Tim La Porte, owner of Iliamna Air Taxi, vividly remembers seeing it in July 1977 as he and passengers banked near the lake's surface. The group spotted something very fish-like for a few seconds, maybe 15 feet long based on the size of a nearby skiff. "It arched its back and hit the water, which was glassy calm, and this wake radiated out from the great big splash," he said. "We saw a great, big tail going sideways, back and forth, going down." "I don't believe it's a whale, and it didn't act like the seals we've seen for years,...