NOAA Teacher at Sea Blog

August 5, 2015August 21, 2021

Kathleen Gibson, Hammerheads on the Line, August 4, 2015

NOAA Teacher at Sea
Kathleen Gibson
Aboard NOAA Ship Oregon II
July 25 – August 8, 2015

Mission: Shark Longline Survey
Geographic Area of the Cruise: Atlantic Ocean off the Florida and Carolina Coast
Date: Aug 4, 2015

Coordinates:
LAT 3323.870N
LONG 07736.658 W

Great Hammerhead Photo Credit: Ian Davenport — Great Hammerhead (Photo Credit: Ian Davenport)

Weather Data from the Bridge:
Wind speed (knots): 28
Sea Temp (deg C): 29.2
Air Temp (deg C): 24.2

Early this morning the night shift caught and cradled a great hammerhead shark (Sphyrna mokarran). This is a first for this cruise leg. I’m sure that just saying “Hammerhead” conjures an image of a shark with an unusual head projection (cephalofoil), but did you know that there are at least 8 distinct Hammerhead species? Thus far in the cruise we have caught 4 scalloped hammerheads (Sphyrna lewini), one of which I was fortunate to tag.

Science and Technology Log

All eight species of hammerhead sharks have cephalofoils with differences noted in shape, size, and eye placement, to name a few. Research indicates that this structure acts as a hydrofoil or rudder, increasing the shark’s agility. In addition, the structure contains a high concentration of specialized electro sensory organs (Ampullae of Lorenzini) that help the shark detect electric signals of other organisms nearby. The eye placement at each end of the cephalofoil allows hammerhead sharks to have essentially a panoramic view with only a slight movement of their head – quite handy when hunting or avoiding other predators.

Comparison of Scalloped and Great Hammerhead Sharks
Image Credit: NOAA Fisheries Shark Species

Great hammerhead sharks are highly migratory. They are found worldwide in tropical latitudes, and at various depths. There are no geographically Distinct Population Segments (DPS) identified. The great hammerhead, as its name implies, is the largest of the group and average size estimates of mature individuals varies between 10-14 ft in length with a weight approximately 500 lb.; the largest recorded was 20 ft in length. The one we caught was ll ft. in length.

As with most shark species, the numbers declined rapidly between 1975 and 1995 due to the fin fishing industry and focused sport fishing often fueled by fear and misinformation. One has to wonder what the average length was before that time.

Scalloped Hammerhead sharks are the most common hammerhead species. Their habitat overlaps that of the great hammerhead, though they are more often found in slightly shallower waters. In contrast to the great hammerhead, scalloped hammerheads are only semi-migratory, and scientists have identified Distinct Population Segments around the world. This is important information when evaluating population size and determining which groups, if any, need regulatory protection.

Weighing a small Scalloped Hammerhead Photo Credit: Ken Wilkinson — *Weighing a small scalloped hammerhead*
Photo Credit: Ken Wilkinson

Scalloped Hammerhead on deck. Photo: Erica Nuss — *Scalloped hammerhead on deck*
Photo: Ian Davenport

The average life expectancy for both species is approximately 30 years. Males tend to become sexually mature before females, at smaller weights; females mature between 7-10 years (sources vary). In my last log I discussed shark reproduction – Oviparous vs. Viviparous. (egg laying vs. live birth). All hammerheads are viviparous placental sharks but reproductive patterns do differ. Great hammerheads bear young every two years, typically having 20-40 pups. A great hammerhead recently caught by a fisherman in Florida was found to be pregnant with 33 pups. Scalloped have slightly fewer pups in each brood, but can reproduce more frequently.

Career Spotlight – NOAA Corps

Setting and retrieving the Longline requires coordination between Deck Operations and the Bridge. Up until now I’ve highlighted those on deck. Let’s learn a bit about two NOAA officers on the Bridge.

The NOAA Corps is one of the 7 Uniformed Services of the United States and all members are officers. The Corps’ charge is to support the scientific mission of NOAA, operating and navigating NOAA ships and airplanes. Applicants for the Corps must have earned Bachelor’s degree and many have graduate degrees. A science degree is not required but a significant number of science units must have been completed. It’s not unusual for Corps recruits to have done post-baccalaureate studies to complete the required science coursework. New recruits go through Basic Officer’s Training at the Coast Guard Academy in New London, Connecticut.

Lt. Lecia Salerno – Executive Officer (XO) – NOAA

: Lt. Lecia Salerno at the helm or the Oregon II during Longline retrieval.

Lt. Salerno is a 10-year veteran of the NOAA Corps and has significant experience with ship operations. She was recently assigned to the Oregon II as the XO. This is Lecia’s first assignment as an XO and she reports directly to Captain Dave Nelson. In addition to her Bridge responsibilities, she manages personnel issues, ship accounts and expenditures. During these first few weeks on her new ship, Lt. Salerno is on watch for split shifts – day and night – and is quickly becoming familiar with the nuances of the Oregon II. This ship is the oldest (and much loved) ship in NOAA’s fleet, having been built in 1964, which can make it a challenge to pilot. It’s no small task to maneuver a 170-foot vessel up to a small highflyer and a float, and continue moving the ship along the Longline throughout retrieval.

Lecia has a strong academic background in science and in the liberal arts and initially considered joining another branch of the military after college. Her assignments with NOAA incorporate her varied interests and expertise, which she feels makes her job that much more rewarding.

Lt. Laura Dwyer on the Bridge of the Oregon II — Lt. Laura Dwyer on the Bridge of the *Oregon II*

Lt. Laura Dwyer- Junior Officer – NOAA Corps

Laura has always had a love for the ocean, but did not initially look in that direction for a career. She first earned a degree in International Business from James Madison University. Her interest in marine life took her back to the sea and she spent a number of years as a scuba diving instructor in the U.S. and Australia. Laura returned to the U.S. to take additional biology coursework. During that time she more fully investigated the NOAA Corps, applied and was accepted.

Laura has been on the Oregon II for 1.5 years and loves her work. When she is on shift she independently handles the ship during all operations and also acts as Navigator. What she loves about the Corps is that the work merges science and technology, and there are many opportunities for her to grow professionally. In December Laura will be assigned to a shore duty unit that is developing Unmanned Underwater Vehicles (UUV).

Personal Log

Measuring a Sharpnose Photo: Kristin Hannan — *Notice the white spots on the dorsal side of this atlantic sharpnose, characteristic of this species.*
Photo: Kristin Hannan

It’s amazing to think that just over a week ago I held my first live shark. We caught over 30 sharks at our first station and our inexperience showed. At first even the small ones looked like all teeth and tail, and those teeth are not only sharp but carry some pretty nasty bacteria. It took all of us (new volunteers) forever to get the hooks out quickly without causing significant trauma to the shark–or ourselves. A tail smack from this small-but-mighty tiger shark pictured below left me with a wedge-shaped bruise for a week!

Immature Male Tiger Shark. He's cute but he taught me a lesson with his tail. — *Immature Male Tiger Shark.*
*He’s cute but he taught me a lesson with his tail.*

Since then we have caught hundreds of sharks. We’ve caught so many Atlantic Sharpnose that on occasion it seems mundane. Then I catch myself and realize how amazing it is to be doing what I’m doing– holding a wild animal in my hands, freeing it from the circle hook (finally!), looking at the detailed pattern of its skin, and feeling it’s rough texture, measuring it and releasing it back into the sea.

Sandbar Shark on the Line — *A beautiful sandbar shark on the line.*

I’m pleased to be able to say that my day shift team has become much more confident and efficient. Our mid-day haul yesterday numbered over 40 sharks, including a few large sharks that were cradled, and it went really smoothly.

Weighing in. Hook out - No Problem! Photo: Jim Nienow — *An Atlantic Sharpnose weighing in at 2.1 kg.*
Photo: Kristin Hannan

Out it Comes - No Problem Photo: Ian Davenport — *Taking a closer look at an Atlantic Sharpnose shark.*
Photo: Ian Davenport

At this point I’ve had a chance to work at most of the volunteer stations including baiting hooks, throwing off the high-flyer marker, numbering, gangions, throwing bait, data entry, tagging shark, removing hooks, and measuring/ weighing. A highlight of last night was getting to throw out the hook to pull in the high-flyer marker at the start of retrieval. I’m not known for having the best throwing arm but it all worked out!

Ready to Throw Photo: Kristin Hannan — *Ready to Throw*
Photo: Kristin Hannan

Got it! Photo: Kristin Hannan — *Right on Target!*
Photo: Kristin Hannan

Question of the Day: What is this?

NOAA SHARK FACTS: Bite off More that you can chew

For more on hammerheads: click

For my incoming Marine Science students — Investigate two other hammerhead species. How are they distinguished from great hammerheads?

August 4, 2015August 21, 2021

Cristina Veresan, Nets and the Wet Lab, August 3, 2015

NOAA Teacher at Sea
Cristina Veresan
Aboard NOAA Ship Oscar Dyson
July 28 – August 16, 2015

Mission: Walleye Pollock Acoustic-Trawl survey
Geographical area of cruise: Gulf of Alaska
Date: Monday, August 3, 2015

Data from the Bridge:
Latitude: 58° 51.5 N
Longitude: 149° 30.8 W
Sky: Scattered Clouds
Visibility: 10 miles
Wind Direction: SSE
Wind speed: 8 knots
Sea Wave Height: <1 feet
Swell Wave: 0 feet
Sea Water Temperature: 16.3° C
Dry Temperature: 17.2 ° C

Science and Technology Log

Once it is determined where to fish, the scientists also have to decide which trawl to deploy and tow behind the ship in order to catch the targeted fish. The most common trawl we use to catch mid-water pollock is the Aleutian wing trawl (AWT). Our AWT is 140 meters long, and it can be fished anywhere from 30-1,000 meters underwater. A net echosounder is mounted at the top of the net opening and transmits acoustic images of fish going in the mouth of the net in real time to a display on a computer on the bridge that is monitored by the scientist and the Lead Fisherman. Additionally, at the entrance of the codend (the end of the net where the fish are collected), a stereo camera called the CamTrawl takes pictures of anything entering the codend. CamTrawl pictures are later analyzed to determine species and lengths of the fish that were caught. Sometimes the net is fished with the codend opened and the catch is only evaluated based on what is seen in the CamTrawl images. As this technology gets perfected less fish will need to be brought onboard.

A view of the stern as the deck crew prepares to deploy the AWT. Note the net reel at the bottom of the frame. — A view of the stern as the deck crew prepares to deploy the AWT. Note the AWT on the net reel at the bottom of the frame.

Cooperation among many different people is necessary during a trawl. The wet lab team prepares the CamTrawl to collect data. The deck crew physically handles all the gear on deck, including attaching the CamTrawl camera, net echosounders, and physical oceanography instruments to the net and deploying and recovering the net. From the bridge, the Lead Fisherman controls the winches that move the trawl net in and out of the water. Once the trawl net is in the water, the scientists work closely with the Lead Fisherman and the officers to ensure a safe, effective trawl. Sometimes the trawl net will be down for a few minutes, and other times it will be closer to an hour. Once the net is back on the ship and emptied out, the catch and CamTrawl images are ready to be analyzed by the scientist and wet lab team.

CamTrawl images were filmed by two cameras in stereo and so scientists can run a program that calculates length. — Fish are filmed in stereo so scientists can run a program that calculates their length.

Two other nets, more seldom used, are the bottom trawl net, known as the Poly Nor’easter (PNE) and the Methot net, used to catch krill and zooplankton. The PNE is deployed if there is a large concentration of fish close to the ocean floor. It is smaller than the AWT and it is usually lowered to just above the ocean floor. The Methot net was named after Dr. Richard Methot, a famous fisheries modeler who designed the net. This net has an opening of 5 square meters, and it has a finer mesh than the AWT or the PNE. At the end of the net is a small PVC codend where the sample is taken from.

Shipmate Spotlight: Interview with Kirk Perry

Kirk Smith, Lead Fisherman and Chief Boatswain — Kirk Perry, Lead Fisherman and Chief Boatswain

What is your position on the Oscar Dyson?
I am the Lead Fisherman and also sailing as active Chief Boatswain.

What training or education do you need for your position?
I went to Cal Poly San Luis Obispo and got a BS in Natural Resource Management. I have certifications from the Coast Guard like an AB (Able-Bodied Seaman) unlimited, which means I have over 1070 days sailing as an AB. I also have a Masters license to operate a 100-ton vessel. You need a lot of fishing experience.

What do you enjoy the most about your work?
Fishing! Obviously. You just never know what you are going to get, and it’s always exciting.

Have you had much experience at sea?
I have been fishing since I was 10 years old and I helped a neighbor build a boat and go salmon fishing in Monterey Bay. When I visited family in Hawai’i, we would go trolling, set net fishing, beach casting, and spearfishing. I have been sailing professionally with NOAA for 11 years on different vessels in Hawai’i, Mississippi, and here in Alaska.

Where do you do most of your work aboard the ship? What do you do?
As Lead Fisherman I operate the machinery from the bridge when we are trawling. Basically, I get the fishing gear in and out of the water safely. As Chief Boatswain, I am in charge of the Deck Department, so I schedule crew, assign daily crew duties, maintain supply inventories, oversee the ship’s survival gear, and operate deck equipment like winches, anchor, and cranes.

When did you know you wanted to pursue a marine career?
By 25 years old I knew I had to be on the water, full time, all the time, but I did not get to be here until I was 44 years old.

What are your hobbies?
When I’m not fishing, I like to hunt. Mainly ducks and geese.

What do you miss most while working at sea?
Home, my family. And my own bed!

What is your favorite marine creature?
Tuna because they are so fast powerful and so delicious! When you are fishing for them, it’s like nothing else. It can turn into a wide open frenzy.

Inside the Oscar Dyson: The Wet Lab

The wet lab is where we do most of our work, and it gets really busy in here after a trawl. It is called a “wet” lab because it is designed to get just that. When a trawl net is full of fish, it is emptied onto a table that tilts onto a conveyor belt feeding into the wet lab. We have controls to run the conveyor belt as well as tilt the tableAs the fish are brought in on the conveyor, we sort them in large and small baskets, and then collect data from the different species. The metal counters, outfitted with electronic balances and automated length readers provide us with workspace to process our samples. The work of the wet lab is messy and fun. When we process a catch, fish scales get everywhere! The shiny, sticky little discs coat every surface, especially areas that you touch like the computer screens and handles. It is fun to clean this lab because you spray everything down with the salt water from hoses that are rigged from the ceiling. You can even spray down the computer screens themselves, and then rinse them with fresh water. Water washes over everything and drips down, entering drains in troughs along the edges of the floor.

Processing pollock in the wet lab! Photo by Emily Collins

Personal Log

Whenever it’s time to process fish in the wet lab, I have to get geared up! What is the latest in fisheries fashion, you might ask? Rubber boots are a must. We take the lead of Alaskans and wear brown XtraTuf boots. Once I get my boots on, I put on my Grundens foul weather coveralls over my pants. The weather has been mild, so I have been forgoing the matching foul weather jacket and just wearing a long sleeved t-shirt or sweatshirt. I have not been wearing a hat, but I do pull my hair back. Lastly, I pull on elbow-length yellow rubber gloves over my sleeves.

Before you enter the wet lab, you get geared up here. Sometimes to make a quick entrance/exit, you leave your boots in your coveralls (bottom right)

These boots are made for fishin' — These boots are made for fishin’

I am really enjoying my time with this ship’s crew and the rest of the science party. Everyone has been very welcoming, and, though we work hard, we maintain a sense of fun. If we have down time between data collection, Emily and I play cribbage. Or we go out on deck and take in the sights, like the Holgate glacier we passed the other day. Quite a few people on board have spent time in Hawai’i, so we can ‘talk story’ about the islands from all the way up here in the North Pacific. It is amazing how we are all connected in some way through our love of the ocean.

My voyage of discovery continues…

glacier — We sailed within 4 miles of Holgate Glacier on a beautiful sunny morning

August 4, 2015August 21, 2021

Jeanne Muzi: Aboard the Thomas Jefferson! August 3, 2015

NOAA Teacher at Sea
Jeanne Muzi
Aboard NOAA Ship Thomas Jefferson
August 2 – 13, 2015

Mission: Hydrographic Survey
Geographical area of cruise: North Atlantic
Date: August 3, 2015

Weather Data From the Bridge:

Temperature Fair 81°F (27°C)

Humidity	65%
Wind Speed	SW 12 mph
Barometer	29.87 in (1011.4 mb)
Dewpoint	68°F (20°C)
Visibility	10.00 mi
Heat Index	84°F (29°C)

Greetings from the Thomas Jefferson!

Science and Technology Log:

Now that I am onboard, I am trying to learn as much as possible. The TJ is a busy place and there are lots of jobs to be done. Basically there are separate groups working in different ways, like the Wardroom (which means all the officers on board), Engineering, Deck, Survey and Stewards, but everyone always comes together to work as a team.When one of the small launches returned to the ship late yesterday afternoon, everyone worked together to get it back on board safely. The launch had been surveying and now that data had to be processed in the survey dept.

In the survey dept. there are different scientists working on different projects. This is a station for “Data Acquisition” so there are multiple computers and cameras sharing images, data and information from around the ship and from the sonars.

Survey Technician Stephanie Stabile created this “big picture” diagram, which explains how the different scanning tools communicate with each other to provide the most accurate scans of the ocean floor.

Diagram of TJ's Hydro System — Diagram of TJ’s Hydro System

This picture shows how a survey ship uses its multi-beam sonar.

If you would like to learn more about sonar, check out this video:

http://oceanservice.noaa.gov/facts/sonar.html

I also had a chance to visit the bridge today as the anchor was lifted. I learned how orders are given clearly and information communicated accurately. Lieutenant Commander Hauser gave me a tour of the ship and answered many of my questions. She explained how the national flag is hoisted to the highest position when the ship gets underway.

Lieutenant Commander Hauser and Ensign Anderson with the American Flag. — Lieutenant Commander Hauser (right) and Ensign Anderson with the American Flag.

View from the bow of the Thomas Jefferson

Personal Log:

One of the most important things I learned about today was safety!

Think about why we have fire and evacuation drills at school…It is important to be prepared just in case something happens! It is exactly the same here on the Thomas Jefferson! I was part of a group that was trained on safety issues like fire, abandoning ship and what to do in any emergency. Ensign Perry walked us around the ship and showed us where life jackets, fire extinguishers, steel-toed shoes and hard hats are located. She also taught me how to get in and out of a survival suit. Survival suits (also called “Gumby suits”) are made of foam rubber and are designed to be watertight. They help protect against hypothermia and can keep a person alive and floating until rescuers can find them.

For dinner, everyone on board came to a cookout on the deck near the bow of the ship! Delicious burgers, hotdogs, chicken, sausages and brisket were grilled up and enjoyed. What a great setting for some terrific food!

In my first blog entry the Question of the Day was:

Think about what you know about President Thomas Jefferson…What does he have to do with the Atlantic Ocean?

Here is some interesting information about Thomas Jefferson and the ocean:

As most people know, Thomas Jefferson was a writer, an artist, an architect, a statesmen and a lawyer. He was also one of our most scientific presidents. In 1807, President Jefferson established the Survey of the Coast to produce the nautical charts necessary for maritime safety, defense, and the establishment of national boundaries. The United States Coast and Geodetic Survey is the oldest scientific organization in the U.S. Other agencies that became part of NOAA in 1970 include the Weather Bureau, formed in 1870, and the Bureau of Commercial Fisheries, formed in 1871. Much of America’s scientific heritage resides in these agencies. They brought their cultures of scientific accuracy and precision, stewardship of resources, and protection of life and property to NOAA.

The first Picture of the Day shows a side sonar “fish”. Here is some information about side scan sonars.

Go to this website to find out more!

http://oceanservice.noaa.gov/education/seafloor-mapping/how_sidescansonar.html

Today’s Question of the Day is:

What do the letters XO mean on the hardhat of the person in the center of this picture?

Today’s Picture of the Day is:

Look carefully...What do you think? — Look carefully…What do you think?

What do you see in the scan?

Learning more each day! photo credit: Dan Connors

Thanks for reading this blog entry!

August 3, 2015August 21, 2021

Kathleen Gibson, Wild Weather, August 2, 2015

NOAA Teacher at Sea
Kathleen Gibson
Aboard NOAA Ship Oregon II
July 25 – August 8, 2015

A Nurse Shark in the cradle
Photo taken from the highest point on the ship.

Mission: Shark Longline Survey
Geographic Area of the Cruise: Atlantic Ocean off the Florida and Carolina Coast
Date: Aug 2, 2015

Coordinates:
LAT 3428.300 N
LONG 07705.870 W

Weather Data from the Bridge:
Wind speed (knots): 11.2
Sea Temp (deg C): 29.1
Air Temp (deg C): 25.7

Science and Technology Log: Shark Reproductive Strategies

Rough Seas and bad weather have delayed our sampling. I’m getting use to walking sideways.

Today we reached the northernmost sampling station of our cruise, just off the North Carolina coast. The latest stations have been further off shore than those previous and we’ve caught fewer sharks. However, the sharks we have caught have been much larger. Our catch included Sandbar Sharks, Scalloped Hammerhead, Spinner, Nurse and Black Nose.

Sharks have a number of reproductive strategies ranging from egg laying to placental formation. Oviparous sharks produce and release egg cases made of a collagen (protein). The case surrounds the developing embryo and a large yolk with the vital nutrients required for shark development. This is called lecithotrophic (all nutrients from yolk). Oviparous sharks can take to 2 years to develop within the egg case.

Cat shark adult (Image courtesy of Ian Davenport) — Adult cat shark
(Image courtesy of Ian Davenport)

Cat Shark egg case. Photo Courtesy of Ian Davenport — Cat shark egg case. Photo Courtesy of Ian Davenport

Sharks that give birth to live young are considered Viviparous. Within this category there are two major types. Those that produce eggs with large yolks with all required nutrients, but remain in the uterus for gestation, are called yolk-sac vivipores (ovoviviparous, or aplacental viviparity). In some cases, offspring will consume other eggs (oophagy) in the uterus to gain additional nutrients. An advantage to this type of reproduction is that the young sharks are larger when they are born and have a higher survival rate.

Yolk-sac embryos (Image courtesy of Ian Davenport, Ph.D.)

The last group, considered to be the most advanced, is the Placental Group. As with the other types, a yolk is produced that can initially provide some nutrients to the developing pup. However, in the uterus the yolk sac after it is depleted is modified into a placenta through which nutrients can pass from parent to offspring. While fewer offspring are produced at one time, they are typically more robust and have a higher survival rate. Most of the sharks we have caught on this cruise are placental vivipores.

Placental Shark (Image courtesy of Ian Davenport) — Placental Shark
(Image courtesy of Ian Davenport)

Career Spotlight: Dr. Ian Davenport, Ph.D., Research Scientist

Dr. Ian Davenport, Ph.D., is a Developmental Biologist at Xavier University, New Orleans, and has been a volunteer on this cruise for 7 years.

Dr. Ian Davenport dissecting a female Sharpnose shark.

Ian hails from Manchester, England, and his path to becoming a scientist was quite unusual. Similar to others on board, he always had an interest in Marine Science, and sharks in particular, but school was not a priority early on. He spent time travelling and learned a trade as well. He finally decided to return to school, but being accepted was a challenge. Fortunately Ian’s academic ability was recognized and he was accepted to the University of Newcastle upon Tyne where he studied Marine Biology, but a course in Developmental Biology particularly resonated. He went on to earn his Ph.D. in shark developmental biology at Clemson University.

Ian’s research focus is in evolution of “live bearing.” As noted above, shark species employ a number of reproductive strategies. Placentals are considered to be the most advanced. Ian is studying the eggs of placental sharks and the structure of the cells that surround the egg. His research has revealed some interesting cell features that may aid in nutrient delivery to the developing embryo. If a female shark is caught during the cruise and does not survive, Ian collects the eggs for later study.

Career Spotlight: Chuck Godwin, Deck Crew and Environmental Compliance officer

Chuck has a B.A. in History and has also studied Wildlife Management. Chuck spent 10 years in the Coast Guard and left in 2000, but he was recalled to active service on two occasions – after 9/11 and after Hurricane Katrina. In addition to his work as part of the deck crew, where he is involved in all deck operations, Chuck is also the Environmental Compliance Officer. As such, he manages hazardous waste compliance.

It’s apparent that Chuck enjoys his work. He is all business when he needs to be, but has a knack for adding a note of levity when appropriate. He keeps me laughing, even when the fish aren’t biting. Chuck notes that as a member of the Coast Guard, part of his job was to enforce U.S. fisheries laws. With NOAA he plays an important role in establishing those regulations and this makes the work that much more rewarding.

Personal Log

The weather has been poor since yesterday. Lightning caused a five-hour delay in setting the longline in the night; the ship traversed back and forth over the sampling area waiting for the worst of the storm to pass. Sleeping was a challenge – I think some of us were airborne a few times. Thank goodness for the patch and a few saltine crackers. I took the video below in my bunk as I was nodding off to sleep.

Today’s rough seas and high winds prevented us from using the cradle to bring sharks up to deck height. Ken’s dual laser device, mentioned in my last blog post, was put to good use to estimate the size of the large sharks before they were released.

I need to give shout out to the ship’s cook Walter Coghlan and the second cook O.C. (Otha) Hill. The food has been great and plentiful. ( Homemade Mac n’ Cheese – need I say more?) Walter takes special care to set aside a plate for us if we are on duty during mealtime. The ice cream sandwiches are much appreciated too.

New species seen since last posting: Sharksucker (a type of Remora, Echeneis naucrates), Blacktip (Carcharhinus limbatus)

Trying to get a Remora to stick to my arm. What a strange feeling. (Photo: Kristin Hannan) — Trying to get a Remora to stick to my arm. What a strange feeling. (Photo: Kristin Hanna

The view from the Bridge — The view from the bridge.

Still working on the hooks. (Photo: Ken Wilkinson)

Check out these interesting shark facts.

August 2, 2015August 21, 2021

Leah Johnson: Fish Identification & Pisces Farewell, August 1, 2015

NOAA Teacher at Sea
Leah Johnson
Aboard NOAA Ship Pisces
July 21 – August 3, 2015

Mission: Southeast Fishery – Independent Survey
Geographical Area of Cruise: Atlantic Ocean, Southeastern U.S. Coast
Date: Saturday, August 1, 2015

Weather Data from the Bridge:
Time 12:13 PM
Latitude 033.995650
Longitude -077.348710
Water Temperature 24.37 °C
Salinity 36.179 ppt
Air Temperature 27.4 °C
Relative Humidity 83 %
Wind Speed 15.95 knots
Wind Direction 189.45 degrees
Air Pressure 1012.3 mbar

Science and Technology Log:
I am still amazed at the wealth of data collected aboard the Pisces on this survey cruise. I am getting better at identifying the fish as they are hauled up in the traps, as well as when I see these fish on video. Because of light attenuation, many fish look very different in color when they are underwater. Light attenuation refers to the gradual loss of visible light that can penetrate water with increasing depth. Red light has the longest wavelength on the visible light spectrum, and violet has the shortest wavelength. In water, light with the shortest wavelength is absorbed first. Therefore, with increasing depth, red light is absorbed, followed by orange, then yellow. Fish that appear red in color at the surface will not appear red when they are several meters below the sea surface where they are captured on camera.

For example, we hauled in some blackfin snapper earlier this week. At the surface, its color is a distinct red like many other types of snappers, and it has a black spot near the base of its pectoral fin. When I looked at the videos from the trap site, I did not realize that all of the fish swimming around with yellow-looking tails were the very same blackfin snappers that appeared in the traps! When I remembered that red light is quickly absorbed in ocean water and noticed the black spot on the pectoral fin and shape of the dorsal fin, it made more sense.

Top: Blackfin snapper collected from trap.
Bottom: Video still of blackfin snappers swimming near trap.

I tell my geology students every year that when identifying minerals, color is the least reliable property. I realize now that this can also apply to fish identification. Therefore, I am trying to pay closer attention to the shape of the different fins, slope of the head, and relative proportions of different features. The adult scamp grouper, for example, has a distinct, unevenly serrated caudal fin (tail) with tips that extend beyond the fin membrane. The tip of the anal fin is elongated as well.

Scamp grouper

Another tricky aspect of fish identification is that some fish change color and pattern over time. Some groups of fish, like wrasses, parrotfish, and grouper, exhibit sequential hermaphroditism. This means that these fish change sex at some point in their lifespan. These fish are associated with different colors and patterns as they progress through the juvenile phase, the initial phase, and finally the terminal phase. Some fish exhibit fleeting changes in appearance that can be caught on camera. This could be as subtle as a slight darkening of the face.

The slight shape variations among groupers can also lead groups of scientists to gather around the computer screen and debate which species it is. If the trap lands in an area where there are some rocky outcrops, a fish may be partially concealed, adding another challenge to the identification process. This is no easy task! Yet, everyone on board is excited about the videos, and we make a point to call others over when something different pops up on the screen.

We were all impressed by this large Warsaw grouper, which is not a common sight.

I have seen many more types of fish and invertebrates come up in the traps over the past week. Here are a few new specimens that were not featured in my last “fish” post:

Did You Know?

Fish eyes are very similar to those of terrestrial vertebrates, but their lenses that are more spherical.

lens from fish eye

Lens from fish eye

Personal Log:

I love being surrounded by people who are enthusiastic about and dedicated to what they do. Everyone makes an extra effort to show me things that they think I will be interested to see – which I am, of course! If an interesting fish is pulled up in the trap and I have stepped out of the wet lab, someone will grab my camera and take a picture for me. I continue to be touched by everyone’s thoughtfulness, and willingness to let me try something new, even if I slow down the process.

Me, on the deck of the ship. We just deployed the traps off the stern.

As our cruise comes to an end, I want to thank everyone on board for letting me share their work and living space for two weeks. To the NOAA Corps officers, scientists, technicians, engineers, deckhands, and stewards, thank you for everything you do. The data collection that takes place on NOAA fishery survey cruises is critical for the management and protection of our marine resources. I am grateful that the Teacher at Sea program allowed me this experience of a lifetime. Finally, thank you, readers! I sincerely appreciate your continued support. I am excited to share more of what I have learned when I am back on land and in the classroom. Farewell, Pisces!