Turtle Journal

Don Lewis Wades in Blackfish Creek Sampling Site

Warm, clear and beautiful — summer arrived in the Land of Ooze.  Water temperatures over the tidal flats rose to 72 degrees by late morning.  A glorious way to celebrate May Day.

Three Female and Two Male Diamondback Terrapins

Terrapins took full advantage of the moment and criss-crossed Blackfish Creek with the tide.  While not quite low enough to allow easy capture as they slipped through the rip, still visibility was awfully good and if turtles happened to swim within a few feet, water clarity made it impossible for them to disappear into the muck.  And five terrapins, three females and two males, made that bad choice of approaching too closely.

Two Very Interesting Female Terrapins (#322 and #844)

Two of the females were recaptures (#322 and #844), while the others were all seen for the first time.  And very interesting recaptures they proved to be.  Last May 30th, at 3:30 in the afternoon, these same two turtles were captured in the same location during the same tide.  Now individual recaptures are not a rarity, but to capture the same two turtles on the identical tide one year apart is a coincidence that stretches odds to the breaking. 

These two terrapins look alike, too.  Terrapin 322, on the left, is 18.95 centimeters long and weighs 1150 grams; Terrapin 844, on the right, is 18.80 centimeters and 1136 grams.  Even the shape of their scutes and the shade of their carapaces are similar.

Except for the fact that they nest on opposite banks of Blackfish Creek, one on Indian Neck and the other on Lieutenant Island, they could be twins.  It starts you wondering about the social life of our brackish friends.

Terrapin #1055 — Protypical Male Diamondback Terrapin

Terrapin 1055, a six-year-old turtle, demonstrates all the identifying characteristics of a typical mature male.  And he was kind enough to pose for the camera to illustrate those traits: the smallish “pin head” compared with the broader headed female, and the large thick tail compared with the female’s smaller, thinner tail.  Of course, gender dimorphism with males half the size of mature females is a good indicator, too.  The challenge comes, though, with distinguishing between mature males and pre-pubescent females of roughly the same size.

Don Lewis Examines Male Diamondback Terrapin in Blackfish Creek

 A southwest breeze bathed the Land of Ooze with refreshing warmth.  Blue skies and lazy clouds painted Wellfleet Bay in springtime hues.  Still, few turtles have emerged from brumation.  But with a string of 70°F days in the immediate forecast, it’s only a matter of time.  One hazard surprised me as I waded the creek.  So many pairs of mating horseshoe crabs have gathered in the low tide rip that it has converted the rapids into a virtual minefield.

Eight-Year-Old Male Terrapin #1052  Floats through Rip

Two male terrapins floated through the rip this morning.  Number 1052 came first; an 8-year-old with perfectly pristine carapace and plastron, he tipped the scales at 222 grams and stretched to 11 centimeters long.

Male Terrapin #1047 Swims through Blackfish Creek Rip

A few minutes later a repeat customer swam into view.  Terrapin 1047, you may recall, was first observed a week ago on 23 April in the first group of turtles seen active in 2001 (see Firsts — 23 April 2001).  In the last week, he seems to have warmed up a lot and has become quite active and aggressive.

Male Diamondback Terrapin #1047

He lost 4 grams in weight with his shell peeling off its winter covering.

Still blowing from the north, winds subsided to less than 10 knots and air temperature lingered in the mid 40s, but water over the tidal flats had climbed back to 51°F by 9:30 this morning.  In short, conditions moderated just enough to allow a couple of terrapins to re-emerge from frozen slumber with the renewed promise of springtime.  Horseshoe crabs resumed mating in numbers along the edge of low-tide sandbars in the middle of Blackfish Creek.

Blackfish Creek “Rip” at Low Tide — Turtle Sampling Site

And while sometimes I whine a bit about murky conditions in the turbulent rapids over the rip, I must admit that this morning even I couldn’t find much to complain about.  Water visibility was near perfect and you could see anything that moved through and along Blackfish Creek.

Large Male Terrapin #710 Paddling through the Rip

A mature male terrapin, #710, plopped over the rapids and bobbed along the shallows, snorkeling for air as he paddled toward the safety of deeper water.  Last seen on the evening of 3 June 2000 coming through the same rip, this turtle looked like he enjoyed a good 2000 summer season and survived the winter quite well, too.  Already one of the largest males we have observed in Wellfleet Harbor at 13.1 centimeters carapace length, #710 managed to gain another 5% mass to reach 340 grams body weight.

Ten-Year-Old Female Terrapin #1051 Missing “Toes” and Claws

A 10-year-old female (#1051) spun through the rapids at almost the same time.  She was nearly 17 centimeters long and weighed in at 844 grams.  On closer examination, I noticed she had lost all the toes on her right front limb, and several of the toes and claws on her right rear leg were also gone.

Neither injury slowed her down.  She hissed a warning as I snatched her from the rip and on release she sped toward the creek, leaving a peg hole where her right limb touched the sand.

Terrapin #710 Returns to Blackfish Creek; Note Striped Male Tail

Both turtles seemed stone cold to the touch when I first recovered them from the rip.  As I measured, weighed, documented, and marked them, they warmed up considerably.  And by the time they were released, they had become fully alert and active.  They raced from the beach to the water line and paddled off into the creek at full speed.