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Within Loch Ness

What Did Loch Ness DNA Really Rule Out?

The 2018 eDNA survey weakened the biggest monster claims, but it did not prove that every sighting has one simple answer.

On this page

  • How environmental DNA was collected in Loch Ness
  • Claims weakened by the missing DNA
  • What a negative result cannot prove
Preview for What Did Loch Ness DNA Really Rule Out?

Introduction

The 2018 environmental DNA (eDNA) survey of Loch Ness is often described as having “disproved Nessie”, but that overstates what the research actually showed. The study’s real significance is narrower and more precise. By analysing genetic traces left behind in the loch’s water, researchers found no evidence for several of the most popular biological explanations for a large unknown monster, including a surviving plesiosaur-like reptile, giant catfish, sturgeon or shark. At the same time, the survey did not prove that every reported sighting has a single explanation, nor could it demonstrate that no unusual animal has ever been present. The value of the survey lies in understanding exactly which claims were weakened, and which questions remained open.[University of Otago]otago.ac.nzfirst edna study of loch ness points to something fishyreptile or population of Jurassic-age reptiles such as a plesiosaur present in Loch Ness. “We can't find any evidence of a creature that'…DNA Survey illustration 1

How Environmental DNA Was Collected in Loch Ness

DNA Evidence Reveals The Loch Ness Monster Could Be A Giant Eel | Loch Ness The New Evidence

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Which Monster Theories Were Weakened?

The strongest conclusion concerned the classic plesiosaur hypothesis. For decades, one of the most famous cryptozoological ideas has been that Loch Ness contains a surviving population of long-necked marine reptiles resembling plesiosaurs. The eDNA survey found no reptilian DNA sequences in its samples. Gemmell stated that there was “absolutely no evidence” of reptilian genetic material, making the plesiosaur explanation extremely difficult to maintain in light of the available data.[The Guardian+2CORDIS]theguardian.comnot a giant scaly reptile swimming around in Loch Ness.Read moreThe GuardianLoch Ness monster could be a giant eel, say scientists5 Sept 2019 — Otago University researchers confirm the loch contains no…

The study also weakened several alternative animal explanations that had been proposed over the years. Researchers specifically reported finding no evidence of shark DNA, no evidence of catfish DNA and no evidence of sturgeon DNA in their sampling. These findings challenged theories suggesting that unusual sightings were caused by large Greenland sharks, introduced Wels catfish or oversized sturgeon moving through the loch.[University of Otago]otago.ac.nzfirst edna study of loch ness points to something fishyreptile or population of Jurassic-age reptiles such as a plesiosaur present in Loch Ness. “We can't find any evidence of a creature that'…

Importantly, the survey did not discover DNA from an unknown large vertebrate. Given the scale of the sampling effort and the broad range of species detected, the absence of genetic evidence for a substantial breeding population of large unidentified animals became a significant obstacle for traditional monster theories.[University of Otago]otago.ac.nzfirst edna study of loch ness points to something fishyreptile or population of Jurassic-age reptiles such as a plesiosaur present in Loch Ness. “We can't find any evidence of a creature that'…

In practical terms, the survey made several long-standing claims much less plausible:

  • A surviving plesiosaur or other large reptile living in Loch Ness.[The Guardian+2CORDIS]theguardian.comnot a giant scaly reptile swimming around in Loch Ness.Read moreThe GuardianLoch Ness monster could be a giant eel, say scientists5 Sept 2019 — Otago University researchers confirm the loch contains no…
  • A hidden population of large sharks.[University of Otago]otago.ac.nzfirst edna study of loch ness points to something fishyreptile or population of Jurassic-age reptiles such as a plesiosaur present in Loch Ness. “We can't find any evidence of a creature that'…
  • Giant catfish as the primary explanation for sightings.[University of Otago]otago.ac.nzfirst edna study of loch ness points to something fishyreptile or population of Jurassic-age reptiles such as a plesiosaur present in Loch Ness. “We can't find any evidence of a creature that'…
  • Sturgeon populations large enough to account for repeated monster reports.[University of Otago]otago.ac.nzfirst edna study of loch ness points to something fishyreptile or population of Jurassic-age reptiles such as a plesiosaur present in Loch Ness. “We can't find any evidence of a creature that'…
  • The existence of an obvious, genetically distinct unknown aquatic vertebrate leaving detectable biological traces in the loch.[University of Otago]otago.ac.nzfirst edna study of loch ness points to something fishyreptile or population of Jurassic-age reptiles such as a plesiosaur present in Loch Ness. “We can't find any evidence of a creature that'…DNA Survey illustration 2

    Why the Eel Hypothesis Survived

Loch Ness monster might just be a giant eel

Channel: KiniTV

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What a Negative Result Cannot Prove

The survey’s limitations are as important as its conclusions. A failure to detect DNA is not mathematically equivalent to proving complete absence. Environmental DNA can vary with season, location, species behaviour and population size. A rare visitor or transient animal might leave little detectable genetic material.[Illumina]illumina.comloch ness ednaIn fact, the survey found no reptile DNA of any kind. But it did accurately identify dozens of other species: frogs, toads…Read more…

The researchers therefore avoided claiming that every Loch Ness sighting had been solved. The survey addressed biological hypotheses about large animals living in the loch, not the psychology, optics or environmental conditions behind individual reports. A witness may still have seen something real without that object being an unknown species. Waves, wakes, floating debris, birds, seals, deer and known fish can all create unusual appearances on the water. The DNA study was not designed to test those explanations directly.[University of Otago]otago.ac.nzfirst edna study of loch ness points to something fishyreptile or population of Jurassic-age reptiles such as a plesiosaur present in Loch Ness. “We can't find any evidence of a creature that'…

Another important limitation is that eDNA identifies genetic traces, not population structure or animal size. The absence of reptile DNA strongly undermines the reptile hypothesis, but the method cannot reconstruct exactly what every observer saw over the past century.[University of Otago]otago.ac.nzfirst edna study of loch ness points to something fishyreptile or population of Jurassic-age reptiles such as a plesiosaur present in Loch Ness. “We can't find any evidence of a creature that'…DNA Survey illustration 3

What the Survey Changed in the Nessie Debate

The Loch Ness Monster and eDNA: Why the Mystery is Still Unsolved

Channel: Omni Viewer

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Endnotes

1. Source: illumina.com
Title: loch ness edna
Link:https://www.illumina.com/company/news-center/feature-articles/loch-ness-edna.html

<summary>Source snippet</summary><p>In fact, the survey found no reptile DNA of any kind. But it did accurately identify dozens of other species: frogs, toads…Read more…</p>

2. Source: cordis.europa.eu
Link:https://cordis.europa.eu/article/id/406927-trending-science-is-the-loch-ness-monster-a-really-big-eel

<summary>Source snippet</summary><p>Trending Science: Is the Loch Ness monster a really big eel?12 Sept 2019 — The environmental DNA (eDNA) data doesn't support the be…</p>

3. Source: illumina.com
Title: loch ness edna
Link:https://www.illumina.com/content/illumina-marketing/amr/en_US/company/news-center/feature-articles/loch-ness-edna.html

<summary>Source snippet</summary><p>If there is a monster in Loch Ness, this geneticist will find it10 Jan 2025 — Professor Neil Gemmell has a new plan to expand environment…</p>

4. Source: otago.ac.nz
Title: first edna study of loch ness points to something fishy
Link:https://www.otago.ac.nz/news/newsroom/first-edna-study-of-loch-ness-points-to-something-fishy

<summary>Source snippet</summary><p>reptile or population of Jurassic-age reptiles such as a plesiosaur present in Loch Ness. “We can't find any evidence of a creature that'…</p>

5. Source: theguardian.com
Title: not a giant scaly reptile swimming around in Loch Ness.Read more
Link:https://www.theguardian.com/science/2019/sep/05/loch-ness-monster-could-be-a-giant-eel-say-scientists

<summary>Source snippet</summary><p>The GuardianLoch Ness monster could be a giant eel, say scientists5 Sept 2019 — Otago University researchers confirm the loch contains no…</p>

6. Source: sciencefocus.com
Title: loch ness monster dna study reveals plausible explanation for sightings
Link:https://www.sciencefocus.com/news/loch-ness-monster-dna-study-reveals-plausible-explanation-for-sightings

<summary>Source snippet</summary><p>Science FocusLoch Ness Monster DNA study reveals 'plausible'…5 Sept 2019 — The findings quickly debunked one of the most popular theor…</p>

7. Source: sciencefocus.com
Title: loch ness monster how edna helps us discover what lurks beneath
Link:https://www.sciencefocus.com/nature/loch-ness-monster-how-edna-helps-us-discover-what-lurks-beneath

<summary>Source snippet</summary><p>Eels are very plentiful in Loch Ness, with eel DNA found at pretty much every location sampled –…Read more…</p>

8. Source: Wikipedia
Link:https://en.wikipedia.org/wiki/Loch

<summary>Source snippet</summary><p>LochLoch is a word meaning "lake" or "sea inlet" in Scottish and Irish Gaelic, subsequently borrowed into English. In Irish contexts…</p>

9. Source: otago.ac.nz
Title: otago scientist reveals loch ness monster could be a giant eel
Link:https://www.otago.ac.nz/news/newsroom/otago-scientist-reveals-loch-ness-monster-could-be-a-giant-eel

<summary>Source snippet</summary><p>"…the sheer…Read more…</p>

10. Source: youtube.com
Title: Neil Gemmell
Link:https://www.youtube.com/watch?v=E4y62Pa4b28

<summary>Source snippet</summary><p>Environmental DNA for Biodiversity…Neil is a professor at the University… He will also talk about his contribution to the search fo…</p>

11. Source: linkedin.com
Link:https://www.linkedin.com/posts/illumina_what-if-the-loch-ness-monster-is-more-than-activity-7287869641153032192-RUoX

<summary>Source snippet</summary><p>Illumina's PostSpoiler, it's not a 60 million year old sea reptile. Like · Reply · 6 Reactions 7 Reactions. Will Anderson, graphic · Will…</p>

Additional References

12. Source: researchgate.net
Link:https://www.researchgate.net/publication/342296365_ESSAY_REVIEW_Disappointing_documentary_about_Loch_Ness_Monsters_Nessies_Can_good_documentaries_be_made_about_such_subjects

<summary>Source snippet</summary><p>ESSAY REVIEW Disappointing “documentary” about Loch…Jun 10, 2026 — “About the show:Professor Neil Gemmell uses cutting-edge environmen…</p>

13. Source: facebook.com
Title: we cant discount the possibility that what people see and believe is the loch ne
Link:https://www.facebook.com/otagouniversity/posts/we-cant-discount-the-possibility-that-what-people-see-and-believe-is-the-loch-ne/2711661515511865/

<summary>Source snippet</summary><p>"We can't discount the possibility that what people see and…5 Sept 2019 — "We can’t discount the possibility that what people see and…</p>

14. Source: youtube.com
Link:https://www.youtube.com/watch?v=vHGUbLhCyQs

<summary>Source snippet</summary><p>Loch Ness monster might just be a giant eelScotland's fabled Loch Ness monster could possibly be a giant eel scientist said on Thursday a…</p>

15. Source: youtube.com
Link:https://www.youtube.com/watch?v=U6HWdcjf-P8

<summary>Source snippet</summary><p>The Loch Ness Monster and eDNA: Why the Mystery is Still…You may have seen lots of people pushing the "Nessie Eel" narrative, but is t…</p>

16. Source: youtube.com
Link:https://www.youtube.com/watch?v=6MiiwSuhk8k

<summary>Source snippet</summary><p>DNA Evidence Reveals The Loch Ness Monster Could Be A…DNA Evidence Reveals The Loch Ness Monster Could Be A Giant Eel | Loch Ness The…</p>

17. Source: biotechniques.com
Title: monster hunting scientists could have solved the legend of loch ness
Link:https://www.biotechniques.com/whole-genome-studies/monster-hunting-scientists-could-have-solved-the-legend-of-loch-ness/

<summary>Source snippet</summary><p>any type of reptile or a giant fish. However, the idea that Nessie… Loch Ness Monster might be giant eel, scientists say (2019); · 4…</p>

18. Source: facebook.com
Link:https://www.facebook.com/FishtheNess/posts/yesterday-we-heard-the-results-of-a-large-environmental-dna-or-edna-study-in-loc/2567990963260672/

<summary>Source snippet</summary><p>"Researchers from New Zealand have tried to catalogue all living species in the loch by extracting…</p>

19. Source: researchgate.net
Link:https://www.researchgate.net/publication/390620130_The_Loch_Ness_Monster_If_It%27s_Real_Could_It_Be_an_Eel

<summary>Source snippet</summary><p>000 for a 1-meter specimen, which is reasonable given the loch's fish stock and…Read more…</p>

20. Source: smartwatermagazine.com
Link:https://smartwatermagazine.com/news/university-otago/could-loch-ness-monster-be-a-giant-eel

<summary>Source snippet</summary><p>Could the Loch Ness monster be a giant eel?Sep 9, 2019 — There is also no catfish DNA in Loch Ness based on our sampling…</p>

21. Source: reddit.com
Title: so 3 years ago a new zealand scientist took some
Link:https://www.reddit.com/r/[Cryptozoology

<summary>Source snippet</summary><p>E DNA…The 2018 eDNA survey at Loch Ness didn't find unknown giant eel DNA, it was merely suggested that known eel species in the Loch…</p>

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Loch Ness What DNA Says About the Loch Ness Monster

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