SAN FRANCISCO, Calif. (KCBS)- Greenpeace is intensifying its campaign to persuade Costco to only sell sustainable seafood.

The environmental group says Costco shoppers should buy their seafood elsewhere.

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They’ve encouraged Costco to stop selling red list seafood, including two of its biggest products, Orange Roughy and Chilean Sea Bass.

The message Greenpeace is sending to Costco this week, with a demonstration outside it’s Washington headquarters, includes a blimp hovering overhead with a banner that says, “Costco — Wholesale Ocean Destruction”.

Casson Trenor, a spokesman for the environmental watchdog group, says Costco should only sell sea food that can be harvested without endangering the species.

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“We need to use our purchasing power to support and reward corporations that choose their sea food base on not just on profitability and appeal, but on environmental parameters,” said Trenor.

Greenpeace wants Costco shoppers to boycott the wholesaler’s seafood, but not the entire store and would actually like people to keep shopping there.

“I think it’s important that people keep shopping at Costco because that’s how we’re going to be able to bring our message there,” added Trenor.

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He says Costco sells 15 of 22 imperiled sea species and has done little to change its buying practices to become more sustainable.