sandbar shark – Page 2 – NOAA Teacher at Sea Blog

October 1, 2016August 21, 2021

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.

p1080163 — 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).

p1090143 — 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.”

Photo: Matt Ellis/NOAA Fisheries

Photo: Matt Ellis/NOAA FIsheries

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).

p1080318 — 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.

Paul Felts, Fisheries Biologist, measures the tiger shark’s length. Photo: Matt Ellis/NOAA Fisheries

Then, I release it. Photo: Matt Ellis/NOAA Fisheries

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.

The scalloped hammerhead’s flat extended head is called a cephalofoil. Photo: Matt Ellis/NOAA Fisheries

It’s name comes from the dents, giving the cephalfoil a scalloped appearance. Photo: Matt Ellis/NOAA Fisheries

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.

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.

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).

OLYMPUS DIGITAL CAMERA — Photo: NOAA Fisheries

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

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.

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.

Recaptured sandbar shark

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.

Photo: Matt Ellis/NOAA

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.

The team works quickly. Here, Tim Martin, Chief Boatswain, maneuvers the shark so measurements can be taken. Photo: Matt Ellis/NOAA Fisheries

The hook is then quickly removed and the shark is back in the water within a couple minutes. Photo: Matt Ellis/NOAA Fisheries

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.

Every day was this beautiful. Here I am on the bow, soaking it up. Photo: Kevin Rademacher

This small barracudina captured my attention just as much as the large Sandbar shark.. Photo: Matt Ellis/NOAA Fisheries

I was learning, whether I was crunching numbers or wrestling sharks. Photo: Matt Ellis/NOAA Fisheries

The leech would rather stick to a shark than me. Photo: Matt Ellis/NOAA 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.

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?

July 18, 2015August 21, 2021

Chris Sanborn: Last Day Shark Tagging, July 17, 2015

NOAA Teacher at Sea
Christopher Sanborn
Aboard SRV C.E Stillwell
July 13 – 17, 2015

Mission: Cooperative Atlantic States Shark Pupping and Nursery (COASTSPAN) survey
Geographical area of cruise: Delaware Bay
Date: July 17, 2015

Weather

Day 3 weather was Hazardous with gusts up to 20 knots. Travel in the small C.E Stillwell not advisable.

Day 4 was beautiful and started out with light to variable winds with 0-1 ft seas and ended with 5-10 knots winds with 2-3 ft seas.

Science and Technology Log

Day 3 we attempted our usual 6:00 a.m. departure but after entering the bay it was obvious the working conditions attempting to tag sharks in our small boat would be almost impossible. We monitored the weather for a possible late morning departure but the weather only increased. We set ourselves to remarking the intervals on the mainlines as the markings were very faint and difficult at times to see where to set the gangion.

Ben Church and Matt Pezzullo remarking the thousands of feet of line.

Day 4 We were on the water and had our first line (set) in the water before 7:00 a.m. The conditions were great and we started right outside of Lewes, DE. In the morning we did 3-50 hook sets and 1-25 hook set in what is called deep hole which is on the Delaware side of the main shipping channel that runs through Delaware Bay.

One of the numerous large ships heading up Delaware Bay

As you can see by the picture numerous large ships enter the mouth of the bay and head up.

While we were pulling the line on the deep hole set this large Sand Tiger came to the surface after a lot of hard work by Matt.

At the end of the day we were able to complete a total of 8 sets. After finishing deep hole we spent the afternoon on the New Jersey side of the bay just off Cape May. As can be seen by the July 2015 stations Day 4 was spent at the mouth of the bay. On the Delaware side we did JY10, JY27, JY28 and Deep Hole. All JY sets are 50 hook sets while all others are the larger hooks with 25 per main line.

During the afternoon we did JY26, JY18, EX06 followed by JY19. The order may seem odd looking at the map but sets are planned to ensure that they are retrieved in the correct time frame. JY18 was just off Sunset Beach in Cape May New Jersey.

Day 1 sets: JY24, JY20, JY22, BG02, SB01, SB02

Day 2 sets: JY07, JY01, JY11, JY13, EX04, ST05, EX07

Day 4 sets: JY10, JY28, JY27, Deep Hole, JY26, Jy19, JY18, EX06

The following video is from day 1 but gives an idea of how hard it can be to tail rope the sharks.

Once a shark is tail roped and the gangion is cleated to the front of the boat we can collect the biological data and tag the shark.

The following video is long but if you watch to the end you will see what happens when a hook comes out while a shark is still tail roped.

We also had the opportunity to encounter a few rays. The following video is of a large Spiny Butterfly Ray we caught

Personal Log:

The shark tagging experience was extremely physically taxing but very rewarding. I had the opportunity to gain hands on experience in an exciting research project that will allow me to bring knowledge and excitement back to my classroom. My time working on this survey brought me a memorable experience that I will never forget.

I would personally like to thank the other scientists on the survey Nathan Keith, Ben Church and the Chief Scientist on the cruise Matt Pezzulo for sharing their expertise and knowledge on shark morphology and identification. These individuals were always willing to explain any part of the process or answer any questions I had. They took the time to teach me every part of the process early on so that I could become a contributing member from the start. This type of analysis on sharks takes grit and hard work and I appreciate the opportunity I was given through the Teacher at Sea Program.

August 4, 2014August 21, 2021

Lynn Kurth: Chomp Chomp! August 4, 2014

NOAA Teacher at Sea
Lynn M. Kurth
Aboard NOAA Ship Oregon II
July 25 – August 9, 2014

Mission: Shark/Red Snapper Longline Survey
Geographical area of cruise: Gulf of Mexico and Atlantic
Date: August 4, 2014

Lat: 33 54.763 N
Long: 076 24.967 W

Weather Data from the Bridge:
Wind: 16 knots
Barometric Pressure: 1017.74 mb
Temperature: 29.9 Degrees Celsius

Science and Technology Log:

IMG_2927[1] — Mouth of a sandbar shark. Notice the rows of teeth and don’t worry about the wound from the hook because the hook is carefully removed and the shark heals quickly.

Much to my surprise a sandbar shark will have around 35,000 teeth over the course of its lifetime! Similar to other species of sharks, a sandbar shark’s teeth are found in rows which are shed and replaced as needed. The teeth are not used to chew but rather to rip food into chunks that the shark can swallow. The shape of a shark’s teeth depends on the species of shark they belong to and what that particular species eats. For example, a tiger shark has razor sharp piercing teeth it uses to rip apart the flesh of its prey and a zebra shark has hefty flat teeth because it eats shellfish.

IMG_2929[1] — Great care is taken to remove the hook before the sandbar shark is released. By clipping the barb off, the hook will slide right out. And, if a tooth happens to get damaged it will be quickly be replaced when a new row of teeth moves forward.

Did you Know?

When sharks are born they have complete sets of teeth
It was recently discovered that shark teeth contain fluoride
Human teeth and shark teeth are equally as hard
Shark teeth are not attached to gums on a root like our teeth

IMG_3010[1] — Lynn Kurth getting ready to measure a silky shark before it is released.

Personal Log:

Through the years I have found that when I am doing something I love I usually meet people who I respect and find intriguing. I love being part of science at sea aboard the Oregon II and I’m not surprised that I have met several people who are passionate about issues that I find interesting. One such person is Katelyn Cucinotta, a member of my work shift, who has a passion for the proper care of the marine environment and what she aspires to do in the future to make that happen. Within minutes of meeting Katelyn she began educating me about the decline of several shark species and the difficulties marine life faces with the amount of man-made debris in our oceans. Katelyn co-founded an organization called PropheSEA in order to share information about the issues our oceans and marine species are currently facing.

IMG_3032[1] — Science at sea with Katelyn Cucinotta!