Despite there being many varieties of tuna on supermarket shelves, they are really all very similar no matter which brand you choose, hence I do not have any clear favourites. We either have tuna in spring water, which is very low in fat and calories; tuna in oil which contains 5-10g fat per serve or flavoured tuna which can contain relatively small amounts of tuna but plenty of added oil and sugars. As a general rule of thumb, low fat tuna does not offer a lot nutritionally other than lean protein, so for a better nutrient boost, look for light options in oil, which still offer some essential fats and flavour. Be especially careful of flavoured tuna options as they can be as low as 40 per cent in fish content. pole-and-line, but uses yellowfin and tonggol tuna, and has poor labelling that doesn't specify the species. Woolworths

A purse seine is a large floating wall of netting that encircles a school of fish and is 'pursed' on the bottom, preventing fish from escaping by swimming downward. The catch is harvested by hauling the net aboard or bringing it alongside the vessel. As for suggestions that protein in tuna isn't as bio-available, Austin says there is no evidence this is correct. Carefully place the pancake (batter-side up), using the spatula, on top of the noodles in the other pan. Every major brand in Australia has now agreed to phase in FAD-free, responsibly caught tuna by 2016," says Pelle. "Safcol have been the leaders in this change and were the first mainstream company in 2012 to embrace 100% pole-and-line caught tuna, and this helped change the whole industry." Its new range is 100% cent pole-and-line, but exclusively uses yellowfin tuna and has not yet obtained audited supply chain guarantees of sustainable sourcing. GreenseasDespite its current use of yellowfin tuna, Aldi has taken a potentially helpful step toward letting you know whether the canned tuna in its stores is sustainably sourced. Through its 'trace your tuna' program, the company says it has "traced our entire canned tuna range from where it was caught, through our supply chain and into our stores". Fish is a very good source of protein – it's a complete animal protein, which means it's got all the amino acids and is very bio-available," she says. So, the fact the canned tuna in Australian cupboards is likely to contain smaller species is already a bonus when it comes to reducing mercury risk. According to the Greenpeace article, Woolworths say that they have a sustainable seafood policy, but this does not actually include tinned tuna, thus providing misleading and inaccurate information for customers. In their favour, Woolworths offers a pole and line caught Albacore product under its house brand, however the same cannot be said for the rest of their range, which is still caught through destructive methods that result in the death of sharks and other marine life. Woolworths has no public policy that ensures sustainably or equitably sourced canned tuna. According to the Greenpeace article, Woolworth will not guarantee that they won't source from Pacific Commons conservation areas.

According to Pelle, the massive commercial purse seine operations in the Western Pacific are dominated by Japan, Korea, the United States and Taiwan. He says these huge ships harvest local resources but often exclude local fishers, and they can haul up 3000 tonnes of tuna in a single fishing trip – almost double the annual catch of some Pacific Island countries. Given the very low sample numbers, our data is just a snapshot of mercury concentrations. More research is clearly needed. But let's be honest, none of this information takes into account the main reason not to eat canned tuna: it's often grey and kind of gross. [Like eating rancid cat food — Ed.] You would have to eat around 25 tins (at 95g a tin) of it a week before you hit the maximum tolerable intake of mercury. For pregnant people (or people trying to get pregnant), the limit would be around 12 tins (at 95g a tin) a week.

Tuna in spring water tends to have less flavour, but Austin says it can be a good option for cooking. The dose for pregnant women is approximately half this value — 1.6 micrograms per kilogram of body weight per week). The best approach to sustainability, says Hanich, is the pole-and-line fishing method, in which fish are caught with a single pole, line and hook. Compared to the more prevalent purse seine method (see below), pole-and-line is considered the best way to reduce overfishing and bycatch.

Pelle agrees, saying the dolphin-safe logo is "part of a self-certifying system that isn't credible." Drift-net free

Immediately pile half of the cabbage neatly over the pancake, then the tuna. It looks like a lot of filling but don’t worry, it will wilt. Place the pancetta around the circumference, slightly overlapping, on top - essentially you want to create a band that will help hold the pancake together. Pour over ¼ cup batter around the circumference and in the centre - this will help bind the filling. It will be interesting to see if this commitment translates in to increased sales of Sirena tuna and if other big players in the industry feel compelled to follow their lead. It’s a big advance from the old “dolphin safe” endorsement that many brands carry. They may be “dolphin safe”… up to a point … but much of the tuna is still caught in purse seine nets, using FADs, with by catch issues, in waters of poorer South Pacific nations who’ve leased their extraction rights to big overseas operators. Sustainable fisheries should still be the goal in a world where the population continues to expand and the sea’s resources decline. Pregnant women are advised to limit their fish intake because of placental transfer of mercury to the unborn foetus and the effect of mercury on neural development. Testing three tins

Each year since 2010, Greenpeace has released a list of the most sustainable brands, which takes into account species, fishing methods, labelling, transparency of supply chain auditing, and the level of support for sustainable tuna practice through political, industry and consumer channels.

New

Described as "the benchmark of sustainable fishing practice", it has 100% pole-and-line-caught tuna. Safcol Two separate maximum levels are imposed for fish ― a level of 1.0 mg mercury/kg for the fish that are known to contain high levels of mercury (such as swordfish, southern bluefin tuna, barramundi, ling, orange roughy, rays and shark) and a level of 0.5 mg/kg for all other species of fish. Sitting on the top of the list is the Fish 4 Ever brand. You may not have seen this brand at the supermarket but it is available in many health food stores so do try and find it. Why did it get first place? Fish 4 Ever have been instrumental in using a selective fishing method called 'pole and line'. This means tuna are caught on a hand-held pole and line one by one. It avoids the wasteful catch and death of turtles, sharks and other endangered species. Fish 4 Ever also actively promote established sustainable tuna fisheries and sustainable tuna in political, industry and market forums. They support local coastal fisheries and pay a premium price to local fishers. Fish 4 Ever has a publicly available sustainable and equitable sourcing policy and ensures it is implemented. It appears to be more than a marketing move. "As a result of a collaborative effort by WWF, Pacifical, MSC and John West, Australians will now see over 100 million cans of clearly labelled Pacifical-MSC-certified sustainably sourced tuna in supermarkets," WWF Australia CEO Dermot O'Gorman says. "The magnitude of this – affecting a huge 43% of Australia's canned tuna – makes this a world first." Step 1: Look for sustainable species of tuna The maximum dose of mercury set for the general population is 3.3 micrograms per kilogram of body weight per week. 1,000 micrograms (µg) is 1 milligram (mg).(The guidelines assume all mercury in fish is present as the more harmful methylmercury as a worst case scenario).