03/26/2012 12:08 EDT | Updated 05/26/2012 05:12 EDT

Many canned tuna brands getting more sustainable

Canned tuna sold under the Gold Seal, Ocean's, Safeway and Sobey's Our Compliments brands have improved their commitment to sustainable fishing enough to get a nod from Greenpeace Canada.

The environmental group's second annual sustainability ranking of Canadian canned tuna brands gave a passing grade to six of 14 Canadian canned tuna brands, up from just two in 2011. The only brands that "passed" last year were Wild Planet Foods and Raincoast Trading, which remained at the top of the list.

“We have seen some positive change in tuna markets around the world and now we’re seeing Canadian canned tuna brands step up and commit to sourcing tuna more responsibly,” said Sarah King, the group's oceans campaign coordinator in a statement Monday.

However, Pastene, Unico and Wal-Mart's Great Value and Metro's Selection brands, along with Clover Leaf, remained near the bottom of the rankings, largely because:

- They use tuna caught by fishing methods that Greenpeace Canada considers destructive, such as purse seine fishing with fish aggregating devices. That method involves floating buoys that lure a variety of fish and other wildlife such as sea turtles to a particular site. Fishing boats then use a net to scoop up all species at once, a practice that Greenpeace calls "wasteful" compared to more targeted methods such as trolling or using a pole and line.

- Some use tuna such as yellowfin that are considered threatened.

Meanwhile, Greenpeace said, five brands took the positive step of discontinuing their use of yellowfin tuna, and both Gold Seal and Safeway committed to sourcing all their skipjack tuna from sustainable sources.

Greepeace Canada graded and ranked different brands based on whether they:

- Have a sustainability policy.

- Avoid using tuna from threatened stocks and those caught using "destructive" fishing methods.

- Are able to trace the tuna they use to its source.

- Promote marine reserves and domestic, coastal fisheries.

- Use comprehensive and clear labelling.