Divers monitoring a rotting whale carcass off the coast of Oahu came face-to-face with what may have been the largest great white shark on record.

Diver Ocean Ramsey believes the shark was more than 20 feet long and 8 feet across. It's possible that the great white shark is pregnant and was in search of extra nutrients.

The Hawaii Department of Land and Natural Resources has warned people to stay out of the water around the dead whale.

HONOLULU (AP) — Divers monitoring a rotting whale carcass off the shores of Oahu this week found themselves face-to-face with a massive great white shark, prompting state officials to warn recreational divers and snorkelers to stay out of the water near the dead sperm whale amid reports some people have climbed onto the carcass to take its teeth as souvenirs.

Smaller tiger sharks left when the possibly pregnant great white came to dine on the dead whale Tuesday, diver Ocean Ramsey told the Honolulu Star-Advertiser.

"She was just this big beautiful gentle giant wanting to use our boat as a scratching post," said Ramsey, who posted images of the encounter. "We went out at sunrise, and she stayed with us pretty much throughout the day."

Ramsey studies sharks, advocates for their conservation and leads cage-free shark diving tours. Ramsey and her team observe and identify sharks and share that data with state and federal partners.

Hawaii waters are usually too warm for great whites compared with California's Pacific coast, where they feed on sea lions and elephant seals, Ramsey said. She estimated this shark was more than 20 feet (6 meters) long and 8 feet (2.4 meters) across.

The giant white might have headed to Hawaii because of hunger and a need for extra nutrients in pregnancy, Ramsey said.

The Hawaii Department of Land and Natural Resources said in a statement Wednesday that the decomposing whale carcass had drifted to about eight miles (13 kilometers) south of Pearl Harbor after being towed 15 miles (24 kilometers) offshore days earlier.

The department said tiger sharks have been "almost continuously" feeding on the whale and said it was aware of photos of the great white.

The agency's Division of Conservation and Resources Enforcement Chief Jason Redull said people should stay out of the water around the dead whale.

Read more: An 18-foot great white shark ate a dead whale in front of a boat full of tourists

"We don't want anyone to get hurt if a shark swimming around the carcass mistakes them as food. Understandably, some people want to get into the water either out of fascination or to get photographs, but it is truly dangerous to be around this carcass with so much shark activity," he said.

The agency said there are reports people climbed on top of the whale carcass and removed its teeth, which may be a violation of state and federal laws.

Officials said the carcass it is currently drifting away from shore, but a predicted shift in the winds could once again push it back toward Oahu.

The shark could be the famed Deep Blue based on her size and markings, Ramsay said. Deep Blue is believed to be the largest white shark ever recorded. Ramsey previously swam with the huge shark on research trips to Guadalupe Island, Mexico.

"Big pregnant females are actually the safest ones to be with — the biggest, oldest ones — because they've seen it all, including us," Ramsey said. "That's why I kind of call her, like, a grandma shark."

Sharks usually only bite when they're curious or mistake people for their natural prey but are unpredictable, she said.

This story corrects that Ramsey shares data with federal partners but did not require and was not operating under a federal permit when she encountered the great white.

Information from: Honolulu Star-Advertiser, http://www.staradvertiser.com