>>10014827No. Whales breathe air, and would have to surface frequently enough that a breeding population of Long Whales would not be able to hide in any lake with a reasonable quantity of monster-watchers. We can reliably find orcas and gray whales in the OCEAN, which is a lot bigger, for Cthulhu's sake!
Lake monsters can be accounted for by the fact that we want to believe in monsters.
>>10014830>Sea Snakes are too small and Oarfish are harmless.Harmless, but long. They'd do well for a scary story of something found in the ocean - remember, every sea serpent story we've heard comes courtesy of someone who was NOT eaten by sea serpents.
If you want a legendary sea serpent, may I present pic related?
>clearly reptilian>long>you can forget the legs in retelling>some cultures don't distinguish between lizards and snakes much ANYHOW>swims in the ocean>eats people>longer each time you tell the story 
