In the making of “Jaws,” the three mechanical models of the shark, collectively known as Bruce, earned a reputation for being notoriously unreliable.
Bruce was a temperamental star of the 1975 Steven Spielberg film, and prolonged breakdowns were a common occurrence.
But the title for most unpredictable shark — mechanical or real — might have just been wrested by another great white, this one named Katharine.
Katharine, all 2,300 pounds and 14 feet 2 inches of her, was tagged with a tracking device on Aug. 20, 2013, off the coast of Cape Cod by a crew from Ocearch, a nonprofit that travels the world facilitating ocean and fish research.
For years, Katharine, who is named after Katharine Lee Bates, the writer of the verses to “America the Beautiful,” delighted the public, especially when she drew near coastlines, as reports of her whereabouts appeared on Ocearch’s online tracking map.
Her Twitter account (“misunderstood but sassy girl just tryin’ to get some fish”) gained more than 61,000 followers.
“The people in Florida just fell in love with her,” said Chris Fischer, the founder of Ocearch. “She became the ambassador, the diplomat for the ocean.”
And then came May 12, 2019. A ping placed her about 150 miles off the coast of Charleston, S.C.
After that, nothing. She was not heard from again.
Had she died? Was she looking for a bigger boat? Was she practicing social distancing?
Then at the end of March came a single faint ping. It was first thought to be a “ghost transmission,” said Bryan Franks, an assistant professor of marine science at Jacksonville University in Florida, who works closely with Ocearch.
On April 4, three more pings came in less than 24 hours. Mr. Franks said that many signals in a compressed time led researchers and the satellite company that collects the data to believe it was indeed Katharine.
Rough guesses based on those transmissions put her about 200 miles off the coast of Virginia. Katharine was not considered a full adult when she was tagged in 2013, but she has likely added 1,000 pounds since then, Mr. Fischer said.
Simon R. Thorrold, a senior scientist in the biology department at the Woods Hole Oceanographic Institution in Falmouth, Mass., said it was “not crazy surprising” that a signal was picked up.
The tracker, which is about as long but half as wide as the largest iPhone X model, is attached to the dorsal fin and transmits a ping when a shark breaks through the surface.
Great white sharks can stay below the surface for extended periods — months at a time — and that could explain why there was such a prolonged silence, he said.
Gregory B. Skomal, a senior fisheries scientist at the Massachusetts Division of Marine Fisheries, said “biofouling” — the accumulation of mussels, algae and similar aquatic life that might cling to the bottom of a boat — could have attached to the antenna, rendering it ineffective.
But he expressed some skepticism about the latest signals, given that the tracker’s battery generally lasts about five years.
Gavin J.P. Naylor, director of the Florida Program for Shark Research at the Florida Museum of Natural History at the University of Florida, in Gainesville, Fla., said the assumption that a tracker went silent because a great white shark died would be probably the least likely explanation.
The sharks have a life span of 75 years and, being at the apex of the food chain, tend to have few predators apart from humans, orcas and one another.
Katharine is hardly the only shark Ocearch has tagged, tracked and made into a celebrity with a Twitter account. Another one, Mary Lee, named after Mr. Fischer’s mother, drew even more attention, with 130,000 Twitter followers.
The popularizing of ocean wildlife has a serious purpose, Mr. Fischer said.
He is quick to rattle off Ocearch’s statistics: 37 expeditions, more than 500 tagged animals, including 100 or more great white sharks.
The tissue and blood samples and other data gained are widely shared among researchers, whose work appears in peer-reviewed journals, Mr. Fischer said.
“In the end, if we’re going to have an abundant ocean, why not get everybody involved?” he said.
Mr. Fischer’s interest in water started with the frogs and fish in creeks in his native Kentucky, and expanded to oceans. Ocearch’s efforts were featured on the National Geographic channel’s “Sharkmen” and the History channel’s “Shark Wranglers.”
As for whether cute names, Twitter accounts and T-shirt sales cheapen Ocearch’s serious science and research about sharks, Mr. Fischer said it’s fine for critics to say that but who will pay for the research?
He said all of Ocearch’s work is open sourced and benefits many researchers.
The work can promote conservation efforts and improve protections of sensitive mating and birthing areas as well as deepen the public’s understanding of what the sharks are doing close to coastlines, Mr. Thorrold said.
For instance, Mr. Naylor said, research has revealed that, contrary to popular belief, great white sharks don’t feed exclusively on seals but spend a huge amount of time feasting on fish.
Mr. Thorrold said: “The biggest thing is the sense of the wild ocean — we still have it but we’re losing it fast. This kind of science can help us understand these trade-offs before we make them.”
Popularizing marine wildlife is not a bad thing, he added.
“The more we can interact with the average Joe in the street, the more they can feel a sense of ownership, a sense of stewardship for the ocean, the better it is for everyone,” he said. “It’s a way of bringing the ocean life into our homes.”
No doubt Katharine would be pleased to hear that — if only she would call more often.