Just after midday on Thursday 19th January, the Port of London Authority telephoned us to report a whale swimming in the Thames Estuary on the south side of the Thames Barrier near Ford’s Jetty, Dagenham, Kent. The observer, Martin Pattison, described it as about 20 feet long, dark grey, with a rounded dorsal fin slightly forward of the centre of the back, and surfacing slowly before diving. On the basis of the length estimate, we suggested four options: minke whale, northern bottlenose whale, long-finned pilot whale, and killer whale (but we felt the last was unlikely from the description). The description of the position and shape of the fin actually fitted pilot whale closest (a cautionary point that observers don’t always describe accurately what they see). However, we sent an identification guide to the observer to help confirm him species identity, and gave the Port Authority the telephone number for British Divers Marine Life Rescue (BDMLR) so they could keep an eye on the whale. We had no more sightings of the whale reported to us that day (but later gathered it was seen by others at Greenwich Ferry terminal around 4.30 pm, whilst Liz Sandeman of Marine Connection heard of a sighting of two animals in the Estuary on the Wednesday).
Early on Friday, the whale was sighted well up the river Thames first at Greenwich (around 4.30 am) and then near Westminster (9.30 am) in Central London. It quickly attracted crowds of people including the media, and Sky News started televising it on a continuous basis. By this time, we were bombarded by the media with questions as to its identity and what it was doing there. Our North-east England Regional Co-ordinator, Andy Tait, rushed into a TV store in Newcastle to watch it on Sky News, and confirmed that it was indeed a northern bottlenose whale! The next question to answer was what was it doing there. Either it was in ill health or it simply had become lost in the shallow reaches of the southernmost North Sea, given that its usual habitat are offshore canyons of more than one thousand metres depth such as found northwest of the Shetland Islands, west of the Outer Hebrides, or to the south in the Bay of Biscay. A report of another northern bottlenose whale from near Southend-On-Sea, Essex was conveyed to us, and together with two whales thought to be of this species seen from Aberdeen on Tuesday 17th January, suggested that this Thames whale may have been part of a larger group. Speculating further, the presence around this time of other squid feeding cetaceans (Risso’s dolphin, striped dolphin and long-finned pilot whale – and more recently, sperm whale) in coastal waters of the North Sea indicated that maybe there were unusual quantities of squid temporarily in the region that may have encouraged the species to enter the North Sea.
Whatever the cause for its presence in Central London, the whale was unlikely to survive there for long in the shallows of the river, nor be readily able to find its way out of this narrow busy waterway, and so a rapid rescue was recommended, preferably to the nearest open water rather than returned to the southernmost North Sea. The whale in fact temporarily stranded a few times before the tide started to rise, allowing it at least to move eastwards a bit towards the end of the day. Nevertheless, it was still high up the Thames in the vicinity of Westminster Bridge.
By Saturday morning, news of the whale seemed to grip the nation and beyond, with TV, radio and newspapers reporting it from the United States and Canada to Australia and New Zealand. At lunchtime, the whale remained far upriver between Albert Bridge and Battersea Bridge. So early in the afternoon, BDMLR with help from Zoological Society of London (ZSL) vets, and others, successfully lifted the whale out of the river and onto a barge where it was transported back out to the Thames Estuary. However, sadly, around 7 pm that evening, the whale started convulsing and died. The results of a blood sample taken shortly after the whale was lifted onto the large barge showed that the whale was already suffering severe dehydration and kidney failure as well as some mild muscle damage.
Over the coming days, a team of ZSL vets and scientists led by Dr. Paul Jepson conducted a post mortem of the whale assisted by Professor Antonio Fernández and Dr. Manolo Arbelo (University of Las Palmas, Gran Canaria). The whale was an immature female of 5.85 metres length. Her stomach contained a n umber of squid beaks but she clearly had not fed for some time. The postmortem examination showed no preliminary signs of acoustic trauma or gas emboli (which have been known to cause strandings of beaked whales in the past).
Our general conclusion is that it may have entered the North Sea with others, following squid, and then lost its way, ending up in the southernmost North Sea where it was unable to find its way back into the Atlantic and instead travelled west up the river Thames. The lack of squid (which are an important source of water) over a period of time may have contributed to the whale’s dehydration, and its extended period in very shallow water probably was the cause of its relatively mild muscle damage.
To our knowledge, no other northern bottlenose whale has been recorded this far up the river Thames. However, there have been a number of other records from the Thames Estuary. These include: a female caught off the Essex coast on 23 Sept 1717; one of 6.4 m length captured in the Thames in 1783; one stranded in 1817 on the Essex coast; two males seen in 1891 off the Essex coast (one of these stranded at the end of July, and the other was caught on 3rd August; the latter measured 7.6 m). The stranding occurred in the Thames near Nore Lightship, and was eventually towed into Leigh-On-Sea, Essex. The latter was caught near Creeksmouth, Barking, Essex. More recently, on 9 Oct 1916, one (5.5 m length) stranded at Mucking, Essex. A London record (near Albert Dock, Woolwich Arsenal) from November 1899 reported in some of the national newspapers as the last report of northern bottlenose whale in the Thames, was actually a fin whale.