Field Guide: Third grade naturalists observe trout eggs

By Lauren Hagan, LS Naturalist Teacher

Third grade naturalists are bubbling with excitement over the arrival of approximately 538 rainbow trout eggs from the Erwin National Fish Hatchery in Erwin, Tennessee. When the eggs arrived on Wednesday, February 24, they were just eight days old. Our young scientists visit the science lab each week to learn more about the trout and observe the development of the eggs. We are grateful to Fifth Grade Science Teacher Tobey Balzer '02 for housing our 55-gallon tank and for allowing us to use her classroom on Tuesdays and Thursdays to learn more about these amazing fish.

Students first observed the tiny trout eggs on Friday, February 26. One student described the eggs as “tiny, orange BBs with black eyes.” Since that first observation, we have removed 33 eggs due to a white fungus that can grow on the eggs and spread quickly to other eggs if not immediately extracted. Students have learned about the components of the trout tank and how each part is essential to create the conditions that would exist in a wild trout habitat. The chiller keeps the tank close to 50 degrees, the air stone oxygenates the water, and the filter cultivates important bacteria that assist in maintaining healthy water in the tank.

Friday, March 5 marked an important day in our trout adventure as the eggs began to hatch into tiny alevin (al-a-vin). When the fish transition to this stage in their life cycle, they break out of their shell with the yolk sac still attached. This sac will be their food source until they button up to become fry. In the lab this week, students were able to view the numerous alevins wiggling around in the hatching basket. Students were fascinated to see the miniscule heart beating under a digital Wi-Fi microscope.

In the coming weeks, we will continue to monitor the development of our trout as they progress through the stages of their life cycle. Students will learn about testing the tank water to check the pH, ammonia levels, nitrites, and nitrates. They will discover more about the Tennessee Watershed and the natural trout habitat. Hopefully, with some luck and a lot of care, our trout will reach the fingerling stage. It will be at this point that we’ll travel with all four of our third grade classes to the Caney Fork River to release our trout into the wild. Stay tuned for another update about our rainbow trout in the near future.