A 28ft (9.5m) humpback whale (Megaptera novaeangliae) was found dead in the River Thames near the Dartford Bridge early on Saturday morning.

Scientists from the Zoological Society of London (ZSL) and members of British Divers Marine Life Rescue (BDMLR) received reports that a whale had been spotted in the Thames on Thursday afternoon, but no further sightings were made until the animal was found dead on Saturday and subsequently recovered by a Port of London Authority (PLA) patrol boat.

The team of scientists from ZSL, who were also involved with the rescue of the Thames whale in 2006 and the mass dolphin stranding in Cornwall last year, carried out a post-mortem examination of the juvenile male humpback whale in-situ in facilities provided by the PLA. The post-mortem examination was undertaken as part of the Defra funded collaborative UK Cetacean Strandings Investigation Programme (CSIP), which is managed by ZSL.

Rob Deaville, project manager of the CSIP said “Preliminary results from the post-mortem examination indicate that it may have died as a result of starvation, but further tests are still pending and may provide additional information about what happened to this whale”.

This is the first time that a humpback whale has been found in the Thames. The last humpback whale found stranded around the UK coast line was in 2007 at Port Talbot in Wales.

Rob Deaville added “There have only been 12 strandings of humpback whales in the UK in the last 20 years and this is an incredibly unusual event. Although it’s obviously a sad outcome in this instance, the post-mortem examination has given us a rare opportunity to examine a truly extraordinary animal at close quarters. Information gathered through examinations like these will hopefully help further our understanding of such animals and also help contribute to improving their conservation status.”

Strandings that undergo post-mortem examination can also provide a unique insight into causes of death, diseases, environmental contaminant levels, reproductive patterns, diet and other aspects of the general health of cetacean populations in the seas around our coasts. This provides important baseline data to help detect any future outbreaks of disease, unusual mortality events or responses to environmental change (e.g. climate change). Information from the post-mortem examination will be added to a database on stranded cetaceans, which is managed by the CSIP and provides an essential resource for identifying factors which may cause cetaceans to strand, helping to prevent these events happening in the future.