Factcheck: Will climate change bring great white sharks to UK waters?

Last week, many news publications reported on “a new study” claiming that climate change could lead several shark species to move into UK waters.

For example, an article in the Daily Telegraph said that, as a result of climate change, “dangerous sharks including great whites and oceanic white-tips could be swimming off the beaches of Cornwall within the next 30 years”.

The Independent, Times, Daily Mail, Press Association, Guardian, BBC News and the i newspaper were among the outlets carrying variations of the story.

However, Carbon Brief has discovered that there was no scientific study. Instead, the news was based on the personal opinions of one shark specialist. The scientist had been approached for comment by representatives of Nat Geo Wild – a network TV channel run by National Geographic – who were promoting a series of programmes about sharks.

Carbon Brief has spoken to the researcher, as well as several others, to try to establish whether there is any truth to the idea that great whites could one day inhabit UK waters.

What happened?

The media coverage first began at one minute past midnight last Tuesday (17 July) when several outlets, including the Press Association, Daily Mail, Times, Independent, Sun, Daily Mirror and the i newspaper, published stories. The Daily Telegraph published slightly later at 6.41am.

The reason most outlets published at this time was because the story had been subject to a press embargo. (Journalists are often sent press releases, scientific research and reports ahead of official publication to give them time to plan their news coverage.)

All of the news reports were based on the announcement that 10 shark species currently found in more tropical climates could move into the UK as seas continue to warm due to climate change.

The stories all carried identical – or very similar – quotes from Dr Ken Collins, a senior research fellow within ocean and earth science at the University of Southampton. In most of the articles, Collins was described as having led “new research commissioned by Nat Geo Wild”.

However, several discrepancies existed between the initial reports. For example, most stories claimed that 10 shark species could move into UK waters as the climate warms – but the Daily Mail inexplicably reported that 11 species are likely to arrive.

Similarly, most outlets said that the sharks are due to arrive by 2050 – but the Sun knocked two years off this figure, claiming that they will be “hunting in British waters by 2048”.

There was also confusion about how and why the “research” was carried out. The Press Association, Sun, Daily Telegraph, Daily Mail and the i newspaper all described the news as originating from “a study” – while other outlets described it as “new research”.

A story published by BBC News later on the same day said the news came via “research from the University of Southampton”, whereas the Daily Mirror described it as originating from a “study by respected research institution National Geographic”.

However, the most divisive aspect of the story appeared to be whether or not great whites were among the sharks that could soon be entering UK waters.

The Sun, Independent, Daily Telegraph and Daily Mail mentioned great white sharks in either the headline or top line of their stories.

But several publications – including BBC News and the Press Association – did not mention great whites at all.

Coverage of the story continued throughout last week. The Guardian – which, the following day, produced a picture gallery of some of the sharks that could appear in UK waters – also referred to the news as “research from the University of Southampton”.

By Thursday (19 July), the Daily Mail had alluded four times to the news that “great whites could be swimming in British waters”.

On Wednesday, the paper mentioned the “research” in a story about a blue shark being spotted in Cornwall with the headline: “We told you they were coming!” The news was also mentioned in a comment piece by wildlife broadcaster Steve Backshall – who urged the public not to fear the presence of sharks in UK waters.

On Thursday, the “research” was mentioned again in an article about a man who had been bitten by a seal.

By Friday (20 July), local newspapers had covered the news. The Brighton Argus carried new comments from Collins under the headline: “Great white sharks off Brighton beach by 2050, says expert.”

Over the weekend, the Sunday Times carried a comment piece from Philip Hoare, an author and friend of Collins, which explored how the arrival of new shark species could affect fish already residing in UK waters.

Where did the stories come from?

To better understand why the coverage began, Carbon Brief has located the press release circulated to journalists via email prior to publication.

The press release – which is reproduced in full below – was created by London-based press relations company Taylor Herring on behalf of Nat Geo Wild.

The press release sought to promote “Sharkfest” – a series of programmes about sharks that aired on the TV channel from 16-22 July.  (Click the image to expand.)

(The University of Southampton also released a “report” detailing the news. However, Carbon Brief understands that this was released after the story had first appeared in the media.)

Under the headline, “Sharking hell! Hammerhead and blacktip sharks coming to UK waters”, the Taylor Herring press release lists “10 new species of sharks that could inhabit British waters by 2050”.

The species on the list include the great hammerhead, blacktip shark, sand tiger shark, bigeye thresher, longfin mako, copper shark, oceanic whitetip, silky shark, dusky shark and goblin shark.

Promotional video made for Taylor Herring’s press release.

The press release claims that the list was created as part of “ground-breaking new research by Dr Ken Collins”, which had been “commissioned specially by Nat Geo Wild”.

However, speaking to Carbon Brief, Collins says the list was created as a result of “simple speculation” and is “by no means a scientific study”. He adds:

“It’s not research. It’s opinion. I’ve looked through distribution records and used personal opinions and it is not formal peer-reviewed research.”

Collins tells Carbon Brief that, after being approached by Nat Geo Wild, he spent around “a week” reading scientific papers, studying shark distribution records and considering his own knowledge of historical shark sightings in UK waters in order to create the list. He says:

“I walked into this realising that the nonsense would happen, but, on the back of this, I was trying to spread a conservation message.”

Carbon Brief approached representatives of Nat Geo Wild and Taylor Herring to ask why they felt it was appropriate to describe Collins’s comments as “groundbreaking new research”. At the time of writing, they had not responded to Carbon Brief’s request for comment.

A spokesperson from the University of Southampton tells Carbon Brief:

“We weren’t fully aware of this until the media started to take an interest based on a press release which refers to new ‘research’. We support Ken’s involvement in activities to raise awareness and understanding of sharks, making his experience and academic expertise accessible to a wider audience. We are also aware of the importance and need to maintain the integrity of research, which we work hard to uphold through our media relations activities.”

What about great white sharks?

The press release shown to journalists did not include great whites in its list of 10 shark species that could migrate to UK waters as a result of climate change. Despite this, the possible arrival of great white sharks dominated the news coverage.

Further down in the press release, Collins did mention great white sharks. His quote reads:

“There is considerable debate as to whether we have great white sharks in UK waters. I see no reason why not – they live in colder waters off South Africa and have a favourite food source, seals along the Cornish coast. The only argument against there being great white sharks in our waters is that numbers worldwide are declining so the chances of seeing one around the UK fall year by year.”

In this quote, Collins is commenting on the possibility that great whites could already be swimming in UK waters. (Some anglers and fishermen have reported seeing great whites in recent years – but these sightings have not been confirmed by scientists.)

This quote is included in a number of the reports claiming that Collins believes climate change could cause great whites to appear in UK waters – including in the Daily Telegraph and the Independent.

The Independent runs only part of the quote. It reads:

“As for perhaps the most feared shark species, the great white, Dr Collins said he saw ‘no reason why’ these creatures would not find their way to British waters. ‘They live in colder waters off South Africa and have a favourite food source – seals along the Cornish coast,’ he said.”

The Sun and the Daily Mail carry additional quotes from Collins that are not included in the press release. In both papers, Collins is quoted as saying: “It would not take much of a change in water temperature from climate change, maybe less than one degree, for them to come here.”

However, Collins tells Carbon Brief that he does not believe that climate change would cause great white sharks to the UK.

This is because great whites are already known to swim in sea temperatures similar to those currently found off the coast of the UK. He believes that, at present, the “odd one” might venture close to the UK, but, he says, “there isn’t massive shoals of them ready to eat the entire surf population of Newquay”. Collins adds:

“We don’t need climate change for great white sharks to come to us. Some of the tabloids said, ‘Dr Ken Collins said great whites are running towards us’, but I actually said the reverse. The chances of seeing them year on year are declining.”

Great white sharks face threats from sports fishing, trophy hunting and habitat degradation. They are currently considered “vulnerable” to extinction by the International Union for the Conservation of Nature Red List. Due to these threats, great whites could be “less likely” to swim in UK waters by 2050, Collins says.

What do other scientists say?

While investigating the topic of sharks and climate change, Collins says he was particularly influenced by one scientific paper. This research, published earlier this year in Global Change Biology, investigates how sea temperature influences the distribution of tiger sharks off the coast of eastern Australia.

In this paper, the researchers report that tiger sharks are most commonly found at sea temperatures of 22C – with fewer sharks found at temperatures above and below this, says study lead author Dr Nick Payne, a marine biologist from Trinity College, Dublin. He tells Carbon Brief:

“It’s one thing to say: ‘This particular species is most commonly found at this particular temperature’. But the risk with this is that it might actually have nothing to do with temperature – it might be to do with the type of habitat that’s found at 22C, or the type of prey that’s found at 22C.”

To find out why tiger sharks prefer sea temperatures of around 22C, Payne’s team fitted sharks with accelerometers, which measured the animals’ activity levels at different temperatures. He says:

“We found that they were most active at around 22C. So, by combining those two things together, you show that not only are tiger sharks most abundant at 22C, they’re also the most active at 22C. Those two things in combination provide strong evidence that temperature, per se, is influencing the distribution of these animals.”

The results suggest that, if sea temperatures continue to rise, tiger sharks could be forced “further poleward” to find their optimum temperature, Payne says:

“Getting the kind of data we got for tiger sharks shows, at least for that species, there’s a good chance that, as water temperatures start to increase, they’re going to start pushing away from the equator towards the poles. I think that’s probably the key message that Ken would have taken from our paper.

“While there isn’t, perhaps, evidence showing that the specific sharks that Ken talks are definitely going to appear in UK waters, I think the logic behind those predictions is something I’d agree with.”

Payne also agrees that a rise in sea temperatures would not change the chances of great whites appearing in UK waters. He says:

“Some of the temperatures we’re finding great whites at around the southern hemisphere – around south Australia and south Africa – we already experience those temperatures in the UK, particularly in southern UK, and Ireland. The temperature for the habitat of great whites is already occurring here. We don’t need increased temperatures for UK waters to become suitable.”

Additionally, great whites may be prevented from coming close to the UK by a lack of available prey, says Dr Peter Cotton, a marine biologist from the University of Plymouth. He tells Carbon Brief:

“The main reason that they are not regular visitors here is that there is relatively little for them to eat. Of course, if climate change increases the number of tuna in the UK, there will be something to eat.”

(A previous report from the UK Marine Climate Change Impacts Partnership found that warming sea temperatures could facilitate the return of bluefin tuna to UK waters.)