Worldwide interest continues on second day of Loch Ness Monster hunt
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Organisers say 'bizarre noises' were picked up during the biggest exploration of Loch Ness for decades.
He admitted the weather had been "horrific", with heavy downpours making work to explore the loch with a hydrophone difficult.
Plans to carry out a drone survey were also abandoned due to the weather, although it is expected that will go ahead this evening.
Mr McKenna told reporters gathered outside the Loch Ness Centre that yesterday's weather was known as "Nessie's Revenge" but remained upbeat as he explained how around 100 volunteers had helped with in-person observations of the loch yesterday, with a similar number expected today.
He said "bizarre noises" had been detected in the waters on Friday, before the official hunt began.
"At the moment we don't know if it was the Loch Ness Monster or it was natural sounds," he said. "That is why it is important we do the hydrophone again."
Of the interest shown in this weekend's exercise – the largest since 1972 – he said: "It has been phenomenal."
He said more than 300 people observed webcam footage throughout Saturday and that people from Spain, France and Finland were among the range of nationalities who have involved themselves in the project.
During the briefing ahead of the start of today's activities a volunteer from Poland also made themselves known and there have been comments online from even further afield.
Yesterday Jane Tims said: "I am observing via Lochend webcam from time to time today. Not as boring as I thought it might be.
"The lake is so reflective, I can understand that people see strange surface features from time to time.
"I'll be watching for five hours tomorrow from New Brunswick, Canada."
Mike Nelson posted: "We had a great time at our watch party in Tyler, Texas!!!!"
And Tracy Hickman Descamps said: "Great watching from Tennessee!!! Watching tomorrow!"
The Loch Ness Centre: "We’ve been overwhelmed by the interest and excitement from the volunteers and media alike.
"Nessie fever is well under way here in Drumnadrochit."
As well as lochside watchers in situ and others watching via webcams set up at 17 locations around the loch Mr McKenna and others are again due to explore the waters by boat equipped with a hydrophone between 10am and 1pm, with drones being deployed in the evening.
Mr McKenna said sightings had been reported by webcam observers all of which will be investigated further although he admitted a lot of these were likely to be "false alarms" due to the weather on Saturday.