Aquaculture, or fish farming, is the world’s fastest-growing food production sector. But the key ingredients in commercial fish feed – fishmeal and fish oil – come from an unsustainable source: small fish, such as anchovies and herring, near the base of ocean food webs.
My colleagues and I have developed a high-performing, fish-free aquaculture feed that replaces these traditional ingredients with several types of microalgae – abundant single-celled organisms that form the very bottom of the food chain in fresh and saltwater ecosystems around the world. To test this approach, we developed our feed for Nile tilapia – the world’s second-most-farmed fish, exceeded only by carp.
Our research showed that tilapia fed our fish-free diet grew significantly better, achieving 58% higher weight gain than tilapia fed conventional feed. The resulting cost per kilogram of tilapia raised on our feed was lower than for fish raised on conventional commercial feed.