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Have You Seen the Loch Ness Monster?

I have. No, not the long-necked, hump-backed star of so many grainy black and white photographs. I’m talking about a small predatory flatworm that lives deep in the waters of the loch.

March 2018

The flatworm, Phagocata woodworthi, is native to North America and is thought to have been transported to Loch Ness on the unwashed equipment of monster hunters in the late 1970s. It’s now present in the Loch in large numbers where it preys upon other invertebrates and out-competes our native flatworm species.

Phagocata woodworthi © Stephen Luk

That the Loch Ness flatworm survived the long journey from North America (probably in the cocoon stage) is testament to the tenacity of these invasive species which makes them so successful. One of our more recent arrivals, the Killer shrimp (Dikerogammarus villosus) can survive up to 15 days on damp waders - more than enough time for it to be carried from one end of the UK to the other.

Sadly many more of these international hitchhikers have unwittingly been transported across the world to the UK. It’s not only monster hunters that can spread non-native species. Dinghy sailors, windsurfers, anglers, wild swimmers, even dog walkers that let their furry friends swim in ponds and rivers can all cause the spread of these non-native species.

Fortunately there is some good advice to prevent the spread of invasive non-native species.

  • Check your equipment and clothing for live organisms in particular in areas that are damp or hard to inspect.
  • Clean and wash all equipment, footwear and clothes thoroughly. Use hot water where possible. If you do come across any organisms, leave them at the water body where you found them.
  • Dry all equipment and clothing - some species can live for many days in moist conditions. Make sure you don’t transfer water elsewhere.

By following these simple guidelines you can help avoid being the next person to unleash a monster into the British countryside.

Learn more about how to prevent the spread of non-native species at then test your biosecurity knowledge at

Craig Macadam, Conservation Director, Buglife

Follow @bugsymac1 and @Buzz_dont_tweet on Twitter

Invasive Species Week 2018 runs from 23 - 29 March - check out all the action at #InvasivesWeek

The opinions expressed in this blog are the author's and not necessarily those of the wider Link membership.