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Don Lewis, Massachusetts Audubon Society,
Fox Island Wildlife Management Area

A Spate of Spat — 26 May 2002

White caps in protected Chipman’s Cove?  You bet.  A northeast wind blasted off the ocean at 25 to 30 mph.  In Buzzards Bay to the south, these gusts created a seven-foot chop that swamped and sank a 22-foot fishing boat.  So what were three tiny kayaks doing in Wellfleet on Saturday afternoon?  Surfing the swells?  Well, yes and no, not really.  They were, of course, searching for turtles.  Not an easy task when riding a fiber glass bucking bronco.

We did managed to net two turtles.  And both of these terrapins were adorned with oyster spat, one (#1256, an 11-year-old female, see below) was carrying two spats.  Since we first noted this phenomenon on 11 May (see Glorious Day; use back button to return to this page), we have recorded seven turtles with spat that had set on their shells.  All were female turtles ranging in age from 6 years old to 15 years old; all were captured in Chipman’s Cove.

A search through the now 23-year database for Wellfleet Bay terrapin research shows no other record of oyster spat observed on turtles.  On the other hand, 2002 represents the first season we’ve surveyed Chipman’s Cove this extensively so early in the spring.  Local experts say these spat look like they’re a year old.  In Wellfleet waters, oysters spawn in July and “set” that is, fix themselves onto a solid surface like a rock or another shell in August.  So, one would assume that we should have noticed this activity in previous years when we were searching Chipman’s Cove in June, July, and August.  You have to admit, it’s rather hard to miss.

Beside #1256, the other turtles captured with spat are shown below.  Reading from top left to top right, then bottom left to bottom right, they are: (1) #613, a 15-year-old female, on 24 and 25 May; (2) #1214, an 11-year-old female still pre-pubescent, on 11 May; (3) #1255, a six-year-old pre-pubescent female, on 24 May; #1231, a 10-year-old female, on 19 May; #1243, a 12-year-old female, on 21 May; and #1227, a 15-year-old female, on 17 May.

To get a sense of the extent of this phenomenon, so far in 2002 we have captured 67 unique individuals in Chipman’s Cove.  Of that number, 50 were female and 15 were male.  So, the percentage of females with spat is 14; the overall percentage is a little over 10 percent.  Several of these turtles were shedding, yet the oysters did not come off with the peel.

Yesterday, the 25th, marked the first really workable tide in Blackfish Creek for the 2002 season.

Four terrapins were netted as they were flushed out of the creek by a –0.3 foot tide.  Two were males: #903, a 7-year-old first spotted in July 2000; and #1076, a 10-year-old male first seen 30 May last year.  The two females were first timers.  Number1257 is a mature 9-year-old, and #1258 is a pre-pubescent six-year-old.  While last evening was marginally exploitable, the constant churn of westerlies this spring has transformed Blackfish Creek into near opaqueness at least a month ahead of schedule.  Usually the murk comes from summer richness brought by warm weather; this season it’s merely thick silt.