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A sustainable, alternative option for fishing bait…

Farming By Rob van Zyl, Partner, Building Services – 28 October 2020

Two fishing rods visible with the sea and a pink and blue sky


Rob van Zyl in a dark suit and tie with office blurred background

Rob van Zyl

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Did you know that the maggots used as fishing bait are the larva of the common fly and are bred on maggot farms?

If we asked, could you think of any other purpose for breeding maggots, be they bluebottle or black soldier flies? Your answer would probably be no, however one of Cundall’s clients has developed a highly sustainable solution to tackle food waste using them. Their vision is to grow larvae by giving them local food waste (such as potatoes and coffee grounds) which will allow the larvae to grow to a size where they can be processed into a highly sustainable protein flour that can be used in large scale aquaculture environments.

The demand for fishmeal, a critical ingredient in aquaculture and livestock feeds, is already outpacing the supply available from the commercial fishing industry. Therefore, there is an urgent need for new and sustainable sources of complete protein for use in feeds.

The process is well developed - collect local food waste at source, transport this waste to purpose-built indoor facilities scaled for up to 350 tonnes of waste per day and use black soldier fly technology which uses the life cycle of the fly to sustainably upcycle nutrient waste which can be sold back into the farming industry. Black soldier flies, unlike house flies, do not spread diseases which is why they are ideally suited for this use.

Research has also demonstrated that larva growth is affected by changes in their local micro-environment, which needs to be closely monitored and controlled.

As in other forms of vertical farming, the farming of black fly larva needs vast quantities of closely controlled air temperature and humidity within the breeding chamber, where they pupate, mate and lay eggs. Too hot or too cold and the larva will die; if the air is too dry, the nutrient substrate will dry out ahead of the lifecycle of the larvae, and they cannot feed.

At the end of the lifecycle, it is important that the nutrient substrate is sufficiently dry to separate the larva (which can be used for protein) from the solidified substrate (which can be used for compost).

This close control of the fly larvae’s environment on such a large scale requires a lot of energy. The enormous amount of ammonia produced by the flies also needs to be scrubbed out of the air to keep the facility safe for humans. Our client has developed innovative methods to minimise this consumption so that the facilities can provide a sustainable way forward to feed the planet. If you would like to know more about the work that Cundall is doing in this area then please leave a comment below.