Students tour Stilly Fish Hatchery
August 27, 2008 · Updated 4:02 PM
ARLINGTON Students from Arlington, Marysville and Everett toured through the Stillaguamish Fish Hatchery Nov. 30, gaining a greater appreciation of the work that the Tribe and its volunteers put into preserving the local salmon population.
Fifth-graders from Presidents Elementary were joined by home-schooled students from kindergarten through 11th grade with the New Hope Mennonite Church in rotating through stations covering salmon anatomy, water quality, habitat, and the harvesting and fertilization of their eggs.
Courtney Alexander was one of the Stilly-Snohomish Fisheries Enhancement Task Force volunteers on hand to guide the students through the process, starting with a hands-on look at freshly killed chum. She pointed out that the fishes slime is an antimicrobial agent that protects them from infections and allows them to cut through the water more effectively. She then identified the differences between human and fish organs.
The gills are so red because water flows through them, directly into the bloodstream, Alexander said. Another fish organ we dont have is the swim bladder, which they can inflate or deflate with air to rise or sink in the water.
Alexander explained that salmon can smell hundreds of miles downstream and have layers of teeth to help them swallow their prey whole as they continue swimming. Because the salmon expend so much energy on returning to their birthplaces to spawn, she added that their bodies often start to decay once they return to fresh water.
Alexander and the students left the dead chum to see live fish jumping up ladders into holding pens, as she showed how the hatchery tests the oxygen content of the water.
Theres more oxygen in cold water, so they like it when water is cold, said Alexander, as she took the waters temperature. It should be 64 degrees or lower. The salmon need eight particles of oxygen per million to survive.
Alexander elaborated that a stream with varying current speeds allows the fish to rest when theyre tired, before taking in more oxygen from rushing water. She clarified that fish prefer to lay their eggs in rocks, rather than sand, since rocks provide more durable cover and muddy water deprives them of oxygen.
Salmon are often essential to the health of a forest, Alexander said. When they die, their decomposition releases nitrogen, which fertilizes the trees and other plants.
Alexander informed the students that trees protect fish in turn, not only by providing shade from the warm sun with their leaves, but also by holding onto the soil of the streambed with their roots.
Kip Killebrew, fish enhancement biologist with the hatchery, showed the students how harvested eggs and sperm are combined in the hatcherys trays to fertilize the eggs.
If somebody needs a heart transplant, that heart has to be alive for it to be put into that person, Killebrew said. These sperm and eggs can stay alive for 24 hours after theyre harvested, but once theyre mixed, I only have 30 seconds to get their tray back onto the rack, because after that, the slightest bump could kill them.
Killebrew emphasized that ensuring a continuous flow of water into the trays is just as important to the fertilized eggs survival, because if their oxygen supply isnt replenished, theyll suffocate and shrivel up. He concluded his remarks to the students by summing up what the juvenile salmon eat at the hatchery.
Since we cant grow billions of bugs for them to eat, like theyd find in streams, we have to come up with salmon power bar substitutes, said Killebrew, who listed the ingredients as wheat germ, fish parts and blood, shrimp oil and vitamins.
Many of the students alternated between giggling and making disgusted faces, but their reactions with Killebrew were tame compared to when Kevin Gladsjo showed them how to harvest the eggs, by gutting the fish with hooks.
The salmon really benefit the life cycle of the Pacific Northwest, and help provide a big industry for the region, said Jeri Schellenberger, one of the mothers with the New Hope Mennonite Church. Its fascinating to see all they do.
Its good to learn about the salmon, said Presidents Elementary fifth-grade teacher Andy Medley, a first-time visitor to the hatchery. Its one of the most important organisms in the ecosystem in this part of the country.