other crew members, or head to the flying deck to spot seabirds and marine life, or simply take in the stunning ocean views. Another interesting way to pass the time is visiting the bridge, where you can see how the ship is navigated, maneuvered, and commanded.

Let’s not forget “Activities and Crafts with Katy,” which can bring a whole new adventure to your day. Today, this included visiting the lab and looking at the different species of marine organisms that have been collected, such as stingray barbs, dogfish, and scallop shells. Katy then showed us how to make our own Acadian Redfish otolith (ear bone) earrings. “Scientists use the ear stones (bones) as a way to age the fish. Also called otoliths, they are bones found right behind the skulls of bony fishes.” (Smithsonian)

The balance of work and downtime can make those long shifts much more manageable and even enjoyable, offering moments to connect with colleagues and the environment around you in a way that few people get to experience.

view of two rows of large brown comfy-looking recliners facing a tv screen mounted on the wall above cabinets. there is a bookcase off to one side. — The Lounge area.

the flying deck - the uppermost deck on the ship - is bisected by the ship's yellow mast. a tall metal frame appears to be shade structure but may serve additional purposes. There are picnic benches and beach lounge chairs. — The Lounge area.

Did You Know?

“One atmosphere is equal to the weight of the earth’s atmosphere at sea level, about 14.6 pounds per square inch” (NOAA Water Pressures at Ocean Depths). Beneath the ocean’s surface, water pressure increases by approximately one atmosphere for every 10 meters of depth.

To illustrate just how intense this pressure can be, we conducted a simple yet fascinating experiment. We decorated 16 ounce styrofoam cups with artwork, then placed them in a mesh bag attached to the CTD Carousel Sampler. The CTD , along with the cups, was submerged to a depth of about 500 meters (1640.42 feet), where the pressure equals roughly 725 pounds per square inch (psi). We repeated this process by submerging the cups to 200 meters (656.17 feet), which equals about 291.18 psi.

As the cups descended into the depths, the increasing water pressure caused them to shrink dramatically because the air inside the cups was compressed. This simple experiment vividly demonstrates how powerful the forces at play beneath the ocean’s surface can be.

three styrofoam cups in a row on a table or desk surface. the leftmost cup is the standard size, undecorated. The middle cup is 30-40% smaller. It's colored with marker to be a flower scene, with "2024" written around the top rim. The rightmost cup is the smallest, probably less than half the size of the original. It says Go Wildcats, August 2024, Henry B Bigelow. — This is a normal size ounce styrofoam cup (left side). Here is the cup after it was submerged 200 m below the ocean surface (middle). The last cup was submerged 500 m and then again at 200 m (right side).

July 3, 2024

Nick Lee: First Days at Sea, July 2, 2024

NOAA Teacher at Sea

Nick Lee

Aboard NOAA Ship Oscar Dyson

June 29 – July 20, 2024

Mission: Pollock Acoustic-Trawl Survey

Geographic Area of Cruise: Eastern Bering Sea

Date: July 2, 2024

Weather Data from the Bridge:

Latitude: 59° 54.8 N
Longitude: 171° 54.9 W
Wind Speed: 14 knots
Air Temperature: 5.0° Celsius (41° F)

Science and Technology Log:

We’ve been sailing for just under two days, and I’ve already had an opportunity to witness lots of science aboard NOAA Ship Oscar Dyson!

We spent the first day transiting to the start of the survey – I am part of Leg 2 for this cruise, and so we are picking up where Leg 1 left off. Since we won’t be able to find every pollock in the Bering Sea, we will need to rely on a representative sample, and then our data will be used to estimate the total stock.

The map below shows the intended path of our cruise, and the vertical lines represent transects, or lines along which we will collect data, spaced 40 nautical miles (or 74 km) apart so that we can cover the entire region with the time we have. Since we just recently arrived at the start of our survey, I’m still learning about the different data the science team will be collecting – more on that in a future blog post!

nautical chart of the Bering Sea, showing the land of Alaska to the east and a portion of Russia in the northwest. The cruise trajectory is overlaid in bold blue or red lines, with north-south transects connected by shorter westward connections. The blue transects start in Dutch Harbor and head west; the red transects are farther west — Map of the survey with the portion that I’ll be participating in shown in red, and the portion that has already been completed in blue.

On our way to our survey site, I was able to launch a drifter buoy through NOAA’s Adopt-a-Drifter Program. Unlike some other buoys, a drifter buoy is not fixed to the ocean floor. Instead, they float and “drift” with the ocean currents. Importantly, drifters are equipped with some sort of drogue – an underwater anchor. This way, the surface float (and the drogue) will move with ocean currents, but won’t be influenced as much by wind.

illustrated diagram of a drifter buoy. a white ball floats at the water line; this is labeled "Surface float - designed for moving on the surface with currents." The float has an Antenna, labeled: "the drifters transmit the data they collect as well as their position via satellite." Data is depicted as a gray triangle extending up from the antenna to a satellite in the sky, which is communicating with a satellite dish on land. Beneath the float, down into the water, extends a black cable, thicker toward the float. It's labeled: "Sensors: Sea Surface Temperature sensor and various measuring systems." The cable connects to what appears to be gray cylindrical tube, waving in the water labeled "Drogue: The buoys have some form of subsurface drogue or sea anchor." — Drifter Buoy diagram (Image Credit: NOAA Adopt a Drifter Program)

Deploying a drifter is as simple as dropping it into the ocean! I was able to deploy our first drifter last night off the stern (back of the ship). Our drifter was wrapped in biodegradable packaging for a safe deployment, but once in the water it should have opened up and extended to its full length.

a repeating video clip of Nick starting to toss the drifter buoy over the rail of NOAA Ship Oscar Dyson. he is wearing a helmet and a life vest, and looking away from the camera. — Deploying an ocean drifter.

Once deployed, the drifter transmits its location via satellite, and scientists are able to use this data to better understand ocean currents. You can track my drifter’s trajectory here!

In addition to a GPS that tracks location, drifters are often equipped with sensors for temperature, pressure, salinity, and more. Below is the path my drifter took in its first day after deployment, and the sea temperatures it encountered.

a map of a small section of the ocean between 191.2 to 192.0 degrees W and 55.4 to 56.2 degrees N. A series of colored squares form a small spiral in the middle; the squares range in color from orange to purple. Beneath the map there's a key explaining that the colors indicate temperature, ranging from purple (6 degrees Celsius) to red (7 degrees Celsius.) — Drifter trajectory and sea surface temperature.

I also was able to observe the deployment of a CTD (conductivity, temperature, and depth) sensor. CTD measure some of the same properties as drifters, but CTDs are lowered down into the water and then raised back into the boat. This means that CTDs only collect data at one geographic location at a time, however, they collect data throughout the entire water column, from the surface down to the ocean floor (~80 meters at our last deployment). CTDs can also collect water samples at different depths, allowing scientists to study them further. NOAA has a great resource on CTDs here!

view of the conductivity, temperature, and depth probe (in the center of a cylindrical metal apparatus) suspended from a cable just beyond the railing of the ship; it is about 10 feet above the ocean's surface at this point. in the distance, the sky is gray and cloudy, and the ocean is gray and calm. — CTD being lowered to collect data.

Personal Log:

When I applied to NOAA’s Teacher at Sea Program, I was told that one thing that was required of all its participants was flexibility. This is especially true for cruises leaving from Dutch Harbor, where bad weather and flight cancellations are common. On this leg, a series of travel delays meant that we left port a day later than expected. However, this meant that I was able to spend some time exploring Dutch Harbor!

Dutch Harbor is one of the most remote and beautiful places I’ve ever visited. During my wanderings around the town, I spotted whales, a fox, and plenty of bald eagles. Alaska’s military history is also apparent in the hills surrounding Dutch Harbor, which are full of World War II bunkers.

view of calm blue ocean waters from a green hillside; in the distance, two ships are visible — Views from Dutch Harbor (left), inside a World War II bunker (center), and one of many bald eagles (right).

view under the archway of a bunker - there's sand underneath and open vegetation beyond — Views from Dutch Harbor (left), inside a World War II bunker (center), and one of many bald eagles (right).

Since we left port, there’s been a lot to adjust to about living on a ship. The ship is a bit of a maze – lots of narrow hallways and hidden staircases. After making a lot of wrong turns, I’m starting to get a sense of the layout.

Work happens on the ship at all hours of the day – I’ve been assigned the night shift (4 pm – 4 am), so as a natural morning person, I’ve completely changed my sleep schedule! Because someone is always working, that also means that someone is always trying to sleep, so I’ve learned to be careful about not letting doors slam behind me.

view of a stateroom: two berths (bunk beds), a chair, a window with curtains, a hiking backpack and a bag. — My stateroom for the next three weeks.

This morning, we practiced our first set of safety drills. To simulate what would happen if we needed to abandon ship, everyone was required to don a survival suit (also called a “Gumby suit”). It was quite a process to put on the suit – luckily one of the other scientists, Mike, gave me some pointers ahead of time!

Nick poses, thumbs up, for a photo in the survival suit; it covers his mouth and nose — Gumby suit

I’m looking forward to learning more about life at sea over the next few weeks!

Did You Know?

NOAA Ship Oscar Dyson was named after an Alaskan fisherman and activist who worked to improve the industry for other Alaskans (https://www.omao.noaa.gov/marine-operations/ships/oscar-dyson )

June 13, 2024June 13, 2024

Charlotte Sutton: Learning the Lasker, June 11, 2024

NOAA Teacher at Sea

Charlotte Sutton

Aboard NOAA Ship Reuben Lasker

June 7 – June 18, 2024

Mission: Rockfish Recruitment and Ecosystem Assessment Survey (RREAS)

Geographic Area of Cruise: Pacific Ocean; U.S. West Coast

Date: June 11th, 2024

Weather Data from the Bridge

Date: Tuesday, June 11, 2024
Latitude: 35.42 °N
Longitude: 121.22 °W
Sea Wave Height: 4-5 ft
Wind Speed: 4 knots
Air Temperature: 57 ° F
Sky: Foggy / light rain

Science Log

Arriving on the Lasker

We’re off! After landing in San Francisco and driving down to Santa Cruz, I arrived on the NOAA Ship Reuben Lasker by way of small boat transfer. The Lasker was anchored in Monterey Bay, and sent a small boat to pick up myself and some of the science team and crew to be taken aboard. We boarded the small boat, the “RL-2 Shark,” then traveled to the side of the Lasker where we were hoisted up via a winch. I then got a full tour around the ship, and the opportunity to meet many people who work on the Lasker, including members of the science team, NOAA Corps, and Lasker crew.

Teacher at Sea Charlotte Sutton poses for a photo on board the small boat RL-2 Shark. She's wearing a life vest and a hard hat and holding in her hands a jacket with neon yellow reflective coloring. Behind the small boat, we can see the Santa Cruz harbor. — Charlotte boards the RL-2 Shark in Santa Cruz

a view up the portside of NOAA Ship Reuben Lasker, facing the aft deck, as seen from the small boat the water's surface. Winch cables and a frame have been lowered off the side of the large vessel. We can see a davit arm toward the aft. — Charlotte boards the RL-2 Shark in Santa Cruz

The Night Shift

Running a ship like the Lasker is a 24-hour-a-day operation. At all times there are some groups of people sleeping and others who are working. The majority of the science crew works at night, so my day typically begins with dinner at 5:00 pm and then working with the science team from approximately 9:30 pm until 6:30 am. As a morning person this was very difficult at first! But after two nights working, I’m finally adjusting to our new schedule.

What is the Goal of the Survey?

The main scientific focus of the upcoming mission is the Rockfish Recruitment and Ecosystem Assessment Survey (RREAS). This survey has been conducted since 1983, and collects data on rockfish and other organisms in their ecosystem.

Rockfish are a very important fish commercially and recreationally in California and on the West Coast. One of the primary purposes of the survey is to use the data collected to help provide additional information about the management of commercial and recreational fisheries off the west coast.

CTD Operations

On the ship's deck at night, a man stands facing away from the camera, looking down a large apparatus nearly the height of his shoulder. Inside a round metal frame are gray cannisters arranged in a circle (the "rosette"), surrounding a scientific probe mounted in the center. A cable extends from the top of the appartus out of sight. The man wears a hard hat, a life vest, and sunglasses and grasps a gray rope looped through a rung of the rosette. Another man, also wearing life vest and hard hat, is seen at a distance beyond the apparatus. It's nighttime. — CTD rosette, ready to be deployed into the ocean.

I began my first night shift by observing a CTD deployment. CTDs are instruments that measure Conductivity, Temperature and Depth (CTD). CTD measurements are conducted approximately 5-6 times a day, and twice at night. The CTD descends down into the ocean to a depth of up to 500 m . There are other instruments and sensors attached to the CTD that measure things like chlorophyll levels and oxygen levels. The data taken from the water column serves as a foundation for scientists to understand the ocean environment.

All of the CTD data, and all the data that the Lasker collects, is free and available to the public.

Trawling

a hand-drawn diagram of a trawl net in two positions: net while fishing (on top) and net deployment and retrieval (bottom.) The lines are all labeled: we see the headrope (with buoys) at the top of the net, the footrope (small buoys) at the base of the opening, the bridle lines, door leg and transfer lines, the doors, and lines "to trawl winch" and net "to cod end." — Hand-drawn diagram of trawl net, courtesy of scientist Tanya Rogers.

When do we trawl?

The reason the science team trawls at night because there is net avoidance during the daytime, meaning the fish will see the net coming during the day and swim away from it. Other creatures migrate towards the surface at night. In a pattern called vertical migration, these mesopelagic species migrate to shallow waters to feed during the night, while spending day hours at depth.

Having more diverse species to study is useful for the Rockfish Recruitment and Ecosystem Assessment Survey (RREAS). The more data that is collected on rockfish and other species helps scientists to better understand the heath of different fish species, and make predictions and assessments of ocean trends.

How does trawling work?

Each night, the Lasker crew, NOAA corps officers, and science team work together to trawl for different fish species.

“Trawls, which are nets towed behind a boat to collect organisms, have been used by fishers for centuries. Trawls can be divided into three categories based on where they sample the water column: surface, midwater, and bottom.” (NOAA Ocean Exploration)

In our Rockfish Recruitment and Ecosystem Assessment Survey, the science team conducts midwater trawls, at approximately 30m depth to target the fish and other ocean organisms that are targeted for the study.

The last few days we’ve averaged 5 trawls per night. The process begins by deploying the trawling net behind the ship into the midwater section of the water column, and trawling for fish for either 5 or 15 min. After the net is brought in, the contents of the trawl are sorted, measured, and recorded by the science team. This data will be later analyzed to help better understand the ocean ecosystem.

Charlotte stands at a large white bin, about three feet long, containing a pile of small silver-colored fish. She uses two hands to hold up a plastic pitcher filled with a sample of the fish - two other empty pitches rest in the bin. Charlotte wears a coat, orange grundens (fishing overalls), long orange gloves, and her Teacher at Sea beanie hat. — Teacher at Sea Charlotte with the catch of a trawl.

Six people stand three to a side along a long metal table and face the camera for a photo. They are wearing heavy fishing overalls and long orange gloves, and each grasps a pair of tweezers in one hand. On the metal table, white plastic trays contain subsets of the catch; in the foregroud, two of these plastic trays contain organisms that have already been sorted and neatly arranged. — The science team sort fish and other organisms from the trawl.

Personal Log

NOAA Ship Reuben Lasker: My New Home at Sea

NOAA Ship Reuben Lasker (photo courtesy of NOAA)

My new home for my time at sea is the NOAA Ship Reuben Lasker. The Lasker is a NOAA fisheries vessel, with a home port located in San Diego, CA.

“The ship’s primary objective is to support fish, marine mammal, seabird and turtle surveys off the U.S. West Coast and in the eastern tropical Pacific Ocean” (NOAA Office of Marine and Aviation Operations).

During my time at sea, the Lasker will be sailing off the coast of California, sailing out of Santa Cruz and back into port in San Diego.

Living on the ship reminds me a lot of my college dorm room. On the ship most people have roommates, and we all have shared spaces like the mess (cafeteria), science labs, outside decks and places to relax. Everyone aboard the ship has been extremely welcoming and kind, always answering any questions I might have and teaching me about life aboard a ship. I am happy to call the Lasker home over my trip at sea!

a bulletin board housed in a case with sliding glass doors, titled OUR CREW. The background of the display is a nautical chart of the California coast around the Channel Islands, though it is mostly obscured. Photos of the crew members are cut out and pinned all over the chart. There's also a magazine article about Reuben Lasker, the ship's namesake. — There are three major teams working and living as a cohesive unit aboard the *Lasker*. The *Reuben Lasker* crew, NOAA science team, and NOAA Corps officers each have distinct roles and work together each day to accomplish various science projects.

view of a sunset over a calm sea — Sunset aboard the *Lasker*.

Did you know?

Adjusting to working the night shift (approximately 9:00 pm – 7:00 am) as a typical morning person has meant sleep is often on my mind. Chatting before our second night shift, scientist Ily Iglesias shared with me how dolphins sleep. Both dolphins and whales sleep much differently than most mammals. Known as unihemispheric sleep, dolphins

“only rest half of their brain while the other half stays awake to breathe. Also, most whale and dolphin respiratory and digestive tracts are completely separate, so they don’t get water in their lungs when feeding underwater.” (NOAA Fisheries).