Pollution could be to blame for rise in whales and dolphins washing up dead on British beaches, report finds

Whales and dolphins washing up on Britain's beaches have increased in the last seven years against the previous period.  - PA
Whales and dolphins washing up on Britain's beaches have increased in the last seven years against the previous period. - PA

Pollution could be to blame for the number of whales and dolphins washing up dead on Britain’s beaches nearly doubling in five years, a new report has found. 

The number of stranded marine mammals, including dolphins, whales, harbour porpoises and turtles, has risen from around 600 in 2012 to over 1000 in 2017, according to a seven-year review published by Defra and led by international conservation charity ZSL.

And chemical pollution, one of the biggest killers of marine mammals in the UK, is a significant, but “invisible", problem, according to Rob Deaville, cetologist and report author.

“The biggest issues we deal with are fishing gear and the issue of chemical pollution, that is a significant problem,” Mr Deaville told The Daily Telegraph.

“It’s a harder issue to sell because it’s an invisible problem, you can’t see it like you can see plastics on the beach, or plastics in animals stomachs. 

“We’re probably facing the localised extirpation of some (marine) populations in the UK and europe because of exposure to chemical pollutants." 

Harbour porpoises were the most commonly washed up marine mammals. - Credit: Kathy James/Seawatch Foundation /PA
Harbour porpoises were the most commonly washed up marine mammals. Credit: Kathy James/Seawatch Foundation /PA

Last year, a report by the University of St Andrews and ZSL found Britain’s last remaining Killer Whale pod could be wiped out due to chemical pollutants making the females infertile. 

The chemicals, polychlorinated biphenyls, known as PCBs, were once widespread in paints, adhesives and electronics but were banned in the 1970s.

But Mr Deaville said they still persist in the marine environment because they are "so resistant" to being broken down and other pollutants. While other chemicals, such as those used on the bottom of boats to prevent them from bowing, and flame retardants for sofas, are still leaching into the sea. 

“They are insidious, you can’t see them and so the perception is they are not a problem,” Mr Deaville said.

Researchers from the UK Cetacean Strandings Investigation Programme (CSIP) have been recording strandings since 1990, but 2017 represented the highest number in any single year.

This latest report found strandings have risen by 15 percent on the previous seven-year period, with nearly 5,000 mammals reported washed up on UK shorelines between 1 January 2011 and 31 December 2017.

The team conducted 1,030 post-mortem examinations to identify why individual animals had died.

Rob Deaville performing a post mortem on a porpoise at the Institute of Zoology, ZSL London Zoo.  - Credit: Dan John/ZSL /PA
Rob Deaville performing a post mortem on a porpoise at the Institute of Zoology, ZSL London Zoo. Credit: Dan John/ZSL /PA

Infectious disease and incidental entanglement in fishing gear - also known as bycatch - were two of the most common findings.

But the cause of the infectious diseases were commonly attributed to pollution from chemicals. 

Between 1991 and 2017, 753 mammals were diagnosed to have died as a result of infectious disease, making it the most common cause of death.  

Bycatch accounted for 23 per cent of common dolphin deaths and 14 percent of harbour porpoise deaths.

Others caused directly by humans included 25 animals killed by ship-strike and a single Cuvier's beaked whale that suffered a gastric impaction following the ingestion of marine litter in 2015.

Mr Deaville added although it is difficult to conclusively say what has driven the rise in the standings, multiple causes are likely to have contributed to the increase, including more reports of sightings and seasonal variation in the population density of some species.

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