Fish Food Makeover: Algae Steps Up to the Plate

For decades, the industry has depended heavily on wild-caught fish to supply critical feed ingredients aquafeed. Sardines, anchovies and menhaden have made up the majority composition of these ingredients and caught through reduction fishing. But overfishing has become a major concern by NGOs, consumers and governments and has threatened marine ecosystems. As aquaculture grows the demand for fishmeal would outstrip sustainable supply if heavy dependence on it continues. With environmental pressures mounting and wild fish stocks under strain, alternatives are being sought out. Sustainable aquaculture means not just farming fish responsibly but also feeding them responsibly — and reducing fishmeal is a major part of that. Bring on microalgae!

Microalgae hold great promise as aquafeed ingredients, offering a variety of nutrients such as protein, lipid, and carotenoids. Algae species such as Chlorella vulgaris, Arthrospira platensis, Dunaliella salina, and Nannochloropsis oceanica are known for their high protein content, ranging from 40 to 70%, making them highly nutritious for aquafeeds. Likewise, with its high content of omega-3 fatty acids, particularly DHA, Schizochytrium sp. offers significant potential as a replacement for fish oil in aquafeeds. Pigments in microalgae, like astaxanthin, enhance nutritional performance in aquaculture. This carotenoid offers antioxidant benefits, protecting fish from oxidative stress and supporting the health and coloration of species like salmon and shrimp.

Studies have demonstrated that algae meal can significantly replace fishmeal in numerous aquaculture species, providing a valuable alternative protein source. Algae oil, on the other hand, stands out for its ability to fully replace fish oil without negatively affecting growth or fish health. Recent studies in Atlantic salmon and rainbow trout have shown that conventional fish oil can be completely replaced by Schizochytrium sp. (T18) oil, with no negative effects on nutrient digestibility and growth performance,

As aquafeed looks to reduce pressure on wild fisheries, find consistency & supply stability and lower their environmental impact microalgae presents as an alternative that could hit the mark against these challenges. But, it doesn’t come without major obstacles. Aquafeed is not only the largest carbon footprint for farms, but also the largest cost and microalgae does not help in that department.  Right now at current harvest potential, microalgae is expensive. Scalability is also a major hurdle for large scale production of microalgae. At present scalability, it would not be possible to produce sufficient volumes for the growing demand anticipated for protein from aquaculture.     

While costs and scaling are still challenges, investment is growing. Major feed companies and biotechnology startups are racing to refine production methods, improve nutrient yields, and bring down prices. Microalgae has the potential to be a preferred choice for alternatives to fish oil and fish meal when compared to at land-based crops like soy or canola, as keeping aqua based feed for aquatic animals is important to the industry. As technology advances, algae-based feeds are expected to become increasingly competitive — helping the aquaculture sector move closer to a truly sustainable future.