SHIPS exploring for oil off Scotland may have been to blame for disorienting a whale that swam up the Thames in London last January.

Millions watched on television or lined the banks of the Thames to cheer on rescue teams as they vainly tried to save it. Now an autopsy on the female northern bottlenose whale has indicated that humans not only failed to save the creature but also were largely to blame for its death.

In its final weeks the whale was poisoned, starved and possibly disoriented by the sonar booms of the oil industry. In the end the well-meaning attempts to save the animal may have hastened its death.

Hundreds of miles from its north Atlantic hunting grounds, it was so desperate for food that in its last minutes it was scavenging through the muddy shallows of the river.

After its death the animal was cut up by the government-funded cetacean strandings project and pieces sent to experts to chart the creature’s final days and establish how it died.

Preliminary results from a postmortem earlier this year suggested dehydration and muscle and kidney damage had contributed to its death at the age of about six years. Its typical life expectancy is 40 to 50 years.

Experts have found that its last meals consisted of algae from the riverbed, part of a rubber glove worn by one of the rescuers and a small potato.

“The potato was right at the front of its stomach, so it is probably something it swallowed as little as an hour before it died,” said Colin MacLeod, a marine biologist from Aberdeen University, who carried out the autopsy on the whale’s stomach.

The examination showed the whale’s last decent meal was at least a fortnight before its death. It consisted of hundreds of squid, of which only the beaks remained, in the whale’s deepest stomach.

An analysis of the whale’s blubber and liver showed its body was laced with toxic chemicals used in paints, pesticides and detergents. The most toxic were PCBs, banned in the 1970s.

This finding suggests pollution may be reaching farther out to sea than previously thought, as northern bottlenose whales are deep-sea feeders.

The scientists’ findings — to be shown on a Channel 4 documentary this Thursday — also suggest humans played a role in the whale ending up hundreds of miles from its usual habitat.

Northern bottlenoses spend much of their time in the Norwegian Sea and the Arctic. Summer migration takes them southwest into the north Atlantic Ocean.

However, MacLeod said possible changes in water temperature caused by climate change had driven the whale’s main food, the gonatus armhook squid, into the North Sea.

“If the whale then followed its natural migratory instincts to go south and west it will find all its pathways blocked by coastline,” said MacLeod.

Another theory is that the whale’s disorientation was caused by ships’ sonar. Some have blamed the Royal Navy. But Professor Rodney Coates, an expert in marine acoustics, says the culprits may have been ships exploring for oil off the coast of Scotland. They fire sound waves at the sea bed from giant guns, analysing echoes for the presence of oil and gas.

After entering the Thames from the English Channel, the whale swam 33 miles up the river to Battersea Bridge.

When attempts to usher it back to sea failed, rescuers tried to lift it on to a barge to carry it out to sea. Experts now admit they may have put an unbearable strain on the whale by lifting it out of the river. One hour after being loaded on to the barge it died, its main organs failing through shock.

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