By Kate Prengaman Yakima Herald-Republic
UNION GAP — Carrying buckets, crawling under barbed wire and a chance encounter with a garter snake were all part of science class for La Salle High School students Thursday.
The students released thousands of small salmon they raised at the school’s mini hatchery into Ahtanum Creek at the St. Joseph Mission.
They dumped bucket after bucket of water and the 2-inch-long fish — known as fry at this stage — swam into the unknown. Each fish will try to find a small pool and spend the year eating and trying not to get eaten, growing a bit larger before heading downstream next year.
Sophomore CC Imrie said she had mixed feelings about letting the fish go. She and her classmates had raised them from eggs, taking turns feeding them throughout the day at the hatchery tucked behind the school’s tennis courts in Union Gap.
They managed every step, from spawning adult coho salmon last fall to releasing the juveniles this week. Their environmental science teacher, Brother Jack Henderson, said his students learn so much that he’s built his curriculum around the salmon program, which started in 2011 in collaboration with the Yakama Nation.
“I’m kind of sad but also happy to let them go,” Imrie said. She joked that she’d like to catch and eat them someday, if they survive and return as adults.
But, of the more than 10,000 fish reared and released, odds are that only two might manage to return as adults and spawn, said Todd Newsome, a fish biologist for the Yakama Nation who manages its coho reintroduction programs.
It’s tough being a tiny, tasty fish with an arduous journey ahead: After a year in the creek, the coho swim down the Yakima River and then the Columbia, past five dams, to spend a year feeding in the ocean before swimming all the way back to spawn.
Coho went extinct in the Yakima River Basin, officially in 1985. The Yakama Nation began its hatchery program using coho from the lower Columbia in 1996.
Now, thousands of coho return every year to the Yakima Basin and the numbers are growing, Newsome said. He hopes the Yakamas’ programs, including their collaboration with the students, can eventually re-establish a wild, stable population of coho in Yakima Valley creeks and streams.
Ahtanum Creek is perfect coho habitat, Newsome said, because the fish like lower elevation streams with lots of little side channels.
“Historically, the whole Valley would be small creeks running through these woods,” Newsome said. “That’s why the coho went extinct, the loss of valley side channels.”
Another factor was that some years, Ahtanum Creek used to go dry in places, Henderson said. After both lawsuits and collaborative efforts, today the creek maintains flowing water year-round and farmers have installed screens on the irrigation diversions to prevent fish from swimming down ditches and out into the fields.
“The fact that we are able to have salmon in the creek year-round is a huge success,” Henderson said.
The creek also supports steelhead, bull trout in the upper reaches, and some young spring chinook.
Habitat work is just as important as hatchery work to restore salmon populations, Henderson said. That’s why the school has also partnered with the tribe and the North Yakima Conservation District to restore the section of Ahtanum Creek that runs along the school grounds.
They created more side channels and expanded the floodplain, stabilized the banks and planted native vegetation, Henderson said. He turned that project into another learning experience for his students.
Two La Salle-raised fish swam past the school last year, the first from the hatchery program to return, Newsome said. Some of last year’s fish have recently been detected at John Day Dam, south of Goldendale on the Columbia River, making their way out to sea.
Biologists know because a subset of the school’s salmon have been injected with tiny tags that contain an electronic identification code that can be read by biologists or at the dams’ fish ladders.
Sophomore Luis Hernandez explained that they put an anesthetic in the water to numb the fish before injecting them with the tags.
“You just hold the fish in your fingers and inject them in the belly, right under the side fin,” Hernandez said.
Imrie added that she learned a lot about what fish need to survive, in both the hatchery tanks and in their natural habitat.
“I learned how hard it is to actually raise a fish,” she said.
Imrie, Hernandez and the other students agreed that raising the fish had been a lot of fun. Newsome hopes the experiences stick.
“Ten years from now, whatever they do in life, these kids are going to be on the side of fish. That’s the hope,” he said.