By Matt Walker
Editor, Earth News
The whale is seen again off Barcelona
A mysterious gray whale sighted off the coast of Israel in the Mediterranean Sea has been seen again off the north east coast of Spain.
The second sighting, made 23 days and 3000km after the first, has continued to perplex whale experts.
Gray whales were thought to be extinct across the Atlantic Ocean, so the appearance of an individual within the Mediterranean Sea was a major surprise.
Now it is not clear where the whale is heading or why.
Once, three major populations of gray (also spelt grey) whale existed: in the western and eastern North Pacific Ocean, and in the North Atlantic.
However, the North Atlantic population of gray whale became extinct sometime in the 17th or 18th Century, for reasons that are not clear.
No sightings of the species had been made in the Atlantic Ocean since.
That was until a single individual gray whale was sighted off the coast of Herzliya Marina, Israel on 9 May this year.
That sighting excited and bemused experts: it could either mean that the gray whale had recolonised the Atlantic Ocean, or that a single gray whale had shattered the record for the longest known migration by the species, which usually make a round trip of 15-20,000km each year.
Previous sighting off Israel
On 30th May 2010, members of SUBMON, a non-governmental organisation dedicated to the conservation and assessment of marine habitats, sighted a gray whale in front of Barcelona's harbour.
Whale expert Manuel Castellote at the US National Marine Mammal Lab compared photos of this whale with those taken earlier in May in Israeli waters.
These comparisons confirmed the match, the Whale and Dolphin Conservation Society (WDCS) have announced.
"It's wonderful news to hear of a resighting of this animal, where it's heading is the burning question," says Nicola Hodgins of the WDCS, which has its headquarters in Wiltshire, UK.
The whale appeared to be consistently heading south at a slow pace.
It is the first time a gray whale has been seen in the western Mediterranean Sea.
"Its likely route would be to leave the Mediterranean, and then head north along the coasts of Portugal and France, possibly coming as far north as the UK and North Atlantic waters" says Ms Hodgins.