The salmon tank was first established in November 2013 after TCC dismantled the 600 gallon marine aquarium due to multiple structural issues (of most concern was the bowing of the plexiglass sides, an omen of catastrophic failure!) In the place of the marine aquarium, TCC partnered with the Washington Department of Fish and Wildlife’s Salmon Cooperative program and Puget Creek Restoration Society to raise coho salmon and release them into Puget Creek. The first batch of eyed coho salmon eggs (250 of them, to be precise) was picked up on December 2nd, 2013 from Voight Creek Hatchery in Orting. TCC released those salmon into Puget Creek during Earth Week on April 24th, 2014.
TCC picked up the second batch of 250 eyed coho eggs from the same hatchery exactly one year after the first batch. Those eggs had all hatched by December 11, 2014 and started swimming and eating solid food during the week between Christmas and New Year’s. Between hatching and “swimming up” they hang out on the bottom of the tank in the dark, absorbing the yolk in their yolk sac for nutrition. Once the yolk is gone they are light enough to swim and they can come out from under the black felt we use to darken the tank and simulate their early natural habitat: living under the gravel in a stream bed. When the eggs have hatched they are called alevin. Once they “swim up,” they are called fry.
Professor Shaun Henderson’s Biology 100 classes are monitoring the water quality in the tank as well as the development of the salmon. “The students are most excited about having a direct role in helping return salmon to Puget Creek. They enjoy watching the salmon grow and know that its partly their monitoring work that ensures their survival,” says Henderson. Although the survival rate of the eggs is greatly increased in these first stages of development, 10-20 of them don’t make it after they have absorbed their yolk. Some just don’t eat enough in their first few weeks. The folks at the hatchery explained that they need to learn to eat – some catch on quickly and grow in strength and aggressiveness while a few seem to lurk at the bottom of the tank, getting thinner and thinner and eventually dying.
The release this second batch is expected to be during Earth Week (April 20th – 26th). Look for the release date sometime in March!