Emily Sprowls: The pressure is on! March 23, 2017

 

NOAA Teacher at Sea

Emily Sprowls

Aboard Oregon II

March 20 – April 3,2017

Mission: Experimental Longline Survey

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NOAA Ship Oregon II

Geographic Area of Cruise: Gulf of Mexico

Date: March 23, 2017

Weather Data from the Bridge

13:00 hours

28°03.9’ N 89°08.3’W

Visibility 10 nm, Haze

Wind 3kts 100°E

Sea wave height <1 ft.

Seawater temp 25.1°C

 Science and Technology Log

The past two days have been devoted to setting extremely deep longlines. Each of these sampling lines take many hours, as we have to slowly reel out over 3 miles of line, give it time to sink, soak, and then reel it back in.   The line that we put out today is even a bit longer than usual, because I got to be in charge of “slinging” the hooks onto the line and I was not very fast at getting the four different sizes of hooks ready

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A Mexican grenadier fish

. Have I mentioned how patient everyone is with the “Teach” aboard?

This morning we pulled up 97 empty hooks from 1250 meters before we caught the amazing grenadier fish! It suffered barotrauma, which is a nicer way of saying that its eyes and swim bladder inflated like balloons from the inside as it was hauled up from the high pressure depths.

One of the scientists onboard studies ocean food chains by examining the contents of fish stomachs. The stomach of the Mexican grenadier fish contained a fully intact armored shrimp!

Personal Log

Today I took advantage of the calm, calm seas to try the workout equipment onboard. They have all kinds of gear to help folks stay active and work off the delicious food in the galley. There is a rowing machine, stationary bike, weight bench, Jacob’s ladder, and elliptical. I used the elliptical machine because it was way too hot on the upper decks to use the exercise bike. Even with the very calm seas, there is a little bit of rolling, which made it an extra challenge for me keep it going!

Kids’ Questions of the Day

These questions about the Oregon II are from Harmony elementary students:

  • How big is the boat?       How tall? How long?

The boat is 175 feet long and 80 feet tall.

  • How much does the boat weigh?      

The boat weight is 800 tons. This is not how much the boat would weigh if you put it on a scale, but how

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TAS Emily Sprowls dons a survival suit

much weight the boat can carry if it were loaded full of cargo. We are not carrying nearly that much weight because a lot of the space on the boat is for equipment and for scientists and crew to live aboard.

  • How fast can it go?

Typically, the boat can go about 10 nautical miles per hour using both engines. She can go a little faster if the wind and current conditions are just right.

  • What is the boat made of?

The boat is made of steel and aluminum.

  • What are the white balloon things on top of the boat?

The white domes cover satellite dishes for the internet and phone.

  • What are the poles on the boat for? Are there sails?

The two yellow poles on either side of the boat are the outriggers used to

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This array houses the Conductivity, Temperature, and Depth probe.

pull a wide trawling net, much like a shrimp boat. Scientists trawl the bottom to study benthic organisms, including shrimp, but also sponges, crabs and bottom-dwelling sharks.

  • What new technologies does the boat have?

The Oregon II turns 50 years old this year!   It has been sailing the Atlantic Ocean since before I was born, but the crew is constantly fixing and replacing equipment on the boat. Even though she is old, she is very safe and reliable. Nevertheless, we still have to prepare for emergencies, including the possibility of needing to abandon ship while wearing the goofy-looking, but life-saving survival suits.

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Styrofoam Cup Test!

Scientists have brought new technology on board, including plenty of computers to collect, sort, store and analyze all the data we collect. One of the computers is connected to a device called the “CTD” with a set of sensors for Conductivity, Temperature, Depth and Dissolved Oxygen. Today the CTD went all the way to about 1100 meters (3700 ft.), and we tethered some styrofoam cups to the outside to subject them to the extreme pressure at that depth.

 

Emily Sprowls: It’s a shark eat shark world down there! March 22, 2017

NOAA Teacher at Sea

Emily Sprowls

Aboard Oregon II

March 20 – April 3, 2017

 

Mission: Experimental Longline Survey

Geographic Area of Cruise: Gulf of Mexico

Date: March 22, 2017

Science and Technology Log

This first leg of the Oregon II’s research for the season is an experimental longline survey. This is an exciting cruise for everybody, as we are all anxious to see what comes in on each line, and we hope to find some rare and little-studied species.

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Reeling in a shark caught on one of hook of the longline

A longline is a type of fishing gear that deploys one very long and very thick fishing line with many hooks attached. A fisheries survey is a systematic sampling of the ocean to assess fish populations. This mission is experimental because we are testing the longline at extreme depths and we are using different kinds of hooks in order to catch as wide a variety of species as possible.

Things have been busy onboard from the very first day, as we have been setting out and hauling longlines around the clock. We are headed deeper and deeper into the Mississippi canyon of the Gulf of Mexico with each station, starting at 100m and have worked our way down to 750 m, where we currently have a line “soaking” before we haul it up to record what we caught.

Personal Log

Life on the ship is divided into night and day watch. I’m “on days,” which means I’m work noon to midnight. I am so lucky to be a cruise with a lot of seasoned marine scientists and a great, hard-working crew. Shark scientist Kristin Hannan is the Field Party Chief and has taken me under her wing to get me settled and teach me as much as she can (without making me feel like the newbie that I am)!

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Oil rigs on the horizon

The seas have been calm and the water is the most beautiful color of blue! We are pretty far out to sea, and I have been amazed to see so many oil rigs off in the distance. They glow like small cities at night, and I think they look like strange robots walking on the horizon during the day.

 

Kids’ Questions of the Day

These questions are from the 1st-2nd grade and multi-age classes at Harmony School.

  •  How do you catch the sharks?

We catch the sharks by setting out 100 baited hooks at a time on a very long fishing line. A winch reels in the 3 miles of line after a couple of hours, and we record what is on every single hook.

  • How do you find the sharks?

We rely on the sharks finding our baited hooks. We put weights on the line so that it will sink all the way down to the bottom. We are fishing so deep that it takes almost an hour just for the line to sink! The sharks find the bait using their incredible sense of smell.

  •  What do sharks eat? Fish? Squid? Cookies? Other sharks?

We are baiting the hooks with pieces of squid. The process of baiting hundreds of hooks has left my clothes covered with squid ink!

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Hooks baited with pieces of squid

Sometimes they catch sharks with fish (mackerel), but squid bait stays better on the hooks, and deep-sea sharks clearly like squid, which also live in deep water. While this mission is experimental, the scientists onboard do not think we will have much luck baiting a hook with a cookie – it will just dissolve in the sea (besides the cookies in the galley are so delicious that there are no leftovers)! One type of deep-sea shark makes their own cookies… cookie-cutter sharks (Isistius) bite “cookies” out of other fish with their amazing jaws. Maybe we’ll catch one!?!

Last night we hauled in one hook with only a shark head on it…. What do you think happened to the rest of the shark?

 

Denise Harrington: Let Kids Be Kids, October 18, 2016

NOAA Teacher at Sea

Denise Harrington

Aboard NOAA Ship Oregon II

September 16-30, 2016

Mission: Longline Survey

Geographic Area: Gulf of Mexico

Date: Tuesday, October 18, 2016

Location: 45 27’19″ N  123o 50’33″ W, Tillamook, Oregon

Weather: Rainy, windy, cloudy, and cold (nothing like the Gulf of Mexico).

Meet a Scientist: Dr. William “Trey” Driggers

Trey Drigger’s passion for aquatic predators was born in a lake at his grandparents’ house in Florida, while his dad, a jet pilot, was off fighting in the war in Vietnam.  When his dad left, Trey’s mom loaded the two boys and two dogs into the car and headed north to her parents’ lakefront home in Florida.  Soon thereafter, one of the dogs, used to swimming in safer waters, got eaten by an alligator that lived in the lake.  Trey feared the gators but also must have been fascinated by the life and death struggle between two animals.

With thoughts of fighter pilots and alligators, Trey was one of those students teachers might find challenging. He had trouble focusing on the mundane.  But through books, he could get a little bit of the thrill he sought.

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He knew he was destined to do something cool, just like his dad. Yet by the end of college Trey was still unsure of what he wanted to become.  One day, he was in the library when the spine of a book caught his eye: Sharks Attack.  After reading this book his childhood fascination with aquatic predators was reinvigorated. During a trip to the Smithsonian Museum of Natural History, Trey purchased a book entitled “Sharks in Question.” The last chapter was about how to become a shark specialist.  What, he thought, I can make a living studying sharks?!

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Trey quickly finished up his history degree and began two years of science classes he had missed.  In Marine Science 101, the professor said “If you are here for sharks, whales, or dolphins, you can leave right now.”  Trey took the warning as a challenge, and began his now spectacular career with sharks.

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Trey and Chief Boatswain Tim Martin measure a sandbar (Carcharhinus plumbeus) shark while fisheries biologist, Paul Felts, records data.  Photo: Matt Ellis/NOAA Fisheries

His attraction to the mysteries of the deep and the written word has resulted in many discoveries, including a critical role in the discovery of a new species, the Carolina hammerhead (Sphryna gilberti). Recently, Trey’s research has focused on, among other things, examining the movement patterns of sharks. However, understanding the movement patterns of sharks is tricky.  Many have large ranges and occupy numerous habitats under the surface of the ocean that covers over 70% of our planet.  Most sharks can’t be kept in captivity.  For all these reasons and more, sharks are mysterious and fascinating creatures.

So which sharks are currently catching Trey’s attention? One of his many interests is a group of bonnethead  (Sphyrna tiburo) sharks that have been recaptured over multiple summers in specific estuaries in South Carolina.

Like other hammerhead sharks, the bonnethead shark has a cephalofoil.  Why do hammerheads look like that?

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The photo of this bonnethead shark was taken in 2010 by a fellow TAS, Bruce Taterka, also aboard the Oregon II.

Theories abound about the funny looking hammerheads, whose heads look more like wings than hammers.  As Trey says, many people have speculated “the hammerhead has a cephalofoil because ….” giving a single reason.  Some say the cephalofoil acts as a dive plane, pulling the shark up or down as it swims, others say the distance between the nostrils allows it to smell better, honing in on prey, some say it is to compensate for their blind spot, and still others hypothesize that the shark uses its head to pin down prey.

 

Many people have asked this question, but very few get to work like Trey does, collecting data, making observations, and analyzing the data. He says the best part of his job is “when I figure something out that no one else knows.” One day, looking at data a friend collected in Bull’s Bay estuary, near Charleston, South Carolina, he noticed a pattern of the same sharks getting recaptured there year after year.  A small group of different aged, different size friends going to enjoy their summer together to Bull’s Bay while another group always going to the North Edisto estuary every year?  Why?

Trey hypothesizes that in the summer, blue crab abound in that spot, and are thick with eggs. The bonnetheads have the shortest gestation period of all sharks, four months, and need a lot of nutrients.  Their heads, shaped just right for holding down a blue crab, and their convergence at Bull’s Bay on the fertile female crabs, may just be the elements necessary to get a shark pup from embryo to viability.  Pretty cool!

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Here, a juvenile bonnethead shark is being measured.  Photo: NOAA Fisheries

With all this evidence supporting a hypotheses that the bonnethead shark cephalofoil is used for holding down prey, one might predict that Trey’s next publication on the topic will make that conclusion.

“People want to pick one answer,” Trey says, but “there is a lot more that we don’t know than we do.”   There is often more than one right answer, he continues, more than one solution to a problem.  Speaking about fishing regulation, conservationists and fishermen, Trey suggests that both sides need to understand that the other side has positive things to contribute.  He lives his life this way, moving fluidly among the deck crew, officers, stewards, and scientists looking for commonalities.  Together, all the members of the team play an essential role in keeping the ship and survey moving forward.

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Kevin, Matt Ellis, NOAA Science Writer, Paul, and Trey were the four other members of the day shift science team.  I took my christened baiting gloves home with me as a souvenir.

Personal Log

Each member of the crew shared insights and skills that I will take back to my classroom and incorporate into my life

My work as a NOAA Teacher at Sea was one of the most challenging experiences of my life. I knew very little about fish before stepping aboard the Oregon II, and from the crew have gained understanding of and appreciation for fish, other marine species, and the diversity of life on our planet.  I’ve learned that while the Gulf of Mexico is home to the world’s largest fisheries, the human impact from industries, watershed runoff, development, and other sources is unbelievable.

When the time for science arrives, or weaves its way into the other subjects as it always does, students’ eyes light up.  I know I am far from a professional scientist, but through NOAA,  I can now speak authentically and accurately about what happens in the field and why.  My students have become mini-scientists, speaking among themselves about collecting data as if it were a playground game.

As I listened to NOAA Corps Officer David Reymore share memories of a Make a Wish trip with his son to Disneyland, I learned to take each moment with a child as a gift and was also reminded of the sacrifice crew members and their families make in support of science during their weeks, months, and years at sea. Thank you, each and every NOAA crew member aboard the NOAA fleet, for your service.  With the time away from family as the only negative, I learned that the many different careers available through NOAA provide great learning opportunities, adventure, and inspiration to those who are ready for some very hard work.

What advice can you give me as a teacher, I ask Trey.  “Quote me on this,” he says with a smile, “don’t give kids so much —- homework.  Let them be kids.”

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NOAA Corps Officer Brian Yannutz wears his lucky shark hat as we bring in the long line.

Laughing, shaking my head in amazement, leafing through my journals, I have enough inspiration from these two weeks to last a lifetime.  How did I get so fortunate?

 

 

Denise Harrington: What Fish Do I Eat? October 3, 2016

NOAA Teacher at Sea

Denise Harrington

Aboard NOAA Ship Oregon II

September 16-30, 2016

Mission: Longline Survey

Geographic Area: Gulf of Mexico

Date: Monday, October 3, 2016

I asked Kevin Rademacher, Research Fisheries Biologist at the Pascagoula, Mississippi Lab, what fish I could eat and still support sustainable fisheries.  He answered with a question, “Have you read the book Four Fish?” When I finished reading the book by Paul Greenberg, I spoke to Kevin again. “What do you think now?” He asked.

I said “There is something about wild fish that makes me want to catch and eat them, but I worry about whether we are eating wild fish out of existence.”

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Yellowedge grouper (Epinephelus itajara). Photo: Matt Ellis/NOAA Fisheries

“Have you talked with Adam?  He’s the numbers guy,” Kevin said.  It seems like the good teachers are always sending students away in search of their own answers.

Adam Pollack is a contract Fisheries Biologist with Riverside Technology, Inc., and works on the night crew.  We sometimes cross paths at midnight or noon.  Catching him wouldn’t be easy.

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Here, Adam measures a shark too large to bring on deck.  Photo: NOAA Fisheries

During one of these transition times, we had a moment to talk.  I asked Adam about his earliest fish memory.  He smiled.  “At about five, I went fishing with my dad.  We had a house in the mountains surrounded by a bunch of lakes.”  Adam and his dad would sit by the lake with their lines in the water “watching the bobber disappear.”  He smiles again.  These little largemouth bass changed his life.

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Adam takes a selfie with a red drum (Sciaenops ocellatus).

At first, he was set on becoming a professional bass fisherman but made a practical switch to marine biology.  He took all the science electives and the hardest math classes he could.  He went on to Southampton College on Long Island, New York, where he got lots of hands-on experiences beginning in his freshman year.  He believes a good education should include lots of opportunities, as early as possible, for interactive learning in a real world environment.

Once he graduated, Adam got his dream job: working in the Gulf of Mexico during the field season and then crunching numbers the rest of the year.  He takes the data scientists collect to the SouthEast Data, Assessment, and Review (SEDAR).  SEDAR is a cooperative process through which scientists, fishermen, and policy makers look at the life history, abundance trends, and other data to determine how many fish we can catch sustainably.

Adam, and many others, also look at how catastrophic events like Hurricane Katrina and the Deepwater Horizon oil spill affect marine species in the Gulf of Mexico.  After Hurricane Katrina, he said, shrimping efforts died down by about 40%.  The effects of the oil spill are still a little murky.  Many of the biologists on board initially predicted dire and immediate effects.  Yet unlike the spill in Alaska, the warm Gulf of Mexico water is host to bacteria, plants, and other living things that might be eating up the oil.  Many questions, such as whether these living things will mitigate the effects of a spill, are still being asked. “Deepwater Horizon is always on our minds,” Adam says.  There are also naturally occurring events like harmful algal blooms and long term issues like climate change that affect fish populations.

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Oil rigs dot the horizon as Tim Martin, Chief Boatswain, gets ready to retrieve the longline. Photo: Matt Ellis/NOAA Fisheries

 

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Here, Paul Felts, Fisheries Biologist, weighs a yellowedge grouper (Hyporthodus flavolimbatus). Photo Matt Ellis/NOAA Fisheries

“Can you tell me about snapper?” I asked Adam.  Red snapper (Lutjanus campechanus), assessed every other year, is a hot button topic for commercial and recreational fishermen alike in the Gulf. The species was in decline. Recreational fishermen went from a 180 day season to catch fish to an 8 day season and from 10 to 2 fish a day per person.  Commercial fishermen weren’t happy either: they could only take 49% of the year’s quota for red snapper, while the recreational fishermen get to catch 51% of the quota.  Fairness is not just a second grade concern, it is a major sticking point in regulating fisheries world wide.

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Snapper is as tasty as it is beautiful.  Photo: Matt Ellis/NOAA Fisheries

Red snapper is a vulnerable species.  Snapper settle to the bottom of the water column from larvae.  They are at high risk of mortality from ages 0-5, the same time when they are close to human activity such as oil rigs, shrimping grounds and easy to access fishing areas.  Those who manage the fisheries are trying to get the snapper through that vulnerable stage.  Like money in the bank accruing interest, a 10 year old snapper can produce more eggs than a five year old.  Before we take snapper from the sea, we must make sure a healthy older population remains to reproduce.

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TAS Denise Harrington holds up two red snapper. Photo: Matt Ellis/NOAA Fisheries.

Once an assessment is complete, scientists determine a maximum sustainable yield:  how many fish can be taken from the population and still keep enough around to make more fish for the future.  Take a look at a shark assessment and a snapper assessment. Looking at these long and complicated assessments, I am glad we have people like Adam who is willing to patiently work with the numbers.

Gathering the best data and making it available to people who collaborate to make informed decisions is an important part of Adam’s job. We all want fish and NOAA fisheries biologists are doing their best to make that happen for us, and for generations to come.

Personal Log

My time aboard the Oregon II has come to an end.  Bundled up in my winter clothes,  I look out over a rainy Oregon landscape filled with fishermen hoping to catch a fall Chinook salmon. Two places with different weather and many different fish species.  Yet many of our challenges are the same.

Back at school, students and teachers welcome me enthusiastically.  Instead of measuring desks and books as part of our Engage NY curriculum, we measured sharks and their jaws.  Many of these students have never been out of Oregon, many have not been to the beach, even though it is only 4 miles away.  With NOAA, South Prairie Elementary students were able to learn about faraway places and careers that inspire them.

Soon these seven year old children will be in charge. I am thankful to the NOAA crews and the Teacher at Sea program staff, as they’ve prepared generations of students of all ages to collaborate and creatively face the task that lies ahead.

 

 

Denise Harrington: A Shark A Day, September 29, 2016

NOAA Teacher at Sea

Denise Harrington

Aboard NOAA Ship Oregon II

September 16-30, 2016

Mission: Longline Survey

Geographic Area: Gulf of Mexico

Date: Thursday, September 29, 2016

Science Log

The cruise is coming to a close. Looking back at my three experiences with NOAA, hydrography (mapping the ocean), fisheries lab work, or shark and snapper surveys,  I couldn’t decide which was my favorite.  Like the facets of a diamond, each experience gave me another perspective on our one world ocean.

Just like different geographic locations and work, each shark species give me a lens through which I can appreciate the mysteries of the ocean.  Every day, I held, measured, kissed, or released a different species of shark. In the Gulf of Mexico, there are 44 shark species frequently caught.  Fortunately, I saw quite a few, and will share some, in the order in which I met them.

Our first night fishing, we caught many Atlantic sharpnose sharks (Rhizoprionodon terraenovae).  They are named for their long flat snout and sharp nose. It seemed whenever we caught one, a bunch more followed. They were abundant and kept us busy.

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Paul Felts, Fisheries Biologist, records measurements while Kevin Rademacher, Fisheries Biologist, wrestles and measures the shark. Matt Ellis, NOAA Science Writer, took amazing pictures throughout the cruise.

Day two, we caught a deep water Cuban dogfish (Squalus cubensis).  

 

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The Cuban dogfish’s huge iridescent eyes were entrancing.

On September 2o, we almost caught a bull shark (Carcharhinus leucas).  We brought the cradle down, but the shark thrashed its way off, refusing to be studied. The bull shark, along with the tiger shark, are “one of the top three sharks implicated in unprovoked fatal attacks around the world.”

Within a couple days of catching the Cuban dogfish, we caught another shark with iridescent eyes. It turns out this similar looking shark was not a Cuban dogfish, but a rare roughskin spiny dogfish (Cirrhigaleus asper).  

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Dr. Trey Driggers, Field Party Chief, and prolific shark researcher, surprised us all when he reported this was the first roughskin spiny dogfish he had ever caught!

The beautifully mottled, sleek, immature tiger shark (Galeocerdo cuvier) caught on September 23 had remarkable skin patterns that apparently fade as the shark ages. Adult sharks can get as large as 18 feet and 2,000 pounds.  Along with the bull shark, it is one of the top three species implicated in unprovoked, fatal attacks worldwide.

September 24 we caught a fascinating scalloped hammerhead (Sphyrna lewini).  The flat extended head of this hammerhead is wavy, giving it the “scalloped” part of its name.  Its populations in the Gulf have drastically decreased since 1981, making it a species of concern.

 

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Here, Kevin measures one of several scalloped hammerhead sharks we caught on Leg IV of the survey.

We also caught a silky shark (Carcharhinus falciformis). Like other Carcharhinus sharks, the silky shark has a sharp “Carchar,” nose “hinus” (Greek derivation), but also has a silky appearance due to its closely spaced dermal denticles.

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I instantly felt the silky was the most beautiful shark I’d seen. Photo: Matt Ellis/NOAA Fisheries

 

We  saw two of the three smoothhound species present in the Gulf.  On September 25, we caught a Gulf smoothhound, (Mustelus sinusmexicanus), a species named less than 20 years ago. Much is left to learn about the ecology and biology of this recently discovered shark.

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Getting ready to weigh the gulf smoothhound, Kevin Rademacher, Fisheries Biologist, stops for a photo.                                                      Photo: Matt Ellis/NOAA Fisheries

Then, I watched the night crew catch, measure and tag a dusky shark (Carcharhinus obscurus).

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Photo: NOAA Fisheries

On September 26, we caught a sandbar shark (Carcharhinus plumbeus).  Despite its size,  the sandbar shark poses little threat to man.

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The sandbar shark’s large fin to body ratio and size make them a prime target for commercial fisheries. Photo: Matt Ellis/NOAA Fisheries

Due to over-fishing, sandbar shark populations are said to have dropped by as much as 2/3 between the 1970’s and the 1990’s. They are now making a comeback, whether it be from fishing regulations, or the decreased populations of larger sharks feeding on juvenile sandbar sharks.

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This sandbar shark attacked a blacknose shark that had taken our bait. Photo: Matt Ellis/NOAA Fisheries

We tagged many sharks during my two weeks on the Oregon II.  If you never catch one of those sharks again, the tag doesn’t mean anything.  But this week, we also caught a previously tagged sandbar shark!  Recapturing a wild marine animal is phenomenal.  You can learn about its migration patterns, statistically estimate population sizes, and learn much more. The many years of NOAA’s work with this species in particular demonstrates that thoughtful, long term management of a species works.

 

On September 27, we almost caught a nurse shark (Ginglymostoma cirratum). The barbels coming from its mouth reminded me of a catfish or exotic man with a mustache.

Today, September 29, was our last day of fishing, a bittersweet day for me.  That nurse shark that got away, or more likely, another one like it, came up in our cradle.

Every day we caught sharks, including a few other species not mentioned here.  Only once our line came back without a fish.  The diverse characteristics and adaptations that allow each of these species to survive in a challenging marine environment inspire biologists as they try to categorize and understand the species they research.   While catching so many different species of sharks gives me hope, many members of the crew reminisce about times gone by when fish were more abundant than they are now.

Personal Log

I am the kind of person who always struggles to return from an adventure.  I have learned so much, I don’t want to leave.  Yet I know my class at South Prairie is waiting patiently for my return. I hope to share these many marine species  with my class so that we all may view every moment with curiosity and amazement.

 

 

 

 

Denise Harrington: Spotlight on a Blacktip Shark, September 24, 2016

NOAA Teacher at Sea

Denise Harrington

Aboard NOAA Ship Oregon II

September 16-30, 2016

Mission: Longline Survey

Geographic Area: Gulf of Mexico

Date: Saturday, September 24, 2016

Yesterday, I was in the crew lounge, working on my next blog, when Eric Hoffmayer, Research Fishery Biologist, called me out to the fantail to see a large deceased female blacktip shark (Carcharhinus limbatus) brought in that morning.

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(deceased) female blacktip shark

The contrast between the gray and white skin caught my eye. The countershading, a dark grey color on top, had a light bronze hue that sparkled in the light. A white band starting at its pectoral fins widened until it merged with the belly at the anal fin.

If there is a mortality, the science team uses the opportunity to dissect the fish, collecting additional information otherwise unavailable.  When we catch a shark, we release it as quickly as possible. The urgency of getting shark back in the water keeps me from carefully studying its detailed characteristics.

While I understand the loss of this particular shark touches many of us on board, understanding the species better through the loss is a practical, necessary approach to  managing the marine environment.  Without an in depth understanding of sharks, their populations, life cycle, and reproduction, there is no way we can sustainably manage fish populations.  Some may find dissection unappealing, and for those folks you may want to skip this blog, but not without first thanking the biologists who do this work compassionately. They keep our fisheries sustainable.

I rubbed my hand from the head to the tail.  It was smooth. Rubbing from the tail to the head felt just the opposite, rough like sandpaper.  Tiny dermal denticles allow sharks to move quickly through the water, an adaptation so amazing, it was put to use by designers of swimsuits in the Olympics and engineers of Navy ships.

Eric, Adam, and Chrissy, placed the shark on the table.  Eric cut the shark and pulled out a long sack that looked like empty sausage casing. At the end of the casing was a tiny shark pup. Trey joined the crew as they took data on each of the six pups.  The shark was pregnant.

The golden colored egg casing is still about six times the size of the pup, giving it plenty of room to grow.

The golden colored egg envelope is still about six times the size of the pup, giving it plenty of room to grow.

 

Here, Trey stretches out the casing demonstrating the significant amount of room left for the pup to grow,

Here, Fisheries Biologist Eric Hoffmayer stretches out the egg envelope demonstrating the significant amount of room left for the pup to grow. In the background you can see the egg envelop of another pup stretching across the table.

From the number of pups in a brood, to the possibility of immaculate shark conception, the reproduction of blacktip sharks is of interest to fishery biologists.  Without knowing all about shark reproduction, how many, and where sharks reproduce, we cannot sustainably manage this species, or fisheries in general.

Trey takes me through each stage of reproduction. The blacktip shark is viviparous, like humans. They are born alive, “vivi,” and develop within the mother getting nutrients through a placenta.

life-cycle-diagram

 

Egg

The shark life cycle begins in the female shark’s ovary with an egg.   Trey hands me an ovary that holds the eggs.  It is a large sack of many small red pinpoint size spheres with about 6 larger marble like balls from the high in the body cavity. These eggs wait to mature until the conditions are ideal for reproduction. At that time, the follicle ruptures, and the egg comes out.

Shark eggs are fertilized inside the female’s body.  The male fills his siphon sacs with seawater, and then flexes his abdomen to shoot the seawater and semen into the female shark through his clasper.

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Now I understand why we spin the clasper of a male shark to determine its maturity.  I was able to rotate this male Gulf smoothhound shark (Mustellus sinusmexicanus) clasper 180 degrees and reported it as an adult male.

Embryo/Pup

The male blacktip shark is often ready to mate in April to May but the females are often not ready to reproduce until June or July.  With many sharks, blacktip sharks included, the sperm can remain inside the female until she is ready to reproduce.  When that moment arrives, the egg slips through the ostium, down the anterior oviduct, and into the oviducal gland where it is fertilized by the sperm. For the blacktip shark, usually 4-6 eggs will be fertilized and develop into shark pups.  Females usually reproduce every other year.

 

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Note that different sharks have different modes of reproduction.  For example, Cuban dogfish (Squalus cubensis) reproduce through aplacental viviparity or ovoviviparity. The tiny pups you see here nourish themselves with the yolk “ovo” and have no placental connection to their mother.  They are born live “vivi,” and able to feed and protect themselves. Some sharks are oviparous, which means they lay eggs  that hatch later.

Initially,  the blacktip shark embryo uses the nutrients from a yolk sac for about 10-11 weeks. For the remaining time inside the mother, the pup increasingly gets nutrients from the mother through a placenta.  They are viviparous and remain inside the mother for approximately 10 months until they can survive on their own.  I held a pup, still connected to its mother by the umbilical cord. The similarities between human reproduction and blacktip shark reproduction surprised me so much I began to question the classification of viviparous sharks as fish.

 

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I held a pup, still connected to its mother by the umbilical cord.

Immature Shark/Juvenile

For approximately two months after it is born, the immature shark has an umbilicus (like a bellybutton) that is still open.  During this phase of the life cycle it is called a neonate, or newborn.  It is otherwise just like a miniature adult blacktip shark.  It can hunt and hide from predators (including its mother).

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Here, Eric and Evan Pettis, Texas Parks and Wildlife Fisheries Biologist, tag, measure, and release an immature blacktip shark.

 Mature Shark/Adult

Individual sharks even within a species mature at different rates, just like humans.  Generally, a male blacktip shark matures between 4-5 years of age, and females between 7-8 years.

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This 1385 mm male mature blacktip shark was brought in our second day of the survey.

How does the shark’s life cycle affect fisheries?

Evolutionarily speaking, placental viviparity gave the blacktip shark and others like it an advantage; the shark is born able to survive independently.  But this adaptation has also has a downside:  the females only produce a small brood, unlike other fish that use broadcast fertilization.

During gestation, the female shark we caught most likely migrated to our current location just off the coast of the Mississippi from deeper waters.  Called the Fertile Fisheries Crescent, the Mississippi Sound is one the most productive seafood areas in the nation.  Another risk to this species is pollution and over-fishing in the fragile estuarine habitat, the juvenile shark’s nursery.

There is demand for the high quality blacktip shark meat, the fins, and even the carcasses for fishmeal. The work NOAA Fisheries does to collect information about shark populations over time and over a wide geographic area not only helps keep blacktip shark populations sustainable, it also gives us valuable information about the ocean’s health in general.

 

Personal Log

Today I reached the half way point in my time on the longline crew.  I finally feel like I am getting into the groove, finding my way around the ship, and meeting people beyond my fishing buddies.  Valerie  McCaskill, Chief Steward, and her cousin, Ava Speights cook amazing seafood, grilled veggies, and au gratin everything. Ava showed me a great piece of exercise equipment, Jacob’s Ladder, to allow me to enjoy the great food guilt free.

Each station, each day, a new adventure.

Denise Harrington: First Day Jitters, September 21, 2016

NOAA Teacher at Sea

Denise Harrington

Aboard NOAA Ship Oregon II

September 16-30, 2016

Mission: Longline Survey

Geographic Area: Gulf of Mexico

Date: Wednesday, September 21, 2016

My first day on the longline cruise seems so long ago with three days of work under my belt. The night before my first shift, just like when school starts, I couldn’t sleep. Trying to prepare was futile. I was lost, lost in the wet lab, lost in my stateroom, lost in the mess. I needed to get some gloves on and get to work, learning the best way I know how: by doing.

At noon, I stepped out the fantail, life vest, gloves, hard hat, and sunscreen on, nervous, but ready to work. The Gulf of Mexico horizon was dotted with oil rigs, like a prairie full of farmhouses. Heat waves rose from the black deck.

Fifteen minutes before arriving at our first station, our science team, Field Party Chief Dr. Trey Driggers, Field Biologist Paul Felts, Research Biologist Kevin Rademacher, NOAA Science Writer Matt Ellis, and I began to prepare for our first station by baiting the hooks with mackerel (Scomber scombrus). I learned quickly that boots and grubby clothes are ideal for this task.

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Once all the hooks were baited, Chief Boatswain Tim Martin and Paul release a high flyer, a large pole with a buoy at the bottom and a reflective metal flag on top.

The buoy, connected to the boat by the longline, bobbed off toward the horizon.

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Tim attached the first of three weights to anchor the line to the sea floor.

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As the longline stretched across the sea, Kevin attached a numbered tag to the baited hook held by Paul.

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Paul passed the baited, tagged hook to Tim, who attached 100 hooks, evenly spaced, to the one mile longline.

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On another station, Paul attached numbers to the gangion (clip, short line, and baited hook) held by Trey.  Each station we change roles, which I appreciate.

Setting the longline is rather predictable, so with Rush and Van Halen salting the air, we talked about our kids, dogs, riots in the news, and science, of course. The tags will help us track the fish we catch. After a fish is released or processed, the data is entered in the computer and shared with the scientific community. Maybe one of these tagged fish will end up in one of the many scientific papers Trey publishes on sharks each year.

The line soaked for an hour waiting for snapper, tilefish, eels, sharks, and other fish to bite. While the line soaked, Mike Conway, skilled fisherman, and I lowered the CTD, a piece of equipment that measures conductivity (salinity), temperature, and depth, into the water.  Once the biologists know how salty, cold, and deep the water is, they can make better predictions about the species of fish we will find.

We attached a bag holding a few Styrofoam cups to see how the weight of the water above it would affect the cup.  Just imagine the adaptations creatures of the deep must have developed to respond to this pressure!

The ship circled back to hook #1 to give each hook equal time in the water. After an hour, we all walked up to the well deck, toward the bow or front of the ship. We pulled in the first highflyer and weight.  We pulled in the hooks, some with bait, and some without.  After 50 hooks, the middle weight came up. We still didn’t have a fish.  I began to wonder if we’d catch anything at all.  No data is still data, I thought. “Fish on eighty three!” I heard someone yell.   I wake from my reverie, and get my gloves on.

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It was a blacknose shark (Carcharhinus acronotus), “pound for pound, the meanest shark in the water,” says Trey. He would know, he’s the shark expert. It came up fighting, but was no match for Kevin who carefully managed to get length, weight, and sex data before releasing it back into sea.

With one shark to process, the three scientists were able to analyze the sexual maturity of the male blacknose together. I learned that an adult male shark’s claspers are hard and rotate 180˚, allowing them to penetrate a female shark. An immature shark’s claspers are soft and do not rotate. For each male shark, we need to collect this data about its sex stage.

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Here, you can see Trey rotating the clasper 180 degrees.

Later, Paul talked about moments like these, where the field biologists work side by side with research biologists from all different units in the lab.  Some research biologists, he notes, never get into the field.  But Kevin, Trey, and others like them have a much more well-rounded understanding of the data collected and how it is done because of the time they spend in the field.

Fortunately, the transition from inexperienced to novice was gradual. The second line was just as easy as the first, we only brought in two fish, one shark and one red snapper (Lutjanus campechanus).

For the red snapper, we removed the otoliths, which people often call ear bones, to determine age, and gonads to determine reproductive status.  I say “we” but really the scientists accomplished this difficult feat. I just learned how to process the samples they collected and record the data as they dissected the fish.

We set the longline a third time. The highflyer bobbed toward the orange sun, low on the horizon. The ship turned around, and after an hour of soaking, we went to the well deck toward the front of the ship to pull in the longline.  The sky was dark, the stars spread out above us.

“One!” “Three!” “Seven!” “Nine!”  The numbers of tags with fish on the line were being called out faster than we could manage.  It seemed like every other hook had a shark on it.  Two hours later we had collected twenty-eight Atlantic sharpnose (Rhizoprionodon terraenovae) sharks and had one snapper to process. Too busy working to take pictures, I have nothing to document my transition from inexperienced to novice except this data sheet.  Guess who took all this data? Me!

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Personal Log

NOAA Ship Oregon II is small, every bunk is filled.  I share a stateroom with the second in command, Executive Officer (XO) Lecia Salerno, and am thankful she is such a flexible roommate, making a place for me where space is hard to come by.

Last night, as I lay in my bunk above XO Salerno and her office, I felt like Garth on Wayne’s World, the thought that “I’m not worthy” entering my head.  All members of the crew are talented, experienced, and hard-working, from the bridge, to the galley, to the engine room, and out on the deck where we work. I’ve made a few mistakes.   I took the nasty thought and threw it overboard, like the slimy king snake eels (Ophichthus rex) we pull from the deep.

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King Snake Eel (Ophichthus rex)

In the morning I grabbed a cup of coffee, facing the risk of being the least experienced, slowest crew member to learn, with curiosity and perseverance.  First day jitters gone, I’m learning by doing.