The largest eel doesn't seem sufficiently large to constitute a monster. So there's nothing to debunk there.
But that blanket dismissal disregards key flaws in human perception and memory:
1. The difficulty in accurately estimating the size of an object seen at a distance, particularly if the object is set against a backdrop (e.g., a Scottish lake) that makes an accurate estimation even more difficult.
2. The tendency to embellish or exaggerate a story over time, especially if the story brings the storyteller a degree of welcome notoriety. Contrast the Spicers' estimate of the monster's size in early accounts (6-8 feet in length) to what they claimed in later retellings of the same incident (up to 30 feet in length).
Combine with these factors with the (subconscious or otherwise) desire of the eyewitness to join the chosen few who have beheld the legendary Loch Ness Monster, thereby writing themselves into the monster lore.
The supposedly "skeptical" stance that Nessie is one (and only one) of the following: a seal, an otter, a boat wake, an eel, etc., IMO is in its own way every bit as wrong as the "woo" claim that Nessie is a plesiosaur or some strange entity out of pagan myth. There have been too many sightings, or more to the point, too many
types of sightings for any
single explanation to suffice. This may seem (at first glance) to run counter to Occam's Razor in that it doesn't seem sufficiently simple and elegant, but my claim is that Loch Ness
really is inhabited by a "monster" (using the strict definition of the word noted in my previous post) that is...
part otter, part boat wake, part toy submarine...
Despite all my protestations, though, I agree that ultimately "there's nothing to debunk". Extraordinary claims require extraordinary evidence, and extraordinary evidence of Nessie is (alas) as nonexistent as Nessie herself.
