JACKSONVILLE, Fla. (AP) — The transmitter attached to a great white shark being tracked on Twitter has fallen silent.

The research group Ocearch says the transmitter on the shark known as Mary Lee has not sent a signal since June 17, when she was swimming off the New Jersey coast.

Founding chairman Chris Fischer and his crew caught and tagged the 16-foot shark off Massachusetts in 2012. Since then, thousands of people have followed Mary Lee on a Twitter page managed by Ocearch .

In a Florida Times-Union report , Fischer said the transmitter's batteries simply may have died, partly because Mary Lee surfaced frequently, which triggered more signals.

Fischer said he expected Mary Lee to live another 20 years.

An Ocearch vessel will depart Jacksonville University next month to search for additional sharks to tag.


Information from: The (Jacksonville) Florida Times-Union, http://www.jacksonville.com