So here we are, my husband and I, standing in a busy Asian supermarket on a Saturday morning and I have two cuts of frozen fish in my hands. My husband and I are discussing which one to buy and we’re considering type of fish, cut, price and how far it’s traveled to our plate. Then I throw a spanner in the works: is it sustainable?

My husband sighs. He does this when I ask him to rinse out his disposable drink cup, and when I am dithering in the toilet paper aisle, trying to work out whether I care enough about the earth to spend an extra 9c a square. It’s the resigned sigh of a moderately green man who is married to an environmental zealot.

The good news – for my marriage and the line of people forming behind us in the supermarket – is that it’s becoming easier to find out what’s actually on your plate, where it came from and how sustainable the fish stocks are.

A quick search on my smartphone brings me to Seafood Watch, a no-nonsense list of seafood stocks, their commonly used alternative names and how likely it is your choice will endanger a species. You can search for whatever is on the menu or the label, tell it where you are and it will tell you whether you should eat it.

Seafood Watch has the low-down on Mahi Mahi. Source: website

Seafood Watch has the low-down on Mahi Mahi. Source: website

Seafood Watch is run by Californian nonprofit Monterey Bay Aquarium, an organization which has a vested interest in keeping our ocean ecosystems healthy and sustainable. There are a few other services that offer similar information – the National Resources Defense Council and Trace and Trust, for example – but the aquarium has invested significant resources in leading the charge in sustainable fisheries. In fact, it has just spent $12.4 million to build an education center in Cannery Row (yes, Steinbeck’s Cannery Row) to help inspire and train the next generation of ocean keepers in a K to year 12 – ahem – school.

On New Zealand’s doorstep is the last pristine marine ecosystem on earth – the Ross Sea. A team of filmmakers went out there recently to investigate the plight of the Antarctic toothfish, which is being overfished and sold in upmarket restaurants worldwide as Chilean sea bass. As top predator, the toothfish’s demise is terrible news for the entire ecosystem. Aside from raising awareness of the issue through their multi award-winning documentary, the folks behind The Last Ocean also convinced several supermarkets to stop selling the fish and is still pushing for the sea to be declared a marine protected area.

Sustainable seafood has been the hardest nut to crack in the farm-to-fork movement, predominantly because fishing is controlled by multiple governments with different commitments to sustainability and policing abilities. Despite this, a standard is set by the Marine Stewardship Council, which traces and certifies sustainable seafood from about 14 per cent of fisheries worldwide. That’s no mean feat for an organization of only 120 people.

The little blue MSC-certified label is almost everywhere lately. Sustainable seafood has hit a tipping point, with the US behemoth retailer Walmart pledging to go completely sustainable by 2015 and Australian supermarket Woolworths committing to getting there “in the long term”. Coles has promised to only buy sustainable tuna from next year.

But there’s work to be done. The National Aquarium in the US says an estimated 20-32 per cent of wild-caught seafood imported there was found to be illegal – and up to a third of seafood sold in the US is mislabeled!

Buying power is one way to change the fate of our endangered fish stocks but government action is needed to track seafood, experts from the Aquarium argue in an op-ed for the Baltimore Sun.

“This ‘boat to plate’ traceability will hold all members of the seafood industry to the same standard, and coupled with better enforcement and import controls, will help discourage illegal activity,” its Chief conservation officer Eric Schwaab and chief scientist at Oceana, Mike Hirshfield wrote.

“With traceability, consumers have more information about where their fish came from, honest fishermen and businesses are not undercut by unfair competition, and we close our markets to seafood products from pirate fishing, which threatens the long-term stability of ocean ecosystems.”

Even fishermen can benefit from technology to keep their catch sustainable. A recent hackathon developed an app called ECOFISH, which allows fishermen to measure and identify fish by photograph.

Saving the world’s oceans and wading through the international mess of fishing regulations? Apparently, there -is- an app for that.

This column originally appeared on the Sciengage site, where I write the environmental science blog.