The Thames Whale - remembering the events ten years on

Rob Deaville

10 years ago a northern bottlenose whale captivated the nation and the world's media when it swam up the River Thames. Rob Deaville, of the Zoological Society of London, was part of the team of experts who attempted to save the Thames whale.

On 20th January 2006, reported sightings of a whale in the Thames began to emerge. It soon became clear that something extraordinary was happening. Today marks the tenth anniversary of the events around the stranding and attempted rescue of what is now known simply as the ‘Thames Whale’. 

Whale in Thames 2006

When we first heard of the sightings, we were keen to learn what we could, so the river police kindly agreed to take us out onto the river to look for it. When we located the whale adjacent to the Peace Pagoda in Battersea Park, we were surprised to see the large, bulbous melon on the head, indicating that it was a northern bottlenose whale (Hyperoodon ampullatus).

They’re more normally found in deep waters off the continental shelf edge, so the North Sea, let alone the river Thames, is a highly unusual place to see them. 

 

British Divers Marine Life Rescue (BDMLR) is a UK charity based in East Sussex, which responds to live strandings throughout the UK and they mobilised their members once it became clear what was happening. Our experience with cetaceans in the Thames has taught us that anything that far up the river system may be facing significant risk, particularly a deep diving species like the northern bottlenose whale. 

On the morning of 21st January, we heard from BDMLR that the whale was still in the Thames and had reportedly stranded several times overnight. This led to the decision to deliberately beach the whale at low tide, partly so it could be assessed by our ZSL veterinary team (Paul Jepson and Becki Lawson). A barge was provided by the Port of London Authority (PoLA) at short notice and the whale was carefully winched on board. The plan was to try to move the whale into deeper water and release it, but only if it appeared still to be in a good enough condition.

Nothing like this had ever been attempted anywhere in the world, so we were all understandably nervous as the lift proceeded.  

 

Thames whale being assessed in the water by ZSL and BDMLR

Once the whale was on board, the barge moved swiftly downstream. Other boat traffic was kept to a minimum by PoLA to aid our transit. As the barge continued its journey downstream, hordes of people lined the side of the river and along every bridge, cheering us as we moved along the river.

One of my abiding memories of that day is moving out into the wider part of the estuary, with the banks of the Thames over a kilometre away, but still dimly hearing people cheering and applauding out of the darkness. 

Sadly, the rescue attempt didn’t succeed and the whale began to convulse at 7pm and it died shortly after my ZSL veterinary colleagues had taken the decision to euthanise it. The boat turned around to shore and the lights on the deck went off. The mood was sombre as we drew closer to shore, where we would unload the body of the whale. 

The next day, we carried out a post-mortem examination on the whale at a port facility in Gravesend where PoLA had given us permission to work. We found that the 5.85m juvenile female was in reasonable nutritional condition, but there was no evidence of recent feeding.

Numerous beaks from the squid Gonatus fabricii were found in the first stomach, illustrating the specialised deep water feeding behaviour of this species. The cause of death was believed to be the result of a combination of factors; including severe pre-existing dehydration and stranding related pathology, which eventually lead to multiple organ failure.

Thames whale Gonatus gonatus squid beaks from stomach of NBW

What have we learnt since the events of 2006? Well, there have been several other live strandings of northern bottlenose whales in the UK after the Thames whale. Blood samples were taken whilst the whales were alive and these also demonstrated that deep diving species such as these are always at risk when they enter coastal regions.

As obligate deep sea feeders, they are unable to feed effectively in the shallow North Sea. They consequently become dehydrated, as they obtain their fluid intake from their diet and if they subsequently live stranded, this would lead to further compromise of the animal.

So in response, the triage or policy of dealing with live strandings of deep water species like this in the UK changed in 2009 and if a northern bottlenose whale were to enter the Thames again, we would probably try to euthanize it on welfare grounds rather than attempt a rescue like the one in 2006. 

thames whale 2006 Head close up

We have also learnt much about this species from the examination of the Thames whale and others like it. Tissues recovered from the whale have entered the national marine mammal tissue archive held at ZSL, providing a vital scientific resource for worldwide research and conservation biology. These samples have helped inform numerous areas of research since the events of 2006, including the population structure of this species, dietary studies and the physiology of deep diving species. The whale’s skeleton was also prepared and placed within the Natural History Museum’s skeletal collection, to aid future academic research.

Our experience with the Thames whale was unforgettable and demonstrated a clear message of the nation’s passion for these animals and their conservation. 

I was particularly struck by the extraordinary reaction of the public, the great response by BDMLR volunteers and the significant cooperation with the Port of London Authority and the river police.

It’s also interesting to contrast the reactions of the public in 2006, with those in less enlightened times. London was at the centre of the whaling industry not too long ago and if the whale had swum up the Thames then, there would have been a far different outcome. So we’ve moved from being a nation of whalers to a nation of conservationists in a really short timescale and this has to be an important conclusion that can be drawn from the events of January 2006.

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