A massive fin whale was found dead at the Pacific Beach in San Diego, said the San Diego Fire-Rescue Department.

SDFD lifeguards were notified of the deceased animal, identified as a juvenile female fin, by National Oceanic and Atmospheric Administration at about 8 a.m. on Sunday. The lifeguards alerted NOAA, who then sent personnel to investigate the situation, said Mónica Muñoz, Public Information Officer at SDFD.

A team of scientists from NOAA's Southwest Fisheries Science Center who responded to incident found no evident cause of death, Michael Milstein, a public information officer with NOAA told USA TODAY.

"Often if the whale has been struck by a ship the carcass will show wounds or hemorrhaging under the outside layer of blubber/skin, but they found nothing like that," said Milstein, adding that the cause of death "remains a mystery at this point".

Milstein said that the investigation team took tissue samples from the whale to review, but results may take a while.

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Moving the massive fin whale

Muñoz said that authorities arrived at the scene with heavy equipment including skip loaders to move the whale into the water so it would float and be towable. The process took several hours and while the lifeguards were finally able to tow the whale out, the whale sank when they reached 1.2 miles from shore.

"The tide may take the carcass out to sea or bring it back in – we just don’t know," said Muñoz.

The official said that on duty lifeguards will continue to monitor the whale and if the animal is observed coming back to shore, an attempt will be made to tow it out again.

The large animal was 52-feet long, according to NBC News.

NBC News reported that throes of people, including personnel from SDFD gathered around the whale, with some even touching the dead animal as lifeguards urged bystanders via their vehicle’s loudspeaker to leave the whale alone.

NOAA researchers eventually arrived on scene and created a perimeter around the whale with the lifeguards' assistance to prevent people from getting too close to the animal and interfering in the investigation, said NBC.

Fin whales are listed as an endangered species

Fin whales are the second-largest whale after blue whales and are classified as endangered species, as per NOAA. The mammal, that gets its name from the fin on its back, near its tail, is found in oceans across the world.

Milstein said that NOAA's latest stock assessment estimates about 8,000 fin whales off the West Coast. The officer said that they are steadily increasing in numbers as they "continue to recover from near-extinction in the whaling era".

Fin whales are less known than some other whale species as they are often found farther offshore and in deeper waters.

"They are not a common species to strand but it does happen," said Milstein.

Saman Shafiq is a trending news reporter for USA TODAY. Reach her at [email protected] and follow her on X, the platform formerly known as Twitter @saman_shafiq7.