The 20th Annual Engineering Design EXPO will be held Friday, April 26, 2013. All EXPO events are free and open to the public and take place at the Student Union Building on the Moscow campus.
Please continue to visit the EXPO site for more information on this year's projects.
Giving Wild Salmon a Hand
Using Recycled Materials to Build Stream-Side Fish Incubators
By Tara Roberts
A recycled refrigerator may be the answer to increasing wild salmon populations.
Salmon eggs in the wild are under constant threat, whether from predators, pollutants or environmental factors, leaving as few as 5 percent of eggs to grow into the fry stage of life. Eggs raised in hatcheries fare much better, with about 90 percent surviving to fry stage.
Cailin Penberthy, Ruth Reeber and Parker Burton with their design for an in-stream incubator. The team designed the model so it can be easily broken down and carried in a small aircraft or mule pack and assembled by one person in remote locations.
A team of engineering students is working to optimize incubators that help wild salmon survive at hatchery levels. These incubators use common, inexpensive materials – a stream-side model can be made from a refrigerator or cooler, while an in-stream model is made of pressboard – so they can be easily implemented by the Native American communities that rely on healthy salmon runs.
Redd Team, named for the gravel beds where female salmon lay their eggs, is made up of three biological and agricultural engineering students – Parker Burton, Nora Sedgwick, and Cailin Penberthy – and two mechanical engineering students – Ruth Reeber and Ujjwal Shrestha.
The project is part of the College of Engineering's capstone senior design program, which pairs students with sponsors on real-world projects.
Ed Galindo, Natural Resources Tribal Cooperative unit director at U-Idaho's Aquaculture Research Institute, sponsors the team. He has been working with wild fish incubators for about 10 years, beginning on the Shoshone-Bannock Indian Reservation, after being inspired by a similar project with brown trout in Wyoming.
While the incubators have been successful so far, Galindo sought out the engineering team to increase their precision and efficiency.
"Before we just looked at how boxes were made," he says."We didn't really ask the scientific and mathematical questions on modeling."
The stream-side incubators use a simple system: water from a spring flows through a pipe into the incubator, then out into the main stream. The people using the incubators put eggs harvested from wild salmon into small plastic-mesh boxes, where they hatch. When the fish reach a certain growth stage, they instinctually know to swim out of the incubator and into the stream.
A key question for Redd Team has been how to keep water flowing through the incubator at a rate that maximizes water oxygen levels while minimizing bacteria and algae growth.
The best answer, the team has found, has been keeping things simple.
"As engineering students, we're taught to be problem-solvers. One of the things I've stressed on this project is let's not over-engineer this," Burton says. "A good engineer knows what to put on the design and what not to."
The team removed items from earlier designs, such as an adjustable outlet, in order to reduce the risk of leaks. They've used flow-modeling software to ensure the incubator's interior layout is working at peak efficiency.
Other than putting the eggs into the incubator on day one, the design allows the fish to hatch, grow and leave with no human contact. Wild fish are genetically stronger than hatchery fish, and they replenish nutrient levels in headwater streams by bringing back nutrients from the ocean. The incubators increase fish populations in their native habitat without the need for a costly facility downstream.
"We want them to hatch naturally," Burton says.
The side-steam model can only be used in accessible places because it is so large, but it has other advantages. For one, the design can be easily replicated. Burton says the team plans to make their instruction manual downloadable so anyone can use or improve on it.
Galindo notes the design's safety in addition to its utility.
"It isn't just randomly using an old refrigerator, but using materials that are safe for fish and humans and the environment, and trying to put those all together," he says.
Galindo says he plans to use the incubators not only as hands-on learning projects, but eventually hopes to add cameras so students in K-12 classrooms can watch the salmon-hatching process live.
This year's team has set a positive standard for collaboration between Galindo and student engineers.
"I learn a lot and they learn a lot, and together we learn even more than I could myself," Galindo says.
The students agreed the experience has been valuable.
"It's more experience working as a team," Sedgwick says. "In your career, you're always going to have to collaborate with others."
Reeber, who has taken the lead on the team's flow modeling, says working with a biological project has taught her a different approach to engineering than her major, mechanical engineering.
Burton says he talks about his senior design project when he goes to job interviews, and it's given him a preview of the work he wants to do as a professional engineer.
"I want my solutions to actually be utilized," he says. "This has been a good way to see how that actually happens."