Rumors of a 'Lake Washington Monster' have persisted over the years. I've been diving in the lake since 1978 and have never seen anything scarier than a squawfish, but one has to wonder if a large, dead, floating sturgeon--if viewed under the right circumstances, as far as surface condition and light--could have inspired these tales. While these fish typically remain close to the bottom, researchers tell us they do, on occasion, rise to the surface and even rise out of the water. One can imagine a quick glimpse of this reptilian body emerging from the lake creating all kinds of interesting theories about what it was.
Sturgeons' presence in the lake baffles scientists and the state fisheries people say the dino-fish are quite rare there and that no Lake Washington sturgeon fishery even exists therein.
I have a fun theory, in 1909, at the conclusion of the Alaska Yukon Pacific Exposition (A large world's fair-like even held at the site of today's UW main campus), the Russian exhibit had included a pool of water containing several small sturgeon which were released into the lake. One can't help but wonder if this old girl was an AYPE participant who was let go to fend for herself.