Food waste to help sustainably farm fish

A study done by the University of Western Australia (UWA) has found that food scraps can be used to raise black solider fly larvae which could act as a nutritional food source for farmed fish.

Funded by the Fisheries Research and Development Corporation, the study found that the insect larvae contained high amounts of vitamins, minerals and amino acids which helped the trial fish’s growth and performance.

The study estimated that the larvae contained about 40 per cent protein and 30 per cent fat, ideal for the aquaculture industry. Aquaculture focuses on the growing aquatic animal populations under controlled conditions.

The larvae in the study were fed to rainbow trout, a key species within the aquaculture industry that is grown across 75 countries.

There is currently a high dependence on fish products both wild and farmed with approximately three billion people globally relying on seafood with as their primary source of protein.

“Globally, we are harvesting wild fish at their maximum levels, which makes further reliance on wild-caught fish unsustainable,” said Katarina Doughty, PhD student at UWA’s Ocean Institute of Biological Sciences.

With the human population expected to surpass 9.6 billion by 2050, the seafood sector cannot meet demand while maintaining sustainable practices, said Doughty.

“Aquaculture can fill the gap between wild harvesting limits and consumer demand, but only if we develop sustainable feed alternatives that maintain fish growth, performance and health,” said Doughty.

Cultivating aquaculture fish populations raises the issue of food competition as it often relies on agriculture sources such as poultry or soybean for feed. These products directly compete with human’s food source.

Isobel Sewell, a PhD student from UWA’s Ocean Institute of Biological Sciences is also analysing how black solider fly larvae could be used to farm barramundi and marron fish.

“I hope to use the findings of my research to develop new sustainable farming practices specific to both species, with the goal of aiding the development of sustainable aquaculture industries in Western Australia,” said Sewell.


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