Algae’s Advancing Role in Aquaculture

Researchers at Sweden’s University of Gothenburg have observed that growing algae, mussels and fish together is not only good for the environment, it also produces better aquaculture harvests.

“We made a pilot-scale experiment to investigate the benefits of co-cultivating fish, mussels and algae where we discovered that co-cultivation creates a win-win situation,” said Luca Rugiu, a researcher in U of G’s Department of Marine Sciences. “In the future, a fish farmer can, for example, reduce the amounts of nutrient emissions from his cultivation by also cultivating algae that use them as a resource; while an algal farmer produces larger and better harvests with algae containing more protein and bioactive substances close to a fish farm.

“Co-cultivation minimizes the negative impact of fish farms on the environment, where cultivated algae absorb dissolved nutrients, such as nitrate and ammonium released by the fish farm. The filtering mussels absorb the nutrients that are bound in particles from the water,” said the algae researcher.

This study showed that the availability of nutrients in the water gave photosynthesis a boost for the algae, which in turn increased the amount of biomass produced.

Chris Chase at seafoodsource.com writes that algae-based products are becoming more and more prominent in the world of aquaculture feed. As global seafood output is forced to increase due to rising global demand, aquaculture has been touted as the go-to solution to keep seafood supplies on track.

Most conventional farmed species are carnivorous and require fish meal or fish-oil based feed to meet growth and nutrition targets. The sources of fish meal and fish-oil vary, from byproducts recycled at processing plants to forage fish such as menhaden or anchovies harvested in huge numbers. Typically, those sources are wild-caught, and thus limited in supply.

With increased demand for feed due to growth in global aquaculture production, the development of algae-based aquaculture feeds has accelerated, with many products now available commercially.

Mr. Chase notes that algae-based feed company Veramaris has partnered with traditional feed manufacturer Skretting to expand the penetration of algae-based products into mainstream markets – the partnership has already led to algal-oil fed trout being featured in French retailers, and Kaufland in Germany also now sells fish fed a diet from Vermaris’s algal oil.

Corbion is another company pioneering new algal-based feeds through partnerships with existing feed manufacturers like BioMar. As of October 2019, more than 500,000 tons of feed sold by BioMar included Corbion’s algae-based products.

“AlgaPrime DHA is grown in closed fermentation tanks where it transforms renewable, sustainable plant sugars into algae containing omega-3 DHA rich oil,” Corbion Global Aquaculture Lead Chris Haacke said. “Our facility sits among sugar cane fields and is located next door to a sugar cane mill in the São Paulo state of Brazil, the major sugar cane production area in Brazil. Producing algae omega-3s via fermentation enables production at scale.”

Corbion’s facility has some of the largest aerobic fermentation tanks in the world and has been producing AlgaPrime DHA at scale for five years.