sharpnose shark – Page 2 – NOAA Teacher at Sea Blog

NOAA Teacher at Sea
Julie Karre
Aboard NOAA Ship Oregon II
July 26 – August 8, 2013

Mission: Shark and Red snapper Longline Survey
Geographical Range of Cruise: Atlantic
Date: Tuesday, July 30, 2013

Weather Data from the Bridge
SW WINDS 5 TO 10 KNOTS BECOMING SE IN THE AFTERNOON
SEAS 2 TO 3 FEET WITH A DOMINANT PERIOD 14 SECONDS
SLIGHT CHANGE OF SHOWERS AND THUNDERSTORMS

Science and Technology Log

Preparing for a haul back. Everyone wears a PFD (personal flotation device) during a haul and a helmet if the cradle is used.

What an incredibly fast-paced morning/end of shift for the night shift! As the day shift was getting up and wandering out to check in, the night shift was putting out their first set of the cruise. Day shift, which I’m on, put out two sets the afternoon/night before. Night shift had to skip two last night because of the current. But this haul back made up for it. The crew processed 64 sharks – Sharpnose and Blacknose – at a swift, demanding pace. It was a learning experience to see them handle it so calmly, never missing a beat.

Night shift volunteers Page Vick and Claudia Friess work together to remove a hook. — Night shift volunteers Page Vick and Claudia Friess work together to remove a hook while Ian Davenport records the data.

Night Shift Watch Leader and NOAA scientist Lisa Jones takes a Sharpnose Shark from a fisherman. — Night Shift Watch Leader and NOAA scientist Lisa Jones takes a Sharpnose Shark from a fisherman and removes its hook.

A weighed, measured, sexed shark is released to the ocean.

At noon it was our turn and by 2pm we were putting out the first of three hauls we would do that day. That first haul brought up 56 sharks in just over an hour’s time. I was recording the data as measurements were taken. We brought up Sharpnose Sharks and Blacknose Sharks. It has been such an eye-opening experience bringing up sharks these last two days because it is so easy to imagine sharks as being enormous and ferocious, which of course some are, but we are bringing up sharks that, for the most part, can be held up with one hand and weigh less than 4.5kg. I think it is important to remember that the images of The Great White and Bull Sharks are not necessarily representative of all sharks. That doesn’t mean that these smaller sharks are not dangerous, it just means they’re not enormous and overwhelming.

Volunteers Holly Perryman and Kevin Travis handle sharks as I record the data. Photo Credit: Claudia Friess

We had just enough time to rebait the hooks and hang out for a few minutes before we set out another set 9 miles later. That haul back was light, but did come with a Scalloped Hammerhead. When we get these large sharks (Nurse, Tiger, Hammerhead, Sandbar), it requires a large cradle attached to a crane. The cradle is lowered into the water and the shark is led on with the line attached to the hook. This requires a lot of precise coordination. The person operating the crane cannot see the shark and is then dependent on those at the opening to be clear and loud with directions. Two people hold ropes that stabilize the cradle. They have to stay in sync so that the moving shark doesn’t throw itself over a side, while another person is trying to control the shark with the line attached to the hook. It’s really incredible to watch this team of skilled fishermen and scientists work so quickly with such a large animal. Each large animal is measured, weighed, tagged, and a small tissue sample is taken. Then the cradle is lowered and it swims gracefully away.

It's Hammer time! This Scalloped Hammerhead was very exciting. Photo Credit: Claudia Friess — It’s Hammer time! This Scalloped Hammerhead was very exciting. Photo Credit: Claudia Friess

A quick dinner later and then we set out what ended up being our last set around 9:30 pm. At 10:50 pm we began our haul back, which was light on Sharpnose and Blacknose. We got a few and they were small, but the real treat was hauling up 4 Sandbars. Of the 4, we brought up 2 because the other 2 got away. The Sandbar is a really beautiful shark. It has a high first dorsal fin and is one of the largest coastal sharks in the world. According to Chief Scientist Kristin Hannan, the Sandbar’s large fin makes it more desirable by fishermen harvesting fins. Having seen these large, but gorgeous, animals and how gracefully they swim makes me sad that they would be desirable for such an unsustainable practice. Fortunately, in 2008 the National Marine Fisheries Service banned all commercial landings of Sandbar Sharks. The Sandbar is currently listed as a vulnerable species due to overfishing.

Kristin Hannan measuring a Sandbar Shark in the cradle.

This haul back gave me a unique perspective. In previous hauls I’d been over where the fish are measured, weighed, and data recorded. But this time I was racking hooks as they came back, which means that I was just below the window where NOAA Corps Officer ENS Rachel Pryor was driving the ship. This is ENS Pryor’s first longline survey and she said it’s the survey that has the deck and bridge the most connected. Because we’re pulling up animals from a bottom longline, the control of the ship is crucial. The driver must control the ship on station making sure it doesn’t drift over the longline and in those instances of bringing up big sharks on the cradle, he or she keeps us on the station so there isn’t too much tension on the line. Whether it’s ENS Pryor, another NOAA Corps officer, or the Captain, Master Dave Nelson, he or she is just as essential to the survey as the people handling the sharks. Truly a team effort.

The set ended right at a shift change and we were lucky to make that switch on a light haul. Most of the hooks came up empty, including emptying of our bait, so something down there enjoyed an easy free meal.

I took the opportunity to watch the stars for a while before heading to bed. I was not disappointed.

Personal Log

During those first three days of no fishing, much reading was done. I finished a book on Sunday and am waiting to start my other book since I only brought two, but others on the ship have been reading a lot during breaks. At least two people have read the entire Hunger Games Trilogy while on board. It should come as no surprise to my students that this makes me VERY happy. The seventh and eighth graders of Armistead Gardens will be returning to school in August for a Hunger Games semester. The eighth graders read the first book before we left school last year, so we are set to keep reading. The seventh graders begin the Games when we meet in August.

Ladies and Gentlemen, let the 19th Longline Games begin! — Ladies and Gentlemen, let the 19th Annual Longline Games begin! Volunteers Claudia Friess and Mike Hendon devouring the Hunger Games trilogy. Both have started and finished the series since we departed Pascagoula.

BOOK REPORT:

I finished the debut novel by Carrie Mesrobian, which is scheduled to be released this fall. I began reading on Thursday the 25^th when I moved onto the ship, but I had to slow myself down because I only have one other book. So I paced it enough to give me a few more days of pleasure. And what a pleasure it is to read such a raw and real book. I read a lot of young adult fiction, mostly for pleasure and sometimes to know what my students are in. I love what young adult literature offers readers in terms of dealing with certain experiences. I have not read many young adult novels written from the male perspective, though. I know there are many, but I have not done a very good job of getting into them. I loved reading Evan. His self-loathing was so real that I was immediately on his side. I thought the sensitive subject matter was handled realistically and appropriately. Well done. Can’t wait to read it again.

An exquisite sunset at the end of a beautiful day.

Did You Know?

I learned this from a science teacher at Armistead Gardens Elem/Middle school – there are FOUR meteor showers peaking last night and tonight – Piscis, Austrinids, Aquariids, and Capricornids. Maybe some of my “shooting stars” were from these meteor showers. Thanks Ms. Palmisano for sharing your knowledge!

This is the 19^th year of doing the Shark and Red Snapper Longline Survey. That’s a lot of data!

Animals Seen

Sharpnose, Rhizoprionodon terraenovae
blacknose, Carcharhinus acronotus
Sea Nettle, Chrysaora quinquecirrha
Sandbar, Carcharhinus plumbeus
Scalloped hammerhead, Sphyrna lewini

Seastar

Volunteer Kevin Travis with a starfish that came up on a clip. Photo Credit: Claudia Friess

NOAA Teacher at Sea
Steven Frantz
Onboard NOAA Ship Oregon II
July 27 – August 8, 2012

Mission: Longline Shark Survey
Geographic area of cruise: Gulf of Mexico and Atlantic off the coast of Florida
Date: August 3, 2012

Weather Data From the Bridge:
Air Temperature (degrees C): 28.79
Wind Speed (knots): 14.14
Wind Direction (degree): 199.05
Relative Humidity (percent): 070
Barometric Pressure (millibars): 1017.95
Water Depth (meters): 58.0
Salinity (PSU): 35.635

Location Data:
Latitude: 3409.72N
Longitude: 17611.11W

SHARKS AT SEA

Our 300^th mission aboard the Oregon II is a Longline Shark Survey. Stratified randomly selected sites have been generated using Arc GIS Software. This eliminates potential bias in sampling and each area has an equal opportunity to be sampled. Two depth strata zones (A: 5-30 fathoms, B: 30-100 fathoms) have been factored for the Atlantic. In order to avoid all sampling sites randomly bunched all together, the area has been divided into 60 nautical mile geographic zones from southern Florida to North Carolina. 60% of our effort (ex. time at sea) is put toward “A” stations and 40% of our effort is put toward “B” stations. This method of picking stations is called proportional allocation.

We are here to find sharks. This is important because so very little is known about them, or many of the other animals living in an extreme environment (extreme for people to live in).

One if the first sharks we caught was a blacknose shark, Carcharhinus acronotus. It is relatively small, a uniform gray color, and has a black tip on its nose.

The most common shark found so far has been the sharpnose shark, Rhizoprionodon terraenovae. Both sharpnose and blacknose sharks are considered to be small coastal sharks by the National Marine Fisheries Service. While similar in size to the black nose shark, the sharpnose shark is spotted. When brought on board, their size is nothing compared to their strength. I guess you have to act tough when you’re little!

Tough though they may be, we caught several sharp-nose sharks that have become bait themselves! I wonder what (kind of shark?) it was that ate the back half of this sharp-nose?

One of the many data we are collecting is the sex of the sharks. Pictured below are a male (top), then female (bottom). The male shark has claspers, which are used for internal fertilization. Claspers are also used to determine a male’s age depending on how calcified they are. This is the standard way to determine sex on all the sharks we have caught thus far.

Another piece of data collected is a clip of flesh from a fin. This is a non-lethal way for scientists to obtain DNA for genetics studies and possibly for use in population structure for identification purposes.

As we saw above, some sharks don’t make it on board alive. While this is uncommon, the opportunity does present itself for more invasive study not done on living animals. Sharpnose sharks give birth to live young (viviparous). Pictured below are young sharks taken from a female. It is interesting to note that whether the shark is male or female can be determined at this early stage. Remember, not all sharks reproduce this way.

Sandbar sharks, Carcharhinus plumbeus, have been the next most common sharks caught. These are quite a bit larger than sharp-nose sharks, averaging 150 centimeters long and 35 kilograms in mass.

We must be safe when collecting data. Shark’s skin is like sandpaper, so if the teeth or tail doesn’t get you, you can also be given a pretty red rash by the scrapping of their skin against your skin.

Sandbar sharks were popular with the shark fin soup industry because they have a very large dorsal fin compared to their body size. Sharks were caught, their fin was cut off, and then the still-living shark was released back into the ocean to die. This practice has been outlawed in U.S. waters.

Watch the video below as a sandbar shark is caught and brought to the Oregon II.

The prettiest shark (at least to me) I’ve seen so far is the tiger shark, Galeocerdo cuvier. They can get very large. Three meters long or more! The ones we’ve found have been smaller. The one I’m holding is very young. The umbilical scar was still visible! Tiger shark teeth are different from most sharks in that a tiger shark’s teeth are made to slice their prey, like the shells of sea turtles.

Sharks don’t have eyelids, like we have eyelids, to protect their eyes. They have what is called a nictitating membrane to protect their eyes. Here is a picture of the nictitating membrane partially covering a sharpnose shark’s eye.

The most unusual shark we’ve caught has been the scalloped hammerhead shark, Sphyrna lewini. Once on board the Oregon II they seemed to be docile (for a shark), however, their eyes on the far ends of their head were always looking, watching what was going on.

Why is their head shaped like it is? Even scientists don’t know for sure. Some think it acts as a hydrofoil to help it move through the water. Other scientists think (because of its large size) it helps detect electrical impulses in the water (like a sixth sense). Do you have any ideas why their head is shaped the way it is?

Scalloped Hamerhead Shark — Scalloped Hammerhead Shark

I have been working the day shift: from noon to midnight. The other crew is the night shift. In addition to what we have seen so far, the night shift has also seen a great hammerhead, Sphyrna mokarran and a silky shark, Carcharhinus falciformes.

We still have five days of fishing left. What will we catch next? I’ll let you know!

Tag: sharpnose shark

Julie Karre: Let’s Haul it Back Now, Ya’ll! July 30, 2013

Steven Frantz: Sharks at Sea, August 3, 2012