As widely reported this week, a new study led by Cambridge University and published in PLOS Sustainability and Transformation concluded that allocating feed fish for human consumption could reduce pressure on marine resources while increasing seafood production.

The lead author, David Willer, Henslow Research Fellow at Cambridge University, wrote:

‘A leading cause of overfishing is, ironically, the demand for fish feed. Over one-third of all fish caught worldwide are fed to farmed animals instead of people. Fish farming, or aquaculture, is the world’s fastest growing food sector. Most of the Atlantic salmon sold in supermarkets in the UK is farmed.

Rearing these large, predatory fish involves feeding them a diet rich in omega-3 fatty acids and protein, nutrients that are also essential to humans for brain development and nerve function. In a new study, my colleagues and I found that if people ate the wild-caught fish, such as sardines, which are usually destined for salmon farms, it would leave nearly 4 million tonnes of fish in the sea and provide an extra 6 million tonnes of seafood.

Salmon raised in coastal farms off Scotland is the UK’s largest food export by total annual economic value (followed by bread and pastries). Our research team carried out a thorough assessment of the Scottish salmon industry, collecting data on fish nutrient content, fishmeal and fish oil composition and examining the transfer of micronutrients from feed to fish.

We found that by removing wild-caught fish from salmon feed and only using fish byproducts instead – such as trimmings and offcuts from the filleting of farmed fish – 3.7 million tonnes of fish could be left in the sea and global annual seafood production could increase by 6.1 million tonnes. Over half of the essential dietary minerals and fatty acids available in wild fish are currently lost to human mouths when these fish are fed to farmed salmon.’

The piece above can be found in full here and the research article is published here. There is also coverage in the Guardian, Science Daily, and Fish Focus.