Lynn Kurth: It’s Shark Week! July 31, 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:  July 31, 2014

Lat: 30 11.454 N
Long: 80 49.66 W

Weather Data from the Bridge:
Wind: 17 knots
Barometric Pressure:  1014.93 mb
Temperature:  29.9 Degrees Celsius

Science and Technology Log:
It would be easy for me to focus only on the sharks that I’ve  encountered but there is so much more science and natural phenomena to share with you!  I have spent as much time on the bow of the boat as I can in between working on my blogs and my work shift.  There’s no denying it, I LOVE THE BOW OF THE BOAT!!!  When standing in the bow it feels as if you’re flying over the water and the view is splendid.

BOW

My Perch!

From my prized bird’s eye view from the bow I’ve noticed countless areas of water with yellowish clumps of seaweed.  This particular seaweed is called sargassum which is a type of macroalgae found in tropical waters.  Sargassum has tiny chambers which hold air and allow it to float on or near the water’s surface in order to gather light for photosynthesis.  Sargassum can be considered to be a nuisance because it frequently washes up on beaches and smells as it decomposes.  And, in some areas it can become so thick that it reduces the amount of light that other plant species need to grow and thrive. However, the floating clumps of sargassum provide a great habitat for young fish because it offers them food and shelter.

IMG_2826

Sargassum as seen from “my perch”

IMG_2906[1]

Sargassum (notice the small air bladders that it uses to stay afloat)

We have hauled in a variety of sharks and fish over the past few days.  One of the more interesting species was the remora/sharksucker.  The sharksucker attaches itself to rays, sharks, ships, dolphins and sea turtles by latching on with its suction cup like dorsal fin.  When we brought a sharksucker on board the ship it continued to attach itself to the deck of the boat and would even latch on to our arm when we gave it the chance.

IMG_2944[1]

The shark sucker attaches to my arm immediately!

The largest species of sharks that we have hauled in are Sandbar sharks which are one of the largest coastal sharks in the world.  Sandbar sharks have much larger fins compared to their body size which made them attractive to fisherman for sale in the shark fin trade.  Therefore, this species has more protection than some of the other coastal shark species because they have been over harvested in the past due to their large fins.

Thankfully finning is now banned in US waters, however despite the ban sandbar sharks have continued protection due to the fact that like many other species of sharks they are not able to quickly replace numbers lost to high fishing pressure.  Conservationists remain concerned about the future of the Sandbar shark because of this ongoing threat and the fact that they reproduce very few young.

IMG_2928[1]

The first Sandbar shark that I was able to tag

Did you Know?

Sargassum is used in/as:

  • fertilizer for crops
  • food for people
  • medicines
  • insect repellant

Personal Log:
I continue to learn a lot each day and can’t wait to see what the next day of this great adventure brings!  The folks who I’m working with have such interesting tales to share and have been very helpful as I learn the ropes here on the Oregon II.  One of the friendly folks who I’ve been working with is a second year student at the University of Tampa named Kevin Travis.  Kevin volunteered for the survey after a family friend working for NOAA (National Oceanic and Atmospheric Administration) recommended him as a volunteer.  Kevin enjoys his time on the boat because he values meeting new people and knows how beneficial it is to have a broad range of experiences.

 

IMG_2798

Kevin Travis

Heather Diaz, July 12, 2006

NOAA Teacher at Sea
Heather Diaz
Onboard NOAA Ship David Starr Jordan
July 6 – 15, 2006

Mission: Juvenile Shark Abundance Survey
Geographical Area: U.S. West Coast
Date: July 12, 2006

Science and Technology Log 

There was no swordfish, set done last night because of our excursion to Catalina Island.  Instead, we set our first line (shark line) at 6am.  We hauled in the line around 10am.  We caught 10 makos, 4 blues, 1 lancetfish, 3 pelagic rays, and 2 molas.  I had the opportunity to videotape the entire haul, which turned out to be one of our most productive.  1 mako died today during the haul because it had swallowed the hook and most likely suffered an internal injury. He was measured, weighed, and dissected for further research.  One of the makos we caught during this set was among the largest three we caught during this entire leg, and it was really interesting to see such a large shark, so close! We set our second line at around 12 noon.  We hauled it in around 4pm. We caught 7 makos and 2 blues.  Two of the makos we caught during this set were among the largest three we caught during this entire leg.

This Mako shark didn’t survive being on the longline. The coloring of the shark is truly beautiful, and their skin is very smooth in one direction, and like sandpaper in the other.  If you look closely, you can see little spots on his nose, which are actually part of his hunting and defense mechanism, and he is able to “detect” things in the water from a long way. Makos don't have a protective “eyelid”, unlike Blue sharks. Karina and João have helped to preserve the jaw, and I cannot wait to show it to my students!

This Mako shark didn’t survive being on the longline. The coloring of the shark is truly beautiful, and their skin is very smooth in one direction, and like sandpaper in the other. If you look closely, you can see little spots on his nose, which are actually part of his hunting and defense mechanism, and he is able to “detect” things in the water from a long way. Makos don’t have a protective “eyelid”, unlike Blue sharks. Karina and João have helped to preserve the jaw, and I cannot wait to show it to my students!

Personal Log 

With our first set, things started off right off the bat with several makos.  Then, we got 2 humongous Sunfish (mola-mola)…and I mean they were huge! Then, we got a huge mako.  He was almost 2 meters long.  It was as long as the cradle itself! I couldn’t believe it.  Everyone was super excited and at that point. During the whole commotion, one mako was pulled over the side nearly dead.

We also had a lancet-fish which they hauled over the side while we were dealing with the monster mako in the cradle….and that was very much alive.  It was flipping all over the place.  Sean picked him up, took the hook out, and tossed it overboard. After we were all done and all the animals had been processed, we went over to look at the mako that they had brought on deck.  Although the mako was near death, it appeared to be still breathing a little, though it might have been a lingering reflex reaction.  After examining him on the deck, they weighed him and then started to dissect him. I have most of the dissection on tape.  It was very interesting to see where all the internal organs are located and to see how their muscle tissue is designed. Dr. Heidi Dewar explained how they use their muscle tissue design to actually preserve body heat. It was really fascinating.  I am excited to show my students her “lecture” on the muscles, and to share with them the dissection video, so that they can see what a shark looks like on the inside.  I think they will enjoy it.

During the second set, I was allowed to get down on the platform with the first two sharks…the first one, Dr. Suzy Kohin, Chief Scientist just explained everything.  The second one, I was able to get in there and actually do the stuff!  I collected the DNA sample of his dorsal fin…I put the tag in his dorsal fin…and, I gave him a shot of OTC in the ventral area. I also got to take its length measurement, which was freaky because I had to grab its tail and pull it straight. I don’t think the shark appreciated that much, and he squirmed a bit.  He was also bleeding. Dr. Suzy Kohin, the Chief Scientist, said that he was bleeding a bit because he had swallowed the hook.  I opted not to do the spaghetti tag (which involves shoving this metal tip into their skin) and I opted not to cut the hook out of its mouth,.…it just seemed really, really, really REAL…and I didn’t want to mess up and come out of it missing a hand or something…or worse, having unintentionally hurt the animal.

Anyhow, I gave my kneepads over to Daniele who jumped in and finished the haul for me on the platform while I did the gangions.  Which, turned out to be too bad, since we got some really huge makos on this haul…everyone was very excited about them.  I think the largest was about 197cm.  They put special tags in the really large makos, which they called a PAT (Pop-Up Archival Tag).  They explained that these tags, which look more like turkey basters, are used to report data on temperature, depth, and even longitude so that they can better track the makos and learn more about their behaviors. They are especially looking for information about diving behaviors and their temperature and depth preferences.  I would love to see what they find out from these fish!

They also use a SPOT (Smart POsition and Temperature) tag.  This is almost translucent and is bolted the dorsal fin (only on larger sharks).  It looks a little like a computer mouse and is oval shaped. This tag sends radio signals to a satellite whenever the animal is near the surface, and they can use this information to track precisely where the animal is in the ocean.

Heather Diaz, July 10, 2006

NOAA Teacher at Sea
Heather Diaz
Onboard NOAA Ship David Starr Jordan
July 6 – 15, 2006

Mission: Juvenile Shark Abundance Survey
Geographical Area: U.S. West Coast
Date: July 10, 2006

This is one of the Mako sharks that we tagged.  You can see the “spaghetti” tag and the OTC tag on his dorsal fin.  After we released him, he came back to see what we were doing on the platform.  Mako sharks will usually dive down deep once we release them from the cradle, but this little guy wanted to come back for one more look.

This is one of the Mako sharks that we tagged. You can see the “spaghetti” tag and the OTC tag on his dorsal fin. After we released him, he came back to see what we were doing on the platform. Mako sharks will usually dive down deep once we release them from the cradle, but this little guy wanted to come back for one more look.

Science and Technology Log 

One team of scientists set a swordfish line at 3am.  We hauled in the swordfish longline at 6am.  We caught one pelagic ray. We set the first shark line at around 8am, and hauled it in around 12pm. We caught one blue shark.  We set the second shark line at around 2pm.  We let it soak an extra hour, and hauled it in around 6pm.  We caught one Blue shark, four mako sharks, and one pelagic ray.

I had an opportunity to take a tour of the engine room with 1st Engineer Chris Danals. We first visited the aft work room. Chris is crafting a wooden boat by hand! It is very neat looking. He said that he builds boats for fun. He showed me the rudder room, and it’s amazing to see how huge these two rudders are. They control the rudder from the Bridge.  In front of the aft work room is the engine room, which you have to climb down a ladder to get into. The noise is so loud that it is deafening, even with earplugs in.  He explained that there are two main engines, which are White Superior engines.  The port side engine is used to power the winch, which we use when we set/haul in the lines.

The starboard engine is the one we use to power the ship.  He said that the engines are diesel engines, and they get about 1 mile to the gallon.  Chris also explained that even though the computers monitor everything in the engine room, they still have to monitor all of the engines in person during each watch.  The engines are huge, each one being at least 6 feet tall and at least 15 feet long.  But, as Chris explained, it takes a lot of power to move a ship this large through the water! The ship’s top cruising speed is 10 knots, but he said we often travel only a few knots, especially when we are setting a line or hauling a line. And, there are times when we are not moving but a few feet per hour, while the longlines are soaking.

Another thing that Chris explained was how the ship makes water.  Since they can only bring a finite amount of water with them to sea, they have to rely on other methods to get fresh water once they are at sea. He said that they pump sea water in, then they use heat to separate the fresh water from the salt.  The only problem is that sometimes we aren’t moving, and the engines need to be hot in order to make water.

Personal Log 

This morning we were kind of between 4 islands: Santa Cruz/Anacapa, Santa Barbara, and Catalina. I think we are headed west today.  You can’t see land anymore, and the waves have become much more intense…several stomach dropping waves this morning and last night. It is very foggy today, and it is quite cool outside.  It actually looks like it might rain.

Everyone was a bit disappointed when our first two hauls yielded only 1 animal each.  But, the last set was better, and everyone is looking forward to seeing if the blocks farther out might have better luck.

The real treat today was a California sea lion (which has been named Eddie).  He was following us after the last haul, eating the mackerel that we were discarding.  Eddie followed us for about 15 minutes, he was quite happy and kept coming up to the surface to look at us and blow water out of his nose. He was so cute! Of course, since we had been having bad luck with the sets, I did not bring my cameras downstairs, so I missed getting a picture of the whole thing!  I am hoping that “Eddie” will come back tomorrow!

During the night, they had to sound the fog horn several times to alert other boats that we were in the area. I thought it was the general alarm at first, but then I realized that it was just fog.