bottom trawl – NOAA Teacher at Sea Blog

September 21, 2026September 22, 2026

Melina Vella: So What’s the Catch? September 14, 2026

NOAA Teacher at Sea
Melina Vella
Aboard NOAA Ship Henry B. Bigelow
September 10 – 30, 2026

Mission: Northeast Fisheries Science Center Bottom Trawl Survey – Leg 1

Geographic Area of Cruise: Northeast Atlantic U.S. Coast

Date: September 14, 2026

Weather Data from the Bridge

Latitude: 32º05.1946’N

Longitude: 074º54.6321’W

Wind: North wind at 10 knots

Air Temperature: 25.5ºC (77.9ºF)

Science and Technology Log

I discovered this week that the project I am on has a much longer name than I thought. It’s been referred to as the “Bottom Trawl Survey” or “The Mission,” and if we’re feeling really fancy, the “Northeast Bottom Trawl Survey.” However, the formal name is the Northeast Fisheries Science Center’s Multispecies Bottom Trawl Survey. With a name like that, it makes sense that folks would shorten it, but there’s actually a lot to learn from the whole title.

This NOAA web page will provide you with tons of technical expertise and a great short video explaining the process. It goes into the nitty gritty of the mission, so I encourage you to check that out for a deep dive. But, if you don’t have time to fall down a research rabbit hole, here’s the basics:

The overarching goal of the Northeast Fisheries Science Center’s Multispecies Bottom Trawl Survey (NEFSC BTS) is to gather fisheries data. There’s a lot of information jammed into that one sentence, but it makes much more sense when it’s broken down.

The Northeast Fisheries Science Center (NEFSC) is part of NOAA’s broader North Atlantic Region, whose range spans from New England to the Mid-Atlantic. Over 70 million people live in the region, many of whom live in coastal or near-coastal zones.

Political map of NOAA's 8 regions: Alaska (its own region), West, Pacific Islands, Central, Great Lakes, North Atlantic, Southeast & Caribbean, and Gulf of America. The states and territories making up a region are all the same color. — Map of NOAA’s regions, with the North Atlantic region highlighted in purple (Map from NOAA).

Northeast Fisheries Science Center’s mission is “to provide the scientific information and tools necessary for productive, sustainable, and healthy marine ecosystems and coastal communities in our region.” There are multiple research facilities scattered along the coast, as well as the country’s oldest public aquarium, Woods Hole Science Aquarium! (Please note that the aquarium is closed through early 2027 for major renovations, but will certainly boast some awesome new exhibits!).

political map of the states of the Northeast NOAA region (Maine to North Carolina) with arrows pointing out the locations of labs in Orono, Maine; Woods Hole, Massachusetts; Narragansett, Rhode Island; Milford, Connecticut; and Sandy Hook, New Jersey. An inset text box reads: "We cover over 160,000 square miles of ocean from North Carolina to Maine." — Functions of the NEFSC are carried out at research facilities in Connecticut, Maine, Massachusetts, New Jersey, and Rhode Island (Map from NOAA).

The NEFSC’s work doesn’t stop on land, of course. Some specimens have to be collected from their natural habitats, sometimes hundreds of meters beneath the sea surface, and brought back to study. Skipping ahead in our project title, that’s where projects like the Bottom Trawl Survey come in.

A trawl is a type of net used to catch fish and other fun sea creatures. There are different types of trawl nets, all with different goals for catching certain types of animals or adaptations to the physical conditions. For example, the net on NOAA Ship Henry B. Bigelow has a rockhopper sweep for rocky bottoms.

hands from three different crewmembers reach out to repair a teal fishing net crumpled up on deck — Science and deck crews working to repair the net.

A bottom trawl targets species in, you guessed it, the bottom of the ocean! The net used in the BTS is standardized down to the model of metal connectors and number of knots in the mesh.

simple, flat line drawing of a fishing vessel at the surface of the ocean towing a bottom trawl net, which a few fish have entered, near the ocean bottom — A ship towing a bottom trawl net (NOAA).

When we say that the project is multispecies, the simple definition of “multiple species” almost doesn’t do it justice. There are obviously plenty of fish to be studied, but also shellfish like scallops and crabs. Much of the data collected is used to perform regional stock assessments, or population measurements, of more than 40 species. All finfish and some invertebrates are all weighed and measured. That doesn’t even include all the invertebrates or plants that we don’t catalog further!

about 15 crabs on a sorting table. there are also buckets of different colors. a gloved hand reaches in from the side of the photo to pick up a crab. — A mixture of different species of swimming crabs being sorted.

Melina, wearing orange overalls and blue gloves, smiles for the camera as she holds an angel shark up for a photo — Holding an Angel Shark.

close-up view of two spider crabs placed next to one another (but facing opposite directions) on a measuring board — Spider Crabs lined up on the measuring board.

Lastly, a survey in this case refers to the methodical collection of scientific information. There are standardized protocols to ensure that the year to year data can be used by researchers. Not all species are processed the same. Some are preserved whole in formalin or freezers, others are simply measured. The procedure really depends on the needs of the researcher. Researchers interested in requesting samples can submit online forms that are reviewed and potentially included as collection points in surveys.

Would you believe me if I told you that the fish collection doesn’t even scratch the surface of the projects onboard? There’s environmental, acoustic, biological, and oceanographic data collected throughout the cruise as well. The Deck and Survey Technician teams play a large role in the execution of those projects, so I’ve witnessed fewer of those operations. I’m excited to connect with them and chat about their roles on the ship.

Personal Log: First Watch

The first couple days on the ship have a “summer camp” feel to them. People that see each other only a few times a year but spend almost every single hour together form a unique bond. Every single meal is together, you’re all working towards a specific set of goals. There’s so much shared history. People are bouncing stories back and forth while I quietly observe from the fringes.

Everyone has been extremely welcoming and helpful, which is a big relief. Still, though, there’s always that sort of (excuse the bad joke) “fish out of water” feeling of entering an entirely new situation. Trying to remember everyone’s names, faces, job titles, organization affiliations–all of it is swarming around in my brain trying to take hold.

Waking up at 11:00pm and starting a twelve-hour shift is not something I’m accustomed to. Luckily, today was a relatively well-paced day with our work spread out with breaks in between to rest and mentally process the massive influx of information I’ve received. The main thing I did today was orient myself with the workflow of the lab spaces.

There’s a Wet Lab, Dry Lab, Acoustics Lab, Chem Lab, Hydro Lab, and maybe even some other secret labs I’ve yet to discover.

view into the empty wet lab; we see a long, empty sorting table to the left, and neat stacks of white buckets and orange baskets down the center of the photo — A view of the port side of the Wet Lab where the fish are taken in on a conveyer belt for sorting into buckets.

a computer tower and array of 10 monitors at a computer desk — The Acoustics Lab has lots of fancy computers that track important things. Being in here gives me a great view of the cameras of the deck operations so I know what stage of the tow we’re in.

All the online research in the world won’t compare to actually seeing the operation in action. My job was to help sort the fish as it comes down the belt. They get sorted by species, and then sometimes even further divided by size and/or sex. After sorting, they get examined and data is collected. My role was to be a Recorder, meaning I assist with organization of the fish prior to measurement, entering data into the computer system, and labeling samples. It’s extremely overwhelming, like trying to quickly learn a new language, but even after one shift I’ve already got a better handle on it.

a hand reaching in from the right of a photo grasps a fish; hands to the left of the photo hold a field guide open to a page with illustrations similar to the fish. in the background, there is a fish measuring board and several computer screens. — Identifying a fish at a workstation in the Wet Lab.

Did You Know?

NOAA was officially established in 1970 to combine the country’s first agencies for physical science (U.S. Coast and Geodetic Survey), atmospheric sciences (Weather Bureau), and conservation (U.S. Commission of Fish and Fisheries). The original emblem design lives on to this day, meant to represent the connection between the Earth, ocean, atmosphere, and ecosystems. Learn even more about NOAA’s history here!

The multifaceted logo has a gull-like figure flying through the sky. According to Dr. Robert White, NOAA’s first Administrator says “A creature of sea, land, and air, the gull adds an ecological touch to the Earth-sky motif.” (Source)

September 13, 2024September 13, 2024

Sam Garson: Everybody’s Trawling for the Weekend, September 12, 2024

NOAA Teacher at Sea

Sam Garson

Aboard Henry B. Bigelow

September 6 – 25, 2024

Mission: Leg 1 of Fall Bottom Trawl Survey

Geographic Area of Cruise: Mid-Atlantic Coast

Date: September 13, 2024

Weather Data from the Bridge:

Latitude: 36.93°N
Longitude: 76.3°W
Wind Speed: E 15 G 21 mph
Air Temperature: 22°C (71°F)

Science and Technology Log

NOAA’s Fall Bottom Trawl Survey began in 1963 and holds the distinction of being the longest-running standardized fishery-independent scientific trawl survey in the world. Its primary goal was to monitor the abundance and distribution of fish species in the northwest Atlantic Ocean, particularly on the continental shelf stretching from Cape Hatteras, North Carolina, to the Gulf of Maine. However, over time, the survey’s role has evolved into something far greater.

With over 60 years of continuous data collection, this survey is not only an important resource for understanding fish population dynamics, but it also serves as a data source for marine research across the globe. The data gathered provides unparalleled insights into long-term trends in marine ecosystems, making it a cornerstone of NOAA’s fisheries management program. This consistency allows scientists to assess how various factors—such as fishing pressure, environmental changes, and oceanographic conditions—affect fish populations over time.

By maintaining strict protocols and procedures across the decades, NOAA ensures that the data collected remains comparable year after year. As a result, this long-running trawl survey is a powerful tool for detecting shifts in marine biodiversity, population fluctuations, and changes in habitat use among species. The findings from the survey inform not only U.S. fisheries policy but also global conservation efforts, positioning it as a keystone project for marine resource management. The enduring nature of the Fall Bottom Trawl Survey has provided a reference point for understanding the impact of climate change on marine ecosystems, as rising ocean temperatures and shifting currents are increasingly influencing species distribution.

NOAA Ship Henry B. Bigelow. Photo Credit: Sam Garson

a diagram of NOAA Ship Henry B Bigelow showing the plankton net, trawl net, and sonar capabilities. title: State of the Art Research Vessel Henry B. Bigelow. box labels identify the following features: (1) Navy designed "quiet" hull does not disturb marine life. (2) Advanced 3-D sonar gives researchers a bigger picture of fish and their marine habitat. (3) Plankton net gives an accurate survey of fish food supply. (4) Fish net can help gauge abundance of fish stocks. — Illustration credit: James Warren / Cape Cod Times, Information source: NOAA

How Does a Trawl Work?

Members of the Bottom Trawl team work in 12 hour shifts, Midnight to Noon and Noon to Midnight. When it is your turn on watch you will wait for the ship to reach the next “station” or sampling site. Once there the survey team will deploy a CTD and possibly a “Bongo” plankton tow.

two crewmembers wearing hard hats, life vests, and gloves stand on the deck of the ship near a large piece of scientific equipment. the conductivity, temperature, and depth probe, along with one water sample bottle, is mounted inside a cylindrical metal frame attached to a cable. — Crewmembers ready to deploy the CTD.

Once on station, the ship will deploy and stream the trawling net for between 16 and 20 minutes at a specified depth. Far from a simple task, this operation of the net streaming behind the ship is monitored closely with technology and data. The watch lead has to work closely with the bridge to ensure that the trawl net is running through the water properly. Monitoring the opening, speed and depth throughout the dive. Once all of that is confirmed to be in good working order you’ll hear the call over the PA, “HAUL BACK!”

photo of a computer screen showing a plot. on the x-axis is time. the y-axis shows depth and "TE Height," and there are three plot lines. — Trawl net monitoring. Photo Credit: Sam Garson

Haul Back

Once the “haul back” call is given the deck crew springs into action to bring the net back on deck, while the science team moves into position in the sorting room. This process starts in the ready room, where everyone keeps their foul weather gear and gloves.

view of a collection of orange rain coats, orange overalls, and large rubber boots spilling out of a closet-type area on one side of a room — Ready Room. Photo Credit: Sam Garson

Once in their foul weather gear, the team will move to their positions along the first of three main conveyor belts. One member of the team will move out to the checker box where all of the trawl contents are first placed. From there the checker will feed the marine life into the first conveyor belt that brings all the specimens up to the main conveyor belt. Here the marine specimens are all sorted into buckets and bins by species, size and sex. The watch leader will tell the team what they are going to “run” that trawl, meaning which species do they leave on the belt to be deposited into bins at the very end. Depending on the goals, catch diversity or needs the watch leader could run everything from squid or crabs to sea robins.

view inside the wet lab. there are rows of stations, each comprised of a metal table with a measuring board, a drainage sink, a work surface, a computer monitor. — Cutting Station. Photo Credit: Sam Garson

Now that everything is sorted into buckets and bins the real data collection begins! The watch is broken into teams of two. A recorder and cutter work together to process every single marine sample for a variety of data products. These trawls are incredibly productive and have lots of scientists from institutions around the country sending in requests for samples and data. This is where the computer screens are so critical. As buckets of samples move down the last conveyor belt, the cutter scans them into the system and then is prompted by the computer to walk through any number of data collection procedures. The recorder enters them all into the computer, bags the samples, and processes the documentation needed. On this cruise we have been freezing samples, collecting otoliths (unfamiliar? check out this great NOAA resource), collecting stomachs and measuring and weighing hundreds of different species across all of our trawls.

trawl nets spread out on deck - they are large, green, with orange buoys attached. one net is attached to the A-frame at the aft of the ship's deck. — Trawl net on deck

empty conveyor belt in the sorting room. one purple-gloved hand reaches in front the right side of the image and rests on the rim of the conveyor belt. — Trawl net on deck

Once that is complete we clean our stations and get ready for the next trawl. Sometimes this could be 30 minutes away, or even an hour, at times. It can be instantly after completing the last trawl. Working in 12 hour shifts, 24 hours a day means that the amount of data we are producing and cataloging is massive, but so is the job of sampling on the scale needed to help scientists answer questions about the ecology, populations, diversity and impacts of climate change along the Eastern Seaboard.

Personal Log

It’s been 10 years since I last sailed and I have been amazed at how quickly I’ve fallen back into the swing of life at sea. The night shift from 12:00 AM – 12:00 PM was a rough adjustment at first, but pretty quickly my body adapted and I settled into the routine.

It has been incredibly interesting to compare my previous time on an ROV based exploration vessel with the reality of a trawl based research mission. The E/V Nautilus was my home for 7 years and walking around the Bigelow definitely brings back some amazing memories, but it also has been a great reminder of how different things are across platforms. The ins and outs of life on Bigelow and the pace of the trawl are worlds different from the 24 hour ops of the ROV missions. I’ll write more on that later, but it has been a really cool comparison to make. It will be interesting to see how the rest of the cruise goes as we are only 3 days into our mission, and lots of cool fish still to come!

Did You Know?

Henry Bigelow was one of the key members of the scientific community who helped found Woods Hole Oceanographic Institute, here is an amazing photo of Henry Bigelow with WHOI’s mascot!

a scanned black and white photograph. A man, dressed in a 3 piece suit and white hat, stands on the deck of a ship - the shoreline is visible at the horizon. he braces himself, his left foot positioned back, because a goat standing it on its hind legs is pushing against his chest with its forelegs. the man holds something with both hands, up toward the goat's face - maybe food. — Henry Bigelow and Buck the WHOI Mascot (1904). Photo Credit: NEFSC NOAA

September 4, 2014April 28, 2021

Sue Zupko, Getting Ready: Is it a Go? September 4, 2014

NOAA Teacher at Sea
Sue Zupko
(soon to be) Aboard NOAA Ship Henry Bigelow
September 7-19, 2014

Mission: Autumn Bottom Trawl Survey Leg I
Geographical area of cruise: Cape May, NJ to Cape Hatteras, NC
Date: September 4, 2014

Personal Log

I am a teacher of the Gifted and Talented at Weatherly Heights Elementary School in Huntsville, AL. I am so very humbled by the opportunity I have been given to conduct research aboard the Henry B. Bigelow with NOAA scientists. This is my second NOAA cruise. I studied deep-water corals aboard the Pisces in 2011 and thought it was my only chance to do something like that. They told me if I did all my homework, and did all my projects well, that good things would come my way. I say that to my students and this is an example of why one should do one’s homework and try hard. You’d better believe that I did my best. I love to learn so a NOAA research cruise and projects with my students are a perfect fit.

Sue in sweatshirt looking up from microscope. Diego in the background. — Me on the Pisces, It was cold in this lab.

In preparing for my first entry I asked my students for advice on what to include. They insisted that I include a “shout out” to them and tell how fabulous our school is.

Here are a few highlights. Weatherly has been recycling aluminum cans to help pay for our outdoor classroom since 1998 when I helped write a grant to get a trailer to collect cans and take them to the recycling center. We have made thousands of dollars through the years and have an Alabama Certified Outdoor Classroom now. Students, parents, faculty, and community volunteers help with it and enjoy learning there. We have raised Monarch butterfly larvae, viewed Ladybug larvae under a microscope from the Tulip Poplar tree, grown melons, touched plants in the sensory garden, and myriad other activities.

We piloted a recycling program for our district. Every classroom has a bin to collect clean paper and plastic. It is collected weekly and tons of items have been recycled as a result.

We participate in a plastic bottle cap recycling program. This is an annual contest city-wide and Weatherly counts and recycles thousands of caps to be made into paint buckets rather than taking up room in the landfill. For many years we recycled phone books and were one of the top three recyclers.

In addition to helping the environment, we are a No Place for Hate school. We also study about the ocean. A lot. I am the faculty advisor for our morning announcements. Our quotes of the week this year are about the ocean and we highlight an ocean literacy principle every day. We now know that marine biologist Sylvia Earle pointed out that “With every drop of water you drink, every breath you take, you’re connected to the sea. No matter where on Earth you live. Most of the oxygen in the atmosphere is generated by the sea.”

On my upcoming voyage with NOAA, I will launch two drifters. In order to be selected for this drifter project, a teacher must have an international partner to share lessons with to learn about the ocean. After an extensive search I found the perfect match. Sarah Hills at the TED Istanbul College teaches English. Her students will be studying map reading starting in September when they return to school. We have already decided that our students will plot the course of the drifters and hypothesize where they will be at specific times based on the ocean currents and winds which will carry them.

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These drifters measure ocean salinity, surface water temperature, velocities (speeds) of the current, and air pressure and are important for understanding more about our weather and the ocean. I can’t wait to get our students communicating. Weatherly’s school theme is “A Village of Learners and Leaders.” Outside my classroom on the bulletin board are some wonderful items from Turkey provided by Mrs. Hills and it says, “A Global Village of Learners and Leaders.” In preparation for tracking our drifters, we are currently tracking former hurricanes and researching how the ocean changes our planet. On their exit ticket today, my 5th graders commented that they liked tracking the hurricanes since they will use the same technique to track my journey and the drifters.

I am so excited. I have spoken with the Chief Scientist, John Galbraith, and understand that I will be working side-by-side with scientists on this fisheries cruise. We will drop a trawl net behind our 209 foot long ship and catch marine creatures. Our job will be to sort the fish (and other marine animals) and learn more about them using measurements and other means such as dissection. Computers play a role in our study and my first assignment will be to collect data in the computer. Wonder what program I will use, and is it similar to Excel which we use a lot?

I asked my fourth graders if they thought I might see a whale. They all responded yes in that group. What do you think?

Teachers at Sea need to be flexible, have fortitude, and follow orders. Let me explain. Right now I am waiting to see if my ship will even sail. The engineers have found a problem and are working to make the ship seaworthy for our voyage. Already our cruise date has changed twice. I must be flexible and be ready to leave on a moment’s notice. There are always some changes, it seems, when dealing with the ocean. On my last cruise a tropical depression (storm) formed over us and we couldn’t begin our research for an extra day.

Sailing is not for the faint of heart. I must be able to work long hours in uncomfortable conditions (they say this is having fortitude). They do supply my “foul weather” gear. Wonder if I will smell like fish at the end of my shift.

One handy piece of equipment I will take is ear plugs. The engines are loud and that helps when it is time to sleep. My shift will be either from midnight to noon or noon to midnight. That’s a long time to work. If we have a good catch, we will be working a lot. That is good for weight loss, as long as I don’t overdo with the fabulous food prepared by the stewards (cooks) in the galley (kitchen).

I was in the U.S. Army years ago and learned to follow orders, the third of the 3Fs. There are NOAA officers whose orders I must follow for my safety and the safety of the other scientists. I also must follow the orders of the NOAA Teacher at Sea directors and my chief scientist. Add to that my principal and superintendent in my district. That’s a lot of bosses giving orders.

Lastly, my students requested that I tell everyone our school motto. “We are Weatherly Heights and we…GO THE EXTRA MILE.” Well, pretty soon I can say, “We are the crew and scientists aboard the NOAA Ship Henry B. Bigelow and we…GO THE EXTRA NAUTICAL MILE.” Can’t wait to see what treasures we will uncover in the ocean.

August 8, 2013August 20, 2021

Melissa George: Scraping the Bottom-Dwellers, August 6, 2013

NOAA Teacher at Sea
Melissa George
Aboard NOAA Ship Oscar Dyson
July 22 – August 9, 2013

Mission: Pollock Survey
Geographical Area of Cruise: Gulf of Alaska
Date: Tuesday, August 6, 2013

Current Data From Today’s Cruise (9 am Alaska Daylight Time)

Weather Data from the Bridge
Sky Condition: Partly Cloudy
Temperature: 15° C
Wind Speed: 7 knots
Barometric Pressure: 1019.6 mb
Humidity: 90%

August 6, 2013: Partly Cloudy or Partly Mountainy?

Sun and Moon Data
Sunrise: 5:15 am
Sunset: 9:33 pm
Moonrise: 5:33 am
Moonset: 8:45 pm

Geographic Coordinates ( 9 am Alaska Daylight Time)

Latitude: 59 ° 20.4 N Longitude: 141° 16.6 W
The ship’s position now can be found by clicking: Oscar Dyson’s Geographical Position

Science and Technology Log

Besides the mid-water trawling, information about the pollock population is gathered in other ways on the Oscar Dyson research vessel. One of these ways is direct, monitoring the pollock by trawling in other parts of the water column; the other way is indirect, evaluating the prey that the pollock feeds on.

Bottom Trawling

Scientists use acoustics to locate the signal for the fish. Sometimes this signal is noticed near the ocean floor. In this case, the PolyNor’eastern (PNE) Bottom Trawl Net is used to trawl for fish. This net is a large net equipped with rubber bobbins that allow it to get close to the benthic region of the ocean without dragging.

During this research expedition, we used the PNE net six times to survey pollock. Often times these trawls brought up other interesting sea life, that were quickly assessed (identified, measured, and recorded) and returned to the ocean. The majority of invertebrate sea animals such as poriferans (sponges), cnidarians (sea anemones), annelids (segmented worms), mollusks (barnacles), arthropods (hermit crabs hiding in mollusk shells), and echinoderms (sea urchins and starfish) were brought up in these hauls. In addition, some interesting species of fish (see this blog’s Trawling Zoology segment below) were gathered in bottom trawls.

Miscellaneous Invertebrates from Bottom Trawl

Using the Methot Trawl

We use the Methot trawling net to sample krill, a type of zooplankton that pollock feeds on. On this voyage, the Methot was used 6 times as well. The Methot is a single net with a large square opening or mouth. The net is deployed from the stern and towed behind the vessel. Inside the Methot is a small removable codend where much of the catch is deposited.

The krill is measured and counted as well. First, the water is drained out, then it is weighed, and a small sample is weighed and counted.

Bottom trawls and Methot trawls are both important aspects of the pollock survey.

Personal Log

Accomplishment

Continuing with Maslow’s hierarchy of needs, I will discuss the top part of the pyramid, how self-actualization, or being involved in creative endeavors to expand one’s full potential, are met on the Oscar Dyson.

A Version of Maslow's Hierarchy of Needs — A Version of Maslow’s Hierarchy of Needs

Since I am an honorary member of the am science team, I am privy to many discussions between the scientists on the team regarding a variety of topics. For example, one side project on the mission is to gather information regarding the abundance and distribution of euphausiids (krill) in the Gulf of Alaska. This research project involves the use of a smaller “critter camera,” engineered and built by two of the MACE (Midwater Assessment and Conservation Engineering) group members, to take pictures of krill at various ocean depths and (ideally) reconcile its distribution with acoustic and Methot trawl data. The goal of the project is to provide insight into the feeding conditions of pollock. The discussions between group members involve postulating, speculating, testing, theorizing, analyzing, teaching, and questioning; clearly this meaty dialog indicates that the process of science is an intellectually stimulating and creative endeavor.

Scientist Team Members--- Abigail, Patrick, and Kirsten---Engaged in a Stimulating Discussion — Scientist Team Members— Abigail, Patrick, and Kirsten—Engaged in a Stimulating Discussion

Did You Know?

One of the people who views my blogs before they are posted is the Executive Officer (2nd in Charge) of the crew on the Oscar Dyson. His name is Chris and on this mission he is “augmenting” or filling in for another employee. Chris administers the day-to-day operations of the crew including logistics, payroll, and travel. Chris is a member of the NOAA Corps; he has both a BS in Marine Biology and an MS in Management Information Systems from Auburn University located in Auburn, Alabama. He grew up in various places in the Midwest (his dad was in the U.S. Airforce) and has worked in several fields including information technology and zookeeping. He applied to the NOAA Corps because he wanted to live and work near the ocean.

Chris, the Executive Officer of the Oscar Dyson — Chris, the Executive Officer of the *Oscar Dyson*

Something to Think About:

In previous posts, we have explored invertebrates encountered on this mission. Today we will look at a group of vertebrates from the class Osteichthyes, a word that comes from the Greek osteon meaning “bone” and ichthus meaning “fish.” We will focus on some of the other fish besides pollock found in bottom trawls. These bottom-dwellers are quite interesting creatures.

One of the most frequently found fish, other than pollock, is a type of rockfish called the Pacific Ocean Perch (POP); the species name is Sebastes alutus (Greek: Sebastes “August, venerable”, alutus “grow, nourish”). This fish actually was seen in many trawls, both mid-water and bottom. As the picture below indicates, the body and fins of the POP are light red; however, there are dark olivaceous areas on back under soft dorsal fin and on the caudal peducle. The maximum length of the fish is 55 cm and it is commonly found at a depth between 100-350 m.

Pacific Ocean Perch (a type of Rockfish)

A fish that belongs to the same genus as the POP is the Tiger Rockfish, Sebastes nigrocinctus ( Latin: niger, “black” and cinctus, “belt”). We found this fish once in a bottom trawl. The bottom of the tiger rockfish is light red to orange with several broad, vertical black-red bands on body. It grows to a maximum length of 61 cm and is commonly found at a depth between 55 to 274 m. Notice how similar it looks to the POP.

Tiger Rockfish, notice the similarities to the Pacific Ocean Perch

One of the most colorful fish that was found in a bottom trawl was the kelp greenling, Hexagrammos decagrammus (Greek: hexa, “six”; grammus, “letter, signal”, deca, “ten”), a fish that generally hangs out in rocky reefs and kelp beds in relatively shallow waters (up to 46 m). The fish is olive brown to bluish grey, speckled with irregular blue spots if male and reddish brown to gold spots if female (those we caught were most likely female). The fish reach a maximum length of 53 cm.

July 12, 2013August 13, 2021

Amie Ell: Deadman’s Bay, July 11, 2013

NOAA Teacher at Sea
Amie Ell
Aboard NOAA Ship Oscar Dyson (NOAA Ship Tracker)
July 7 – July 11, 2013

Mission: Alaska Walleye Pollock Survey
Geographical Area: Gulf of Alaska
Date: July 11th, 2013

Location Data from the Bridge:
Latitude: 56.56 N
Longitude: 152.74 W
Ship speed: 11.3 kn

Weather Data from the Bridge:
Air temperature: 10.7 degrees Centigrade
Surface water temperature: 8.6 degrees Centigrade
Wind speed: 18 kn
Wind direction: 250 degrees
Barometric pressure: 1016 mb

Science and Technology Log:

OLYMPUS DIGITAL CAMERA — Full net on deck

So now that you know what we do with the fish after they are caught, let’s go back and see how the fishermen trawl. There are two large nets at the stern of the ship. Today we used both nets for the first time. The scientists, crew, and fishermen all work together to catch the fish. In the acoustics lab Paul is reviewing and scrutinizing the data he receives from the echo locators mounted on the hull of the ship. There are many factors he must evaluate in order to have a good trawl. There are places in our area that have been marked as “untrawlable”. This is usually due to a sea floor that is rocky. Trawling in these places may ruin the nets. We have completed at least one trawl a day since we have been out to sea. Today we completed two during my watch. The first was with a larger net and was not sent all the way to the bottom. The second trawl was sent to the bottom with a smaller net. The bottom trawl brought up the largest pollock I have seen so far. The longest pollock was 75 cm. We also brought up a salmon, cod, rock fish, and a whole lot of herring.

Crane lifting the net to be dumped into the bin.

The nets are both on large spools and are released or returned with the help of a very large winch. Before the net is released into the water the CamTrawl is attached to it. This is a camera that takes pictures that help the scientists see at what point in the trawl fish were entering the net.

Example photo from the CamTrawl. A Salmon Shark caught on the first leg.

The time that the net is in the water depends on the information about the amount of fish coming from the acoustics lab. Scientists watch the echo information to determine how much time the net should be in the water to catch enough fish to sample. We must have at least 300 pollock to make a complete survey.

The fishermen bring the nets back to the trawl deck and wind them back onto the spools. They then will use a crane to lift the catch and dump it into a bin. From the fish lab we can lift this bin to dump the fish onto the conveyor belt.

Personal Log

Entering Deadman's Bay — Entering Deadman’s Bay

On Monday, we had our weekly fire and abandon ship drills. After the drills I practiced putting on my survival suit. This suit is designed to keep you afloat and warm in the event that you have to go into the water.

On Tuesday, we surveyed up into Deadman’s Bay. It was a beautiful sun shiny day and the scenery was amazing. We were very close to the shore on both sides. I sat out on the trawl deck and scanned the hillsides with my binoculars. I was told that it is common to see bears here, but I did not see any.