If you’re pregnant, breastfeeding or a child, the US Food and Drug Administration and the Environmental Protection Agency now recommend that you eat more fish. Four times as much, to be exact. The agencies are updating their fish consumption advice for the first time in a decade, and a draft released this week would quadruple the recommended level of fish consumption for women who are pregnant or breastfeeding, women who could become pregnant and children.

“For years, many women have limited or avoided eating fish during pregnancy or feeding fish to their young children,” said Stephen Ostroff, the FDA’s acting chief scientist. “But emerging science now tells us that limiting or avoiding fish during pregnancy and early childhood can mean missing out on important nutrients that can have a positive impact on growth and development, as well as on general health.”

This message marks a big change from the one many took away from the 2004 advisory, which recommended that pregnant women eat up to 12 ounces a week and avoid shark, swordfish, king mackerel or tilefish completely because of their high levels of mercury.

The 2004 advisory doesn’t address whether or not those specific species are okay for others; it was intended only for pregnant women. But many other consumers took the advice for themselves. Seafood consumption rates in the US have been declining since then. According to the National Fisheries Institute, Americans ate 16.5 pounds of seafood in 2006. By 2012, that number had dropped to 14.6 pounds, representing a decline of nearly 14% per person. While cost and availability play a factor, so does concern over mercury and other contaminants.

“The FDA messaged the first advisory so poorly,” said Chris Lischewski, CEO of Bumble Bee Seafoods, in an interview last month. “They thought they were being responsible saying seafood is a good part of the diet, but everyone picked up on the one line: pregnant women should avoid seafood.”

Meanwhile, many pregnant women don’t consume enough docosahexaenoic acid (DHA), according to a 2010 Harvard Study, which found that many pregnant women know fish might contain mercury, but fewer know that fish contains DHA – or know which types of fish have more DHA or less mercury.

If the new advisory persuades more people to eat fish, of course, the fish industry – providers of both wild caught and farmed seafood – stands to benefit. It also could be good news for the environment, as seafood has a lighter environmental footprint than chicken, pork and beef – but could potentially lead to more overfishing, given that roughly three-quarters of fish stocks are being depleted faster than they can reproduce, according to the Save Our Seas Foundation.

Unlike the USDA’s dietary guidelines, which are updated every five years, the advisory on methylmercury in fish has remained unchanged until now. Critics say the 2004 advisory may have done more harm than good. They say its message was muddled by both consumers and the media, and was widely embraced by those outside it’s targeted demographic.

Among other things, new science on the impacts of mercury consumption; years of pressure from scientists, nutritionists and the seafood industry; and lawsuits by environmental groups Center for Science in the Public Interest and the Mercury Policy Project have led to the current revision.

The new advice encourages women who are pregnant (or might become pregnant) or breastfeeding to eat a minimum of 8-12oz ounces (227-340g) of a variety of fish each week, and to choose species low in mercury. It is the first time the agency has recommended a minimum amount of seafood women and children should consume. For comparison, Americans eat, on average, less than 15lbs (6.8kg) of seafood a year – which comes out to about 4.6oz (130g) per week – compared with 70lbs (31.7kg) of poultry, 100lbs (45.3kg) of red meat and 600 lbs (272kg) of dairy, according to the National Fisheries Institute (NFI).

Meanwhile, tilefish from the Gulf of Mexico, shark, swordfish and king mackerel – species that, combined, make up less than 1% of all seafood eaten by Americans – are to be avoided. The updated advisory also recommends limiting white (albacore) tuna to 6oz (170g) a week.

The agencies are now taking comments on the draft advisory. Expect vocal participation from NGOs, companies and others.

Bumble Bee, for example, will likely take on the agency’s advice to limit albacore to 6oz (170g) per week. In an emailed statement, the company said: “The suggestion of a 6oz limit to albacore consumption does not match the FDA’s own scientific review, where it notes “maximum benefit” comes from “8oz” of albacore a week, with a ceiling of “56oz” of albacore a week. 56oz a week is a long way from 6oz. Modifying the draft to accurately match the science and ensure it is communicated in a way that pregnant women understand and act on will be crucial to its success.”

Lischewski also warned that the messaging “has to be simple”.

Gavin Gibbons, NFI spokesperson agrees that the advice on albacore needs to be reviewed, and says there’s other language in the advisory he would like to see changed.

“The advisory talks about ounces a lot,” he said. “Consumers talk about meals, so the advice should do that translation for them. When they say that pregnant women need to increase their consumption from 1.8oz to at least 8oz and up to 12oz, what they’re saying is they need to quadruple their consumption. Putting that in terms of two to three seafood meals a week is easier to understand.”

Glenn Reed, president of the Seattle-based Pacific Seafood Processors Association – whose members process most of the fish harvested in Alaska, including halibut, salmon, crab, cod and pollock – says he’ll be meeting with the group’s board of directors next week, and will also be submitting comments.

“We prefer there wasn’t an advisory based on what we know about the health and safety of eating seafood,” Reed said. “The government has been overly cautious, but we’re encouraged by the change in the new advisory recommending a greater amount of seafood consumption per week.”

The FDA’s announcement does suggest a few low-mercury alternatives, including shrimp, pollock, salmon, canned light tuna, tilapia, catfish and cod. But for many pregnant women, it’s the brain-boosting omega-3 fatty acids that are the draw, and seafood like shrimp and tilapia don’t have much of those.

The Environmental Working Group calls the new advice “risky”.

“EWG has concluded people who eat 8 to 12oz of the most popular varieties of seafood would not get enough beneficial omega-3 fatty acids,” the group states on its website. “In some cases, people striving to boost their omega-3 intake could consume dangerous amounts of mercury, a potent neurotoxin.”

FDA spokesperson Theresa Eisenman says there are other benefits to consider aside from omega-3 fatty acids.

“Fish contains high quality protein, many vitamins and minerals, and some types of fish even contain vitamin D,” she said. “Many fish are also low in saturated fat. The nutritional value of fish lower in mercury is especially important during growth and development before birth, in early infancy (for breastfed infants) and in childhood.”

And whether or not the new advisory will be updated on a regular basis (like the USDA dietary recommendations) remains to be seen.

“They have not committed to updating the advice every five years and we have yet to hear how they’re going to communicate the advice,” Gibbons said. There needs to be message testing. It’s great to have new advice, but if it isn’t changing behavior, it isn’t doing any good.”