Archive for September, 2008

Sad Tale of Three Dead Leatherback Sea Turtles

Monday, September 8th, 2008

Leviathans of the sea and giants of the reptile family, leatherback sea turtles define the term superlative.  Ranging in weight up to a ton and the size of a small Volkswagen, no one who has encountered one of these living relics in the wild comes away from the experience unchanged.  They are simply magnificent beasts that peacefully ply the world’s oceans in search of slurpy jellyfish.  The open mouth of a leatherback sea turtle (see below) is perfectly configured for this quest and is the last thing that a jellyfish senses before the lights go out.

Mouth of 650+ Pound Male Leatherback Sea Turtle

Unfortunately, we humans offer them a complex series of lethal obstacles to avoid during their peaceful voyages.  Gill nets drown them, longlines hook them, propellers slice them, weirs trap them and lobster buoys entangle them.  Especially during the summer months in Cape Cod and Buzzards Bays as they chase plentiful jellyfish, endangered leatherbacks face a host of potential threats.

Male Leatherback Arrives at Wellfleet Sanctuary for Necropsy

A freshly dead 650+ pound male leatherback beached in Provincetown on Sunday and Mass Audubon’s Bob Prescott, the state sea turtle stranding coordinator, conducted a necropsy at the Wellfleet Bay Wildlife Sanctuary to determine the cause of death and to gather scientific information to help us conserve this endangered species.  In addition to his staff, Bob (with large caliper below) was assisted by Kara Dodge, a PhD candidate at UNH and former NOAA sea turtle coordinator, and the Turtle Journal team.

Bob Prescott (Calipers), Don Lewis (Camera) and Kara Dodge (Scalpel)

Too large for normal scales, the mass of leatherbacks is determined by weighing the Mass Audubon pickup truck at the dump with the turtle inside, and then re-weighing the truck without the turtle.  The post revealed that this animal had been very healthy.  “It had everything going for it,” stated Bob and Kara.  Both flippers showed signs of a recent entanglement, but nothing so severe that these wounds would have caused death.  Instead, the cause of death was determined to be drowning.  The likely scenario for the death of such an inherently healthy animal is that it got entangled in a buoy line with both flippers wrapped in the rope and perhaps its body trunk as well.  With the last series of spring tides, the turtle may not have had sufficient line to reach the surface.  Like all turtles, leatherbacks are air breathers and will drown if held under water for a sustained period.  How this drowned animal had then become disentangled from the lines that had been wrapped tightly around its flippers is merely a matter of conjecture.

This evening we received a call from Bob Prescott that there had been a report of a dead leatherback on a Westport beach near Horseneck.  We drove out to the site and after about 30 minutes of searching, we discovered a badly decomposed and deflated leatherback sea turtle.  Talking to a local resident, we learned it had been bouncing along the beach for at least the last three days.  We estimated the carapace at approximately 161.3 centimeters, but decomposition and deflation may have altered any accurate rendering of its precise size.  Bones were exposed throughout from head to back to flippers.

Decomposed Leatherback Sea Turtle in Wesport, MA

Another decomposed, 600 pound leatherback washed ashore at Pico Beach in Mattapoisett Saturday night (http://www.southcoasttoday.com/apps/pbcs.dll/article?AID=/20080909/NEWS/809090352/-1/NEWS).  Dealing with one dead leatherback is serious as population numbers of this critically endangered species continue to plummet.  Finding two dead leatherback carcasses in a weekend is a tragedy; but three dead leatherbacks fall beyond emotions and words.  Yet, a ray of turtle hope winked through the afternoon when a call came into the Hotline.  A woman found a small 1/2 dollar size turtle in Plymouth, Massachusetts as kids were placing it in the ocean and the animal was being forced back to the shore by wave action and its own volition.  She thought she had discovered a baby sea turtle, or perhaps a diamondback terrapin hatchling.  A few questions cleared up the mystery.  Color?  Dark, almost black.  Long tail?  Yes, very long.  Bump along the tail?  Yes, like an ancient dinosaur.  Jagged edge along rear of carapace (top shell)?  Yep.  Does it have a yellow “button” in the middle of its tummy?  Yes.  Congratulations!  You are the proud holder of a snapping turtle hatchling.  With just a few more questions we discovered the local fresh water source from whence the hatchling probably came, either through its own design or more likely with the help of local kids.

Snapping Turtle Hatchling

You’re right.  Snapping turtles aren’t endangered and they’re not leatherbacks.  But that doesn’t diminish the joy in helping a hatchling find hospitable habitat where it might have a fighting chance of survival.  Saving one turtle … even a snapper … isn’t a bad way to close the day.

Two-Ton Vehicle Versus Quarter Ounce Hatchling

Sunday, September 7th, 2008

Due to human development and associated pressures, some of the best remaining nesting sites for diamondback terrapins on the Outer Cape are one-lane dirt roads that abut salt marsh nursery ecosystems for hatchlings. Obviously, roadways are extremely dangerous for the female as she spends more than 30 minutes digging her nest, depositing her eggs and covering it once again.  Because these compacted roadways are so hard, and her nest sculpting creates a natural arch to spread the load of vehicular traffic, the eggs appear to do fine through June, July and August as they incubate under the summer sun.

Female Terrapin Nesting in Middle of Dirt Road

But when hatchlings begin to pip and squirm about in the nest, and when one or more begins to tunnel to the surface leaving an emergence hole in the road, then the architectural integrity that served so well during incubation is compromised.  Weight no longer is evenly distributed, and the egg chamber compresses and begins to collapse under the stress. 

Emergence Hole in Middle of Marsh Road on Lieutenant Island

I discovered this little (3 gram) hatchling wedged under the lip of the nest that had been collapsing under the day’s traffic.  Two of its siblings had already been crushed in the center of the egg chamber.

Premie Hatchling Distorted by Road Traffic

In addition to problems with its distorted shape, its eggshell had been invaded by fly maggots that were trying to find a vulnerable orifice to invade.  I had to hand-pick these nasty predators from the tiny hatchling.  Based on experience, I know that this critter will now do quite well.  With a little time, some warm hydration and a bit of TLC, its shell will resume a normal shape and it should be ready to be released into the wild within a few days to a week.

Emerged Terrapin Hatchling Run Over on Marsh Road

I wish the same could be said for another sibling (above) that I found a foot outside the nest and squished in the south tire track of the dirt road.  It’s a dangerous world for a turtle hatchling.  Few survive to tell the tale of their harrowing youth.  But with a little luck and a guardian angel or two, one turtle at a time can be saved and the whole world along with it.

Close-Up of Rescued Distorted Hatchling

Saving a Critically Endangered Sea Turtle

Friday, September 5th, 2008

Nature’s Classroom Teachers Find Endangered Sea Turtle

In keeping with the theme of this web site, “Saving the World One Turtle at a Time,” opportunity came knocking across the ether at 11:30 this morning.  Five teachers from Nature’s Classroom (http://www.naturesclassroom.org/Yarmouth.htm) had traveled to Chapin Beach in Dennis for field orientation on the last day before school resumes next week.  They spotted an apparently lethargic “sea turtle” in a shallow tidal pool.  While most folks would have walked on by figuring that the incoming tide would handle the situation, or while someone else might have made the absolutely wrong choice of tossing the turtle into the sea to fend for itself, the Nature’s Classroom teachers took action.  They called the sea turtle stranding center at Mass Audubon’s Wellfleet Bay Wildlife Sanctuary (508-349-2615) to report the sighting.  The sanctuary called us and the game was afoot. 

Speaking over cell phone with the teachers, we learned that they had a fairly good handle on what constituted a sea turtle, but they were unsure of its species.  We asked that they remain with the animal while we sped to their location … about a 45 minute drive.  As we reached Chapin Beach, the tide was flooding across the tidal flats with a vengeance.  Two teachers were “escorting” the sea turtle in the shallows between sandbars.  A brief look was enough to identify the animal as a Kemp’s ridley, one of the rarest and most critically endangered sea turtles in the world.  By size we could estimate its age at two to two and a half years old.  In other words, this animal was the typical juvenile sea turtle that we find cold-stunned on Cape Cod beaches from late October to December.  But the cold-stunning season is still six or seven weeks in the future.
 
 
Don Lewis Holds Rescued Juvenile Kemp’s Ridley Sea Turtle
 
En route to the beach, we had alerted the New England Aquarium that we were responding to this potential sea turtle stranding.  Now we called them back with the species identification and our assessment of the animal’s condition.  There were early indications, beyond its lethargic behavior when first observed by the teachers, of the potential for future cold-stunning.  The right rear quadrant of its carapace was covered with brown algae; algae was also beginning to form on the rear of the turtle’s plastron.  There was a coating of algae on the top of the animal’s head and some algae buildup on the trailing edge of both front flippers.  There were a few dings on the keel as though it had been wave-tossed against a rock groin or breakwater.  When we observe turtles of this size during the outset of the cold-stunning season, we see the same, but much more extensive, indicators.  At least by the time we arrived on the scene, this sea turtle had become quite strong and active.

Rescued Kemp’s Ridley Sea Turtle (Story in Video)

In conversations with the aquarium and by proxy with NOAA, we weighed three options: immediate release on site, medical examination at New England Aquarium, or immediate release on the southern side of Cape Cod into Nantucket Sound … so that it wouldn’t get trapped by cold waters within the bay and become hypothermic and cold-stun a month of so hence.  Based on our field assessment, the decision was made for us to release the animal into Nantucket Sound from a southern Cape Cod beach. 

We crated the sea turtle for transport in our Element.  (Thank the gods of science that field researchers always come equipped for field emergencies!)  We began the trek across the Cape with a short stop to visit with our friend & colleague Kara Dodge, currently a PhD candidate at UNH and formerly a NOAA sea turtle coordinator.  She had flipper and PIT tags to append and to insert, and it gave us a nice quiet space to acquire the morphometric information we always document for sea turtles found in Cape Cod Bay.
 
 
Don Lewis Reads Caliper and Kara Dodge Records Data
 
Next we rendezvoused at the beach with a photographer from the Cape Cod Times whom we had alerted while driving from Dennis.  With sea turtle stranding season only a few weeks in the future, we didn’t want to miss this opportunity to use a photo-op to make people aware of what’s coming and what they should do and who they should contact.  By 3:15 in the afternoon we had released this fully charged sea turtle into the sound.  When we let it go into the oncoming surf, the turtle exploded forward like a hotrod leaving salt spray rather than rubber as it accelerated from zero to sixty faster than you could say, “Kemp’s ridley.”
 
 
Release of Rescued Kemp’s Ridley into Nantucket Sound
 
Finding a Kemp’s ridley sea turtle in Cape Cod Bay other than on the beach during the cold-stunning season is an extremely rare event.  There has only been one other such happening several years ago of which I am personally aware.  In that case the decision was made to tag it and release it back into Cape Cod Bay with an extremely unsatisfactory outcome a month or so later.  This time we maximized the odds that one of the most critically endangered species would have one more juvenile turtle to grow into adulthood and help restore its population.  We hope to see this turtle’s flipper tags or detect its PIT tag on a nesting beach in Rancho Nuevo, Mexico in another 15 or 20 years.  Or at least we hope that our successors in turtle conservation will see the fruit of today’s adventure in a couple of decades.  (ASIDE:  We’ve always considered it a bit unfair that sea turtles outlive sea turtle researchers.)
 
A hearty bravo to Nature’s Classroom without whose intelligent action this morning, nothing good would have come of today’s event.  And thanks also to a team of dedicated volunteers and professionals from Mass Audubon, the New England Aquarium, UNH and NOAA who responded to the challenge, made the best decision for the animal’s survival and flawless executed its impromptu rescue and release.  And that’s how we intend to save the world:  one turtle at a time.
 
 
Don Lewis Releases Endangered Kemp’s Ridley Sea Turtle

Tracking Terrapin Hatchlings

Friday, September 5th, 2008

Where do hatchlings go once they flee the nest? Using various methods of inference and observation, we have determined that some hatchlings race to the wrack line for safety, others scramble further into the salt marsh grasses and still others opt to remain upland for at least the first winter of their “hidden” years.

Terrapin Hatchling Track Heads Down Turtle Pass Dune

Let’s follow some clues, some tracks and some hatchlings to test these hypotheses.  The high dune of Turtle Pass seems the place to start as we discover a hatchling track descending from an emergence nest atop the dune and heading seaward.

Tracks Assume Colorful Tints as Sun Dances Behind Clouds

Down we go along the shifting slope that morphs in shape and color as shadows dance through the contours of the dune.

Close-Up with Tail Mark Bisecting Track

Let’s experience the descent as though we were a newborn hatchling on its first ski run down the slopes.

Follow Tracks to Hatchling Buried in Salt Marsh Wrack

So, our first experiment leads to the discovery of a hatchling burrowed into the landward edge of the wrack line, buried under last winter’s deposit of salt hay.

But our day isn’t over as we encounter another set of hatchlings scaling the bearberry covered banks off 5th Avenue and passing through an exquisite clump of sea lavender en route to safety.

Terrapin Hatchling Scrambles to Reach Salt Marsh

These little critters eschew the wrack line, which to them seems like a clear cut jungle of logs, and head directly into the thick matting of Spartina patens in the salt marsh system separating east and west sections of Lieutenant Island.

Eastern Box Turtle Hatchlings

Wednesday, September 3rd, 2008
Gardening can yield some unusual crops. A resident of Paine Hollow in South Wellfleet was clearing the plantings around her cottage when she discovered a hole in the mulch covered bed. At the bottom, four perfectly healthy, but grumpy Eastern box turtle hatchlings were hunkered down for an overcast, windy and raw September day. 

Four Eastern Box Turtle Hatchlings

They seem small … that is, until you compare them to diamondback terrapin hatchlings that emerged a short distance away.

DBT & EBT Size Comparison

Comparison of Terrapin (Left) & Box Turtle (Right) Hatchlings

These hatchlings were discovered at the edge of conservation land, the Whale Bone Trail, that I had assesssed last fall as prime Eastern box turtle habitat.  What a beautiful way to have your assessment confirmed!

Eastern Box Turtle Hatchling Close-Up