Fish in ocean

Feeding the fish… fish (Day 71)

Fish in ocean75 per cent of world fish stocks are fully-exploited, over-exploited or depleted.

Consumers and farmers are turning to farmed fish as a source of food, with fish farms aiming to produce nearly two thirds of the global fish supply by 2030.


However, 81 per cent of the fish caught in the wild are currently used to feed farmed fish, making fish farming just as unsustainable.

Eating fish offers huge health benefits; they provide neurodevelopment benefits to women of child rearing age and have been shown to reduce the risk of mortality from coronary heart disease. We need to find a way of farming fish sustainably to continue receiving these health benefits.

Chemical engineers are investigating various avenues to make the aquaculture industry more sustainable and reduce the use of wild fish in farmed fish feed.

Researchers at the Agricultural Research Service (ARS) of the United States Department of Agriculture (USDA) have been working on a way to produce barley feed with higher protein levels necessary for fish growth. By using an enzymatic process to remove the carbohydrate portion of the barley they are able to concentrate the protein in the feed. This method has seen success, with fish being fed the high protein barley feed having significantly greater energy retention, then those who were not. The ARS and partner Montana Microbial Products (MMP) have patented this research and are operating a prototype plant. They hope to be able to build a commercial plant after a trial lasting 12–18 months.

Norwegian fish farm for salmon growing in open sea waterA new technique of using captured carbon dioxide to feed omega-3 fatty acid producing algae has been developed in Norway. A Norwegian consortium, backed by the government, is building an installation at the Technology Centre Mongstad, the world’s largest test facility for carbon capture and storage technologies. This could offer a method of absorbing gases responsible for global warming while producing sustainable fish food.

Wild fish obtain these omega-3 fatty acids from eating algae, plankton and other fish (they cannot produce them themselves), so they have to be supplemented into the feed of farmed fish.

In the UK researchers at Rothamsted Research are pushing boundaries by using GM crops to grow omega-3 fatty acids. Camelina plants have been developed which produce a high concentration of omega-3 fatty acids. This study will run from 2014 to 2017 and assess the usefulness of producing omega-3 fatty acids in this way. If successful this process would need to be applied to producing fish feed by chemical engineers.

Producing sustainable food is not just about making sure what we eat is sustainable; it is about making sure the diet our food eats is sustainable too.

IChemE’s technical policy, Chemical Engineering Matters, indicates the need to look at ways of producing high-protein diets with better nutrient delivery. Ensuring the food we eat is sustainably and healthily provisioned is a key way of doing this.

If you are working to improve animal feeds get in touch and tell us your story.

One thought on “Feeding the fish… fish (Day 71)”

  1. I like the idea of using captured carbon to feed algae. I have always thought that carbon capture and use is much better idea than carbon capture and storage.


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