Fish farms threaten marine eco-system

Consumer demand for fish with high levels of omega-3 fatty acid means half of all fish consumed worldwide are raised on farms.

The health benefits of omega-3 fatty acids are well known, but a new study has found that demand for fish with high levels of these oils is stretching the marine system to breaking point.

This is because farmed fish are fed large quantities of fishmeal and fish oil made from wild-caught species such as anchovy and sardine.

“It can take up to 5 pounds of wild fish to produce 1 pound of salmon, and we eat a lot of salmon,” said Professor Rosamond L. Naylor, study author and director of Stanford University’s Program on Food Security and the Environment.

In 2006, around 20 million tons of wild fish were caught to make fishmeal.

“As long as we are a health-conscious population trying to get our most healthy oils from fish, we are going to be demanding more of aquaculture and putting a lot of pressure on marine fisheries to meet that need,” Naylor said.

“Our thirst for long-chain omega-3 oils will continue to put a lot of strain on marine ecosystems, unless we develop commercially viable alternatives soon.”