https://www.google.com/amp/s/amp.the...say-scientists
Tl;dr - researchers collected 250 water samples from around Loch Ness and did a bunch of DNA analyses. They found lots of invertebrates, some fish, and some DNA from local wildlife (pigs, deer, humans), and to their surprise A LOT of eel dna. The researchers are quick to note: it could be there are a lot of small eels or it could be there are a few big ones. Largest recorded eel from UK was ~5.5kg. Not the size of “Nessie” - but eh.