A beluga whale could have swum into the river Thames

The animal was spotted this afternoon near Coalhouse Fort in East Tilbury, Essex.

Dave Andrews, a consultant ecologist, posted a video on Twitter at noon on 25 September, saying, 'Can't believe I'm writing this, no joke - beluga in the Thames off Coalhouse Fort.

'It's been feeding around the barges for the last hour and hasn't moved more than 200m in either direction.'

Marine mammal experts could not be certain about identifying the species at first, but as more images were captured, evidence suggested that it was indeed a beluga.

Richard Sabin, curator of marine mammals at the Museum, says, 'The latest set of images and videos I’ve seen suggest very strongly that this is a beluga whale, Delphinapterus leucas. The white body colour, absence of a prominent dorsal fin, bulbous forehead and general swimming motion all suggest this very strongly.'

For anyone twitching the #BELUGA its been feeding around the barges (see last tweet for location) for the last hour and hasn't moved more than 200m in either direction. Still present. Heres another video @RareBirdAlertUK pic.twitter.com/S2qxKJyuuD

— Dave Andrews (@iPterodroma) September 25, 2018

Beluga whales (Delphinapterus leucas) normally live in Arctic and sub-Arctic waters, so any beluga in the Thames would be a long way from home. They can be found in the waters around Russia, Alaska, Canada, West Greenland, and Svalbard.

The International Union for the Conservation of Nature (IUCN) reports that belugas have been recorded as vagrant at Japan, New Jersey and Washington State USA, Iceland, Faroe Islands, Ireland, Scotland, France, the Netherlands, and Denmark.

Belugas live in estuaries, continental shelves and slopes, and deep ocean basins in open water, loose ice, and heavy pack ice.

Belugas do swim up rivers in shallow waters, but they do not usually venture this far south, and they tend to stay in social groups. 

The Whale and Dolphin Conservation Society told the BBC that the whale was "obviously very lost and quite possibly in trouble".

In a statement on their website, the Society said, 'Beluga whales are easily identified by their distinctive white markings. While porpoises and dolphins are occasionally seen in the river, sightings of other species are rare.

'Beluga whales inhabit cold, arctic waters off Greenland, Svalbard and in the Barents Sea. There have only been around 20 sightings of beluga whales off the UK coast previously but these have occurred off Northumberland, Northern Ireland and Scotland.'

British Divers Marine Life Rescue will make a decision about intervening with the whale's progress and have sent a representative to the scene.

The Thames whale

This isn't the first whale to lose its way in the river. It's been just over a decade since a northern bottlenose whale swam into the River Thames and drew thousands to watch the dramatic rescue attempt.

On 19 January 2006, a six-metre-long female northern bottlenose whale swam into the River Thames in London.  It had ventured a long way from its home in the deep waters of the North Atlantic.

Richard says, 'The Thames is tidal through central London and changes from salt to fresh water away from the Thames Estuary.

'Whales aren't adapted to life in freshwater courses so unless there is a problem, they normally only appear in our rivers for a short period of time before returning to the sea.'