The mystery surrounding 30 dead sharks found on a UK beach this week will likely never be solved, experts say.
On Tuesday morning (June 6) images emerged of around 30 starry smooth-hound sharks on Prestatyn beach in Denbighshire, North Wales.
According to the Daily Star, marine experts have described it as "worrying" and have been trying to work out what happened.
Rob Deaville is the project manager of the Cetacean Strandings Investigation Programme and also works on shark standings.
He said there is a "whole range" of possibilities, stating: "There’s been a lot of speculation about bycatch and discards, which is certainly a possibility. But there’s other factors as well. They might have been caught out by the tide and left high and dry as a group.
"There might be some social factor to this, some mating behaviour we’re not across yet.
"There may be other factors we can’t diagnose without a post-mortem [disease], although that’s perhaps less likely given the number of animals found together in a short space of time."
His colleague in Wales tried to recover some of the sharks but sadly they had been scavenged by predators. As a result, he said he doesn't think there's a way of determining what happened.
Gem Simmons, from British Divers Marine Life Rescue, also went to Prestatyn beach but was met with the same problem and was unable to take samples.
She said: "The first thing I wanted to check was whether they had any gill damage. There have been a few reports in the area of illegal gillnets but we haven’t got much evidence of that.
"We have found from talking to people on social media that there seems to have been a number of these [shark mass strandings]. This was certainly the biggest one."
A number of starry smooth-hound sharks were also found on a beach in Merseyside in May.
Sadly, Gem agreed we'll likely never know the definite cause of this week's stranding.
She was keen not to point the finger of blame at local fishing communities, who have aided animal rescue operations in the past.
She said: "I wouldn’t want to make an assumption. It could have had a completely natural cause. It could have been a current that brought them in together.
"My personal opinion is that this is worrying, particularly as so many other people have come forward and said they’ve seen potentially sinister stuff in the past few months."
The plan now, she explained, is to collate data on similar incidents in the area and pass it onto Natural Resources Wales (NRW), who are in charge of fishing licenses and could launch an investigation if necessary.
People who spot illegal gillnets (usually made from rudimentary equipment, placed on the shore during low tide and submerged when the tide comes in) should photograph them and report them to NRW.
Gem urged people to contact Marine Environmental Monitoring if they come across a group of dead sharks. She also issued a warning to beachgoers, particularly those with dogs.
Gem said: "It’s just about not removing them, not touching them in any way and also making sure your dogs don’t go near them. Because if it was something biological, an indicator of pollution or something like that, the last thing you want is something to be passed onto your dogs."
