A contest could be run about writing stories with cryptids in it. Or poems! It's a topic that lends itself to such endeavors.
I've never believed in the existence of actual lake monsters around the world, at least not the way they are described or portrayed by media. Giant dinosaurs living in 19m deep waters and not having been captured in photos or film so far? Hardly likely! Even though the Great Lakes are, well, really extensive.
That said, I think it could very well be an unknown variant of a species or something of the sort, or perhaps individual specimen that grow to giant sizes in the closed environment that are lakes. Maybe even invasive species growing to absurd sizes thanks to not having predators in the area!
I mean, look at that sturgeon! Make it twice or even thrice that size and it won't only pass for a monster, it would be a monster.