By Clare Gabriel BBC Wales News website

Experts believe the fin whale was blown off course

Three whales have beached at different points on the Welsh coast in the past week, one was dead, the other dying but the third was put back out to sea.

It is over 100 years since three were washed up in such a short period.

Although experts do not know why, some say it is at best suspicious - and at worst "sinister".

The biggest whale to be washed up was a mighty fin whale on mudflats near Newport in south east Wales last Thursday.

We're ruling out coincidence, but more than that we can't say Countryside Council for Wales

The animal, measuring 18.45 metres and weighing 40 tonnes, had died and a huge operation had to be set up to carve the carcass up where it lay and then dispose of it.

But that was just the start.

On Monday, a Sowerby's beaked whale washed up at Llangrannog in Ceredigion on the mid Wales coast. Rescuers managed after several hours to get this one back into the water.

Rescuers managed to get this Sowerby's beaked whale back in the sea

Records show the last time one of this species beached in Wales was in the Mumbles, Swansea, in September, 1938.

But hours later, another Sowerby's was found a few miles further along the coast at the Parrog in Newport, Pembrokeshire.

Sadly, this one could not be saved and a post-mortem examination has being carried out at London Zoo.

Add to this another Sowerby's found at Rosslare on the other side of the Irish Sea, along with a minke whale at the same location, and wildlife experts say this is no coincidence.

"It's a cause of concern," said a Countryside Council for Wales spokesman. "We think it is suspicious".

Sonar is something the Navy takes responsibly and has spent millions on mitigating its effects Ministry of Defence on claims sonar could affect marine life

"There have also been unusual numbers of dolphins and porpoises stranded alive on the beaches around Wales and the south west of England."

"We're ruling out coincidence, but more than that we can't say".

One theory, the council believed, was that the stricken whales had suffered a form of the bends - the debilitating condition which affects divers who surface too quickly.

The animals could have also surfaced too quickly after hearing a loud noise.

Disposal of the fin whale's carcass was a mighty task

But Cliff Benson, chairman of the Sea Trust of south and west Wales, the marine arm of the Wildlife Trust of South and West Wales, said he believed the latest beachings on either side of the Irish Sea were "sinister".

He said marine wildlife experts were concerned because the Navy had been trying out a new sonar system in the area, and there was good evidence that the sonar could be detrimental to whales and other animals.

He supported the theory that the animals could have been blown off course by the "concentrated, devastating noise of the sonar".

Mr Benson said around 30 whales had washed up off the coast of the Canaries following a Nato exercise involving the use of sonar around three years ago.

Mitigating

However, a Ministry of Defence spokesman said no sonar trials had been carried off the coast of Wales in recent months.

"We trialled it much earlier in the year and last year off the south west and north west coast of Scotland," he said.

Wildlife experts have also been taken on board the ships trialling the sonar system.

"Sonar is something the Navy takes responsibly and has spent millions on mitigating its effects, " said the spokesman.

Richard Sabin, the UK strandings co-ordinator at the Natural History Museum in London, said the last time three whales had washed up in such a short space of time was more than a century ago.

Sightings of the "mysterious" Sowerby's beaked whale were especially rare and normally only off the north and east coast of the British Isles.

"This is an unusual occurrence and we need to see if there is a common causal factor," said Mr Sabin.

Two other fin whales had become beached - in Liverpool Bay and the Solent in the south of England - in the past two months.

These and the one which showed up near Newport last week could have been young animals migrating north from the Bay of Biscay which had somehow got blown off course.