ONTARIO — Several parents accompanied fifth-graders and their teachers from May Roberts Elementary School on Thursday as they released about 85 classroom-raised rainbow trout into the pond at Beck-Kiwanis Park. Students had raised the fish since October of 2018, when they got trout eggs. After the eggs hatched, the students got to watch the fish grow, and began feeding the trout just before Christmas. Oregon Department of Fish and Wildlife provided the funds to obtain the eggs as part of an effort to clean up the pond at the park.
“We tested the pH, nitrate and ammonia levels,” said Taylor Thomas, a fifth-grade student. “If a fish dies and you don’t take it out, it causes high nitrate level, causing more ammonia, then death.”
The trout were housed in three tanks — one in each classroom, which had 200 fish a piece. Of the 600 trout, only 117 survived, with each group varying. One had 80 remaining, another had 35, and one group only had two trout that survived.
The water temperature needed to be at about 50 degrees. In addition, students monitored the temperature, recording ammonia levels, pH, nitrate and nitrite levels.
Teacher Carol Dewitt’s class had the highest surviving group of rainbow trout, and she attributed it to owning a 29-gallon tank. Dewitt said she released fish years ago, and owned the larger tank which she had kept. Dewitt’s tank was different than the smaller 5-gallon coolers the other teachers had.
“My favorite part was when we were pouring thirty gallons of water into the first tank,” said student MacKenzie Tolman. “We had to let it sit overnight [before putting the fish in] to let the water get to fifty degrees or sixty degrees. We tested the ammonia, if it was wrong we re-tested. The fish die on the bottom, they don’t float up. If there was too much ammonia there were bubbles on top.”
While they were raising the fish, students learned about the life cycle of rainbow trout via a biologist from Hines, Oregon. Several student groups also got to participate in dissecting a trout — not the ones they raised, which were still minnow-sized during their release. Dewitt said they were surprised to find the trout’s intestines full of snail shells.
Into the pond
For the big day, students walked to the park from the elementary school.
Dewitt said ODFW officials also recommend not feeding trout before they are released, as their digestion processes can affect the ammonia levels of the water, and in turn impact the rest of the fish. However, the students didn’t know ahead of the release they weren’t supposed to feed the fish, and had done so already.
Several students were upset Thursday when they released their trout.
“My favorite part was when we first got them. My least favorite part is right now,” said fifth-grade student Alyx Chadwick.
The children spent about an hour at the park. The trout were transported inside large ziplock bags, inside buckets, and students watched the fish acclimate for a timed half-hour, in the bags, in the pond.
After that the students opened the bags and set the fish free.
For their next project, Dewitt said, the children will pick up garbage at the park, and are hopeful to eventually see a cleaner pond.
Dewitt said she hopes Fish and Wildlife officers will bring equipment during a future visit to do a test to let the students see what kind of things live in the pond water at the park.