Sugar-Fed Algae For Fish Farms Will Conserve Wild Fish

September 29, 2000

SUGAR-FED ALGAE FOR FISH FARMS WILL CONSERVE WILD FISH

TOWNSVILLE, Australia--Fish and shrimp farmers can raise healthier and more nutritious crops by feeding them algae raised, in turn, on sugar water, according to Allen R. Place, professor, University of Maryland Biotechnology Institute (UMBI).

As an alternative to the seven to nine million tons of fish meal and oil fed annually to aquaculture crops, sugar-fed, or heterotrophic, algae in fish feeds will also help the world conserve rapidly dwindling wild fish populations, Place said today at the International Marine Biotechnology Conference. Place is a research professor at UMBI's Center of Marine Biotechnology (COMB) in Baltimore, Md. USA.

Although soybean and wheat meal have also been studied to replace much of the wild fish meal and oil in farm fish foods, Chlorella and Tetraselmis algae provide the desired omega 3 and omega 6 fatty acids, DHA and EPA, for an aquaculture diet, said Place. "This kind of algae cultured feed is also competitive in cost with using fish products or soybean products in aquaculture feeds." In studies at COMB by Place and colleagues, with industrial partners at Martek BioScience Inc., found that the two species are well suited to growing on glucose sugar in large fermentation tanks.

The heterotropic algae can be fed to fish larvae as an algae meal or as an enrichment diet for small animals, such as rotifers and brine shrimp, fed in turn to aquaculture fish.

Most aquaculture hatcheries grow algae with lights. However, to produce one kilogram of algae with lights cost $11.20, but only $0.81 heterotrophically.

The COMB scientists also found that the nutritional composition of the algae feed can be manipulated to meet specific requirements of different species of finfish and shellfish.

COMB is one of five centers of the University of Maryland Biotechnology Institute, a unique life sciences research and education arm of the University System of Maryland. One of UMBI's first two research centers founded in 1985, COMB has achieved international recognition as a center of excellence in the study, protection and enhancement of marine resources.