Diving for Turtles

lcmm Underwater Archaeology

by Adam Kane

This fall I had the exciting experience of diving for spiny softshell turtles (Apalone spinifera) in Lake Champlain’s Missisquoi Bay.  No, not for eating, these turtles are a threatened species in Vermont.  We worked for McFarland Johnson, Inc., an environmental consulting firm, under contract to VTrans to study the turtle’s behavior.  The goal was to determine whether constructing the new Route 78 Bridge between Swanton and Alburgh had affected the turtles.  Over the last several years a number of these turtles were tagged with radio transmitters to track their movements.  As the batteries inside the transmitters wore down, it came time to re-capture the turtles and switch out the transmitters, lest the turtles become untraceable.  Here at the Lake Champlain Maritime Museum we have lots of tools for working underwater, including, although not by design, useful equipment for capturing turtles.

Adam Kane showing a spiny softshell turtle

Adam Kane showing a spiny softshell turtle

Here’s the really amazing thing about these creatures: they hibernate underwater!  Yes, they take a few big breaths in the fall, go the bottom of the lake, bury themselves, and come up sometime in the spring.  The turtles are able to absorb oxygen through their skin and shell while hibernating. How do you find a buried turtle on the bottom of Lake Champlain?  First, their transmitters get you to within ten or twenty feet of where the reptile is slumbering.  Mark that spot and then send a diver into the water with a metal detector to find the metal in the transmitter.  Once the diver has found the transmitter (i.e. the turtle), then comes the tricky part of digging up the turtle and bringing it to the surface.  Tricky because the formerly sleeping turtle quickly becomes unhappy about being dug up and being held onto by a strange creature.  Once onboard the research boat, the turtles are weighed, measured, and fitted with a fresh transmitter.  After this relatively short bad dream, the turtle is returned to the lake to continue its long nap.

Adam Kane
LCMM Archaeological Director