Loggerhead Musk Turtle (Sternotherus minor)

I spent part of last week assisting
with field surveys for a remarkable river turtle.

Jim Godwin, zoologist with
the Alabama Natural Heritage Program, and his colleagues are investigating a
possible hybrid population of the Escambia map turtle (Graptemys ernsti)
and Barbour’s map turtle (Graptemys barbouri). This unusual
population may occur in the Pea and Choctawhatchee rivers of southern Alabama.
As part of this study, researchers need genetic samples from “pure” Escambia map turtles.  Over the next few days I will be part of this survey, taking place along
the beautiful Conecuh River, located just a bit south of Andalusia, Alabama.

The 1st Day

Trapping turtles is like
hitting in baseball — with those showing up at the plate often not getting a
hit.

Except for a large speckled
perch (i.e., crappie), Jim’s baited hoop net traps are empty. However, a good
score rests in one of the basking traps that he placed beneath a treefall — an
adult male Escambia map turtle. We beach the boat on a sandbar, having decided
to wade-swim the river in hopes of sneaking up on basking turtles.

Finding a mostly-picked-clean
gar carcass in the shallows, we start turning submerged stones and are soon rewarded
with two loggerhead musk turtles. Both of the handsome little bottom-prowlers cut
loose a stink (from glands near the tail) and cock their mouths open. 

  Enlarge PhotoJim Godwin pulls up a net trap

Swimming a turtle 

From the tail end of a
sandbar we spot an Escambia map basking, it’s a large adult female. Her shell
hangs over both sides of a smooth log that rises at a sharp angle from the
river (and she is oriented such that our view of her head is blocked by the log).
All Graptemys species are extraordinarily wary and we were fortunate to
get this close. Godwin, excited, says “She can’t see us…Ok, STAY LOW IN THE
WATER AND KEEP THE LOG BETWEEN YOU AND THE TURTLE, don’t get in her field of
view, and don’t make eye contact with the turtle.” (Who knew Alabamians were so
bossy?)

“Take your time, you can get
this one. Stay low,” Jim says

I begin my approach stretched
out flat on my belly in less than six of inches of water. I alternately lurch,
flop and bounce, moaning all the while, as I grab and pull myself
hand-over-hand across the sand floor of the river, using musculature I had
forgotten. My ego whispers, “this is so cool, I am one bad dude, a surreptitious
Navy Seal on an important mission.”  My ego may have whispered audibly — before I
progress even a few feet I hear Godwin guffaw, “Actually, what you remind me of
is a walrus.”

Jim’s guidance serves me well
and 5 minutes later I am directly beneath the log. I could hear the scratch of her
nails as they found purchase in the log and she began to leap; but “walrus-boy”
was quicker. I got her — and what a gorgeous animal!

Jim and I continue to swim
for turtles. Although we are unable to outsmart any more adult Escambia maps, we do capture two of last years’ hatchlings; their keeled and serrated
carapaces are reminiscent of the sharp-pronged stars thrown by martial artists.
We also snag a vibrantly-patterned juvenile river cooter.

As if turtles aren’t strange
enough, Graptemys (13 known species, all strictly river turtles with ranges
restricted to drainages that flow into the Gulf of Mexico) carry it one big stride
farther.  Sexual dimorphism in size is ridiculously pronounced in many species
(e.g., our nice female ernsti, her prominently humped carapace nearly a
foot long, is five times as heavy as a five inch-long, full grown male). “Megacephaly,”
with grotesquely enlarged heads and expanded jaw surfaces, is also
characteristic of adult female map turtles; these adaptations allow them to
crush and feed on native freshwater mussels.

The sharp slopes above the Conecuh River signal spring, with new flowers of wild hydrangea and Virginia willow adding
color to fern-covered sandstone bluffs on the north side of the stream. At home
in the gentle current — in between active pursuits of basking turtles — we simply float
with the brown water. The afternoon passes in a hurry. As light fades we leave
the river to a chorus of bird-voiced treefrogs; driving back, we spot a fat
cottonmouth on the sand road.

Day 2

Jim Godwin is preternaturally
svelte and continuously wears a wry grin.  His beard has whitened over the
years, his but his bright blue eyes sparkle like when I met him 20 years ago.
He is composed and silently confident; while in his midst I always feel calm
and reassured. The blood of freshwater turtles runs deep in his veins.

Later today, I will look on
as he spends a full hour photographing a single specimen. Our conversation over
southern BBQ last night included in-depth monologues detailing our turtle bites
and other misadventures.

I don the same wet socks,
shorts and shoes that I wore yesterday. Checking a hoopnet, we make out the
pattern of a large brown watersnake resting on the mesh of the trap– its form
rises and falls with the wake of the boat before it spots us and dives
underwater.

I mostly just ride, soaking
sun, picking out warbler and vireo song, as Jim boats us to check and bait
traps. In places the current is strong, sometimes whirlpools shift the boat
suddenly. We bang against sharp snags (often ducking at the last second after
cries of “LOOK OUT!”), and are watching for rusty hooks on old trotlines. Jim
is imperturbable, unflinching, even when, as he pulls a trap from the river, a
long-jawed orb weaver (with legs extended as long as my finger) scampers over
his baldspot.

Searching a sense of purpose,
I plead with Jim to allow me to help, and he obliges. “Well, you’re a good
swimmer, how about diving under here and helping me free this tangled lead line.
It’s hung up bad on some roots about 6 feet down … you’ll have to weasel it loose.” 
He pointed again, then closed with a terse and somewhat ominous “I’ll stay in
the boat.”

  Enlarge PhotoEscambia Map Turtle (Graptemys ernsti)

The lead lines, about 6 feet
tall, are positioned underwater like drift fences, they serve to direct turtles
into  the inverted funnels at the ends of the hoopnet traps. At this trap site,
as at most of the others, Jim had upped the ante by selecting creepy underwater
lairs where the roots of giant leaning riverside sycamores extended like tangled
tentacles into water swirling through undercut banks. These aquatic
microhabitats, you know, are preferred by alligator snapping turtles.

I tighten the draws on my
bathing suit and jump in with the eagerness of a 2nd-grader on his first
school-sponsored trip to the local swimming pool. I soon learn that an artesian
ground water spring must enter the channel here, for the water is spine-straightening
cold. I can’t touch bottom, and when I go under and put my hand a few inches
from my face I see no hand.  There are occasions in my profession when we
remind ourselves that the only thing to fear is fear itself. Submerging and
pulling myself into the nether-regions of the benthos I wonder if the suspended
souls of ghoulish catfish lurk here? Is this where bad alligators are sent for
a “time-out”? Lifting the trap to check it, Jim had disturbed the bait can, and
a pungent slick, spawned via the oil issuing from the rotting tilapia bait,
blossoms and spreads amoeboid across the water surface toward me. 

I unhooked the trap lines and
freed the lead. This made Jim happy.  We retired to a sandbar where, taking his
time, Jim drew minute amounts of blood from a hind leg of each of the adult Escambia map turtles for the genetics study. We photographed our spread of magnificent
reptiles before releasing all of them right where they were initially captured.
It was a productive and highly enjoyable field experience, and I look forward
to more personal time with map turtles.

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