Vegetable Growers Study Tour – Germany, Netherlands
29 August 2014Project Harvest: Vegetable Consumer and Market program
18 December 2014Australian consumers love fish and seafood! Consumption has doubled in the last 10 years and is predicted to continue to grow. However, most wild fisheries are already maximized or in decline. The only way to meet this demand is therefore through increased aquaculture. However, most aquaculture species are still fed, at least in part, on fishmeal made from wild caught fish. This is not only unsustainable, but a major factor limiting increased production. Meal made from insect larvae have been proposed as an alternative. Insects are high in protein and fat, can be reared on waste products and are part of the natural diet of some farmed fish species. This project has examined the potential to use vegetable wastes to grow insect larvae, which can then be used in aquaculture feeds. Of the insects studied, black soldier fly (BSF) appears to be a clear frontrunner. Larvae can live on vegetables alone, ‘self harvesting’ when they are fully mature. Adult flies are found naturally in Australia. They are not pests and don’t carry disease, living long enough only to mate and lay eggs. We have conducted a series of small trials finding out how easily BSF can be reared in captivity, what vegetables they can eat, and how the quality of dried larvae compares to commercial fishmeal. An initial colony of BSF was readily generated from local wild populations and grown through to adults. Although adults have been widely reported to not eat, our flies only mated and laid eggs once they were provided with apple juice. Feeding trials with 2nd generation larvae showed that pumpkin, carrot, eggplant, capsicum and processed vegetable sludge were all readily consumed. They could live on lettuce for only a short time, and these larvae had a much higher water content than those fed other foods. Cauliflower and broccoli were not suitable and sweet potato was non-Âpreferred. It was difficult to calculate the exact amount of feed required to produce the maggots as they liquefy feed before eatin