The Hippo


May 31, 2020








Worm farming
A potential fish food industry

By Ryan Lessard

 The Granite State could be the center of a new agricultural industry, where farmers grow millions of tiny worms instead of crops. 

The science
Researchers at the University of New Hampshire have been studying how to cost-effectively grow and harvest white worms to serve as a nutritious and live form of food for aquarium fish. Research Associate Professor Elizabeth Fairchild recently published her findings in the journal Aquaculture, which focused on what to feed the worms at the lowest costs and the nutritional composition of the worms after eating certain foods. 
White worms, also known as Enchytraeus albidus, are about two to four centimeters long and about half a millimeter wide. 
“They’re like little pieces of spaghetti,” Fairchild said.
During their research, Fairchild fed different groups of worms old produce, leftover bakery bread, sugar kelp raised by university students and spent beer grains from Smuttynose Brewing Co. in Hampton.
It turns out the beer grains were the most cost-effective option and resulted in worms that were high in protein and high in fat.
“Which is exactly what young fish need,” Fairchild said.
Fairchild said she’s planning to publish another study soon that looks at what can be added to the worm’s diet to make it even more nutritious for ornamental fish. Live worm food is preferred not only for their nutritional value, but because certain fish are more likely to eat their food if it’s alive. 
Fairchild first stumbled upon the potential of white worms when a graduate student named Michelle Walsh tried raising winter flounder on three or four types of live food, including white worms, in an attempt to devise a feeding regime that better prepared the flounder for release into the wild in the hopes of someday replenishing ocean stock.
According to Fairchild, Walsh found that the fish who ate the white worms were outperforming the other fish; they grew much faster and had better survival rates. 
They also found that white worms were relatively easy to grow. Fairchild started to  send the worms to anyone willing to experiment with them, like other universities, aquariums, government facilities with aquaculture programs and ornamental fish companies. 
All told, they distributed about 250,000 worms across the country. The recipients then completed surveys on how the fish responded to the worms. New England Aquarium in Boston fed some of the worms to some of their shore birds, like sanderlings, and has expressed interest in receiving some more.
The industry
Fairchild said there’s still a lot they don’t know about the costs of scaling up worm production or the profitability of a commercial endeavor, but she perceives strong and growing demand for the product. This is especially true for the ornamental fish industry.
“I’m sure movies like Finding Nemo and [Finding] Dory have helped spur some of this,” Fairchild said.
Buyers could include fish growers for pet stores or hobbyists who may buy the worms directly for their pets as an alternative to pellets.
“It’s a pretty lucrative market and it’s a growing market,” Fairchild said.
The ornamental fish industry is based predominantly in Florida, Fairchild said, but that region is too hot; the worms prefer a more temperate climate like New England’s. The lab where the worms were grown for their study is generally under 70 degrees, she said.
Their system was modeled somewhat after how the white worms were grown in Russia in the previous century.
“These white worms used to be raised en masse in the former Soviet Union to feed sturgeon fry,” Fairchild said.
Fairchild used what were essentially plastic shoe boxes filled with soil that were stacked up on shelves. In theory, she said, one could fit a lot of worm boxes in a small space.
Aside from feeding and housing the worms, any commercial worm grower would also have to harvest and ship them to buyers. That’s where things get trickier.
The worms get tangled up in the soil, Fairchild said, so master’s student Andrew Pompeo devised a prototype harvesting device that raised the ambient temperature in the soil to an uncomfortable level, forcing the worms to flee through a screen hole underneath the box. But someone would need to figure out how to take the principles of the prototype to scale it for a larger system. 
Then there would need to be a more cost effective way to ship the worms. 
“We were shipping them basically overnight FedEx in ... oxygenated water,” she said.
Since she sent out the worms, she’s already had offers to buy more. 

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