Better Food for Farm-Reared Fish

Undergraduate Raises Trout as part of Research Project

Twice a day, Lexi Bishop feeds her fish.

The trout don’t technically belong to Bishop, although at least for the length of her internship, the fisheries resource major monitors their well-being as part of a research project.

The project at the University of Idaho’s Aquatic Research Institute seeks to pinpoint the most cost-effective and healthy diet for pen-reared trout. Because of a worldwide shortage of fish meal, a staple food for farm fish in commercial operations, researchers are attempting to supplement protein-based meal with a variety of products including algae. The switch could reduce costs of feeding farm raised fish while still providing the nutrients to make them grow big and healthy.

“We’re looking for an alternative to fish meal that still grows strong fish,” Bishop said.

Bishop feeds a combination of fish meal mixed with algae to hundreds of racing trout in 20, bubbling, aerated tanks at the institute’s cold-water laboratory. Each tank receives a different dose of the algae-infused meal in the morning and again in the afternoon.

Algae is inexpensive and easy to produce and collect. An algae-fish meal combination might be the best, cost-efficient alternative to grow fat, healthy fish for table fare, she said.

She has been feeding the trout since they were fingerlings, and now weeks later, they have grown to hotdog size.

“At the end of the study we’ll weigh the fish in each tank, to see how much they have grown and take samples to determine which diet produced the biggest and healthiest trout,” Bishop said.

This internship helped me gain expertise in a field I really didn’t know existed. Lexi Bishop, Undergraduate

Bishop, a junior who is earning a minor in aquaculture, grew up in the relatively fish-friendly enclave of Fruitland, not far from where the Payette River plunges into the majestic Snake.

“I like water and I like fish, so I decided to pursue a fisheries degree here at U of I and earn a minor in aquaculture,” Bishop said. “This research will not only help me find a job in my field, but it is also important to the industry to find new ways to feed growing populations of farmed fish across the globe.”

The Aquaculture Research Institute was established on U of I’s Moscow campus to focus on aquaculture in a state known for its superb wild — and hatchery-raised — fishery. It is a place where student interns such as Bishop can get their feet wet learning about fish rearing.

Because aquaculture is a highly diverse activity involving food production, fishery biology and stock restoration, it touches an array of scientific disciplines.

Bishop likes the field’s mixed bag. She likes knowing that successful aquaculture practices can provide food to a growing global population, and it’s a way to potentially save endangered species.

“Finding better ways to raise and feed fish helps with sustainability of the resource,” she said.

When her fish feeding schedule is replaced by college courses during the school year, Bishop will have a strong knowledge of aquaculture, a field of study not offered at many universities, and one she didn’t know much about before her internship, she said.

“This internship helped me gain expertise in a field I really didn’t know existed,” she said. “I was set on one path, but this internship really broadened my horizons and introduced me to new job opportunities available after graduation.”

Article by Ralph Bartholdt, University Communications.

Photos and video by Alexandra Bishop, senior, College of Natural Resources

Video Editing by Garrett Britton, University Visual Productions.

Published in December 2022.