Algae Adds Color, Value to Finfish Aquaculture

As a chef might plan a healthy meal by carefully balancing the ratio of protein, nutrients, and fats, Senior Research Scientist Mike Lomas and his team are identifying the ingredients for a blend of algae that is the perfect food for fish.

Wild fish stocks are being depleted around the globe, creating a ripple effect that threatens the billions of people who rely on fish for protein and nutrition. Aquaculturists in Maine and around the world are working to replace this crucial food source by growing fish both at sea and at facilities on land – an endeavor that comes with its own challenges.

“Cultivating finfish is the most efficient and sustainable way to make the protein needed to feed our world,” said Lomas, who directs the National Center for Marine Algae at Bigelow Laboratory. “By approaching aquaculture creatively, we can make a real difference to public health.”

Lomas is working to make finfish feeds more nutritious and sustainable by tapping into algae as a source of protein, fatty acids, and other naturally beneficial compounds. By adding the right types of algae to fish feed, he hopes to create a balanced mixture that improves fish health and aquaculture operations.

Salmon are pink because of astaxanthin, a pigment made by algae that has enormous benefits for both fish and human health. One of the most powerful natural antioxidants, astaxanthin provides everything from anti-inflammatory to anti-cancer properties. It is also key to the commercial value of salmon.

“The value of salmon is strictly tied to its color — the pinker it is, the higher the price,” Lomas said. “Just by looking at the fish counter in the supermarket, the connection between the market value and this compound is obvious.”

Failing to absorb enough astaxanthin through their diet leaves salmon pale in color instead of the pink that consumers expect. Many aquaculturists use feed additives to approximate the astaxanthin intake of wild salmon, but these additives are chemically synthesized from fossil fuels.

Lomas sees algae as a more natural and sustainable astaxanthin source, with the potential to transform salmon aquaculture. He is also exploring how salmon can absorb astaxanthin more efficiently, increasing the amount transferred from feed into fish tissue and cutting costs for aquaculturists in the process.

“This is a problem that has existed since salmon aquaculture began,” Lomas said. “We’re trying to use developing technologies to come up with a healthy, sustainable solution.”

Lomas is also seeking ways that algae additives can keep fish, and the environment they live in, healthy. Farmed salmon live much closer together than wild stocks, making it easy for communicable diseases to spread – potentially even reaching wild populations. Additionally, many of the antibiotics used to treat fish disease wind up in rivers and the ocean, where they can have unintended consequences.

Lomas has noticed that some algae produce compounds that are natural antibiotics and actually hamper the growth of bacteria that cause salmon disease. He believes it is possible to choose algae that not only contribute fatty acids or proteins to fish feed, but also contain natural antibiotics that can protect the salmon. By blending together algae with each of these beneficial properties, he hopes to craft the perfect recipe for fish health.

“In the ocean, these compounds work their way up the food chain naturally,” Lomas said. “We’re trying to create that process on land by tapping into ingredients that nature has selected over millions of years to feed salmon.”

Maine is becoming a focal point of the Atlantic salmon industry. The state boasts pristine water sources, long stretches of coastline, and the right water temperature for growing salmon – all of which are attracting aquaculturists. Two land-based facilities are also currently under development in the state to grow salmon in tanks. As this industry gains traction, Lomas hopes that his algae can be part of creating a sustainable, regional brand of salmon raised in Maine.

“Growing algae in the United States is costly, so we’re trying to approach the situation from a different angle to make it possible,” Lomas said. “By making a healthier and more efficient food for salmon, we have the opportunity to translate our science into benefit for society.”