Paul Willgoss, M&S head of technology, made the sourcing promise at a press conference Tuesday that officially announced the retailer had become the first U.K. company to sign up to WWF’s Seafood Charter.

“We want to sell more fish, our customers are interested in eating more fish but they only want to eat fish that is fished responsibly and comes from well managed resources,” said Willgoss.

“The commitment also gives us the opportunity to differentiate our business.”

Last year, M&S became the United Kingdom’s first major food retailer to source only pole-and-line or line-caught tuna for all the products it sells, but Willgoss said the company knew it needed a “much more comprehensive and cohesive plan.”

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