A whale which beached on the Northumberland coast this week was a rare species and not a minke, experts have confirmed.
The 8.6-metre creature was a juvenile sei whale which had likely become separated from its mother, said Richard Ilderton of British Divers Marine Life Rescue.
It was discovered on sands just north of Druridge Bay yesterday morning, sparking a major operation to save its life.
However, experts who attended the scene found that it was suffering from severe malnutrition and were forced to take the decision to put it to sleep.
A pathology team from the Natural History Museum’s Cetacean Stranding Investigation Project travelled to the scene to conduct a post-mortem, which determined that the whale was starving to death.
Mr Ilderton said: “It was in a very poor condition, with thin blubber and poor muscle tone, suggesting it hadn’t eaten for quite some time. It is possible that it was still maternally-dependant, but had become separated from its mother.
“The preliminary results from the post-mortem confirmed this, and it also had plastic in its stomach.”
He added that minke and sei whales appeared very similar, which had led to the initial misidentification. While it was the same length as an adult minke, however, adult sei whales reach twice that length.
“Another reason it wasn’t recognised as a sei whale more quickly is that they are rarely found beached in Britain,” said Mr Ilderton. “Since 1990 there have only been six recorded and 16 since records began in 1913.”
The sei is a type of baleen whale and the third-largest rorqual after the blue whale and the fin whale. It is officially endangered, appearing on The International Union for Conservation of Nature’s ‘red list’ of species.
A fully-grown adult can reach 19.5 metres in length (65ft), with a weight of 28 tonnes. In a single day, it consumes an average of 900kg (2,000lb) of krill and other zooplankton.
The sei ranks among the fastest of all cetaceans and can reach speeds of up to 50kph (31mph) over short distances.
Population is distributed worldwide, with the exception of tropical and arctic zones, and it prefers deep offshore waters.
They migrate annually from cool and subpolar waters in summer to winter in temperate and subtropical waters.
The name sei comes from the Norwegian word for pollock, as they normally appear near to large shoals of the fish.