As Aquaculture Booms, a Shift Toward Plant-Based Fish Feed

Not too long ago, the aquaculture industry was heavily reliant on marine protein (fish meal and fish oil) to feed and grow farm raised fish, using as much as four pounds of fish protein to produce one pound of salmon in order to supply the needed fatty acids and amino acids for optimum fish health.

Efforts to replace this unsustainable system with a plant-based feed using soybeans and other sources that would supply the necessary nutrients had created challenges for animal nutritionists. However, recent advances in aquaculture have indicated that carnivorous farmed fish do not require any fish meal or fish oil in their diets to succeed. Researchers at the Bozeman Fish Technology Center in Montana have been working to formulate an alternative all-vegetarian feed for carnivorous fish farming and report that rainbow trout fed a nutrient-rich all-plant feed are thriving.

“We have been hit over the head with the notion that farming carnivorous fish means that you have to catch fish in the ocean for its diet, but that’s wrong,” says Michael Rust, science coordinator of the NOAA Fisheries’ Office of Aquaculture.

The development of alternative plant-based fish feeds has become more pressing with the booming growth of the aquaculture sector. Between 2000 and 2012 aquaculture production doubled from 32.4 million tons per year to 66 million tons per year. And as protein output from aquaculture overtakes that of beef production, farmed fish are expected to play a key role in feeding the growing global population. And now, due to advances in plant-based fish foods, one pound of salmon can be produced using only one to one and a half pounds of fishmeal – a significant improvement over the three to four pounds needed 20 years ago.

Despite great advances in vegetarian feed formulations in the past ten years, production of the feed has not reached commercial scale and prices remain prohibitive.

“When are you looking at the price of ingredients, sometimes fishmeal just makes more sense,” says Jesse Trushenski, a fisheries scientist at Southern Illinois University. “It still delivers the most digestible protein per dollar. But its price is going to continue to climb because of its unique ingredients, growing demand, and limited supply.”