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.

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Sargassum as seen from “my perch”

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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.

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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.

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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.

 

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Kevin Travis

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