Greenpeace is claiming that when it comes to unsustainable seafood practices, Costco is one of North America’s worst offenders.

Members of the organization hung on yesterday morning outside Costco’s downtown Vancouver warehouse a large banner with the words “Ocean Destruction” and a fishing longline with replicas of endangered ocean species.

“We want to encourage consumers to pressure Costco (to adopt a more sustainable seafood policy),” said Greenpeace oceans campaigner Sarah King.

The rally is part of the environmental organization’s 2010 Taking Stock campaign, which targets Canada’s eight largest supermarkets. The goal of the campaign is to get the stores to purchase and sell more sustainable seafood products.

King said Greenpeace wants Costco to stop selling seafood on a red list of species in danger and to improve how it labels products.

Costco’s U.S. president has agreed to speak with Greenpeace.