Vancouver environmental group 3rd Whale says more seafood eaters have realized the importance of making sustainable choices. (CBC)

Too many restaurant owners don't know whether the seafood served at their sushi bars is caught in a sustainable way, says a Vancouver environmental group that is organizing a contest to raise awareness of the issue.

Emily Jubenvill of 3rd Whale said Tuesday that she has approached 15 sushi restaurants in the West End, but "very few of them heard about … sustainable sushi."

More customers now support sustainable seafood choices, she said, and 3rd Whale is organizing an awareness contest using consumer power to spread the message.

"I love sushi, and I'm always thinking about what are the choices here, what's sustainable [and] what's not," Jubenvill told CBC News.

Emily Jubenvill of 3rd Whale says consumer power is a good incentive to encourage owners to 'green' their businesses. (CBC)

"We walked around the West End and went into every sushi restaurant and told them we have a huge mob of people willing to spend money at your restaurant if you're willing to commit a percentage of your day's revenue to making your restaurant more environmentally sustainable."

The group calls its strategy a "podmob," an idea that originated with a San Francisco group named Carrotmob, which aims to improve the environment by promoting socially responsible choices in businesses, Jubenvill said.

3rd Whale has scheduled Nov. 20 for a group of consumers to eat at the sushi restaurant that pledges the highest percentage of that day's profit toward green measures. As a minimum, the winning restaurant has to vow to amend its menus to include the sustainability ratings of each of the kinds of seafood it offers.

The ratings — either "best choice," "good alternative" or "avoid" — are an indicator of whether too much of a species of seafood is being harvested to sustain population levels in the long term.

Sushi restaurant owner Jonathan Flores says he's committed to adding new, sustainable choices on the menu. (CBC)

Several sushi restaurants in the West End accepted the pitch, and Sushi Bento Express on Robson Street made the highest bid — to commit 31 per cent of its profits on Nov. 20, Jubenvill said.

"After she talked to me I went on the internet, did a little bit of research myself, and I learned a lot of stuff, [and] there's a lot to learn about it," said Jonathan Flores, who owns Sushi Bento Express.

Flores said he didn't realize the environmental differences between farmed and wild salmon until he read the Seafood Watch Sushi Guide published by the Monterey Bay Aquarium in California and recommended by Jubenvill.

"I actually thought farmed salmon was better, and I'm kind of glad that we do have wild salmon," Flores said.

"There's a lot of things we can do, maybe even using recycled paper, changing our containers, not using Styrofoam for takeout."

Flores said he will also try to find an alternative to the freshwater eel on his menu, which is listed as an item to avoid because it's not sustainable.

With files from Lisa Johnson