Most Australian fish have low mercury levels, but larger predatory fish like shark, marlin, and orange roughy have higher amounts, requiring reduced consumption for vulnerable groups (pregnant women, young children) to just once a week or fortnight, while low-mercury options like salmon, tuna, prawns, and whiting are safe to eat more often, even 2-3 times a week. The Australian Food Standards Code sets limits (0.5 mg/kg for most, 1.0 mg/kg for high-mercury fish), but the general consensus is that seafood's benefits outweigh risks for most, provided smart choices are made.
If you choose to eat more than 2-3 serves of fish per week it is important to eat a variety of fish, and avoid those that could have elevated mercury levels, such as Shark (Flake) or Billfish (Swordfish, Marlin).
Fresh and canned Salmon do not contain mercury. Likewise, canned tuna has low levels of mercury because they are smaller and younger fish. For pregnant women to enjoy seafood 3-4 times per week, it is best to avoid species high in mercury.
Summary. Fish that contain high levels of mercury include shark, ray, swordfish, barramundi, gemfish, orange roughy, ling and southern bluefin tuna. Mercury is a naturally occurring element that is found in air, water and food.
Barramundi, a beloved white fish in Australia, boasts a mild, buttery flavour and firm texture. Rich in omega-3 fatty acids and low in mercury, this healthy seafood option is also sustainable, thanks to responsible farming practices and its environmentally friendly nature.
Canned tuna and salmon
It is generally safe for everyone, including pregnant women, to consume two to three serves of tuna or salmon a week, canned or fresh. Canned tuna usually has lower mercury levels than other tuna because tuna used for canning are smaller species that are caught when less than one year old.
Sardines are one of the most recommended fish if we are looking for mercury-free fish. The fact that they are very present in our cuisine facilitates their consumption, as almost everyone is accustomed to eating them either grilled or on skewers. They also provide a lot of protein and calcium.
The Top 10 Healthiest Fish to Eat and Their Benefits
Choices to Avoid.
These fish have the highest levels of mercury. Avoid eating tilefish from the Gulf of Mexico, swordfish, and shark. Also avoid king mackerel, bigeye tuna, orange roughy, and marlin.
Health- and food-focused organizations like the USDA and NIH consistently recommend salmon as a good source of omega-3 fatty acids. Barramundi has a 25 percent ratio of omega-3s to total fat, giving it the highest level of omega-3 fatty acids of any commonly eaten white fish.
Levels of contamination
The danger level from consuming fish depends on species and size. Size is the best predictor of increased levels of accumulated mercury. Sharks, such as the mako shark, have very high levels of mercury.
To avoid unhealthy or unsustainable salmon, steer clear of most farmed Atlantic salmon from open net pens (especially from Chile, Canada, Norway, Scotland, or Tasmania due to pollution, disease, antibiotics, and contaminants like PCBs/PFAS) and wild-caught Atlantic salmon, which is overfished; instead, opt for sustainably-caught wild Pacific salmon (like Sockeye, Coho) or farmed salmon in closed-containment systems with certifications like ASC or BAP for healthier, planet-friendly choices, says Seafood Watch, GoodFish, and EatingWell.
The unhealthiest fish to eat are typically large, predatory species high in mercury like shark, swordfish, king mackerel, and imported tilefish, plus bluefin tuna, which are dangerous for brain/nerve health, especially for pregnant women and children; also, farmed salmon and some imported tilapia/catfish raise concerns for contaminants and antibiotics, while orange roughy and Atlantic cod are often cited for high mercury and overfishing/sustainability issues.
Researchers from Chalmers University of Technology have come up with a novel approach to packaging canned tuna infused in the water-based solution of amino acid cysteine. It was shown to remove up to 35 percent of the accumulated mercury in canned tuna, significantly reducing human exposure to mercury via food.
However, Australia has a well-deserved reputation for high quality and safe seafood and commercially produced seafood sold in Australia must adhere to strict quality controls. Do not consume shellfish you have harvested yourself unless you know the water it is grown in is safe.
Other mercury removal options include home remedies such as eating a nutrient- and vitamin-rich diet, increasing fibre intake, and drinking more water to flush out mercury from the body.
Symptoms of organic mercury poisoning from long-term exposure include:
Fish are largely linked to mercury poisoning because of the water they live in. All seafood contains small amounts of mercury, but large fish tend to have higher levels of mercury because of their consumption of smaller fish that carry it as well.
Choose fish and shellfish that are lower in mercury such as salmon, trout, tilapia, cod, sole, sardines, shrimp, oysters, and other shellfish. For the most health benefits, choose fatty fish such as salmon, trout, herring, chub mackerel, and sardines. o These fish have healthy omega-3 fatty acids.
These non-game fish are the ugly, sucker-mouthed, snaggle-toothed, mottled menagerie of undesirables which includes suckers, gar, bowfin, snakehead, carp, buffalo, freshwater drum, and many others.
Fish you should never eat
It is safe for everyone (including pregnant women) to consume canned tuna as part of their fish intake. Canned tuna generally has lower levels of mercury than tuna fillets because smaller tuna species are used and the tuna are generally younger when caught.
Low estimates of mercury concentrations in shrimp (0.012 ppm, wet weight [ww]; Smith & Guentzel, 2010) may suggest that shrimp should be consumed more often than other, higher trophic marine species.
Shark, swordfish and marlin: do not eat these if you are pregnant or trying to get pregnant. All other adults, including breastfeeding women, should eat no more than 1 portion per week. This is because these fish can contain more mercury than other types of fish, and can damage a developing baby's nervous system.