Fish waste does not have to be wasted, Heron School students are proving.
Sure, it may be useless discard to fish, but Heron students are using ammonia from the waste to grow vegetables through a continuous process called aquaponics, combining aquaculture with hydroponics.
Along the way, 6th-graders are learning about science, nature, chemistry, plant essentials and fish requirements.
“It’ s pretty fun to do,” said Jade, 12.
The experiment always has a happy ending, with an edible crop – most recently, kale, which students used to make salad. In the past, Heron students have grown sweet peas, zucchini, cucumbers, radishes and Brussel sprouts. Teacher John Meehan oversees the school’s aquaponics and students from Tony Thomas’ class maintain its system and plants.
Here’s how the project works: A group of tilapia fish swim in a water-filled tank, producing wastewater that
is pumped into an attached plant-growing bed, where expanded clay pellets convert ammonia into nitrites and nitrates essential to crops. The process continues hour after hour, day after day, helping both fish and plants grow over time.
Meehan said students participating in aquaponics are learning responsibility by testing PH levels in the fish tank. They’re also learning about ammonia levels, water conservation, testing methods and plant harvesting. They use charts to document plant heights and weights, Meehan said.
“It’s cross curricular because it’s science, it’s math, they’re learning about biology, they’re learning about measurement statistics and things like that,” he said.
Miranda, 11, said classmates seem to enjoy the vegetables grown but aren’t always eager to hear about the fish waste.
Gianna, 12, said she likes to think of aquaponics as a pleasant job. “It’s a responsibility that we have to do at recess,” she said. “I also like taking care of the fish.”
Jade said she has learned to work better with other students.
Abigail, 11, said she might use lessons learned from aquaponics for years to come. “I think I might want to start growing my own garden when I get older,” she said.
