Due to the technology used, the transmitters only have a life of eight to ten months. The batteries fail and the transmitter will fall harmlessly off the turtle's shell once this time is up.
Turtles can also knock the box off when moving between rocks.
As these are living animals, their welfare is paramount when attaching the transmitters and researchers accept the transmissions will be lost. The information they are able to gather in this space of time is, however, essential for turtle conservation. The CCC's main website has more details about the transmitter technology.