Fewer people are reporting sightings of the Loch Ness monster, amid concerns scepticism about its existence could threaten tourism in the region.

There have only been two reports of sightings this year, compared to three in 2006 and much lower than a decade ago, when the annual number sightings was consistently in the double digits.

"It's becoming a potential crisis," said Mikko Takala, 39, a founding member of the Loch Ness Monster Fan Club who runs four webcams on the lake's north shore.

Loch Ness is about 750 feet deep and is deeper than most parts of the North Sea.

There have been more than 4000 purported sightings of "Nessie" since a surgeon vacationing at the lake in the 1930s released a photo allegedly capturing the legendary monster on film.

Since then, the monster has been a key tourism draw, bringing an estimated £6 million a year into the Highland economy.

The faithful have speculated whether Nessie is a completely unknown species; a sturgeon, even though they have not been native to Scotland's waters for many years; or even a last surviving dinosaur.

In the age of digital cameras, webcams and video recorders, it is surprising that the number of reported sightings is falling.

Adrian Shine, 58, a naturalist who has investigated the mystery of the monster for 20 years, thinks the trend shows the world has become more sceptical.

"I think we live in a more pragmatic age, and that people are becoming more aware of the sort of illusions that can occur on water," he said.