These are the first observed Elwha River salmon to naturally migrate upstream into the park, according to a statement released by the park.
When the Elwha Dam became operational in 1913, 25 years before Olympic National Park was created by Congress, more than 70 miles of Elwha River habitat were blocked to fish passage.
Salmon and steelhead were restricted to spawning in the five miles of the river below the Elwha Dam, just west of Port Angeles and outside the national park.
Steelhead were discovered above the now-demolished dam earlier this summer.
The chinook also known as king salmon were observed above the Elwha Dam site, approximately two miles upstream from the boundary of the park, by Phil Kennedy, lead fisheries technician.
"We knew this was going to happen, and as I saw the fish roll, my heart jumped," Kennedy said.
In the park's announcement, headlined "Return of the Kings," Todd Suess, Olympic's acting superintendent, said:
"This has been an extremely exciting summer. First we see a renewal of a culture with the uncovering of the creation site of the Lower Elwha Klallam tribe, and now we see the renewal of the legendary chinook in Olympic National Park."
The tribe is a partner with the National Park Service in the $325 million federal project to remove the Elwha and Glines Canyon dams and restore the Elwha River and its fish runs.
The chinook salmon run in the Elwha was legendary, with stories of salmon weighing 100 pounds and swimming in schools that filled the river, before the two dams were built without fish ladders.
In recent years the Elwha's king salmon population had plunged to a few thousand annually.
Creation spot discovered
Earlier this month it was announced that the tribe's creation site a rock with two deep depressions was found among the 1,100 acres of land that emerged after the Elwha Dam was removed and the lake behind it had drained.
Sacred to the tribe, the site is where, by tribal teaching, the Creator bathed and blessed the Klallam people, and where tribal members for generations sought to learn their future.
It had been submerged behind the Elwha Dam for 99 years.
In addition, the park service also reported finding a site in a nearby location that documents human use as far back as 8,000 years ago, establishing it as one of the oldest known archaeological sites on the Olympic Peninsula.
The news of the chinook came as the four-day 2012 Elwha River Science Symposium began Monday at Peninsula College in Port Angeles.
Scientists are sharing what has been learned during the first year of the Elwha River restoration project.
The Elwha dam removal project the largest of its kind in U.S. history is well ahead of schedule.
By summer 2013, the glacier-fed Elwha River is expected to flow freely as it courses from the Olympic Mountains to the Strait of Juan de Fuca.
The last remnants of the 108-foot Elwha Dam were removed in March.
Glines Canyon Dam, eight miles upstream, will be gone by early next summer.
Glines has been knocked down by explosives and huge hydraulic hammers to less than half its original height about 90 feet of the 210-foot-high dam are left.
The dam removal work was originally scheduled to run through 2014.
After the two dams were built, all five native species of Pacific salmon and steelhead, a sea-going rainbow trout, were confined to the lower five miles of the Elwha.
Once Glines Canyon Dam, 13 miles up river, is removed, salmon, steelhead and other fish that mature in the ocean and return to rivers to spawn will once again have access to more than 70 miles of spawning and rearing habitat, much of it within the protected boundaries of Olympic National Park.
Scientists knew ocean-going fish would eventually return to the Elwha River once the two massive concrete dams were torn down.
They just didn't think it would happen so soon.
Biologists tracking fish in a tributary of the Elwha in June spotted wild steelhead that they said made it on their own past the site where the Elwha Dam stood for nearly a century.
"We're wildly excited," said Mike McHenry, fish habitat manager for the Lower Elwha tribe, said after the steelhead were spotted.
"It just confirms what we have known all along that these fish are quite capable of recolonizing the Elwha once we get the dams out of the way."
Fully recolonizing the river is expected to take years. All fishing in the river has been closed for five years.
"Observation of these chinook in Olympic National Park is a wonderful addition to the naturally returning steelhead recently observed by NOAA Fisheries and Lower Elwha Klallam tribe downstream of the park boundary," said Olympic National Park fisheries biologist Sam Brenkman.
"We can now say that restoration of anadromous salmon in Olympic National Park is underway."
Peninsula Daily News is a media partner of KOMONews.com