otoliths – NOAA Teacher at Sea Blog

June 21, 2023June 21, 2023

Laura Guertin: Collecting Data: Icthysticks and Otoliths, June 21, 2023

NOAA Teacher at Sea

Laura Guertin

Aboard NOAA Ship Oscar Dyson

June 10 – June 22, 2023

Mission: 2023 Summer Acoustic-Trawl Survey of Walleye Pollock in the Gulf of Alaska

Geographic Area of Cruise: Islands of Four Mountains area, to Shumagin Islands area
Location (10:45AM (Alaska Time), June 21): 55^o 29.7525′ N, 156^o 44.7276′ W

Data from 10:45AM (Alaska Time), June 21, 2023
Air Temperature: 8.4 ^oC
Water Temperature (mid-hull): 8.2^oC
Wind Speed: 8 knots
Wind Direction: 20 degrees
Course Over Ground (COG): 76 degrees
Speed Over Ground (SOG): 11 knots

Date: June 21, 2023

Once the echo sounder has shown us the position of an aggregation of Alaska walleye pollock (we hope they are pollock and not some other fish species), we lower the trawl net and see what we can catch. This is where the trawl sonar and CamTrawl (see previous blog post) come in handy to give us an idea of what is going into the net. It’s an amazing coordination of effort between the acoustics lab (who decides where to trawl), the bridge for navigation, and the deck crew for setting/retrieving the haul.

We aim for trawling at the mid-water level, where the pollock are typically found. Pacific Ocean perch (POP, or rockfish) can also be found in the mid-water level in the Gulf of Alaska, especially just off the shelf break. Bottom trawls can yield pollock and other fish (e.g., POP and other rockfish species, various species of flatfish).

Once the trawl net has been brought back on board, the catch is emptied into a bin called a table. There is a door on the side of the table that opens into the fish lab. Once the table door opens, the fish spill into the laboratory where they travel down a conveyor belt for the initial sorting. Our target species is the pollock. We weigh everything that ends up onto the sorting table, either in bulk (by species) or individually.

Pollock moving along the sorting belt
Pile of Pacific Ocean perch (rockfish) after being hauled on the ship
Small squid that fell out of the trawl net on deck.

A subset of around 250 pollock are set aside to collect length data. The length of these of each individual pollock are measured on an Ichthystick. This is another invention by Rick Towler and Kresimir Williams (remember the CamTrawl? (see previous blog post)). As described in their article An inexpensive millimeter-accuracy electronic length measuring board, these NOAA scientists describe using magnetic measuring technology that, to millimeter resolution, takes a measurement when you placed a magnet on a sensor that runs the length of the board. For our pollock measurements, we were looking to record the fork length, and a quick placement of the red magnet along the fish tail sends the data to a computer program called CLAMS (Catch Logger for Acoustic Midwater Surveys).

Bins of pollock waiting to be measured on the Ichthystick
Ichthystick logo with a pollock sketch
Computer end of Ichthystick, which digitally shows the value of fish length and is written to CLAMS
Sketch showing what is measured for the fork length of a fish. From Corvallis Forestry Research Community.
Pollock lying on Ichthystick getting its fork length being measured
Two scientists measuring pollock fork length on Ichthystick

Another subset of approximately 50 pollock are set aside for additional data collection on individual specimens – length, weight, sex, maturity, and age. Otoliths (e.g., ear bones) are removed, and sometimes organs are removed and measured (ovaries for maturity development analyses, liver).

a black and white image showing pairs of otoliths from different fish species. Each otolith is white and gray in contrast with the solid black background; lighting reveals the ringed growth pattern — Otolith pairs (two per individual fish) from an assortment of Bering Sea fish species. Walleye pollock is located in the top left. Note: otolith sizes are not on a relative scale. Photo: NOAA Fisheries.

What are otoliths, and why remove them? Otoliths are ear stones, or ear bones, found in fish. To give you an idea of why we remove ear bones, let’s start by thinking about trees and corals… trees grow a new ring on their structure each year, and corals have differences in their skeletal density between the seasons (both trees and corals are also used to reconstruct past climate conditions (proxy data for paleoclimatology)). By counting the rings on trees and coral, we can calculate the age of that specimen. It turns out that fish also have a way to record their annual growth – and it occurs in their ear through Fish Otolith Chronologies.

Scientists are very interested in studying otoliths. When otolith data are combined with data on fish size, scientists are able to determine the growth rates of fish, which then combined with the survey work, helps inform annual fish stock assessment reports. We don’t do any of the otolith analyses on the ship, but we do collect the samples with a detailed label and all the corresponding data (fish length, sex, weight, location) that is sent back to the NOAA Fisheries Alaska Fisheries Science Center for analyses and entered into their Fish Otolith Collection Database.

Rockfish otoliths
Zoom of rockfish otoliths
Otoliths still inside a pollock
Placing an otolith cleaned in freshwater into a vial for storage and shipment for analysis

Did you know… More than 30,000 otoliths are read annually by NOAA Fisheries Alaska Fisheries Science Center scientists. So far, the Science Center has collected more than 1.1 million fish otoliths for ageing. (from NOAA Fisheries)

To learn more about the fascinating studies of otoliths and what NOAA Fisheries is doing, check out these websites:

NOAA Fisheries Age and Growth – NOAA Fisheries scientists assess the age and growth rates of fish species and populations to better monitor, assess, and manage stocks. There is also a separate site for Age and Growth Research in Alaska.

NOAA Fisheries Age and Growth Homework: Determining How Old Fish Are

NOAA Fisheries Near-Infrared Technology Identifies Fish Species From Otoliths – NOAA Fisheries scientists are developing ways to use near-infrared spectroscopy (NIRS) analysis of otoliths (fish ear stones) to provide accurate information for sustainable fisheries management faster.

If you are really curious to explore some fish otolith data, check out the Alaska Age And Growth Data Map, an interactive map displays collected specimen information from recent age and growth studies from Alaska Fisheries Science Center.

Screenshot from the Alaska Age and Growth Data Map website. On the left is a map of Alaska with lots of orange, blue, and green circles marking sampling locations. To the right are two graphs plotting lengths (y-axis) against ages (x-axis) for walleye pollock sampled in 2021. Blue circles (or box-and-whisker plots) represent samples from the Western Bering Sea and green circles represent samples from the Eastern Bering Sea.

July 11, 2019July 12, 2019

Erica Marlaine: Oh, the Places You’ll Go! July 6, 2019

NOAA Teacher at Sea

Erica Marlaine

Aboard NOAA Ship Oscar Dyson

June 22 – July 15, 2019

Mission: Pollock Acoustic-Trawl Survey

Geographic Area of Cruise: Gulf of Alaska

Date: July 6, 2019

Weather Data from the Bridge:

Latitude: 55º 4.07N
Longitude: 156º 42 W
Wind Speed: 3.2knots
Wind Direction: 96º
Air Temperature: 10.3º Celsius
Barometric Pressure: 1025.7. mb
Surface Water temperature: 11.05º Celsius
Depth of water column: 1,057.6 meters

If you love science and exploring, consider a career in the NOAA Corps!

NOAA Corps

The NOAA Corps is one of our nation’s seven uniformed services (along with the Army, Marine Corps, Navy, Air Force, Coast Guard, and Public Health Service Commissioned Officer Corps). NOAA Corps officers are an integral part of the National Oceanic and Atmospheric Administration (NOAA), an agency of the U.S. Department of Commerce. NOAA and the NOAA Corps can trace their lineage to 1807 when President Thomas Jefferson signed a bill for the “Survey of the Coast.” The survey work was done by Army and Naval officers along with civilian men and women. The Coast Survey was actually the first federal agency to hire female professionals! Their duties included charting our nation’s waterways and creating topographic maps of our shorelines, which made our marine highways among the best charted in the world.

Today, the NOAA Corps is an elite group of men and women trained in engineering, earth sciences, oceanography, meteorology, and fisheries science. NOAA is comprised of the National Weather Service, National Marine Fisheries Service (NOAA Fisheries), Office of Oceanic and Atmospheric Research (NOAA Research), National Environmental Satellite, Data and Information Service, National Ocean Service, and the Office of Marine and Aviation Operations. NOAA Corps officers operate NOAA’s ships, fly aircraft, manage research projects, conduct diving operations, and serve in staff positions throughout NOAA.

NOAA Officer Spotlight

I had the opportunity to speak with Ensign (ENS) Lexee Andonian (although by the time this is published Ms. Andonian will have been selected for LTJG (Lieutenant junior grade)! ENS Andonian has been a member of NOAA Corps for almost 2 years, and loves her job, but it was not something she originally considered as a career (or even knew about). She first learned about NOAA while working at a rock climbing gym. A patron mentioned it to her, and offered to show her around a NOAA ship. She went home and googled NOAA. With her interest piqued, she decided to accept the patron’s offer, and went to Newport, Oregon to tour the NOAA Ship Bell M. Shimada (which is actually the sister ship of the NOAA Ship Oscar Dyson. A sister ship means they were based off the same blueprint and can serve similar projects.)

ENS Andonian applied for the NOAA Corps, but was waitlisted. NOAA is highly selective and accepts a very limited number of applicants (approximately 15-25 twice a year.) Undeterred, she applied for the next NOAA class, and was once again waitlisted, but this time she was accepted off the waitlist. After 5 months of training at the Coast Guard Academy, she was ready to begin her assignment onboard a NOAA ship, where additional hands-on training occurs non-stop. Each NOAA Corps member wears a multitude of “hats” while onboard. ENS Andonian is currently the Acting Operations Officer, the Navigation Officer, the Environmental Compliance Officer, and the Dive Officer. ENS Andonian loves that her job allows her to see unique places that many people never get to explore since they are not accessible by plane or car. Asked what she misses the most from home, she said, “Bettee Anne” (her dog).

Science and Technology Log

Today I was introduced to a few new species in the fish lab. Until now, most of the jellyfish have been Chrysaora melanasta, which are beautiful and can be quite large, but today I saw 2 egg yolk jellyfish, aptly named as they look like egg yolks.

I also saw a lumpsucker, which is the cutest fish I have ever seen. Lumpsuckers look like little balls of grey goo. He (or she) seemed to look right at me and kept opening and closing its mouth as if trying to say something. Lumpsuckers have a suction cup on their bottom which allows then to adhere to rocks or other surfaces.

Personal Log

As a teacher, I create experiences for my students that will take them out of their comfort zone so that they can realize just how much they are truly capable of. On the NOAA Ship Oscar Dyson, it is my turn to step outside my own comfort zone. If you would have told me a few months ago that I would feel comfortable being elbow-deep in live fish and jellyfish, or dissecting fish to see whether they are male or female, or slicing into a fish’s head to collect otoliths (ear bones), I would not have believed you, but that is how I spend every day onboard the Oscar Dyson, and after 2 weeks, it feels like something I have done all my life. It is an experience I highly recommend to everyone!

A slice is made slightly behind the pollock’s eyes.
Otoliths are then removed using forceps.
Walleye pollock otoliths.
Otoliths are bottled and sent for further analysis.

June 27, 2019

Karah Nazor: The Glowing Dolphins of the Channel Islands and Interview with UCSC Graduate Student Ilysa “Ily” Iglesias, May 31, 2019

NOAA Teacher at Sea

Karah Nazor

Aboard NOAA Ship Reuben Lasker

May 29 – June 7, 2019

Mission: Rockfish Recruitment & Ecosystem Assessment

Geographic Area: Central California Coast

Date: May 31, 2019

Game Plan and Trawling Line: Channel Islands San Nicolas Line

I am up on the flying bridge and I just saw two humpback whales spouting, an albatross soaring and a large Mola Mola on the sea surface. In this blog I will write about an amazing once in a lifetime experience that from last night- May 31, 2019. The first haul was called off due to an abundance of Pacific White-Sided Dolphins, Lagenorhynchus obliquidens, (as reported by the inside marine mammal watch prior to net deployment), so we motored on ahead to the second station, but dolphins chased the ship all the way there, too. One strategy to encourage marine mammals to leave is for the ship to stop moving with the hope that the dolphins become disinterested and vacate the area. This pod was intent on having a party at the ship so Keith Sakuma encouraged everyone to just go outside to observe and enjoy the dolphins!

Fishing on this survey takes place at nighttime (so the fish do not see the net) and Scripps graduate student Kaila Pearson and I stepped outside on the side deck into the darkest of dark nights. Kaila and I carefully placed one foot in front of the other because we couldn’t see our feet and where to step next. I was afraid I would trip. When I asked Keith Hanson if we should use a flashlight to safely make our way up to the top deck, he suggested that we stay in place for a few minutes to allow our eyes to adjust. Within 5 minutes or so objects around us started to present themselves to us within the black void. We could eventually see our feet, each others faces, the dolphins, and even the finer features of the sea surface.

Within a few minutes Ily Iglesias reported seeing bioluminescence, a type of chemiluminescence that occurs in living things, such as the familiar green glow of lightening bugs in the Summer in the South. This glow results from oxidation of the protein luciferin (present in photophore cells/organs) by the enzyme luciferase. It its excited state, lucifern emits light. This reaction is known to occur in some marine bacteria, dinoflagellates (single celled photosynthetic organisms), squid, deep sea fish, pyrosomes and jellyfish, and I am fortunate to have observed many of these creatures already on this research cruise (see photos below). Some animals have photophore organs and generate their own luciferin, while others are hosts to bioluminescent bacteria.

The large photo organ is a large green circle under the eye of the deepsea longfin dragonfish, *Tactostoma macropus*.

California lanternfish, *Symbolophorus californiensis*, with photophores under the lateral line and the ventral surface.

Blue lanternfish, *Tarletonbeania crenularis*, collected from a bongo net at 265 meters. Photophores line the ventral surface of the body.

*Cranchia scabra* “baseball squid” with large photophores lining the eyes.

Chiroteuthis veranii squid — *Chiroteuthis veranii* squid

When dinoflagellates floating on the sea surface are agitated, they glow. At first when I was trying really hard to see this, I noticed a couple of tiny flashes of green light, sort of like lightening bugs, but it wasn’t anything super obvious. In time, I noticed clouds of faint light, sort of like a glowing mist floating the water’s surface, that moved up and down with the swell. I hypothesized that dinoflagellates on the sea surface were being agitated by the passage of waves through them and Ily suggested that it was caused by schools of anchovies.

Since the dolphins were intent on staying, we decided to head to the next station. I knew that as the ship began to move that the bow would be breaking through surface water that had previously been undisturbed, and I predicted the bioluminescence would be much more intense.

As we took off, the dolphins began to bow surf and, as I predicted, the dinoflagellates were activated and this time their glow was a bright white. As the dolphins surfaced to breath, their skin became coated with the glowing algal cells, creating an effect as if they were swimming in an X-ray machine. The dolphins were literally glowing white swimming in a black sea! We were so entranced and excited by the beauty, we screamed in delight. I am sure the dolphins heard us cheering for them. They too, seemed excited and could see each other glowing as well.

Next we saw the faint cloud of dinoflagellates caused by Northern anchovies (Ily was right) up ahead of us. As the ship encountered the school of small (~ 3-6 inch) fish, they also started to glow really bright and it was easy to see all of the individual fish in the school. The dolphins could also see the glowing fish and split off in different directions to hunt them. There were hundreds of fish that dispersed as they were being chased creating a pattern of short white glowing lines somewhat like the yellow lane markers on the highway.

The display was unlike anything I have ever witnessed. It was like the Aurora Borealis of the sea. Despite our best efforts, our cell phone cameras were unable to pick up the bioluminescent signal, however, we do not need photos because the patterns of light will be forever embedded in our minds. The dolphins eventually tired from the surf and chase and departed. Ily said the experience was “an explosion of light that overwhelmed the senses” while Flora said it was “better than fireworks.”

With no marine mammal sightings at the third station, we completed a five minute haul in the deep channel and collected a huge white bin of anchovies (see photo of Keith Hanson with this catch below). In this catch we found a few Mexican lampfish, 3 king of the salmon, a lot of of large smooth tongues, a lot of salps, a few pyrosomes and one purple striped jellyfish. The purple-striped jelly (Chrysaora colorata) is is primarily preyed upon by Leatherback turtles. Haul 2 was conducted over shallower water near San Nicolas Island and we only found salps and four small rockfish in the catch. After these two hauls, we called it a night and wrapped up at 4:15 a.m.

Scientist Spotlight: Ilysa Iglesias, NMFS SWFSC FED/ University of California Santa Cruz (UCSC)

Ilysa “Ily” is a doctoral student who works in John Field’s Lab at UCSC. She is studying the fish we are collecting on this cruise as part of her research. She is very knowledgeable about all of the survey research objectives. She is also one of the most positive and gregarious people I have every met. Ily grew up in Santa Cruz, CA, and enjoys surfing, hiking, gardening and raising chickens. Ily is a fan of early marine explorer Jacques Cousteau, who often wore a red beanie/toboggan and a blue shirt. Ily came prepared and brought six red hats (that she knit herself) for each of the members of the sorting team. Ily’s favorite fish is the hatchetfish. She was thrilled when we found on in the catch!

Ilysa with hatchetfish — Ilysa Iglesias with deepsea marine hatchetfish

A deepsea marine hatchetfish caught in the bongo which was deployed to depth of 265 meters.

Ily obtained a Bachelor’s degree from UC Berkeley in integrated biology and a Masters Degree from the University of Hawaii in Zoology with a specialization in marine biology. Her thesis was on the function of intertidal pools as a nursery habitat for near-shore reef fish. She compared otoliths (fish bone ears) of fish reared inside and outside of tide pools and compared their growth rates. Otoliths can be used to the age of the fish much like counting rings on a tree and stable isotope analysis reveals information about where the fish were reared.

Ily, Flora and Kristin have all used otoliths in their research and taught me how to locate and collect the sagittal otolith from anchovies and myctophids. It is a tiny ear bone (one of three) that is positioned near the hindbrain of fish. See photos below of the otoliths we collected. This is a technique that I will definitely take back to my classroom and teach my McCallie students.

Photomicrograph of otoliths we collected from blue lanternfish (top) and Northern Anchovy (bottom) and observed under the dissecting microscope.

After obtaining her masters degree, Ily was Conservation Fellow for the Nature Conservancy in HI and worked in octopus fisheries before returning home to join NOAA’s salmon team and then the rockfish team as a Research Associate. Ily has just completed the first year of her doctoral work in the Field Lab and expects to complete the program within 5 years.

On this cruise, Ily is collecting small fish called Myctophids for her research. These are small bioluminescent fish that live at depths of 300 and 1,500 m in the bathypelagic zone. In this survey, we encounter these deep sea dwellers during their nightly vertical migration up to the edge of the photic zone at depths we are targeting. They are likely chasing their prey (krill) on this upward journey. It is amazing to me they are able to withstand the pressure change. Mcytophids are also known as lanternfishes and have bioluminescent photophores dispersed on their bodies. The fish sorting team analyzes the position of these organs to help distinguish between the different species. There are 243 known species of myctophids, making these little fishes one of the most diverse vertebrates on Earth. They are so abundant in the sea that they make up 65% of the ocean’s biomass, but most people have never heard of them!

In 2014- 2015 there was an anonymously high sea surface temperatures off of the Pacific Coast known as The Blob. Marine scientists are still elucidating the effect of the hot water had on fish populations and ecosystems. Ily explains that “atmospheric forcing caused changes in oxygen and temperature resulting in variability in the California current.” The water was less nutrient dense and caused a reduction in phytoplankton. This disruption of primary production propagated up the trophic cascade resulting in die offs of zooplankton, fish, marine mammals and birds.

Ily is using the catch records and acoustics data from the rockfish survey to study changes in distribution and abundance of myctophids from before, during and after The Blob (2013-2019). She aims to understand if and how their trophic position of myctophids was affected by the unusually high sea surface temperatures. Using elemental analysis isotope ratio mass spectrometry to analyze the Carbon and Nitrogen atoms incorporated into fish muscle, Ily can determine what the myctophids were eating each year.

September 24, 2017

Kate Schafer: So Many Snappers… September 24, 2017

NOAA Teacher at Sea

Kate Schafer

Aboard NOAA Ship Oregon II

September 17 – 30, 2017

Mission: Shark/Red Snapper Longline Survey

Geographic Area of Cruise: Gulf of Mexico

Date: September 24, 2017

Weather Data from the Bridge:

Latitude: 28^o 25.1’ N
Longitude: 94^o50.3’ W

Broken sky

Visibility 10 nautical miles

Wind speed 13 knots

Sea wave height 2-3 feet

Temperature Seawater 28.8 ^oCelsius

Science and Technology Log:

This is a shark and red snapper longline survey, and the sharks tend to steal the stage. They are bigger (for the most part), more diverse and definitely have more of a reputation. I have been surprised, however, by how much I’ve been drawn to the snappers. They are a beautiful color, and tend to come up in groups that are pretty similar in size.

The Northern Red Snapper (Lutjanus campechanus) is commonly fished in the Gulf of Mexico, both recreationally and commercially. It turns out that the commercial fishers get 51% of the catch quota and the recreational fishers get 49%. The methods for dividing up those two basically equal pieces of the pie is different between the commercial and recreational fishers. In addition, the commercial fishing catch is monitored very closely, while the recreational fishing catch numbers are largely unknown. Plus, the states have their own waters that extend out to different distances, depending on the state, and the federal waters extend from the state water boundary to 200 nautical miles offshore. So, in other words, managing the fishery is quite complicated.

So, how do all these fishing rules and regulations get established and modified over time? A law was passed in 1976, called the Magnuson-Stevens Fishery Conservation and Management Act, and one of the key parts of the act established eight regional management councils for regulating fishing in federal waters (more information on the act here: http://www.nmfs.noaa.gov/sfa/laws_policies/msa/). It also established the 200 nautical mile extension of federal waters from land. The Gulf of Mexico Fishery Management Council (GMFMC) is responsible for creating Fisheries Management Plans (FMPs) for fisheries within the U.S. federal waters of the Gulf of Mexico, from southern Texas, along Louisiana, Mississippi, and Alabama, and down the west coast of Florida. This graphic shows the catch limits for red snapper and other species for 2017 set by the GMFMC. For red snapper, the catch limit is close to 14 million pounds.

2017ACLBLOGGraphic_07-17-1024x663 — Annual Catch Limits as set by the Gulf of Mexico Fishery Management Council (http://gulfcouncil.org/fishing-regulations/federal/)

The data that we are collecting helps scientists and policy makers to determine what the annual catch limit for a particular season should be. For each fish that we bring on board, we measure the fish length and weight, as well as the weight of the gonads. In addition, we collect their otoliths (ear bones) and samples of the ovaries of females. These both help managers to estimate the age and size of the population, and future populations as well.

Otoliths are calcium carbonate hardened structures and are present in the part of the inner ear that is responsible for balance. Humans and other vertebrates have them too, and they can be used to tell the age of the fish. The otoliths of Lutjanus campechanus are quite large. There seems to be an overall relationship between the habitat of the fish species and the size of the otolith. Species like Lutjanus campechanus that live along reefs and rocky structures have much larger otoliths than species like tuna that swim up in the water column. Flying fish, which we’ve seen a lot of, also have large otoliths, given their body size, probably aiding them in knowing where they are as they glide through the air.

Well, we have been collecting a lot of data over the past couple of days to help inform these policies in the future! Each line we’ve pulled in lately has had a dozen or more snappers on it, and they are a lot of extra work as compared with the sharks, due to all the samples we have to collect once we’re done. A couple times, we’ve barely finished before it was time to start baiting lines again.

Personal Log:

As I mentioned earlier, I’ve really come to love the red snappers. Their eyes are the same color as their skin and I’m just awed by their size. I am used to snappers that I’ve watched on coral reefs, and even the largest species I’ve seen on reefs are nothing compared with these guys.

SnapperEye — Red snapper (Lutjanus campechanus) eyes

I’ve also adjusted to the shift in my day, as evidenced by the fact that I’m finishing this up at 1 a.m. It has been a long time since I’ve been on this kind of late night schedule. I’m enjoying it, especially because I know when I return to California, I’ll be getting up at 5:30 a.m. again.

Did You Know?

That snappers eat a wide variety of different foods, including fish and various types of crustaceans? Here are a couple of items we’ve found in the ones we’ve caught. Can anyone identify them? I studied the second group for my Ph.D. dissertation!

May 3, 2017May 8, 2017

Kimberly Scantlebury: Sharks, Snappers, and Sealegs, May 2, 2017

NOAA Teacher at Sea

Kimberly Scantlebury

Aboard NOAA Ship Pisces

May 1-May 12, 2017

Mission: SEAMAP Reef Fish Survey

Geographic Area of Cruise: Gulf of Mexico

Date: May 2, 2017

Weather Data from the Bridge

Time: 11:25

Latitude: 2808.4978 N, Longitude: 09329.9347 W

Wind Speed: 18.69 knots, Barometric Pressure: 1015.6 hPa

Air Temperature: 27.4 C, Water Temperature: 24.4 C

Salinity: 35.9301 PSU, Conditions: sunny, no clouds, small waves

Science and Technology Log

There are several ways data is collected for the SEAMAP Reef Fish Survey in order to have a more complete understanding of the reef system. One of them is fishing with vertical long lines with Bandit reels. We are fishing for snapper species (Lutjanus sp.), grouper species (Serranidae sp.), and certain species of amberjack (Seriola sp.). There are three reels mounted on the vessel’s starboard side. The fishing works by dropping a weighted line with ten mackerel-baited hooks per reel, which then ends with an orange float. The boat is kept as still as possible and we wait a designated period of time before reeling up the lines.

I fished with deckhand James and Texas A&M graduate student, Jillian. The other lines were fished by NOAA scientists Joey, Kevin, John, and other deckhands. Our first try we caught two large spinner (Carcharhinus brevipinna) sharks that escaped back to sea. The other lines caught smaller sharks and a couple red snappers. We ended up catching and returning six sharks.

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Even though we were not aiming to catch sharks, they are part of the ecosystem and the data is collected. The data is written down on paper first and then transferred to computer databases. Some of the sharks required wrangling and less data was collected before releasing them live to prevent harm to shark and people.

The red snappers were weighed, measured in different ways, sexed, the sexual development was determined, and then retained, meaning we kept the fish. The otoliths (ear bones) and gonads (reproductive parts) were also weighed, labeled with an unique bar code, and stored for later analysis down at the Panama City Lab.

Determining variability of fish ages is possible due to this important work. Otoliths work similar to aging tree rings. Under a microscope you can clearly read each year. By comparing fish size to gonads, it has been determined a thirty-year-old red snapper can produce more eggs than 30 one year old red snappers. It is easy to see the research conducted on NOAA Ship Pisces is vital to managing and protecting our nation’s seafood supply.

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Personal Log

The movement aboard a ship this size is different than smaller vessels I’ve been on such as a ferry, lobster boat, and other research vessels. Right now we are expecting to not work Thursday due to high seas and wind. The NOAA Ship Pisces’s 208 feet sways in every direction-up, down, all around. The adjustment period for acclimating to this unpredictable movement is referred to as, “getting your sealegs.” This is also an apt metaphor for my time adapting to life on board.

Other than research protocols, Teachers at Sea need to learn what to do in case of emergencies. The science staff, including myself, received a safety briefing before leaving port. Each person is assigned a muster station where they are to report if there is a Fire or Man Overboard. A separate location is assigned for Abandon Ship. Each emergency has a designated series of short or long horn blasts from the ship so it is clear to all what is happening.

Later, the whole ship drilled Abandon Ship. As fast as possible, we each carried our personal flotation device (PFD) and survival suit (referred to as a Gumby suit) to our life raft station. I then practiced how to get the suit on in less than a minute.

Did You Know?

As a New Englander, I talk faster than most people on NOAA Ship Pisces, whose home port is Pascagoula, Mississippi.

There are a lot of oil rigs in the Gulf of Mexico. We have not seen any other vessels out here, but can often see a half dozen rigs at a time. In fact, NOAA Ship Pisces was recognized for, “outstanding and successful emergency mobilization by providing acoustic monitoring survey operations under hazardous and arduous navigation conditions in support of the Deepwater Horizon Oil Spill recovery efforts.”

Oil rigs in sight as equipment is brought back aboard.

July 3, 2015August 21, 2021

David Walker: Equilibrium at Sea (Days 6-9), July 3, 2015

NOAA Teacher at Sea
David Walker
Aboard NOAA Ship Oregon II
June 24 – July 9, 2015

Mission: SEAMAP Bottomfish Survey
Geographical Area of Cruise: Gulf of Mexico
Date: July 3, 2015

Weather Data from the Bridge

Weather has fortunately continued to be calm. The only main deviation from clear skies has been haziness (symbolized “HZ” on the above weather log from 7/2/15). On 7/2/15, sky condition varied from FEW (3-4 octas) in the very early morning, to SCT (3-4 octas) and BKN (5-7 octas) at midday and afternoon, to SCT (3-4 octas) in the evening and night. Swell waves have varied throughout the past couple of days, from less that 1 meter to around 3 meters in height.

Science and Technology Log

The past few days honestly blend completely together in my mind. I feel as though I have reached an equilibrium of sorts on the boat. The night shift has proceeded normally – station to station, trawl to trawl, CTD data collection at each station, plankton collected periodically throughout the shift. Certain trawl catches have been exceptionally muddy, which poses a further task, as the organisms must first be separated from all of the mud and cleaned, before they can be identified.

A fairly standard catch, loaded onto the belt, yet to be sorted

Sorted Catch — A sorted catch, ready for measuring and weighing

In addition, on Day 6, the trawl net was damaged on a couple of occasions. I’ve realized that a trawl rig is quite the complicated setup. The trawling we are doing is formally called “otter trawling”. Two boards are attached at the top of the rig to aid in spreading out the net underwater. To allow the net to open underwater, one of the two lead lines of the net contains floats to elevate it in the water column. A “tickler chain” precedes the lead lines to stir fish from the sea floor and into the net. The fish collected by the net are funneled into the terminating portion of the net, called the “cod end”. FMES Warren Brown is an expert when it comes to this entire rig, and he is in charge of fixing problems when they arise. On Day 6, Warren had to fix breaks in the net twice. With help from Lead Fisherman Chris Nichols and Skilled Fisherman Chuck Godwin, new brummel hooks were attached to the head rope for one of the door lifting lines, and a new tickler chain was installed.

Otter Trawl — Cross-sectional diagram of an otter trawl (Image Source – Penobscot Marine Museum)

New Tickler — FMES Warren Brown measuring out a new “tickler chain” for the net

Brummel Hook — Lead Fisherman Chris Nichols and Skilled Fisherman Chuck Godwin installing a new brummel hook to the head rope for one of the door lifting lines (caption source – FMES Warren Brown)

I also learned a lot more of the specifics involved in the workup of the plankton catch. The dual bongo contains two collection nets in parallel. Plankton is removed from the cod ends of these nets, but not combined. The plankton from the left bongo is transferred to a mixture of formaldehyde (10% v/v) and sea water for preservation. The plankton from the right bongo is transferred to 95% ethanol. The reason for this is that different solvent mixtures are needed to best preserve different parts of the plankton in the sample. The formaldehyde solution is best for fixing tissue, yet it tends to dissolve hard parts (for example, otoliths, discussed below). The ethanol solution is better for preserving hard parts (bones, cartilage, etc.). This explains the need for two bongos. Workup of collected plankton from the Neuston net is similar, except many non-plankton species are often collected, which have to be removed from the sample. Highlight non-plankton species from the past couple days have been sailfin flyingfish (Parexocoetus brachypterus) and a juvenile billfish (Istiophoridae). Neuston-collected plankton is transferred to 95% ethanol. This solvent is the only one needed here, as only DNA analysis and stock assessment are conducted on Neuston-collected plankton. All plankton is shipped to Poland, where a lab working in collaboration with NOAA will analyze it. Samples are broken down according to a priority species list sent by NOAA.

Lowering Bongo — Fisheries biologist Kevin Rademacher and Skilled Fisherman Chuck Godwin lower to bongo nets into the water for data collection

Bongo Plankton — Plankton from the left bongo, preserved in a mixture of formaldehyde (10% v/v) and sea water

Plankton from the right bongo, preserved in 95% ethanol

Neuston Plankton — Plankton from the neuston net, preserved in 95% ethanol

Sailfin Flyingfish (Parexocoetus brachypterus) — A sailfin flyingfish (Parexocoetus brachypterus) caught with the Neuston net

Juvenile Billfish (Istiophoridae), — A juvenile billfish (Istiophoridae) caught with the Neuston net. It has been placed in a disposable plastic spoon for scale.

The CTD survey is coming along nicely. Progress through July 1 is shown on the below bottom dissolved oxygen contour. Similar trends to those commented on in my last blog post continue to be observed, as a further area of hypoxia has been exposed near the coastline. You can see that our survey is progressing east toward Mississippi (we will finish this leg in Pascagoula, MI, though the survey will continue on to the Florida coast during Leg 3).

CTD Data — Updated bottom dissolved oxygen contour map, from CTD data (progress through July 1, 2015)

Rinsing CTD — Rinsing off the CTD instrument with fresh water after data collection

A couple of other distinct memories stand out in my mind from the past couple of days:

Sexing “ripe” fish. Sometimes, certain species of fish are so fertile over the summer that certain individuals are deemed “ripe”. Instead of cutting into these fish, they can be more easily sexed by applying pressure toward that anus and looking for the expression of semen or eggs. One of the species for which this technique is most often applied this time of year is the Atlantic cutlassfish (Trichiurus lepturus). One must be careful, however, for as I found out, the gametes sometimes emit from the anus with much force, shooting across the room. It only takes wiping fish semen off of your face once to remember this forever.

Flying fish. I saw my first flyingfish (Exocoetidae) during a plankton collection with the neuston net. The net would scatter the fish, and they would fly for cover, sometimes 10-15 meters in distance. Amazing.

Preparing sand dollars. Interestingly, the sand dollars we caught (Clypeaster ravenelii) looked brown/green when they came out of the ocean. Sand dollars are naturally brownish, and in the ocean, they are most often covered in algae. We kept a couple of these organisms to prepare. To prepare, we first placed the sand dollars in a dilute bleach solution for awhile. We then removed them and shook out the sand and internal organs. We then placed them back in the bleach for a little longer, until they looked white, with no blemishes. The contrast between the sand dollar, as removed from the ocean, and this pure white is quite remarkable.

Sand Dollar (Clypeaster ravenelii) — Sand dollar (Clypeaster ravenelii), as removed from the ocean

Cleaning Sand Dollars — Fisheries Biologist Kevin Rademacher rinsing off sand dollars (Clypeaster ravenelii) before placing them in bleach solution

Sand Dollar — Sand dollar (Clypeaster ravenelii), after bleach treatment

Otoliths. Fisheries biologist Kevin Rademacher showed me a nifty way to remove the otoliths from fish. Otoliths, “commonly known as ‘earstones,’ are hard calcium carbonate structures located behind the brain of bony fishes,” which “aid fish in balance and hearing” (Florida Fish and Wildlife Conservation Commission). When viewed under microscope and refracted light, otoliths show a pattern of dark translucent zones (representing period of quick growth) and white opaque zone (representing periods of slower growth). By counting the white opaque zones (called “annuli”), fisheries biologists can estimate the age of the fish. Granted, this process differs for different fish, as different fish species have different otolith size. Accordingly, a species standard is always prepared (usually a fish raised from spawn, from which the otoliths are taken at a known age) to estimate the growth time associated with one whole annulus for the particular species. Sample otoliths are compared to the standard to estimate age. Otolith analysis also allows scientists to estimate “growth rates,…age at maturity, and trends of future generations” (Florida Fish and Wildlife Conservation Commission). On this survey, we only take otoliths from fish that are wanted for further laboratory analysis, but are too large to store in the freezer. On some surveys, however, otoliths are removed from all fish caught. I got to remove the otoliths from a large red snapper (Lutjanus campechanus). The first step is to make an incision to separate the tongue and throat from the lower jaw. The hand is then inserted into the hole created, and using a fair bit of force, the throat and gills are ripped away from the head to expose the vertebrae. The gills are then cut from the base of the vertebrae, to expose the bony bulb containing the sagittal otoliths. Diagonal cutters are then used to crack open the boney bulb containing the sagittal otoliths, and the otoliths are removed using forceps.

Cutting off the gills form the base of the vertebrae to expose the boney bulb containing the sagittal otoliths

Using diagonal cutters to crack open the boney bulb containing the sagittal otoliths

Personal Log

I am still feeling great on the boat. The work is quite tiring, and I usually go straight to the shower and the bed after my shift ends. Interestingly, I think I’m actually gaining quite a bit of weight. The work is hard and the food is excellent, so I’ve been eating a bunch. I’ve been getting 7-8 hours of sleep a night, which is more than I normally get when I am at home, especially during the school year. One thing I have been noticing ever since the trip started is that I have been having quite nightmarish dreams every night. This is rare for me, as I usually either don’t have dreams or can’t remember the ones that occur. I initially thought that this might be due to the rocking of the boat, or maybe to the slight change in my diet, but I think I’ve finally found the culprit – Dramamine®. Research has indicated that this anti-motion sickness drug can cause “disturbing dreams” (Wood, et al., 1966), and I have been taking this medication since the trip started. This hypothesis is consistent with the observation that my nightmares lessened when I reduced my daily Dramamine® dose from 2 pills to one. I finished Everything is Illuminated and have begun a new novel (Tender is the Night, by F. Scott Fitzgerald). I am now well into the second week of my trip!

Did You Know?

Earrings can be made from fish otoliths (ear stones). These seem to be quite popular in many port cities. Check out this article from the Juneau (Alaska) Empire Newspaper.

Notable Species Seen

Longspine Swimming Crab (Achelous spinicarpus)

Furcate Spider Crab (Stenocionops furcata coelata)

Scaled Slipper Lobster (Scyllarus depressus) — Commonly called “bulldozers” by fishermen

Barnacles (Cirripedia) on the back of a blue crab (Callinectes sapidus)

Octopus Suckers — Suckers on the limb of a common octopus (Octopus vulgaris)

Cobia (Rachycentron canadum) — Commonly called “ling” or “lemon fish”

Planehead Filefish (Stephanolepis hispidus)

Iridescent Swimming Crab (Portunus gibbesii)

Atlantic Spadefish (Chaetodipertus faber)

Singlespt Frogfish (Antennarius radiosus)

Spanish Mackrel (Scomberomorus maculatus)

June 2, 2014August 21, 2021

Spencer Cody: Science at Sea, June 1, 2014

NOAA Teacher at Sea

Spencer Cody

Aboard NOAA Ship Pisces

May 27 – June 11, 2014

Geographical Area of Cruise: Gulf of Mexico

Mission: SEAMAP Reef Fish Survey

Date: June 1, 2014

Observational Data:

Latitude: 27˚ 50.503 N

Longitude: 93˚ 46.791 W

Air Temp: 26.3˚C (79.3˚F)

Water Temp: 23.3˚C (73.9˚F)

Ocean Depth: 126.8 m (416 ft.)

Relative Humidity: 84%

Wind Speed: 7.8 kts (9.0 mph)

Barometer: 1,009.5 hPa (1,009.5 mbar)

Science and Technology Log:

It was not until the Pisces arrived at its first survey area off the coast of Texas that I was able to appreciate the volume of scientific data collection that this vessel could collect. It took most of the 27^th and all of the 28^th to arrive at our initial survey area. While in transit, the Pisces is constantly collecting data. Data such as air temperature, wind direction, relative humidity, wind speed, and barometric pressure are recorded and periodically reported back to NOAA and the National Weather Service and from other marine vessels to improve data on meteorological events in the Gulf and weather forecasts.

In addition to collecting meteorological data, the Pisces uses a fishery acoustics system called the ER-60 to track depth and various sea floor features. This system can also be used to monitor biomass such as fish, coral, and even plankton. Once we arrived at our initial survey area within the SEAMAP survey grid, the amount of science conducted increased dramatically. In the survey areas, the camera array is dropped to the sea floor to survey fish populations. In most cases we are looking at fish habitat from 50 to 120 m deep. Video and still photos are taken of fish attracted to the bait bag filled with squid. To ensure that sampling is both consistent and unbiased for the survey, pictures and video are pulled at random from all four cameras on the camera array. It is important that the same procedures are carried out throughout the SEAMAP survey gird concerning data collection in order to be able to reliably compare different survey areas and track species development and abundance.

In order to assist the camera array in obtaining accurate information about precisely how deep the camera array is when it is recording fish population data, a Temperature Depth Recorder or TDR is attached to the camera array to compare position in the water column to what the ship’s fishery acoustics system is displaying. This is necessary in case the camera array has fallen off an underwater cliff or is hung up on some other topographic feature.

106_0233 — The Conductivity Temperature and Depth or CTD submersible probe can measure the salinity of the water, temperature, pressure, plankton concentrations, dissolved gases, and water samples at different depths.

The Conductivity Temperature and Depth submersible aids the ship’s acoustic equipment in determining an accurate depth of the ocean bottom. Since sound travels at different velocities in water that has different densities and temperatures, information regarding the salinity and temperature of the water must be fed into the ship’s fishery acoustics system to calibrate the system for it to accurately read the bottom depths. If temperature or salinity are not taken into account, the depth will either be too shallow or too deep compared to the true value.

The Pisces not only has the ER-60 for fishery acoustics, but it also has a state of-the-art multi-beam echo sounder, the ME-70, that has 27 transducers that are aligned in a configuration allowing for scans of wide swaths of the ocean bottom. In fact, the Pisces has engines that are specifically designed to run quietly enough to accommodate such advanced acoustic equipment. The ME-70 is used for mapping various sample areas of the SEAMAP survey.

While the camera array can be used to measure the length of some of the fish viewed, it cannot reliably determine characteristics such as age or sex. Determining age or sex just through appearance can be very tricky in the Gulf and is frequently unreliable. Many species of fish will grow at different rates depending on available forage and other environmental factors. This is an issue that is also commonly encountered among freshwater fish in South Dakota. Complicating fish characteristics even further, many reef fish are one or the other sex at different phases of their lives. They are not strictly male or female but change roles depending on complex physical or environmental factors. With so many factors complicating these characteristics, live catches are necessary to determine the full story of what is going on with reef fish in the Gulf.

For live catches we use bandit reels. Bandit reels are similar in concept to a standard fishing rod and reel except they are built for heavy duty sea fishing. The reel and rod are attached to the side of the ship. One hundred pound test line is used with a five pound sinker weight. Each line for the bandit reels has ten hooks, a small float that keeps the hooks in a vertical column, and a large float that keeps the ten hooks just above the ocean bottom.

Again, in order to guard against bias in the results, we use the bandit reels with a set procedure. For our survey we are using three bandit reels at a time each with ten hooks. The bandit reel stations are in radio communication with the dry lab, where the chief scientist is coordinating the sampling, and the bridge, which is keeping the ship in position for the lines preventing lines from running under the ship. Since we want to be as objective as possible without contributing to any type of bias in the sampling, each line was in the water for exactly five minutes. Even though it may have went against every natural inclination of most fishermen and fisherwomen, we were not allowed to jig our lines or do anything that might attract more fish to our bait. In addition to standardizing the number of hooks and the length of time spent fishing, three different sizes of hooks are used and rotated out from each bandit reel station; consequently, one of each of the three hook sizes is always being used for each survey area.

105_0180 — White, nickel-sized disk-like structures called otoliths can reliably age fish. They are inner ear structures that grow in size as a fish ages allowing calcium carbonate deposits to form over the course of its life. Scientists can read these calcium carbonate deposit rings like rings in a tree to determine the age of the fish. Credit Harriet Nash for the photo.

107_0275 — After all the measurements are taken of the fish and their otoliths and gonads have been sampled, the information must be added to the database for use in the SEAMAP Survey. Credit Adam Pollack for the photo.

After five minutes of fishing, the lines are brought up and fish are tagged one through ten to keep fish identified with a specific hook and depth. The tagged fish are then taken to the wet lab for measurement readings. In the wet lab, fish length, weight, sex, and phase of reproductive development are recorded. Since reproductive development, and sometimes even sex, can be difficult to determine, a sample of each fish’s gonads (ovaries or testes) are removed and placed in a labeled specimen vial for confirmation in the lab back on land. The otoliths (inner ear bones) are removed from the fish, as well, in order to reliably age the fish back in the lab. Once the measurements are recorded, they need to be added to the database to be compiled with the gonad and otolith specimens. This is just a small piece of the monitoring that is occurring in the Gulf through NOAA. The Gulf of Mexico is a remarkably diverse expanse of ocean and requires significant scientific research in order to understand and track fish populations and the habitat and forage that sustain them. Without these types of intensive scientific studies on the ocean, we could not possibly manage or attempt to conserve a natural resource that we would, otherwise, have little to no understanding of.

Personal Log:

Since we had arrived off the coast of Texas a couple of days ago, we have been slowly back tracking to Pascagoula as we go through our survey areas. The weather has been beautiful the last couple of days; however, sea swells do cause the boat to jostle around a bit. Each day we see more species on the surface of the water and through our camera array under the water. Since the science log is rather long for this post, I will talk more about life at sea and the different types of organisms we are encountering in future posts.

Did You Know?

Fish identification can be a tricky business in the Gulf of Mexico. Many species of Gulf fish alter their physical appearance depending on their reproductive development, environmental factors, or phase of physical development. Fish will even appear to have different patterns depending on whether they are viewed under our out of water.

May 8, 2014August 20, 2021

Chris Henricksen: Standing My First Watch, May 8, 2014

NOAA Teacher at Sea

Chris Henricksen

Aboard NOAA Ship Henry B. Bigelow

April 29–May 10, 2014

Geographical area of cruise: Gulf of Maine

Mission: Spring Bottom Trawl & Acoustic Survey

Date: May 7, 2014

Air Temp: 9.1°C (48.38°F)

Relative Humidity: 73%

Wind Speed: 10.83mph

Barometer: 1011.7mb

Science and Technology Log

My section stands watch from midnight to noon–twelve hours on, twelve hours off. Today I stood my first watch, acting as one of three “recorder” on the fish sorting line. A recorder’s role is to assist his assigned “cutter” by entering requested measurement data (e.g., length, weight, etc.) of individual fish into a computer database. The cutter processes fish by identifying the species, then performing any number of actions (i.e., cuts, as in, with a knife) in order to retrieve information about particular fish for later use by scientists. Such data will consist of measuring, weighing, and sexing the fish, as well as checking the contents of its stomach. Other particular data may be gathered, such as collecting otoliths (ear bones) from the head of the fish.

photo of net prep — Preparing the net for our first trawl

After getting underway, the captain called a series of drills, one of which was abandon ship. During this exercise, I reported to the aft deck of the ship, donned a “Gumby” survival suit, which is bright orange/red, keeps you warm while in the water, and helps you to stay afloat. Following that, we had a collision drill. In a disaster scenario, everyone has a muster station, so that we can be counted, and then help control the situation, if need be.

photo of abandon ship drill — Abandon Ship Drill

Today was my first of about a dozen watches I will stand. It went smoothly, but there was considerable down time. The first stations (the areas in which the nets are lowered and trawling begins) were about 25 nautical miles from one another, so it took a couple of hours to steam from one station to the next. During this time, I was able to relax, grab a bite, or hang out with other members of my watch. Personal Log The food aboard ship is very good, and there is plenty of it. Between mealtimes, the cook makes sure that plenty of drinks and snacks are available, so there is no reason to go hungry aboard the Henry B. Bigelow. The ship has a huge library of DVDs with many new movies. We can also watch TV thanks to a satellite connection (DirectTV). The only things I am not allowed to do are 1) re-enter my stateroom after going on watch, as there is always an off-watch shipmate trying to catch some shuteye, and 2) make a surprise appearance on the bridge, which is where the NOAA officers navigate and steer the ship. That’s for safety, and I am sure they would welcome me, as long as I called ahead first. I am tired, but feeling pretty good. I boarded the ship wearing an anti-motion sickness patch, fearing that, after twenty years of not being at sea, I might be susceptible to seasickness. The medicine made me feel awful, so I took it off, and now feel much better! I had almost forgotten how much I enjoy the rocking of a ship. It’s an especially good way to fall asleep–gently rocking…

August 23, 2013August 20, 2021

Liz Harrington: The Temporary Lull in the Action, August 21, 2013

NOAA Teacher At Sea
Liz Harrington
Aboard NOAA Ship Oregon II
August 10 – 25, 2013

Mission : Shark/Red Snapper Bottom Longline
Geographical area of cruise: Western Atlantic Ocean and Gulf of Mexico
Date: August 21, 2013

Weather: current conditions from the bridge:
Partly cloudy
Lat. 29.18 °N Lon. 84.06 °W
Temp. 75 °F (24 ° C)
Wind speed 10-15 mph
Barometer 30.04 in ( 1017.3 mb)
Visibility 10 mi

Science and Technology Log:

It has been just over a week now since I’ve been aboard the Oregon II. The catch has not been as abundant as it was the first couple of days of fishing, but that tells the scientist something as well. So far I’ve experienced three water hauls – not one fish on any of the 100 hooks! Even though we are not catching many fish (for now), the fishing will continue until it is time to return to port. Don’t get me wrong, we are still catching fish, just not as many as we had been. Occasionally we pull up something other than fish, like eels, skates, crabs or sea stars. This is called the bycatch. In the previous blog I explained how the line was set. In this one I’ll explain about the catch.

OLYMPUS DIGITAL CAMERA — “Fish On”. A Sandbar Shark is brought alongside the ship to be cradled.

crab as bycatch — This crab, part of the bycatch, wouldn’t let go of the bait.

preparing for haul back — Lead Fisherman Chris Nichols (right) and Fisherman Buddy Gould prepare to retrieve the high flyer.

Hauling in the line is similar to setting it out. The fisherman handle the line and the science team process the fish. Our team includes a person manning the computer to keep track of the hook numbers and the condition of any remaining bait; a person “racking” (carefully but quickly returning the gangions into the storage barrels); and a “data” person to write down information about each fish, and the rest of the team will be “wranglers” (those who handle the catch). We all rotate through the jobs. I like to be a wrangler, but the racker and computer folks get a nice view of the fish being brought on board. Everything we catch is brought on board, weighed and measured.

tagging Tiger Shark — The Day Team tagging a Tiger Shark

Many species of sharks are tagged and a fin clip is taken to obtain its DNA. They are given an injection of a chemical which will help to age the shark if it is caught again. The entire process only takes a few minutes because they are trying to get the sharks back into the water as soon as possible. The scientists and crew are all very conscientious about doing what is best for the marine life. What’s really nice is that we all take turns tagging the sharks. It is just so exciting to be up close to them, especially the big ones. You can feel the strength and power beneath that sandy skin.

weighing a shark — Sometimes sharks are too heavy for the handheld scale, so they are hoisted up to be weighed. Notice the scientist to the right to get sense of its weight.

processing fish — Kristin and Cliff find otoliths at the end of the rainbow.

The boney fish that are caught are also weighed and measured. After the haul back (when the line is in, gangions are stored, high flyers returned and deck hosed down), they are brought to the back of the ship to have otoliths removed and tissue samples taken. The otoliths are boney structures in the fish’s inner ear which are sensitive to gravity and acceleration. As the fish grows, each year a new layer is added to the otoliths – similar to tree rings. By examining the otoliths under a microscope its age can be determined. I was taught how to remove the otoliths, so now (given enough time – I need plenty) I can help process the fish. Learn more about the procedure here.

Personal Log

It has been easy for me to acclimate to life aboard the ship because all of the people are so friendly and interesting. The ship is always rocking but I don’t even notice it any more. It actually lulls me to sleep at night, along with the constant sound of the engine and particularly the gurgling sound of the water moving along the hull (frame of ship). I was a little worried that I might get seasick in the beginning of the cruise, but I didn’t. The only problem I had was that reading or working on the computer made me queasy, but that only lasted for a couple of days. Quarters are tight, but they make good use of all of the space. Most of the bedrooms (called staterooms) sleep two people. We all eat in a room called the galley. It only holds twelve people at a time, so when we are done eating we leave to make room for someone else. The food on board is delicious and abundant. The chief steward, Walter Coghlan, does a great job providing a variety of choices. There is literally something for everyone. If we have free time, there is a lounge area with a huge selection of movies.

I like to spend my free time out on the decks, if I can find a place in the shade and the breeze. I love to look out over the water. And the sky stretches from horizon to horizon in all directions, something I don’t see in the mountains of Vermont. The cumulus clouds develop during the day and I can usually see a thunderstorm somewhere by late afternoon. It’s a beautiful view. Yesterday we were visited briefly by a small group of dolphins. Their acrobatics were very entertaining. They were here and then gone. That seems to be the continuing theme here; you never know what you are going to see.

Dolphin visit — A small group of dolphins swim along side the ship.

Did you know? The ship makes it own fresh water from the sea water. There is a reverse osmosis desalination system located down in the engine room. The fresh water is stored in large tanks, so it is always available.

volunteers await a haul — Volunteers Micayla, Daniel, David and Cliff waiting to do some wrangling.

New Term

Foul Hook – when a fish is hooked in a place other than its mouth (ie -fin or body)

More examples of bycatch.

little tunny — Micayla holds a Little Tunny (yes, that’s it’s real name)

yellowedge grouper — Yellowedge Grouper ready for processing

July 8, 2013August 13, 2021

Amie Ell: Fireworks, Fish, and Flukes, July 6, 2013

NOAA Teacher at Sea
Amie Ell
Aboard NOAA Ship Oscar Dyson (NOAA Ship Tracker)
June 30 – July 21, 2013

Mission: Alaska Walleye Pollock Survey
Geographical Area: Gulf of Alaska
Date: July 6th, 2013

Location Data from the Bridge:
Latitude: 55.29.300 N
Longitude: 156.25.200 W
Ship speed: 10.7 kn

Weather Data from the Bridge:
Air temperature: 8.6 degrees Centigrade
Surface water temperature: 8.6 degrees Centigrade
Wind speed: 14 kn
Wind direction: 210 degrees
Barometric pressure: 1008.5 mb

Science and Technology Log:

The Oscar Dyson is equipped with several labs to accommodate the researchers on board. In this blog post I will describe to you what is happening in the wet/fish lab. This is where I have experienced quite a bit of hands-on data collection.

Pollock being separated on the conveyor belt.

After a trawl, the crew dumps the load of fish into a bin. Inside the lab we can raise or lower this bin to control the amount of fish coming onto a conveyor belt. Once the fish are on the belt the scientists decide how they will be separated. We separate the pollock according to age into baskets. They are categorized by size; under 20 cm (age 1), under 30 cm (age 2), and any larger than 30 cm

At this time we also pull out any other sea creatures that are not pollock. So far we have pulled up quite a few jelly fish, la lumpsucker, shrimp, squid, eulachon, and capelin. These are also weighed, measured, and in some cases frozen per request of scientists not currently on board.

After organizing the pollock into appropriate age groups, we then measure and record their weight in bulk. Scientists are using a scale attached to a touch screen computer with a program called CLAMS to record this information. The pollock are then dumped into a stainless steel bin where their sex will be determined. In order to do this the fish must be cut open to look for “boy parts, or girl parts”. After the pollock are separated into female and male bins we begin to measure their length.

This is the tool used for measuring length of the fish.

The tool used to measure length is called the Ichthystick. This tool is connected to the CLAMS computer system. The fish is placed on the Ichthystick and a pointer with a magnet in it is placed at the tail end of the fish. There are three different types of length measurement that can be done: fork length, standard length, and total length. When the magnetic pointer touches the Ichthystick it senses that length and sends the information to the CLAMS computer system.

One of these bins of fish is placed aside for individual weighing, length measurements, and removal of otoliths. You may recall that I mentioned otoliths in the last blog post. These ear bones are sent to a lab and analyzed to determine the age of each of these individually measured fish. The Alaska Fisheries Science Center has created a demonstration program where you can try to determine the age of different types of fish by looking at their otoliths. Click here to try it yourself! (I will add hyperlink to: http://www.afsc.noaa.gov/refm/age/interactive.htm)

Personal Log:

One afternoon while waiting for the fishermen to bring up the trawl net, I watched a group of porpoises swimming behind the ship. Another day I was able to see whales from up on the bridge. These were pretty far out and required binoculars to see any detail. I observed many spouts, saw one breach, and some flukes as well.

There is quite a bit of downtime for me on the ship while I am waiting in between trawls. I get to read a lot and watch movies in my free time. I have had the opportunity to talk with different members of the crew and learn about their roles a bit. The chief engineer gave me a tour of the engine rooms (more about this with pictures in a future post.)

The 4^thof July fireworks show on the Oscar Dyson was like no others I have ever experienced. Two of our crew, Ben & Brian, dressed in official fire gear shot expired flares off the ship into the sea. America themed music was played over the PA system. I have attached a video of our fireworks display. Happy Independence Day everyone!