The Results

The results come after scientists took hundreds of samples of water from Loch Ness and nearby lochs. DNA from each sample was captured, extracted and sequenced. This gave the team 500 million sequences that when compared against global DNA databases show a comprehensive picture of life present in the Loch –  the bacteria, the fish, and everything else in between. 

Most species are so small you can barely see them but there are a few that are larger and the big question is - "is there anything big enough to explain the sorts of sightings people have made over the years that have led to this myth or this legend of a monster or creature in Loch Ness?”

 
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IS THERE ANYTHING THAT MIGHT EXPLAIN NESSIE?

One of the most popular theories is that there might be a Jurassic-age reptile or population of Jurassic-age reptiles, such as a plesiosaur present in Loch Ness.

Unfortunately, we can't find any evidence of a creature that's remotely related to that in our environmental-DNA sequence data. So, we don’t think the plesiosaur idea holds up based on the data we have.

We also tested other predominant theories of various giant fish; whether it be a giant catfish or a giant sturgeon, an eel, or even a shark such as a Greenland shark. There is no shark DNA in Loch Ness based on our sampling. There is also no catfish DNA in Loch Ness based on our sampling. We can't find any evidence of sturgeon either.   

The remaining theory that we cannot refute based on the environmental DNA data obtained is that what people are seeing is a very large eel.

We find a large amount of eel DNA. Eels are very plentiful in Loch Ness, with eel DNA found at pretty much every location sampled  – there are a lot of them.

Researchers had earlier suggested that a giant eel might explain some sightings. That idea then lost popularity as theories about extinct reptiles became more common. But there have been ongoing reports of very large eels by a number of witnesses.

Are they giant eels? Well, our data doesn’t show their size, but the sheer quantity of the material says that we can't discount the possibility that there may be giant eels in Loch Ness. We need to investigate more to confirm or deny the theory.

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NO DIRECT EVIDENCE OF NESSIE, BUT PLENTY OF NEW DISCOVERIES

 

In total we identified 11 species of fish, 3 species of amphibian, 22 species of birds and 19 mammals, most of which are species known to be resident in or around Loch Ness.

One of the more intriguing findings was the large amount of DNA from land based species in the Loch system. These included high levels of DNA from humans and a variety of species associated with us, such as dogs, sheep and cattle. We also detected wild species local to the area e.g. deer, badgers, foxes, rabbits, voles and multiple bird species. These findings show eDNA surveys of major waterways may be useful for rapidly surveying the biological diversity at a regional level.

We also looked for evidence of species that have recently invaded Loch Ness, including the Pacific pink salmon. So far this species' entrance into Loch Ness seems to have been modest – we did not detect it in our samples. However, given the two year annual cycle of this species large numbers would be expected to be highest in odd years, so further sampling might detect more of this species.

We have also discovered a lot of new microbial diversity through the project. One interesting find is a bacteria most commonly associated with salty waters in the freshwater loch. There will be more surprises as our investigations of the 1000’s of species detected continue.


 

HOPE FOR NESSIE BELIEVERS?

 

Environmental eDNA metabarcoding approaches are powerful but limited by the genome regions they target. We know we have not identified every species present in Loch Ness, but we doubt we have missed any major groups of living things. That we identified all known fish species from Loch Ness in our eDNA data provides some reassurance our approach was sound.

That said, any survey must accept that it may not find all species present because sampling effort is inadequate, the species is migratory (e.g. sturgeon), small, at low abundance in the system, sheds cells at low rates, or is missed by the metabarcoding.

Loch Ness is vast and given that eDNA signals in water dissipate quickly, lasting days to weeks at most, there remains the possibility that there is something present that we did not detect because we sampled in the wrong places at the wrong time, or our metabarcoding method could not detect “Nessie” because the sequence could not be matched with anything in the sequence databases.

Our investigation, like every investigation before it, has no definitive proof of the monster. Proving something does not exist is pretty much impossible. We do however have a further theory to test, that of the giant eel, and it may be worth exploring this in more detail.

SOME FINAL THOUGHTS OF THE RESULTS AND THE PROJECT

Our study of environmental DNA captured everything we thought is in the loch. We now have an excellent database that will enable us to identify trends and changes in the loch environment through future testing. That is the benefit of eDNA – it is a powerful tool to document the living things (both large and microscopic) present in a given place. It will be extremely useful in the future as the technology becomes quicker and more accessible.

The “monster-factor” has also provided us with an opportunity to showcase the science of eDNA to the world, and the project has drawn enormous interest.

A documentary team from Travel Channel has been on the journey with Professor Gemmell and his team, and a two-hour special will premiere in the United States on Travel Channel and in the UK on Discovery Channel on September 15, 2019.