DOC accidentally kills 800 rare snails
A faulty temperature control has resulted in the death of about 800 rare giant snails taken from the Stockton plateau on the West Coast.
The Department of Conservation (DOC) took nearly 6000 Powelliphantia snails from the plateau in 2007 to protect them from Solid Energy's Stockton opencast mine development.
Four thousand had been re-released, but about 1600 remained in three temperature controlled cool rooms and environmental chambers as part of a captive programme funded by Solid Energy.
DOC spokeswoman Jose Watson said the snails were meant to be kept at 10 degrees, but a glitch sent the temperature in one of the cool rooms down to zero.
''The temperature probe ... measured the temperature incorrectly. It said it was really hot in the container so it sent a message to the chiller unit to cool the unit down.''
The accident happened over Labour Weekend, and no one knew how long the snails were exposed to the freezing temperatures, Watson said.
''Snails in the wild do withstand quite cold temperatures. We weren't sure what the impact was going to be from this event.''
The temperature probe was replaced and snails were left in the warmer environment for two weeks before conservancy staff checked up on them.
''It's become apparent that it's been very bad for them,'' Watson said.
Staff were still counting snails, but just one survivor had been found so far.
A captive breeding programme was going well, Watson said, and the loss should be recovered in two to three years.