ASBURY PARK, N.J. — The public may have heard the last of Mary Lee, an adult great white shark who wears a tracking device.
The tag on the female shark's dorsal fin has not been detected by satellite since 6:54 a.m. ET June 17, when she was swimming off the coast of Beach Haven, N.J., about 20 miles northeast of Atlantic City.
The likely reason that Mary Lee's 129,000 Twitter followers have not heard directly from her electronics in almost six months is a dead battery, said Chris Fischer, founder of Ocearch. His research group that tagged the apex predator and had the only known human contact with her.
"We might hear from her again, but we might not. Her tag may have run its course," said Fischer, who is confident the shark is alive. "She's the queen of the ocean. She's a 50-year-old-or-so mature white shark that absolutely dominates wherever she goes."
Mary Lee is an adult Carcharodon carcharias, the scientific name for a great white shark. Recent studies have found the sharks can live into their 70s.
She weighed 3,456 pounds and measured 16 feet when she was tagged Sept. 17, 2012. She could be bigger now.
Mary Lee has been a creature of habit for the past five years, according to Ocearch's Global Shark Tracker. So she probably has been heading toward warmer waters off the coast of Georgia or Florida.
Ocearch, a nonprofit research group, is tagging great white sharks to study their life cycle. Mary Lee was captured off the coast of Massachusetts' Cape Cod in a game of "cat and mouse" that took 1½ hours, Fischer said.
He named the shark after his mother.
While Mary Lee was on board the Ocearch vessel, researchers placed a Smart Position Only Tag, known as a SPOT, on her dorsal fin to record her movements in real time. They took DNA samples.
When Mary Lee's dorsal fin has been above the surface of the ocean for at least 90 seconds, a satellite picked up her position and sent it to Ocearch's shark tracker. So her tag still could be working; she might not have come to the surface long enough for be detected.
Why and how often great white sharks surface is not well known to researchers. What is known: Because they are big fish and not mammals, they do not need to come to the surface for oxygen as a dolphin or whale does.
Ocearch has tracked Mary Lee for more than 39,975 miles at hundreds of locations in the past five years, according to her Ocearch webpage. Of more than 300 sharks that Ocearch has tagged in its 10 years of existence, Fischer said the longest a tag lasted was eight years and only on one shark.
► October 2015: Shark researchers puzzle over Mary Lee's mysterious ways
► July 2015: Evidence points to great white shark nursery off New Jersey
Mary Lee is the shark that put Ocearch on the map and saved the research group from going under, Fischer said.
One of the people responsible for that is shark enthusiast Jo O'Keefe, 72, of Carolina Shores, N.C. In 2013, she started watching Mary Lee's track as the shark was coming down the coast.
"I called TV stations and newspapers in each city she was approaching and explained the entire GPS global tracking system, took them to the website, taught them how to track her," O'Keefe said. "Ocearch did not know why Mary Lee was getting famous until months later when I contacted them."
► May 2015: Great white shark Mary Lee tracked near Maryland coast
► February 2013: 'Wranglers' keep tabs on speedy great white sharks
Mary Lee became a media sensation overnight, which led to a $3 million sponsorship from Caterpillar diesel engines, Fischer said. And now Mary Lee is helping undo the fear of great white sharks created as a result of Steven Spielberg's 1975 blockbuster Jaws.
"When I first heard about Mary Lee I thought it was a great opportunity for kids to learn about these sharks," O'Keefe said.