hammerhead shark – NOAA Teacher at Sea Blog

August 7, 2025August 8, 2025

Cheryl Milliken: It’s a Great Day to Go Fishing, August 5, 2025

NOAA Teacher at Sea

Cheryl Milliken

Aboard NOAA Ship Oregon II

July 25 – August 10, 2025

Mission: Bottom Longline Survey, Leg 1

Geographic Area of Cruise: Atlantic Coast of Florida

Date: August 5, 2025 11:25 PM

Weather Data from the Bridge

Latitude: 34° 40.1455′ N
Longitude:075° 45.5686′ W
Wind speed: 8 kts
Wave height: 1 m
Air temp.: 29.4 C
Sky: Clear

Science and Technology Log

Yesterday we reached our northernmost station, off the coast of Cape Hatteras. These shark lovers were hoping to catch a great white there, and we had two lines that were bitten through, so there may have been one that escaped (his name was Winston, in case you were wondering).

a large tiger shark hooked (momentarily) on a line, swimming in the ocean. — Large tiger shark that bent the hook and swam away before we could cradle and measure her.

close up view of two hooks resting on a metal surface. the bottom hook is a standard "circle hook" - it curls now quite all the way around into a circle. the top hook is only slightly curved. — Large tiger shark that bent the hook and swam away before we could cradle and measure her.

During that station we caught two Atlantic sharpnose sharks, a large tiger shark (estimated to by 2.25 meters, or more than 7 feet long), a baby tiger shark (0.87 meters, or a little less than 3 feet), and a male great hammerhead shark that was 2.71 meters (almost 9 feet!) long.

view of a great hammerhead shark visible just below the surface of the water; it is attached to a line — Great hammerhead shark waiting to be hoisted alongside the ship for tagging and measuring.

I was so excited that I was able to tag and fin-clip the great hammerhead! From not really having much background experience with or knowledge of sharks beyond dogfish, I have had a tremendous exposure to these apex predators!

close up view of a round fiberglass buoy: white on top, blue on the bottom. the white section is decorated with stickers and marker drawings.

close up view of a round fiberglass buoy: white on top, blue on the bottom. the white section is decorated with stickers and marker drawings. this angle shows a drawing of a red snapper.

view from across the deck of three people wearing life vests carrying the drifter buoy

two men in life vests lift the drifter buoy (the buoy and its attached drogue) up toward the rail of the ship. it is nighttime.

two men wearing life vests toss the drifter buoy over the rail. it is night time.

Photos: decorations on Drifter #3, launched by Josh and Sean south of Cape Hatteras on Tuesday night.

Near the next station, we were able to launch the third drifter close to the Gulf Stream. I can’t wait to share the information about these drifters with my students! The Adopt a Drifter program has lesson plans that you can check out here: Adopt a Drifter Teacher Resources.

Here are links to see where our drifters are:

Our goal in launching these drifters was to put them into the Gulf Stream to see how they behave. Perhaps they will all stay in the Gulf Stream, or perhaps they will veer out because of eddies. We shall see!

Interview with Gretchen Kruizenga

Gretchen stands next to the CTD rosette on the deck of NOAA Ship Oregon II. the sky is blue with puffy white clouds, and the ocean is a very vivid blue. — *Gretchen Kruizenga, senior survey technician on NOAA Ship* Oregon II, explaining to new staff the purpose and procedure for launching the CTD (Conductivity, Temperature, and Density) apparatus.

Gretchen, the ship’s senior survey technician, always has a smile on her face. She has been so helpful and supportive to me as a newbie on this project, and I appreciate her level-headed guidance and patient encouragement as I learn all the new things. Gretchen’s high energy level and enthusiasm is appreciated. She works with the science crew to bait hooks, then she hustles to collect water quality data from the CTD (short for conductivity, temperature, and depth). Gretchen grew up in Walworth, WI (graduating from Big Foot High School!), then earned a degree in Biological Sciences (minoring in Environmental Science) from Florida Atlantic University (FAU). Her avid affection for sharks is contagious. She has had an amazing breadth of experiences so far, which led her to this job in January 2023.

Why is your work important?

“My job is vital for keeping the scientific operations running. For example, when a sensor breaks, I can replace it to keep them collecting water quality information for the survey.”

What are your responsibilities? This position is new to me.

“I am in charge of maintaining and operating scientific sensors and oceanographic sampling equipment. My job on this vessel is different than on other NOAA vessels because since this ship is small, I also stand a science watch.”

What do you enjoy most about your work?

“I love being able to work on my two biggest career passions: water quality data collection and scientific data collection. I consider myself to be the luckiest person on the ship.”

What tool do you use in your work that you could not live without?

“I’d have to say multimeter. It allows me to figure out if cables are broken or if sensors are getting enough power without having to bring the whole apparatus into the lab.”

When did you know you wanted to pursue a career in science or an ocean career?

“My dad took me to see the ocean for the first time at South Padre Island, TX, when I was 9 years old. I knew then that I wanted the ocean in my life in any capacity it could be. I originally wanted to work for National Geographic to write blogs about places around the world. I got an internship in South Africa with Oceans Research, where I fell in love with sharks. When I’m not on Oregon II, I work with American Shark Conservancy out of Jupiter, FL, to collect water quality data and shark information on recreational shark ecotourism diving boats. I gave a presentation at the American Elasmobranch Society in 2023 about that citizen science work. We collect data that would otherwise be missed.

“I found this job when I googled “NOAA shark research” and found out about this [bottom longline] survey. I’ve always wanted to work with Trey [Driggers] on this shark survey. Being able to contribute to the stock assessment data that I’ve been looking at for years is crazy.”

What is the toughest part of your job?

“The toughest part of my job is keeping a healthy work-life balance. The needs of the ship means being away a lot, which impacts maintaining social relationships.”

What part of your job with NOAA did you least expect to be doing?

“I do more electrical work than expected. I have to read a lot of manuals because there aren’t a lot of people who can answer those questions for me.”

How do you help wider audiences to understand and appreciate NOAA science?

“Coming from an outreach background, I love to share everything I learn with others. I share links and stories on Instagram to get the message out there to anyone who will listen. I do wish we had more outreach opportunities.”

Do you have any outside hobbies?

“I like to make epoxy waves (www.etsy.com/shop/GretchenEpoxSeas), kickbox, and scuba. I like to see my friends. I like to push myself out of my comfort zone. I love to travel (favorite place is Iceland).”

What do you think you would be doing if you were not working for NOAA?

“This is my dream job, but if I can’t work here anymore, I would try to do anything that combines my technical expertise with sharks.“

Personal Log

This time is flying by, and yet every day seems to blend into the next. We have a television on in the science lab while we are moving between stations, and yesterday a Meg (Megalodon) marathon was on… I I loved the quote from the movie, but the portrayal of a long-thought-extinct shark coming back to kill all the people was a little more than I wanted to think about (spoiler alert: especially when one megalodon launched itself out of the water and onto the research vessel in the movie…)

Although I am not going to officially interview her, I want to give a shoutout to Tera Winters, the other watch member who is affiliated with the University of Miami’s Cooperative Institute for Marine And Atmospheric Studies. Tera has been a veterinarian in Tallahassee and Panama City, FL, but has added marine science to her skill set. Tera takes pride in working efficiently, particularly when she is back in the lab processing otoliths (ear stones) from bony fishes to estimate growth rates and ages of individual fish. This information is a critical part of the stock assessment information, because managers need to know how long it takes (in addition to size) for fish of a certain species to reach sexual maturity. Tera has been responsible for FT-NIRS scanning, imaging, weighing, and ageing thousands of otoliths from red snapper. Without this information, the catch limits of red snapper may be miscalculated. I have been privileged to work with such amazing professionals.

Did You Know?

Sharks were around 200 million years before the dinosaurs, and they have persisted for 450 million years. Don’t you think it would be a tragic event if humans caused the extinction of any of the over 500 species of sharks that have been identified?

August 8, 2023August 10, 2023

Martin McClure: Navigating the Seas, August 7, 2023

NOAA Teacher at Sea

Martin McClure

NOAA Ship Oregon II

July 25– August 9, 2023

Mission: Shark/Red Snapper Bottom Longline Survey

Geographic Area of Cruise: Gulf of Mexico/Atlantic Ocean

Date: August 7, 2023

Latitude: 30°33.167’N

Longitude: 81°04.685’W

Air Temperature: 31° Celsius

Wind Speed: 12.01 knots

Rachel, wearing a navy blue NOAA Corps uniform, stands for a portrait photo next to a plaque on an exterior wall of the ship that reads: R.V. Oregon II, designed by R. H. Macy for U.S. Department of Interior Bureau of Commercial Fisheries, built by The Ingalls Shipbuilding (Company), a Division of Litton Industries, Pascagoula, Mississippi, 1967 — Executive Officer Lieutenant Commander Rachel Pryor

Navigating NOAA Ship Oregon II is at once one of the most important and complex tasks on board. It is in motion 24 hours a day and must have skilled individuals to keep the crew safe and accomplish the mission of the survey. I spoke with Commander Adam Reed, Acting Commanding Officer, and Lieutenant Commander Rachel Pryor, Executive Officer, about this task.

Oregon II operates on two engines with one propeller (prop). It has a controllable pitch prop. This means that the pitch of the blades can be changed in order to change speed or even reverse the direction of the ship. The rudder turns the ship to port or starboard. There are also bow thrusters that turn the bow one way or the other.

There are a variety of devices that the navigator uses to know where the ship is, and to stay on course. They have two different GPS devices, in case one goes out. Additionally, they have a magnetic compass as well as a gyrocompass.

A storm and cruise ship off near Jacksonville, FL.

There are two radar units to see where other ships are and to get detailed weather information. One unit is more precise than the other but may pick up rain storms which may interfere with spotting ships. The other unit will still work in that situation.

When navigating, it is important to not just maintain the correct heading but also monitor course over ground. Even though the ship is heading in the right direction it can be pulled off course by the water currents and winds. This is very important to keep in mind not only across long distances but also when approaching the high flyer to pick up the longline. They must approach at a 90° angle and then turn to follow the longline. This is a fairly precise maneuver that is affected by both wind and current.

view of the bridge, empty of personnel. It is lined with windows facing three sides. We see control panels and map tables, the helm, electric boxes on the interior wall. — The bridge. This is where NOAA Corps officers navigate *Oregon II*.

One important factor affecting the operation of the ship is the weather. Careful consideration of any weather conditions must be factored into any decisions made. No one is allowed on the deck if there are winds of 25 knots or more, waves of 4-5 feet, or lightning within 25 miles. Weather information is always monitored through five different sources. Decisions must be made while consulting and comparing different sources of data.

Executive Officer Rachel Pryor explained that there are two types of weather patterns to keep in mind when considering operations. The first are small squalls, which can be fast moving and may have lightning. These squalls may keep moving in the same direction and you can calculate when they will arrive. But they can sometimes dissipate, change course, or stay where they are. There are also larger weather systems to consider. These tend to be slower moving but can have seas “kicking up,” increased wind speeds, and lightning. These may require seeking some sort of shelter or even docking at a port.

photo of a screen displaying radar data from the website Windy.com. We are looking at map centered approximately on Brunswick, Georgia, extending south to the northern counties of Florida, north to Charleston, and west to about the border of Alabama and Georgia. The radar shows a storm system concentrated on the Georgia-Florida border with other storm patches in central Georgia. — Radar showing an approaching storm system.

Weather has impacted the survey several times during this cruise. One of the most memorable was when I was working my shift and we were told to expect a long delay due to the weather. After about 30-45 minutes we were told to go ahead and bait the hooks and lay the longline. It takes about 2 ½ hours to run a station from putting the first hook in, to pulling the last one out of the water. The weather was beautiful and the seas were relatively calm during the station. Within a few minutes of finishing, the winds began to kick up as a system approached. In my estimation, these were pretty amazing calculations by Lieutenant Commander Pryor who was Officer of the Deck (OOD) for the haul.

The other incident to include here was a larger storm system that we were told on a Tuesday would arrive on Friday. Sure enough, it did. We headed in for cover near Cape Fear, NC. In this case, all fishing stopped and we sailed in an oval pattern keeping the waves to the bow or stern as much as possible. This led to a work stoppage of about 36 hours. In both cases careful calculations were made to keep the crew safe and maximize mission success.

Meet the Crew: Taniya Wallace, Fish Biologist

Taniya and another crew member stand on deck, each wearing life vests, work gloves, and rubber boots. The other crewmember grips a small (2-3 foot long) shark firmly with two hands, holding it at an angle toward Taniya. Taniya grasps the shark's head with her left hand and reaches with her right to remove a hook. Both Taniya and the unnamed crewmember look down at the shark, focused on their work. — Fish biologist Taniya Wallace unhooks a small shark

Taniya Wallace is a fish biologist contractor on the science team here on Oregon II. Taniya hails from Ocean Springs, Mississippi, where she grew up and still lives. Her mother is a teacher and her father works in naval ship design. Taniya credits her 6th grade teacher with first inspiring her interest in science. She says, “Science challenged my mind and made me wonder how things worked.”

After graduating high school, she got a summer internship at the Gulf Coast Research Laboratory where she developed an interest in marine biology. Taniya attended Mississippi Valley State University in Itta Bena, Mississippi. She played softball for her university and they won the Southwestern Athletic Conference championship three years in a row! At Mississippi Valley State, she earned a degree in biology with a minor in chemistry.

Taniya sits at a desk, facing a computer with two monitors. The screen is too bright to make out. She holds a microphone from an intercom system up to her mouth with her left hand, perhaps ready to read out data or provide direction. — Taniya works on a computer

After college she was hired as a contractor during the Deepwater Horizon disaster working on small boats trawling for fish and crustaceans to gather samples for NOAA Fisheries Seafood Inspection program. This was a three month contract.

Next, she was contracted to work with NOAA for the Plankton Unit for the next four years. On the surveys, she worked with the team to collect plankton (microscopic organisms) in three different sized nets. Then, back in the lab, she sorted and identified decapods (crabs, lobster, shrimp) and red snapper.

In 2014, she moved to the trawl survey. In this survey, they pulled a large net behind the boat and caught a variety of marine animals. They sort, identify and record measurements on what they find on the boat. Back at the lab, they would identify unknown species. This included different kinds of fish as well as invertebrates. She explained to me that the science team uses only scientific names so, often, she may not know the common name of species she is cataloging.

Here on the shark and red snapper survey her computer and data entry skills are evident. She catalogs otoliths (ear bones) and other parts quickly and easily. I am not sure if patience, kindness and equanimity are requirements of her job but she, like the other members of the science crew, excels in these qualities. And, her shark handling skills are really impressive.

Personal Log: A very exciting haul!

Every day continues to be full of new experiences and animals. Yesterday, there was a haul which on paper would look pretty boring but it proved to be anything but. First, we brought up a royal sea star ( Astropecten articulatus), a beautiful hand sized star with cream colored feet, with orange edges filled by a deep purple band. I half expected Trey, our lead on the science team, to claim it for Clemson. (Go tigers! Or, is that LSU? Yes, there is a school rivalry playing out among the science team.)

close-up view of a sea star held on the open palm of a gloved hand. the sea star is purple and orange with cream-colored 'feet' that looks like frills. — Royal sea star

Hook number 33 had a feisty seven foot nurse shark. The next shark, a nearly seven foot sandbar shark, was on hook number 43.

Hook number 49 had a baby tiger shark that was being pursued by a great hammerhead. The hammerhead was closing in on its prey when the gangion tightened and the tiger shark was hauled out of the water. I cannot say what was in the hammerhead’s brain, but it was certainly animated. For the next few minutes, it searched in vain for the tiger shark, circling and making several passes on the starboard side of the ship and showing its dorsal fin.

view over the rail of NOAA Ship Oregon II of a hammerhead shark swimming at the surface of the water in the direction of the ship — Hammerhead, thwarted in pursuit

Confusion? Anger? We can only speculate but I can imagine how strange the situation was from the hammerhead’s point of view. “Just another second and then, yum. Wait… where did it go?” I know this is purely unscientific and I am anthropomorphising (giving human characteristics to animals) but it really was a sight to witness.

Now where did that darn fish go? I know its here somewhere.

Later on that same haul, we hooked into a large tiger shark. It is not unusual to see a shark sucker or cobia, maybe two, hanging out around the shark as we bring it in. We have even caught a shark sucker on a hook. But this tiger had at least 10 cobia following it in.

A group of cobia following a tiger shark.
Photo credit: NOAA Corps Lieutenant Junior Grade Cassidy Ring

She was big and had no intention of getting tagged.

She broke the line, and we were not able to measure and tag her. In this haul, only one fish was landed, but each of those events excited all involved and will be remembered and shared long into the future.

Martin rides a stationary bike in the workout room, facing the camera and smilng for a photo. He is wearing a Nokomis Staff t-shirt that reads "We run with the wolves" and a Teacher at Sea hat. A rack full of weights is visible on the floor to his right. — Enjoying some time off shift.

Animals seen: Shark sucker, royal sea star, brittle star, sea fan, nurse shark, cobia, royal tern

Did you know? Sometimes hammerhead sharks swim on their sides.

September 25, 2019

Kathy Schroeder: The Great Hammerhead / Setting the Longline, September 24, 2019

NOAA Teacher at Sea

Kathy Schroeder

Aboard NOAA Ship Oregon II

September 15-October 2, 2019

Mission: Shark/Red Snapper Longline Survey

Geographic Area of Cruise: Gulf of Mexico

Date: September 24, 2019

Weather Data from the Bridge

Latitude: 29.15258
Longitude: 93.02012
Temperature: 87°F
Wind Speeds: E 10 mph

Science and Technology Log

My last blog left off with a late night longline going in the water around 9:00pm on 9/23/19. We were able to successfully tag a great hammerhead, a scalloped hammerhead, and a tiger shark. We also caught a blacknose shark, three gafftopsail catfish (Bagre marinus), and three red snappers.

female great hammerhead — *Female great hammerhead caught on 9/23/19 aboard NOAA Ship* Oregon II

male scalloped hammerhead — *Male scalloped hammerhead caught on 9/23/19 aboard NOAA Ship* Oregon II

Deploying the Longline

Today I’m going to explain to you the five jobs that we rotate through when we are deploying the longline. When there are about 15-20 minutes before deployment we grab our sunglasses, personal floatation device (pfd) and rubber boats and head to the stern of the ship. All scientists are responsible for helping to cut and bait all 100 gangions (hooks and line). The hooks are 15/0mm circle hooks and the gangion length is 3.7m long. The bait used for this is Atlantic mackerel cut into chunks to fit the hooks. We are all responsible for cleaning the deck and the table and cutting boards that were used.

baiting hooks — *Kristin cutting bait and Taniya and Ryan baiting the 100 hooks*

The first job on the deployment is setting up the laptop computer. The scientist on computer is responsible for entering information when the high flyer, the three weights (entered after first high flyer, after gangion 50 and before final high flyer), and the 100 baited gangions entered into the water. This gives the time and the latitude and longitude of each to keep track of for comparison data.

The second job is the person actually putting the high flyer and buoy in the water. Once the ship is in position and we receive the ok from the bridge it is released into the water. The high flyer is 14ft from the weight at the bottom to the flashing light at the top. (see picture)

The third job is the “slinger”. The slinger takes each hook, one by one, off of the barrel, lowers the baited hook into the water, and then holds the end clamp so that the fourth scientist can put a tag number on each one (1-100). It is then handed to the deckhand who clamps it onto the mainline where it is lowered into the water off the stern.

numbers on gangion — *Placing the numbers on the gangion before being put on the mainline*

The final job is the barrel cleaner. Once all the lines are in the water the barrel cleaner takes a large brush with soap and scrubs down the inside and outside of the barrel. The barrels are then taken to the well deck to get ready for the haul in. The last weight and high flyer are put into the water to complete the longline set, which will remain in the water for one hour. Everyone now helps out cleaning the stern deck and bringing any supplies to the dry lab. At this time the CTD unit is put in the water (this will be described at a later time).

Personal Log

Last night was so exciting, catching the three large sharks. During this station I was responsible for the data so I was able to take a few pictures once I recorded the precaudal, fork, and total length measurements as well as take a very small fin sample and place it in a vial, and record the tagging numbers.

Shout Out: Today’s shout out goes to my wonderful 161 students, all my former students, fellow teachers, especially those in my hallway, my guest teachers and all the staff and administration at Palmetto Ridge High School. I would also like to thank Mr. Bremseth and Michelle Joyce for my letters of recommendations!

I couldn’t have been able to do this without all of your help and support. I have sooo much to tell you about when I get back. Go Bears!!

April 13, 2017April 13, 2017

Emily Sprowls: Whirlwind Return to Shore, April 11, 2017

NOAA Teacher at Sea

Emily Sprowls

Aboard NOAA Ship Oregon II

March 20 – April 3, 2017

Mission: Experimental Longline Survey

Geographic Area of Cruise: Gulf of Mexico

Date: April 11, 2017

Weather Data

The weather on the last scheduled day of the cruise was so bad (12 ft. seas! 30 knot winds!) that the ship came into port early on Sunday. The strong winds and waves kicked up and a string of severe storms and tornadoes swept through the area just after my flight home left on Monday morning.

Science and Technology Log

The last few days of the cruise brought in a lot of sharks, fish and data. We were kept pretty busy, putting in and hauling out 3 or 4 lines each shift. In total between both shifts we set 53 stations and caught 679 vertebrate specimens (not counting the invertebrates: sea stars, sea cucumbers and all those isopods)! There were points when this was totally exhausting and repetitive, but then there were moments when we were holding sharks and it was all worth it! We caught some amazing creatures, and some just floated or flew by for a visit like jellyfish and migrant birds.

In between stations the scientists worked to collect and label tissue samples from the specimens needed by different research labs, including fin clips, parasites, muscles, and eye lenses.

Migrating songbird visitor

Portuguese man-o-war jelly

Tissue specimens from bony fish

Personal Log

To be completely honest, there was a point about two-thirds through the cruise when I felt pretty tired, a little bit nauseous, and like I had already seen and learned so much that I was ready to go home. That happened to be a day when another thunderstorm blew in, and we had to take a break from sampling. That terrific weather break (during which we lounged with popcorn and a not-so-terrific movie) also coincided with the forecast suggesting a possible early end to the cruise. Suddenly, it seemed like my trip was almost over — I realized that I had so many more questions for my new scientist friends and not enough time to learn everything!

Fortunately, the scientists on board were very kind and eager to answer my students’ questions with the best information they could find. We had several engaging discussions while answering the kids’ questions… in fact, at one point we were so engrossed in a conversation about dogfish life history that we were suddenly interrupted by radio calls from the deck and bridge that we had missed hauling in our line! We grabbed all our gear: boots, gloves, life jackets, hardhats, clipboards, cameras, laptop; and ran out on deck as fast as we could muster. We had all forgotten it was April Fool’s Day! Ha!

Oregon2 crew — NOAA Corps Officers LCDR Lecia Salerno, LT Reni Rydlewicz and ENS Chelsea Parrish

I am so grateful to the entire crew for their hospitality and their willingness to teach me about their jobs. They shared not only their homes on the boat, but also their own stories and knowledge about the work we were doing. I was lucky to share my first boat experience with Ensign Parrish, who was on her first cruise as a newly minted NOAA officer. Her infectious smile and clear love for being at sea, all while learning the ropes of the Oregon II, helped pull me right along with her enthusiasm.

The main person responsible for my excellent experience aboard was the Field Party Chief.

Baby tiger shark — The amazing shark wrangler Kristin Hannan with a young tiger shark!

Kristin Hannan was friendly and generous with her time, all while coordinating stations with the bridge, managing the scientific crew, and preparing for the next research trip. She was also indefatigable! By the time I would get my baiting gloves off, catch my breath, and get ready to help clean up, she had already finished scrubbing the barrels and decks! Most endearing, however, were her encyclopedic knowledge of shark anatomy and population ecology, and her love of all things shark (even the movie JAWS), tempered by a clear, rational, scientific perspective on issues facing the Gulf of Mexico.

Eventually, the trip drew to a close. As we approached the final sampling stations, there were many species I had hoped to see that hadn’t come up yet. It was as if all I had to do was wish for them and they appeared in the final hauls: Stingrays – CHECK! Big bull shark – CHECK! Beautiful baby tiger shark — CHECK! Adorable spinner shark — CHECK!

I started to see why this work was so addictive and attractive to the crew. But, at the end, I was definitely ready to be on stable land and order whatever I wanted from a restaurant. Going home to my incredibly spacious queen-sized bed and enormous 50 square foot bathroom was also quite nice! I loved my adventure at sea, while I also so admire the tenacity and grit that the scientists and crew on the Oregon II have for living the boat life for much, much longer than two fun weeks. Thank you!

Kids’ Questions

What types of sharks will you catch in the Gulf?

On our leg, we caught the following shark species:

Blacknose shark , CARCHARHINUS ACRONOTUS
Spinner shark, CARCHARHINUS BREVIPINNA
Blacktip shark, CARCHARHINUS LIMBATUS
Sandbar shark, CARCHARHINUS PLUMBEUS
Gulper shark, CENTROPHORUS GRANULOSUS
Little gulper shark, CENTROPHORUS UYATO
Tiger shark, GALEOCERDO CUVIERI
Dusky smoothhound shark, MUSTELUS CANIS
Gulf smoothhound, MUSTELUS SINUSMEXICANUS
Sharpnose shark, RHIZOPRIONODON TERRAENOVAE
Scalloped hammerhead shark, SPHYRNA LEWINI
Cuban dogfish shark, SQUALUS CUBENSIS

We also caught the following batoid species:

Southern stingray, DASYATIS AMERICANA
Roughtail stingray, DASYATIS CENTROURA
Bullnose ray, MYLIOBATIS FREMINVILLII
Clearnose skate, RAJA EGLANTERIA

What is the most populous type of shark in the Gulf of Mexico?

Sharpnose sharks were the most common in our sampling (we caught 247!) Bonnethead sharks are the more common species closer to shore, and blacktip sharks tend to be more common out farther to sea.

Are some shark species more or less sensitive to pollution?

Bull sharks are tolerant of extremes in water conditions (they have been found in the Mississippi River!), so they may be less sensitive to pollution. In general, hammerhead species are more sensitive and younger sharks are also in sensitive life stages, so they might be more sensitive. This is exactly the kind of questions that scientists might be able to answer more definitively someday using the large amounts of data collected by the Oregon II.

What are sharks’ lifespans?

Each shark species is different, but generally they live a long time. Small sharpnose sharks can live about 10 years. Dogfish can live up to 70 years. Other sharks average about 30 years. There is speculation that a Greenland shark has lived over 100 years! These long lifespans are part of the reason many shark populations are vulnerable because it takes them a long time to reach maturity and they do not reproduce quickly. Life history information about sharks is important to know as the NOAA scientists help manage fisheries.

September 15, 2016March 26, 2021

Barney Peterson: What Are We Catching? August 28, 2016

NOAA Teacher at Sea

Barney Peterson

Aboard NOAA Ship Oregon II

August 13 – 28, 2016

Mission: Long Line Survey

Geographic Area: Gulf of Mexico

Date: Sunday, August 28, 2016

Weather Data is not available for this post because I am writing from the Biloxi/Gulfport Airport.

WHAT ARE WE CATCHING?

This is a long-line survey. That means we go to an assigned GPS point, deploy hi-flyer buoys, add weights to hold the line down, add 100 baited hooks, leave it in place for an hour, and retrieve everything.

mackerel-bait-fish — Mackerel is used to bait the hooks.

As the equipment is pulled in we identify, measure and record everything we catch. Sometimes, like in the case of a really large, feisty shark that struggles enough to straighten or break a hook or the lines, we try to identify and record the one that got away. We tag each shark so that it can be identified if it is ever caught again. We tally each hook as it is deployed and retrieved, and the computer records a GPS position for each retrieval so scientists can form a picture of how the catch was distributed along the section we were fishing. The target catch for this particular survey was listed as sharks and red snapper. The reality is that we caught a much wider variety of marine life.

We list our catch in two categories: Bony fish, and Sharks. The major difference is in the skeletons. Bony fish have just that: a skeleton made of hard bone like a salmon or halibut. Sharks, on the other hand, have a cartilaginous skeleton, rigid fins, and 5 to 7 gill openings on each side. Sharks have multiple rows of sharp teeth arranged around both upper and lower jaws. Since they have no bones, those teeth are embedded in the gums and are easily dislodged. This is not a problem because they are easily replaced as well. There are other wonderful differences that separate sharks from bony fish.

Bony Fish we caught:

The most common of the bony fish that we caught were Red Groupers (Epinephelus morio), distinguished by of their brownish to red-orange color, large eyes and very large mouths. Their dorsal fins, especially, have pointed spikes.

chrissy-with-enormous-grouper — Chrissy holding an enormous grouper

We also caught Black Sea Bass (Centropristus striata) which resemble the groupers in that they also have large mouths and prominent eyes.

A third fish that resembles these two is the Speckled Hind (Epinephelus drummondhayi). It has a broad body, large mouth and undershot jaw giving the face a different look. Yes, we did catch several Red Snapper (Lutjanus campechanus), although not as many as I expected. Snappers are a brighter color than the Red Groupers, and have a more triangular shaped head, large mouth and prominent canine teeth.

The most exciting bony fish we caught was barracuda (Sphyraena barracuda). We caught several of these and each time I was impressed with their sleek shape and very sharp teeth!

Most of the bony fish we caught were in fairly deep water.

Eel

Flying Fish

Sharks:

We were fortunate to catch a variety of sharks ranging from fairly small to impressively big!

The most commonly caught were Sandbar Sharks (Carcharhinus plumbeus): large, dark-gray to brown on top and white on the bottom.

Unless you really know your sharks, it is difficult for the amateur to distinguish between some of the various types. Experts look at color, nose shape, fin shape and placement, and distinguishing characteristics like the hammer-shaped head of the Great Hammerhead (Sphyrna mokarran) and Scalloped Hammerhead (Sphyrna lewini) sharks that were caught on this trip.

great-hammerhead — Great Hammerhead Shark

The beautifully patterned coloring of the Tiger Shark (Galeocerdo cuvier) is fairly easy to recognize and so is the yellowish cast to the sides of the Lemon Shark (Negaprion brevirostris).

Tiger Shark

Lemon Shark

Other sharks we caught were Black-nose (Carcharhinus acrontus), Atlantic Sharp-nosed (Rhizoprionodon terraenovae), Nurse Shark (Ginglymostoma cirratum), Blacktip (Carcharhinus limbatus) and Bull Sharks (Carcharhinus leucus).

Atlantic Sharp-nosed

Nurse Shark

Bull Shark

Several of the sharks we caught were large, very close to 3 meters long, very heavy and very strong! Small sharks and bony fish were brought aboard on the hooks to be measured against a scaled board on the deck then weighed by holding them up on a spring scale before tagging and releasing them. Any shark larger than about 1.5 meters was usually heavy and strong enough that it was guided into a net cradle that was lifted by crane to deck level where it could be measured, weighed and tagged with the least possibility of harm to either the shark or the crew members. Large powerful sharks do not feel the force of gravity when in the water, but once out of it, the power of their weight works against them so getting them back into the water quickly is important. Large powerful sharks are also pretty upset about being caught and use their strength to thrash around trying to escape. The power in a swat from a shark tail or the abrasion from their rough skin can be painful and unpleasant for those handling them.

PERSONAL LOG

The Night Sky

I am standing alone on the well deck; my head is buzzing with the melodies of the Eagles and England Dan. A warm breeze brushes over me as I tune out the hum of the ship’s engines and focus on the rhythm of the bow waves rushing past below me. It is dark! Dark enough and clear enough that I can see stars above me from horizon to horizon: the soft cloudy glow of the Milky Way, the distinctive patterns of familiar favorites like the Big Dipper and the Little Dipper with its signature bright point, the North Star. Cassiopeia appears as a huge “W” and even the tiny cluster of the “Seven Sisters” is distinct in the black bowl of the night sky over the Gulf of Mexico. The longer I look the more stars I see.

This is one of the first really cloudless nights of this cruise so far. Mike Conway, a member of the deck crew came looking for me to be sure I didn’t miss out on an opportunity to witness this amazingly beautiful show. As I first exited the dry lab and stumbled toward the bow all I could pick out were three faint stars in the bowl of the Big Dipper. The longer I looked, the more my eyes grew accustomed to the dark, and the more spectacular the show became. Soon there were too many stars for me to pick out any but the most familiar constellations.

As a child I spent many summer nighttime hours on a blanket in our yard as my father patiently guided my eyes toward constellation after constellation, telling me the myths that explained each one. Many years have passed since then. I have gotten busy seeing other sights and hearing other stories. I had not thought about those long ago summer nights for many years. Tonight, looking up in wonder, I felt very close to Pop again and to those great times we shared.