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David Willer
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Zoologist David Willer investigates sustainable aquaculture

Leathersellers Scholar David Willer and Dr David Aldridge are on a mission to work out how to look after our planet and people’s health at the same time. 

Both zoologists in the University of Cambridge Conservation Research Institute, they want to demonstrate that bivalve shellfish – oysters, scallops, mussels and clams – can be a source of affordable, sustainable and nutritious food.

“In the developed world, over two billion people eat too many calories but not enough nutrients to stay healthy,” says the Fitzwilliam College PhD student David (Willer), “and a billion people in the developing world don’t have access to enough food. We believe bivalves are the answer!

“This is about providing people with food that is environmentally sustainable but also nutrient dense,” he says. “We know that meat and fish have a greater environmental impact than plant-based foods. But the environmental footprint of bivalve aquaculture is even lower than many arable crops in terms of greenhouse gas emissions, land and freshwater use.”

Bivalves sit right at the bottom of the food chain. They are filter feeders, and eat whatever is suspended in the water, which is usually either decaying organic matter or algae. This is in stark contrast to salmon farming, which takes five kilos of wild fish for every kilo of salmon produced. Willer says that if just 25% of this ‘carnivorous fish’ aquaculture was replaced with an equivalent quantity of protein from bivalve aquaculture, 16.3 million tonnes of CO2 emissions could be saved annually – equivalent to half the annual emissions of New Zealand.

Bivalves offer other environmental benefits too. Farming them has many benefits on marine ecosystems including the provision of nursery habitats for fish, coastal protection, and helping to clean up waterways by filtering out nuisance algae and suspended sediments.  

Across the world there is a huge area of coastline suitable for growing bivalve shellfish – an estimated 1,500,000 square kilometres, equivalent to over six times the total area of the United Kingdom. Willer says that developing just one percent of this could produce enough bivalves to fulfil the protein requirements of over one billion people.

There is just one last challenge to overcome before bivalves could help to feed the world. “They’re not actually a food many people tend to like,” admits Willer, “and I think that’s probably one of the biggest challenges. We can increase the production of a very sustainable food, but if no-one eats it, it’s pointless.”
Rather than trying to convince the rest of us to change our dietary preferences, Willer and Aldridge are looking at novel ways to make bivalves more palatable – essentially by disguising them. One idea is to swap out fish – which is often sourced unsustainably – for processed clam meat in a new form of ‘bivalve fish finger.”

This article was originally published on the University website - see the original version.

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