Soy Helps Keep Growing Aquaculture Sector Sustainable

It might be difficult to imagine soybeans from the U.S. heartland feeding fish in Southeast Asia, but checkoff-funded research illustrates the benefits of using soy meal in fish diets and could result in a dramatic increase in the global demand for U.S. soy.

David Bengston, Ph.D., studies aquaculture sustainability as well as using soy meal in summer flounder diets. He recently explained how soy-based feed increases farmers’ profit potential, aiding in aquaculture sustainability and improving the health of the fish.

Q: What does your research involve?

A: We want to determine the carrying capacity for water bodies used in aquaculture operations in Southeast Asia. Carrying capacity is the body of water’s ability to assimilate aquaculture waste and provide enough oxygen for the fish we’re trying to grow. A lot of operations in Southeast Asia, especially in freshwater lakes and reservoirs have exceeded their carrying capacities so we use models and formulas to help regulators figure out the aquaculture level that keeps the fish healthy and maximizes profit potential.

Q: Why is this research important for the future of aquaculture?

A: If you don’t consider carrying capacity, you can enter a boom-and-bust cycle where aquaculture production increases until it exceeds the allowable level, and the survival of the fish declines. Exceeding carrying capacity negatively impacts water quality, sediment quality and oxygen levels. Disease-level goes up, fish mortality rates increase, fish quality goes down and farmers lose.

Q: Why is this research important to U.S. soybean farmers?

A: A fishmeal diet causes part of the carrying-capacity problem in the countries I’ve mentioned, and research supports soy as a replacement feed. Fishmeal, which consists of small fish harvested from the oceans, is often used in denser “sinking diets.” Farmers can’t see the fish eating the sunken pellets so they may put too much feed in the water, increasing waste. Soy protein, on the other hand, is often used in floating feeds, which are being promoted by the U.S. Soybean Export Council personnel,  so farmers can see the fish eating the soy-based pellets, preventing excess waste. By illustrating the benefits of using soy, the research will expand markets for U.S. soybean farmers.

Q: You’ve also done some research on summer flounder. Why did you concentrate on that species?

A: At first we began researching soybeans, which cost less than fishmeal, as a potential feed ingredient to mitigate the high production costs for summer flounder. But after introducing soy into fish diets, we found disease occurrence, which had previously hurt production, decreasing in the summer flounder subjected to bacterial challenges in our experimental protocol. So, for the last two years, we have been trying to determine the particular components of soy meal that might increase disease resistance.

Q: What do you want U.S. soybean farmers to know about the summer flounder research?

A: The research may help develop a flounder aquaculture industry in the United States since it will illustrate how soy helps decrease production costs. Because summer flounder is representative of other flounder species, the conclusions we reach about the benefits of soy in marine diets may apply to many flounder operations globally. And if we can identify the component of soybean meal that boosts the immune system, that could be widely applicable in aquaculture as well. So we could see an increase the use of U.S. soy in aquaculture operations across the world.