Whole Foods Market, the US-based natural and organic retailer, has implemented "enhanced standards" for all farmed seafood sold at its stores.

The strict guidelines, implemented for its 270 stores in the US, Canada and the UK, are designed to help reduce potential environmental impacts and will require suppliers to pass an independent, third-party audit that reviews every detail of the standards.

"For years our seafood standards made us a leader in our industry. Now, we have taken an additional step by embarking on an intensive process to further develop and enhance our farmed seafood standards," said Carrie Brownstein, seafood quality standards coordinator for Whole Foods. "By working closely with the farmers who produce the highest quality farmed seafood for our shoppers, Whole Foods Market is proud to set the bar even higher."

To date, Whole Foods prohibited the use of antibiotics, added growth hormones, preservatives such as sulfites, poultry and mammalian by-products in feed, and genetically modified or cloned seafood.

The additional standards will now require producers protect sensitive fish habitats such as mangrove forests and wetlands, monitoring water quality to prevent pollution, and sourcing feed ingredients responsibly.

Suppliers must also provide detailed information on farming practices and pass independent third-party audits, and refrain from using toxic chemicals and pesticides.

"When a leading retailer like Whole Foods makes this kind of commitment to standards for farmed seafood, suppliers around the world will work to meet the requirements," said Becky Goldburg, a senior scientist with Environmental Defense Fund, which contributed to the policy.