Beginning about 14,900 years ago, salmon begin to colonize Puget Sound. During the last ice age, when a 3,000-foot-thick glacier moved out of Canada and traveled as far south as Olympia, no salmon, or any other fish species, could inhabit the Puget lowland. Almost two thousand years would pass before conditions became right for the salmon to enter the recently excavated lowland, which they did when a connection was made between what is now the Strait of Juan de Fuca and Puget Sound.
LINK (via History Link)
