Researchers have counted 74 dead turtles since December in Wellfleet marsh.
March 25, 2000
By JOHN LEANING
STAFF WRITER
WELLFLEET - As more dead diamondback
terrapin turtles appear in the Fox Island
Wildlife Management area marsh, naturalists
are no closer to discovering how these
protected amphibians died.
"The mortality is staggering, unbelievable,"
said Robert Prescott, executive director of the
Massachusetts Audubon Society's wildlife
sanctuary and a lead naturalist checking the
turtle deaths.
Since December, sanctuary volunteer Donald
Lewis has found 74 dead terrapins, most in
advanced stages of decomposition.
Naturalists determined, based on the state of
decomposition, that most of the dead terrapins
died prior to the onset of freezing weather,
which retards decomposition.
However, Prescott now believes that there
was more than one occurrence of whatever
killed the turtles, since some found earlier this
week show even more decay, meaning they
died earlier than previously thought.
"This was not a single incident. It happened
a number of times through the fall," he said.
Backtracking to the fall can help establish
when turtles died, but no one knows what
killed them.
"There are so many. I'm surprised we didn't
see anything," he said.
It could have been related to shellfishing
activity, or it could have been something
completely different, Prescott said.
"That's one of the pieces we just don't
know," he said.
Someone moving a mooring along the
bottom could have dislodged some turtles after
they went into hibernation in October. The
centerboard of a sailboat being moved or sailed
at low water could have done the same thing.
Prescott said everyone will be working
together to try and find out.
"The fishermen are talking to us about this
and we're talking to fishermen," he said. "They
are on our committees. We are working with
the locals to discuss the matter.
"Come this summer, we'll have volunteers
pay more attention, walking beaches and sand
flats to see if they can see anything."
Prescott said it was impossible to gauge just
how serious these deaths will be to the local
terrapin population.
The discovery of some mature dead females
means there could be impacts on terrapin
populations in the immediate future, but long-range effects were uncertain.
"We've already seen a decline, we think, of
turtles nesting on Indian Neck. It was
decreasing before the mortality started," he said.
Mystery in the marsh
Researchers attempt to find out why Wellfleet's diamondback turtles are dying
March 19, 2000
By JOHN LEANING
STAFF WRITER
WELLFLEET - Two years ago, Don Lewis
retired from his post as a senior intelligence
analyst with a secret arm of the Defense
Department, leaving behind his satellite maps
and other tools of the trade. Now his tools are
rubber boots and plastic specimen bags, and
he's embroiled in an environmental whodunit in
his own back yard.
As a volunteer with the Massachusetts
Audubon Society, Lewis trudges through the
Fox Island Wildlife Management area looking
for diamondback terrapins, listed as an
endangered species in Massachusetts. Since
Dec. 7 Lewis has found 66 carcasses, and he
and wildlife experts believe that as many as 100
may have died.
The diamondback terrapin is in ample supply
in other parts of the country, and is still
commercially harvested for food in some
places. It is considered threatened here because
Cape Cod Bay is its northernmost habitat, said
Tom French, assistant director of the state
Division of Fisheries and Wildlife, and head of
the state's Natural Heritage and Endangered
Species Program.
French rated the Wellfleet die-off a 6 on a
scale of 1 to 10 in terms of the Cape's overall
diamondback terrapin population, an 8 or 9 for
the Wellfleet Bay population.
There are believed to be several thousand
terrapins on the Cape. Besides the Wellfleet
marsh system, they are found around the Great
Marsh in West Barnstable, Sandy Neck and
areas in Pleasant Bay.
The area in Wellfleet that Lewis patrols, and
where he has found all 66 dead turtles, is
within the state's Fox Island wildlife
management area. It is the only diamondback
terrapin habitat on the Cape where the deaths
are occurring.
The ooze patrol
The marsh is wild and desolate. Grasses are
now brown and bent over, hiding tiny rivulets
where the turtle carcasses were left by the tides.
"The turtles are very difficult to find, almost
impossible to the untrained eye," Lewis said as
he walked through one area where he's found
carcasses in the past.
Lewis makes his patrols during low tide, the
only time the interior of the marsh and the
deeper creeks are accessible.
"It's a treacherous terrain. Now that the
marsh has thawed, you can fall into pockets.
I've literally had to claw myself out," Lewis
said, noting that he always brings his cell phone
with him, just in case.
After the turtle patrols, he returns coated in
black, smelly ooze from the marsh. He says his
wife bans him from the house until he sheds his
fetid clothes.
The former National Security Agency official
estimates he spends 25 hours a week on the
patrols, and another 25 hours working the
numbers and locations on his computer.
Deaths began in late autumn
Robert Prescott, executive director of the
Massachusetts Audubon Society's Wellfleet
Bay Wildlife Sanctuary, said, "I wish we had an
answer. We just can't seem to figure it out. But
a lot of turtles keep popping up in an advanced
state of decomposition."
The site-specific nature of the turtle deaths
tends to eliminate natural causes, French said.
If it were weather, there would have been dead
turtles all over the marsh system.
None of the turtle shells, called carapaces,
showed any signs of scratching or gnawing by predators.
Working backward from the date the
carcasses were first discovered, naturalists
believe the turtles died sometime in late
October or November, because the carcasses
had time to start decomposing before freezing
weather arrived. Analysis of the remains is
almost impossible because of the advanced decomposition.
Lewis spotted a live turtle Oct. 26, which he
uses as the last date the turtles were moving
before going into the muddy creek bottom to
hibernate for the winter.
The first dead diamondback appeared Dec. 7.
"It's a day that will live in infamy for turtle
research," Lewis said, adapting the line from
President Franklin D. Roosevelt's address to
Congress on Dec. 8, 1941, when the United
States declared war on Japan after its Dec. 7
attack on Pearl Harbor.
Since then the turtle carcasses have appeared
with some regularity in the same areas of the
marsh. The numbers peaked March 11, 12 and
13, when Lewis picked up 24 dead turtles.
Young, old, male, female, the entire range of
the diamondback terrapin population started to
become mortality statistics in records Lewis
meticulously keeps on his computer.
Lead suspect: oystermen
Prescott said that every year naturalists
customarily find a half-dozen or so dead
turtles, killed by exposure as ice in the creeks
shifts, moving the water channels and
uncovering the hibernating turtles.
But this was much more than the normal ice kill.
Prescott and others think the deaths might
have been inadvertently caused by
shellfishermen dragging for oysters. The drag
could have scraped the hibernating turtles from
the bottom, and they could have died from
related injuries or exposure. Since the turtles
clump together to hibernate, one tow of the
drag could do a lot of damage, he said.
Prescott and others have no hard evidence,
but he does plan to meet with shellfish
constable Richard Dickey and the town's
shellfish advisory committee to discuss the
matter. Proposals could include a ban on
dragging in the marsh when the turtles are hibernating.
"We don't need to do anything immediately.
The best thing is to talk, and see what they
think is a solution," Prescott said.
French pointed out that the unusually high
number of dead turtles has not been seen
before. Even without the more intense
monitoring Lewis has given the habitat since
last July, French said, such high numbers would
have been noted in the past.
The fatalities, he said, were "probably the
result of an unusual activity."
"It's a mystery, and that's part of the
interest," said Audubon's Prescott.
If it is determined that the turtle deaths were
caused by human activity, steps can be taken to
prevent a recurrence.
"But if it's from natural causes, there is not
much we can do," Prescott said.
"It's a tragedy to find the dead turtles, but if
it can help us save the diamondback terrapin
species, then it's God's work," Lewis said.
