Tuesday, March 29, 2011
About 30,000 little chinook salmon in five minutes: That's 6,000 a minute, or roughly a hundred every second; all gushing out of a hose attached to a giant silver vehicle that looks like it should be carrying gasoline, or milk.
Up Lolo Pass Road, along the West Fork of the Hood River in an old gravel pit surrounded by forest, the 2-year-old smolt are poured into an Olympic-swimming-pool-sized holding pond fed by a nearby creek and draining into the river about 50 yards below.
At about 6 inches long, they don't look much different than small rainbow trout; but in several years, when they return to the same area to spawn, they'll be the venerated kings of the river, some weighing in at 20, 30, even 40 pounds. That is, of course, only the ones that survive the long and arduous journey to and from the ocean; and the ones that find their way back up the Columbia, up the Hood and up the West Fork to the area where they now rest.
And, for the last 15 years, that has been the goal of this cooperative project between the Confederated Tribes of Warms Springs and Oregon Department of Fish and Wildlife.
Chinook are thought to have been extinct in the Hood River since the mid-1960s.
"By the time counting started in the 1980s, chinook in the Hood River were long gone," said Ryan Gerstenberger, CTWS fisheries biologist. "The overall goal of this program is the reintroduction of spring chinook to the river."
A primary reason for that, he said, is to provide a fisheries harvest for tribal members and sport fishers.
Once in their temporary holding ponds, the fish will be fed and monitored regularly for a month before being released into the nearby West Fork.
"The acclimation ponds do a couple important things," Gerstenberger said. "They increase the survival of the fish by giving them a chance to rest and adjust after the stress of being transported from hatcheries. It also increases imprinting, which gives the fish a better chance of returning to the same place."
The fish that were trucked-in Tuesday afternoon came from Round Butte Hatchery on the Deschutes River. Another batch from Carson National Fish Hatchery on the Wind River arrived the next day and was released into a second holding pond, where they will have the same acclimation period before being released.
The fish are at the smolt stage, which means they are ready to head downstream to the ocean; a journey that should take most less than a week. They will then spend a few years in the ocean, where they will mature, feed and grow until they are ready to return to their place of origin.
The need for the holding ponds is largely because the CTWS hatchery facility on the west fork isn't big enough to rear the nearly 150,000 spring chinook they will release into the Hood River this year.
The Parkdale Fish Hatchery on Red Hill Road raises the eggs from brood stock, then ships them to other hatcheries where the fish grow for about two years.
Although raised in other tributaries of the Columbia, the goal is to have the fish return to the Hood River. The acclimation ponds increase that chance.
"If we were to bring the fish up here and put them straight in the river, there's a good chance many that survive would still come back to the Hood," Gerstenberger said. "Fish imprint by collecting a series of smells. They follow those in reverse order on their way back up. If we increase the imprinting, it reduces the amount of fish that get confused - called strays - on their way upstream."
Tracking the fish to find out how many survive and return to the Hood River will be tricky now that Powerdale Dam is gone. From the late 1990s until it was removed last year, ODFW utilized a trapping facility at the dam that allowed them to document virtually every fish headed upstream. It also the agency to regulate the percentage of hatchery versus wild fish allowed upstream.
Now that the dam is gone, regulating that ratio and monitoring the success of the program will be much more difficult.
For monitoring; every single fish in the spring chinook program has a numbered tag implanted into its snout that can be traced back to its origins. But the fish needs to be killed to get to the tag. About 10 percent have more advanced radio tags, called pit tags, that can provide information when close enough to a scanner. For example, fish with a pit tags passing through Bonneville Dam's fish ladder can be scanned as they swim by an antenna. Biologists can then use that data as an average to get a general idea of run timing and numbers.
For regulation; ODFW will utilize a series of fish traps and weirs along the river. They will monitor traps to collect native fish for brood stock and regulate numbers of hatchery fish that have the opportunity to spawn in the wild.
Another means of regulation is the sport fishery, which will go through a big change this year. See the accompanying story for details.