Gary Campbell, keeper of the Official Loch Ness Monster Sightings Register, admitted that he was ‘worried’ by the lack of sightings, adding: “Last year was a record year with eight sightings but then she seems to have disappeared.”
Nessie usually appears in the summer, although it isn’t unheard of for her to be spotted during the winter months.
Despite the high number of Nessie sightnigs in 2016 - the best year since 2000 - the last recorded sighting of Scotland’s most famous resident was on August 21 last year.
In September, a whisky warehouse worker snapped what appeared to be one of the most convincing images of Nessie.
But friends of Ian Bremner believe the 58-year-old took a photo of three seals in the loch.
However, Mr Bremner’s picture fits in perfectly with the widely-believed description of Nessie being a long serpent creature which stretches as far back as the early 1930s.
Mr Bremner’s photograph closely resembles some of the most notable examples of the creature.
Encounters from 1933 report a 10ft long limbless creature crossing the road leaving behind a slimy trail of undergrowth.
And in 2001, two fishermen reported seeing a dark 6ft long blob sticking its head out of the water - but were adamant that it was not a seal.
Mr Campbell is hopeful that, with more people visiting Loch Ness over the Easter period, more sightings may be reported in the near future.
He told The Scotsman: “It’s quite unusual for this length of time to pass with no sightings at all.
“We’re quite worried that there has been an eight-month gap since the last sighting. This is especially so when you consider that pretty much everyone will have access to a camera phone to take video and pictures – we would have expected at least something in that time period.
“When it comes to the reported sightings of Nessie, we reckon about half of those sent to us don’t make it on to the register – what’s really strange is that there has been nothing reported at all – not even sightings of things that we can discount.
“It might be, however, that people are becoming more savvy - it’s also pretty easy to compare any pictures you’ve taken with known creatures in the loch that are already online somewhere.
“It’s the contrast between this eight month period and the early part of 2016 – that had the largest number of sightings since the year 2000.
“For some reason it’s gone from Nessie being seen in lots of different parts of the loch to nothing – this is the part that’s concerning us.”
He added: “We’re really hoping that with the longer evening light that comes with summer and the fact that the Highlands seems to be booming with tourists that someone will see something soon.
“It might well also be via the webcam at the loch – two of last year’s really good sightings came from it so there is an incentive for those who can’t make it to the loch to visit to sit at home and keep an eye out over the web.”
The last sighting was made near Drumnadrochit on the west side of the loch, by Argyll-based government worker Ian Campbell.
During a cycling trip, he spotted two creatures, measuring around 30ft in length, near the shore.
On the same day, another man in the area reported seeing ‘dark or black shapes’ in the water near Urquhart Castle.
And the advancement of webcams has led to a number of sightings being made by those overseas.
The first sighting of 2016 was made by a Canary Isles resident via webcam on March 24.
The majority of sightings are not included on the register - because there is often a simple explanation behind them.
If a sighting is proven to be a hoax, or can be put down to strange ripples or branches, then it is struck from the register.
Mr Campbell has logged over 1,000 sightings since he began keeping records more than 20 years ago.