Loggerhead sea turtle necropsy, and a second chapter

A memento mori, delivered from sea to sand, from Poseidon to Psamathe. The turtle washed onto the Atlantic shore of St Catherines Island. Given the parlous state of sea turtle populations, every breeding adult is important, so a vet from the non-game division of the Georgia wildlife agency came to the site to determine the cause of death.

The turtle been floating dead for a week or so before washing up. The large number of barnacles on her shell indicate that even while alive, she’d been slowing for some weeks.

2015-06-12 turtle necropsy 0022015-06-12 turtle necropsy 003The vet gave the carcass a check with the pit-tag scanner to make sure that this turtle had not been previously tagged by turtle biologists. No signal.

2015-06-12 turtle necropsy 008The esophagus, covered in downward-pointing rubbery fingers. Loggerhead turtles swallow crabs, then grip them in their throats as they expel excess water.

2015-06-12 turtle necropsy 015There were no fish hooks or plastic debris in the gut, only remains of crustacea. A horseshoe crab leg from the large intestine:

2015-06-12 turtle necropsy 017Microbial decomposition was well-advanced (stand upwind…), but the “turtle soup” (as the vet called it) revealed no obvious cause of death.

2015-06-12 turtle necropsy 010The turtle was likely born on this beach or one closeby. She traveled the Atlantic gyre as a youngster, then wandered the ocean for at least thirty years, perhaps as many as sixty. To misquote the Bard, food for vultures, brave turtle: Fare thee well, great heart.

They have their exits and their entrances, And one turtle in her time plays many parts… an exit, yes, but also many entrances:

crawlt…the crawlway of a sister or cousin of the deceased, oaring up the beach to dig a nest. She chose a poor spot, one that would get flooded, so the St Catherines Island Sea Turtle Program relocated the nest to a safer place. One of the traveling eggs:

turtle eggHopefully the egg, and its one hundred siblings, will hatch and then swim out to the Atlantic gyre in mid-August.

Here is a fabulous figure from a recent article by Katherine Mansfield and her colleagues on satellite-tracked loggerhead turtle hatchlings (source: Mansfield, K. L., Wyneken, J., Porter, W. P., & Luo, J. (2014). First satellite tracks of neonate sea turtles redefine the ‘lost years’ oceanic niche. Proceedings of the Royal Society of London B: Biological Sciences, 281(1781), 20133039.). The upper map is colored by depth, the bottom one by water temperature. Lines show the paths of individual hatchlings.

turtle map

8 thoughts on “Loggerhead sea turtle necropsy, and a second chapter

  1. Fountainpen

    Wonderful creatures!!
    I remember flagging down two strong
    Men in a car to help me save a large
    Large snapping turtle crossing a highway
    I the Upper Peninsula of Michigan!
    It was something to see this man carry
    The turtle by its tail to safety!!!!

    Fountainpen

    Reply
    1. hayden

      i even miss the necropsies…always have liked dissections

      a friend of mine from grad school just laid eyes on a leatherback on tybee!!

      Reply
      1. David George Haskell Post author

        Ha! Missing necropsies is a sure sign that you are permanently infected with the biology virus. Incurable, I’m afraid.

        Only a handful of leatherbacks on St C over many decades. Would be great to see one!

        Reply
  2. pupperwupper

    https://en.wikipedia.org/wiki/Minn_of_the_Mississippi Meant as a children’s book but so much more, I highly recommend this “story book” about a freshwater turtle. The story follows Minn, a snapping turtle, on her life journey from the source of the Mississippi river to the Gulf of Mexico. The book is packed with information about “chelydra serpentina” , the river , the people along the river (mound builders, early explorers, 20th century commerce, etc.) , other animals, maps, all beautifully illustrated. It is a great book to use to show children or anyone for that matter what it takes for the animals around us to survive. It’s just a very special book!

    Reply
  3. Jim Markowich

    Thanks! That was educational. The esophagus was rococo… not sure about how its structure relates to the crabs that the turtles eat, but would probably need a diagram to understand that.

    Reply

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