Black soldier flies as a sustainable feed alternative for aquaculture
Main Street Farms is exploring the use of Black Soldier Flies (Hermetia illucens) as a feasible supplemental food source for farm-raised tilapia. Our goal is to decrease feed costs and reliance of unsustainable fish food, and increase farm net income. We are experimenting with methods to raise and breed Black Soldier Flies year-round in a greenhouse in a northeast climate.
Adrianne Traub, project coordinator, is responsible for daily feeding, data collection, design overview, and material and supply purchasing. Robert Bonagura, farm manager, is responsible for construction, maintenance, and daily feeding. Allan Gandelman, farm owner, is responsible for overseeing project requirements and directing overall project. Neil Ringler is technical advisor for entimological support.
The project initially used 55 gallon drums to hold larva as they grew in the greenhouse. After a summer season, we found the drums were a viable container for the larva to grow, but were not an efficient use of space because of thier shape and lacked effective drainage. Also the planned storage space semi-below ground lacked adequate ventilation. We began using plastic totes as an alternative to the 55 gallon drums. They are cheaper to purchase and we are able to stack them on a shelving unit in order to save space.
To increase the size of the colony, a breeding cage was constructed indoors with adequate heating and humidity. It was found that the larva were pupating into flies inside the cage, but not laying eggs. The most likely explanation was the flies need wavelengths in natural light that standard light bulbs do not emit. The cage was reconstructed in the heated greenhouse in the fall, but flies were still not laying eggs. We expect this was a lack of sufficient heat.
The purpose of the breeding cage is to control how many larva reproduce and how many are fish food. However, throughout the entire summer season, larva were unexpectedly maturing into flies inside the feeding bins, mating, and laying eggs back into the bins on their own. This allowed for a continuously growing population even though the breeding cage success is still in progress.
As winter approached we thought that the larva would continue to eat, grow, and keep warm through their own metabolic processes inside a heated greenhouse (45F-80F). By mid October the larva were still eating, but at a rate that was too slow for maturation. The bins were moved onto a table covered in plastic, and heated with a small space heater. The totes were aligned so all drainage could flow into one common gutter and then down into a bucket. The slope of the table still allowed larva to instinctively crawl upward and into a catchment system. This system permitted larva to continue their fast metabolic process, pupate, mate, and lay eggs back into bins all in one system throughout the winter.
Results have triggered changes in our experimental setup. As the project progressed we found some designs worked better than others. Breeding has so far occurred best naturally without any enclosed space. Black Soldier Fly larva prefer foods with low cellulose content, and grow faster with more food available.
Impacts and Contributions/Outcomes
Main Street Farms, LLC
116 North West Street
Homer, NY 13077
Office Phone: 6077450419
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