White orcas, once rare, becoming more common
It was only six years ago, on 11 August 2010, whale researchers working in the western North Pacific first encountered something very unusual: a white male killer whale, or orca. Since then up to as many as eight have been observed.
Far East Russia Orca Project (FEROPS) scientists have just published a paper in the journal Aquatic Mammals in which they document the existence of 5 to 8 white orcas in Russian waters.
An albino orca viewed in the wild is something not very often experienced due to the fact that they are believed to have a very short lifespan.
Iceberg an all-white male orca, was the first one spotted off Russia's Commander Islands in the North Pacific in 2010 by FEROPS scientists and then seen again, in 2012.
Believed to be about 22 years old now, the whale has appeared healthy on the numbers of occasions it has been spotted. Scientists do not yet know why the whales are white, but some think their white colouring could be caused by albinism.
The latest spotting of Iceberg was recorded by American researcher Erich Hoyt, 65, of the Far East Russia Orca Project who was also the very first person to see the animal in 2010.
He told the BBC at the time: "We've seen another two white orcas in Russia but they've been young, whereas this is the first time we've seen a mature adult.