A West Australian research program using soldier fly pupae as fish feed could be a game changer for Australian aquaculture, according to one of the industry’s leading scientists.
By Sean Murphy
Craig Lawrence, an internationally acclaimed 25-year veteran currently running the WA Department of Fisheries’ freshwater research and hatchery, said a long-term soldier fly trial on barramundi and rainbow trout diets could deal with one of aquaculture’s biggest problems; its use of more fish per kilogram than it actually produces.
Doctor in front of tanks used for aquaculture research
“Australia imports large amounts of fish meal every year, not all of it for aquaculture, but one of the problems we have with aquaculture is we actually take about 10 tonne of fish out of the ocean to produce about one tonne of aquaculture of a carnivorous species, so this makes it environmentally better,” Dr Lawrence said.
Worth nearly $1 million in cash and resources, the research project comes after a ground-breaking six-week trial conducted by University of Western Australia (UWA) masters student Isobel Sewell.
The trial found trout fed on a diet consisting wholly of soldier fly pupae had growth matching those eating fish meal or combinations of both.
Dr Lawrence said he was hopeful the expanded trial, funded by the Fisheries Research and Development Corporation, would show the nutritional benefits of the insect-based diets would outstrip feed produced using lupins and soy beans.
“They [soldier fly pupae] are high in proteins and they’re high in fats, ” Dr Lawrence said.
“The important thing is to make sure they’re the right fats, the right omega threes, the right omega sixes, because we want to be able to produce fish that not only grow well but also are healthy eating for people, and that’s something that plant substitutes for fish meal fail to deliver.”
Aquaculture: What is it?
The cultivation of food resources from the sea or of inland waters.
The initial UWA trial was conducted in partnership with a research and development farm owned by Perth-based Future Green Solutions.
The company’s founder Luke Wheat said he was developing a soldier fly farm system which converted food waste into feed.
“Those insects are absolutely voracious feeders,” he said.
“They convert that into really high-value proteins and oils, and then we’re harvesting those proteins and oils to incorporate into traditional aquaculture and horticulture feeds.”
The small scale of Australia’s emerging insect farm sector had hampered development of an aquaculture feed industry, he said, but this was likely to change as more farms grew to an industrial scale.
Producer holding insects used for fish feed in a box.
“One of the big hurdles for the insect industry globally is finding a way to find really smart mechanisation methods which can turn the current, fairly highly labour-intensive processes we use in a laboratory setting … to something where we can push a button and set-and-forget-type factory setting, where we can start processing hundreds of tonnes of waste a day.”
Mr Wheat added he would soon commercialise and market an engineering-based farm system.
“With aquaculture growth forecast, it’s one the fastest growing feed industries in the world, and to be able to be doing that sustainably moving forward we need to get smart about what we’re feeding fish that are grown in an aquaculture setting,” he said.
“So that was always our main focus, but the waste conversion and the production of soil amendments and high quality fertilisers, I suppose, initially we saw it as a by-product but it’s actually a really fantastic environmental and sustainable outcome of this industry,” Mr Wheat said.