Is it a blue whale or not? The slaughter in Iceland of what is claimed was a member of the endangered species has triggered outrage and left experts puzzled about its true identity.
"There has not been a blue whale harpooned by anyone for the last 50 years until this one," Sea Shepherd, an international non-profit marine conservation movement, said in a statement on Wednesday.
The group, which published photos of the mammal being butchered for export at an Icelandic whaling station on the night of July 7, said the fishermen "posed for photos next to and even on top of the whale in a sign they knew very well this was a rare blue whale".
But Icelandic experts are not completely certain whether it is indeed the world's largest leviathan, which the International Whaling Commission has been protecting since 1966.
They're also not sure if it could be the endangered fin whale, the second largest animal on the planet, which can only be legally hunted in Iceland despite an international moratorium on whaling.
Kristjan Loftsson, CEO of Hvalur hf, the whaling station which slaughtered the animal, said they did so believing it was a fin whale.
Most of the fin whales killed are exported as meat to Japan.
"We see blue whales all the time and identify them by their blowholes...but we leave them alone," he told AFP.
For Gisli Vikingsson, a scientist at the Marine and Freshwater Research Institute in Reyjkavik, the butchered whale's characteristics are similar to both the blue and fin whale.
"There is a large dorsal side with a small dorsal fin like a fin whale...this explains perhaps why it was hunted as such," he told AFP, adding its "size and markings on the side are like those of a blue whale."
He added the whale could even be a hybrid species resulting from cross-breeding between the fin and blue whale, which is a rare phenomenon.
Since 1987, five such animals have been observed in Icelandic waters and they are known to be infertile.
All killed whales in Iceland undergo DNA tests after the hunting season and the results are released during the fall.
However, due to the controversy surrounding this particular case, a test will be done earlier than planned and the results are expected at the end of July.
But Sea Shepherd said the fishing crew which butchered the animal mixed its parts with previously caught fin whales, making "it difficult or impossible to locate during potential inspections by the authorities".
"This shows how inaccurate and imperfect this hunting is and there is no need to continue it," Sigursteinn Masson, Iceland representative for the International Fund for Animal Welfare, told AFP.
Should the killed whale be confirmed as a hybrid, then things could become even more complicated as there are no laws to protect them.
"Hybrids are much rarer than the blue whales," Masson said.