USDA lead scientist explains aquaculture's need for algae

By Luke Geiver | November 02, 2011

Aquaculture has passed the 50 percent mark, meaning it now provides more fish for human consumption than wild harvested fish, according to Rick Barrows, lead scientist for USDA’s Agricultural Research Service. “Aquaculture is growing very quickly,” he said. “It is currently a $97 billion global business, growing at 9 percent per year.” Barrows, who told a crowd at the 2011 Algae Biomass Summit that he gets calls all year long about people with fish feed products and ingredients for use in aquaculture, said we still have a limited knowledge of ingredients. And this “is where algae fits in,” he said.

For Barrows, there is a huge need for alterative ingredients and worldwide fish feed researchers are looking for every ingredient possible. “Over the last 20 years the yield of fish meal has been pretty much constant,” he said, “so we aren’t getting any more fish feed out of the ocean and we [aren’t] getting any more fish meal ingredients.” So, he asks, “What are we going to do?”

Part of the answer for Barrows is algae. “All types of species in aquaculture are interested in the essential fatty acids that can be found in algae because that is what makes fish a heart-healthy, brain-healthy food,” Barrows said. Although it is possible to use animal feed for fish meal, the cost is too expensive and certain minerals and vitamins would need to be replaced.

Using the six-step process for evaluated ingredients in fish meal, along with two separate studies that showed the effectiveness of algae-based fish meal, Barrows explained that algae can act as the next big ingredient for fish meal used in nearly every species, ranging from warm to cold water varieties.

The six-step evaluation process begins with compositional analysis of the ingredient, then the effect of the feed intake (compatibility and digestibility) is measured, followed by the absorption rate of the ingredient by the fish; then a fry screening is performed to further evaluate the first three steps. The fifth step measures the effect of the ingredient in question on the pellet forming manufacturing process, and finally, the ingredient is measured by the amount of growth it promotes in the fish.

In a recent study that used solar dried spirulina as the fish meal, “we found that the product had a significant increase in feed intake,” Barrows said. As for the functionally, they saw dramatic expansion as the meal was much more dense and easier to handle. Growth trials also showed the algae-based fish meal performed well on rainbow trout that were fed the meal.

 A white seabass study that created a total of eight different diets, four of which were based on a mixture of fish meal with algae in different doses, and four different entirely algae-based diets, also showed promising results. “The fish fed the fish meal diet with spirulina added showed no increase in growth rate, however, the fish-meal-free diet showed significant increase in growth rate,” adding that “they gained significantly more weight.”

“I had to repeat this three times before I had the courage to say we outperformed the commercial diet,” he said, “because I’m usually happy if we can match the commercial diets.”

Although the algae-meal study shows the promise of algae as a fish meal or ingredient substitute, Barrows pointed out that in some cases the algae-meal decreased the mortality rate of the fish to nearly 70 percent, a number he said can be attributed to either a missing nutrient or the increased feed intake by the fish. Neither is a breaking point he said, as diets can be adjusted to compensate for such occurrences. And in the end, regarding his talk on aquaculture and the need for algae, Barrows said, “I just wanted to show you that new ingredients are badly needed.” 



3 Responses

  1. fatalage



    Solydra story is opening a huge can of worms at the DOE LOAN GURANTEE LOAN PROGRAM. Its not just about the Solar loan guarantee program. Look at all the millions in fees collected by the DOE LOAN GUARANTEE PROGRAM with projects 20% completed. Also, an audit needs to be done on DOE GRANTS to individuals from the DOE that are now working in private industry. Very incestuous! There needs to be an audit on each individual loan program for amount funded and results! The US taxpayer has spent over $2.5 billion dollars over the last 50 years on algae research. To date, nothing has been commercialized by any algae researcher. The REAL question is: Does the DOE BIOMASS PROGRAM really want the US off of foreign oil or do they want to continue funding more grants for algae research to keep algae researchers employed at universities for another 50 years? In business, you are not given 50 years to research anything. The problem is in the Congressional Mandate that says the DOE can only use taxpayer monies on algae research, NOT algae production in the US. So far, research has not got the US off of foreign oil for the last 50 years! anonymous

  2. Ron



    Thanks Luke, great info. Will be setting shop in aquaculture and Solar/Wind energy on a beach soon.Training and knowledge has been fantastic. Had enough of people like "anonymous" and NY weather Will look out for new articles and will search for your stuff. We will keep borrowing from the Chinese to buy oil from unstable places to burn and keep screwing up this earth.That's OK with people like "anonymous."

  3. Dallas Weaver, Ph.D.



    The concept of using algae in aquatic diets provides a significant market at a reasonable price point between the insignificant health food type niche markets and the totally huge energy markets. This stepping stone market prices many algae species in the $1000 to $1500/ton range and could allow algae biomass production business to expand and achieve economies of scale up to a market in the 5 million tons per year range. That gets you into the total algae farm size in the million+ Hectare class before you need to think about lower value fuel markets. If your algae has the correct fatty acid distributions (high long chain omega-3 fatty acids), you don't even have to extract or process the oil and can sell it at a much higher price that editable oils or fuel oil.


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