National Geographic Daily News
Gerry Carney, chief husbandry man, and John MacLeod, site manager, check stock at Scottish Sea Farms, Lismore North farm on January 13, 2011 in Oban, Scotland. Scotland's fish farming industry has been boosted by the news that an agreement has been reached between the Scottish Government and China to export salmon to Asia for the first time.

Gerry Carney and John MacLeod check stock in pens at Scottish Sea Farms, a salmon producer in Oban, Scotland, in January 2011.


Brian Clark Howard

National Geographic

Published March 19, 2014

Demand for salmon is soaring and is driving expansion of aquaculture—fish farming. For years, environmentalists advised conscientious consumers to avoid farmed salmon, but that's starting to change, thanks to an evolving industry.

Rich in protein and heart-healthy omega-3 fatty acids and low in saturated fats, salmon is increasingly being marketed as a healthy food. Demand for salmon has risen more than 20 percent in the last decade. Consumption is three times what it was in 1980.

That voracious appetite is increasingly being supplied by aquaculture, which now provides 70 percent of the global salmon market (2.4 million metric tons). In 2013, the largest market for farmed salmon, the United States, consumed 353,000 tons of the fish.

About five years ago, global aquaculture production surpassed wild catches as the primary source of all seafood consumed. Two years ago, global aquaculture production passed global beef production.

Over the past decade, many environmentalists advised consumers not to buy farmed salmon. The carnivorous fish are fed animal-derived proteins, typically supplied as "fish meal" or fish oil made from other species, especially anchovies. Because it can take four or five pounds of fish meal to yield one pound of salmon flesh, the inefficiency caused concern among environmentalists.

Plus, farmed salmon are sometimes able to escape from the oceanside pens they are raised in, potentially spreading disease or undesirable genes to wild populations already under stress from overfishing, pollution, and habitat loss. Fish feed has also been shown to have been contaminated with PCBs and other toxins that can make their way into the food supply.

An Industry Evolves

But the salmon-farming industry has progressed in cleaning up its act, said Jason Clay, WWF's senior vice president for market transformation. Clay, who participated on a panel on farmed salmon at Seafood Expo North America in Boston on Tuesday, started discussions with leading salmon growers in 2002 called the "Salmon Aquaculture Dialogues." Those talks eventually led to the development of a set of sustainability standards called the Aquaculture Stewardship Council (ASC) in 2010.

"There was never really disagreement about what the impacts [of salmon farming] were; the issues that came up were, What is acceptable impact and what is possible to achieve?" he said. "It took eight years to get those standards written up."

The Aquaculture Stewardship Council is an independent nonprofit organization based in the Netherlands. Founded by WWF and the Dutch Sustainable Trade Initiative, it maintains a yardstick against which aquaculture growers can be measured in terms of their social and environmental impacts. So far, a small percentage of salmon grown on farms in Norway has been shown to meet the group's standards, but much more is on the way in various countries, says Clay.

In August 2013, 15 large salmon farm companies, representing 70 percent of the world farmed salmon market, joined together to form the Global Salmon Initiative (GSI). The companies pledged to source 100 percent of their salmon from farms that meet ASC standards by 2020.

Those standards include 152 different indicators, says Clay, including low tolerance for escaping fish, limits on antibiotics, a prohibition on genetic engineering, and sustainability and safety guidelines on food the fish can be fed.

A photo of a man checking salmon stock.
In January 2011, Scotland began exporting farmed salmon to Asia for the first time.

What's the Food Ratio?

At the World Ocean Summit in Half Moon Bay, California, in late February, Andrew Sharpless, the CEO of the advocacy group Oceana, said, "Aquaculture comes in three flavors: good, bad, and indifferent."

"If you are farming a filter feeder like a clam or oyster, you are doing something tremendously good for the planet: You are cleaning the ocean and filtering something people don't want to eat, algae," said Sharpless. If you are farming fish that feed on plants humans consume, such as tilapia or catfish, "your contribution is about equal to being a chicken farmer and putting it underwater. Could be worse, could be better," said Sharpless, referring to the fact that large-scale chicken farming requires massive amounts of grain.

"If you are farming fish that eat fish, you are reducing the amount of fish available for humans to eat. Farmed salmon are dreadful for feeding people and for protecting ocean health, though they might make good business sense," said Sharpless.

But Clay disagrees. He says those calculations are based on old data, when it took three or four pounds of wild-caught bait fish, ground up as fish meal, to produce one pound of sellable salmon. The target in the new ASC guidelines is a ratio of 1.4, or about half of what the industry was doing overall in 2000, says Clay.

Furthermore, Clay says the accounting is a little more complex. About half of a farmed salmon's mass is currently not used for food, but much of that can be repurposed as feed for another farmed species, such as shrimp or trout, he says. That should be taken into consideration when counting protein ratios.

"Getting to a ratio of one to one is the goal, but it's just not going to happen in a year," says Clay. "We're below two already, and we went from four to two in the last 15 or 20 years so we are on the right trajectory. We have to keep working on it instead of saying, 'It's not good enough and it's not going to be.'"

The key, says Clay, is to ensure that any wild-caught fish that is processed into meal is sustainably harvested, something that is addressed in the ASC standards.

For their part, the GSI argues that salmon farming is likely to play an important role in feeding the world. Avrim Lazar, a Canada-based consultant with the GSI and another speaker on the panel in Boston, says the middle class will increase in coming years. "They are all going to ask for animal protein, whether anyone likes it or not, so it's going to be produced. Our job is to do that with a minimal footprint," says Lazar.

Doris Soto, the senior aquaculture officer for the Food and Agriculture Organization (FAO) of the United Nations in Rome, says, "It's important to remember that there is no free meal; all industries have an environmental cost."

Lazar adds that the driving force behind the industry going greener has not been consumer pressure, since only a small number of people specifically ask for sustainable salmon. "There is huge market demand for any kind of salmon, and changes are driven less by immediate market pressure and more by a sense that if you want to operate in the oceans you need a social license," says Lazar, referring to the fact that the public has a stake in what happens in the ocean.

"Governments and communities have had the question of whether [salmon farming] is a legitimate use of the ocean."

Soto calls the ocean "common property." Fish farming is "not just like a farm on land, so you have responsibilities," she says.

Lazar says the relative newness of salmon aquaculture as a global business provides an "opportunity to get things right at the early phases." Although carp have been raised in Asia for many centuries, the current industry is relatively "very young," he says. Therefore, growers are trying to "lay down wiring and figure out how they should behave," he says.

Soto adds that best practices developed by GSI members are being shared with developing countries, particularly in places like Africa, where there is keen interest in starting aquaculture businesses.

A photo of a man holding a salmon.
John MacLeod, the site manager at Scottish Sea Farms, holds up a salmon.

Alternate Farming Methods?

Clay says there has been a lot of experimentation when it comes to salmon aquaculture. Some test sites in Norway have tried raising salmon without feeding them any fish, using other proteins instead. "The price has not yet been acceptable in the marketplace," says Clay.

On Chile's Patagonian coast, DuPont is growing salmon in a different way through a new subsidiary called Verlasso. DuPont engineers in a lab in Iowa developed transgenic yeast that make omega-3s, a desirable compound that salmon don't make themselves but normally get from their food.

The yeast is then blended into feed pellets, taking up about 10 percent of the bulk. The rest is made from plant material and other nutrients, including some fish meal and oil. But because the company uses about a quarter as much fish oil as its competitors do, it has gotten the fish input ratio down to one to one, says Scott Nichols, the Delaware-based president of Verlasso.

"Raising salmon on [three to four parts of fish] is inherently unsustainable," says Nichols. "It doesn't meet the goal of having fish in the future, and it doesn't result in net production of fish."

Nichols says Verlasso raises salmon in pens at a density not to exceed 12 kilograms of fish per cubic meter of water. The industry norm is 25 kilograms per cubic meter, he says.

"So we address two issues: Our environmental load is lower because we don't increase the number of pens as we decrease density. Our fish have more room to swim, they're more active, so they have a different flavor and texture, one most people find very agreeable."

Nichols says his salmon have a fat content of around 11 percent, compared with 8 percent for wild salmon and 17 to 22 percent for "traditionally farmed salmon."

In recognition of Verlasso's progress on key environmental issues, the Monterey Bay Aquarium recently recognized the company's salmon as a "good alternative" in its influential Seafood Watch program, the first time ocean-raised salmon has been so designated. The fish are available at a number of restaurants and grocery stores in the U.S.

Genetically Engineered Fish?

Some boosters say the next step in salmon farming is genetically engineering the fish themselves. Massachusetts-based AquaBounty Technologies has spent several years developing a fish it calls AquAdvantage salmon. The company hopes to raise sterile Atlantic salmon females that can grow to market size in half the time of conventional salmon, thanks to a growth hormone–regulating gene from Chinook salmon and some genetic material from ocean pout.

AquaBounty first submitted data to the Food and Drug Administration for review in 1996 and has been raising generations of the experimental fish in closed pools in the Panamanian highlands. The FDA has yet to approve the fish, which was the first genetically engineered animal introduced into the food supply.

A decision on the fish is still pending. In September 2010, an FDA advisory panel said that the fish is "highly unlikely to cause any significant effects on the environment" and that it is "as safe as food from conventional Atlantic salmon," although the agency said more testing was needed. Still, the company has reportedly had financial difficulties.

No genetically modified salmon are currently permitted under the ASC guidelines. In a position statement, the Sierra Club said it opposes genetically engineered fish, arguing that the fish pose "an even greater hazard to natural stocks and are even more difficult to properly evaluate and to monitor than [genetically engineered] crops."

Even fish in inland ponds can be swept away by floods or transported by birds, says the Sierra Club.

In the meantime, there are signs that farmed salmon is getting leaner and greener, Clay says.

Follow Brian Clark Howard on Twitter and Google+.

angela koch
angela koch

Why is my comment still pending from yesterday morning?

angela koch
angela koch

Awwww National Geographic, shame on you! Fish farms are filthy, they're full of diseases that spread to wild fish populations, the farms import these exotic foreign diseases into BC's west coast through their fish farm eggs. They place their farms in the middle of wild salmon migration routes, they don't clean up their tonnes and tonnes and tonnes of chemical laden shite that covers reefs and ocean floors. The farms self proclaim to shoot thousands of seals, sea lions and other animals that try and get at their fish. Now we're seeing huge trucks full of hydrogen peroxide by the farms. That means the sea lice have gotten out of control and the peroxide is a last resort. What's so sad about this is that the fish are said to writhe around terribly in this chemical as it burns them, and many die from the shock. And the studies show those predator fish fed a more plant diet cannot digest them and they ALL develop tumors in their stomachs which eventually turn cancerous. If these fish could scream they'd be begging for mercy, so sad what we do to these poor creatures :( 

You also forgot to mention that the industry just lobbied and won the rights to now also feed pigs as well as chickens to farmed salmon, I wonder how kosher that's considered to be? Also what you forget to mention is that the industry also lobbied to get the chemical amounts of "ENDOSULFAN" raised by 10 times the allowable limit. Perhaps that's why doctors and scientists are warning pregnant women and children not to eat farmed salmon. Why did you not mention that?  If you're going to write a report, then perhaps one so obviously not biased would give readers the real skinny on what this filthy industry is all about.

Steve Lloyd
Steve Lloyd

This 'article' reads as an advertisement by the salmon feedlot industry, completely lacking in the most basic journalistic credibility. Here in British Columbia a massive effort has begun to save wild salmon from decimation. Atlantic salmon feedlots are being shoe-horned into a narrow straight which many wild runs must pass through, more and more of the latter not returning at all to spawn, or returning diseased. Our current federal government actively suppresses research including last year's Cohen Commission report that revealed these realities, dismissing scientists who do not toe the industry line. This article is a serious disservice to the awareness and to the physical well-being of your readers, to wild salmon, and to ecosytems and human communities which have long depended upon them. Shame on you.

Chloe Neild
Chloe Neild

I think one of the main concerns with GM salmon are fears it'd be farmed in open cages at sea from which farmed salmon frequently escape. If GM salmon were to be farmed in recirculation systems, based on land, from which escape is impossible, many concerns would be put to rest. 

There is also the issue of labelling. So long as it is clear what's in the packet and consumers are able to make informed decisions, a further set of concerns would be resolved.  

Jim Quinn
Jim Quinn

It's a shame that conventional aquaculture is so hostile to competition from transgenic salmon.   The GMO salmon has repeatedly been shown to be safe, and it obviously has much less of an environmental footprint.   

The scientific community overwhelmingly endorses genetic engineering as a way to feed more people while doing less environmental damage.   It's too bad that a shrill minority of alarmists have so thoroughly demonized a green technology.   

Arthur Sevestre
Arthur Sevestre

Shocking participation in greenwashing an inherently destructive industry, National Geographic! Shame on you.

It starts with "Demand for salmon is soaring and is driving expansion of aquaculture—fish farming."

That in itself is nonsense. Expansion of aquaculture, itself driven by the need to produce to the max whatever it is you produce, is driving up increased sales.That's how the game works. Very rarely is it demand which forces industry to expand. Did people demand iphones, pads, pods and all that stuff, or did industry make them and use public relations (a term coined by Edward Bernays because propaganda, which it is, sounds so bad) to make people want to buy them? 

Salmon farming is not the greatest cause of the decline of wild salmonids, but it is certainly not doing any good. Sea lice from the farms kill wild salmonids and thereby reduce the already diminished returns by about 30% (conservative estimate) every year. It may be the final shove to severely stressed populations. And salmon farming is on the increase everywhere where it's already used, so the effect will only get worse.

Andrew Allen
Andrew Allen

Chloe and James make many excellent points.

In addition, there are two disturbing facts that have not been mentioned.  According to the article:

1: "That voracious appetite [for animal protein] is increasingly being supplied by aquaculture, which now provides 70 percent of the global salmon market (2.4 million metric tons). In 2013, the largest market for farmed salmon, the United States, consumed 353,000 tons of the fish."

2: "The carnivorous fish are fed animal-derived proteins, typically supplied as "fish meal" or fish oil made from other species, especially anchovies. Because it can take four or five pounds of fish meal to yield one pound of salmon flesh, the inefficiency caused concern among environmentalists."

3: "About half of a farmed salmon's mass is currently not used for food, but much of that can be repurposed as feed for another farmed species, such as shrimp or trout, he says."

So, given:

(a) The tremendous demand for farmed salmon (for those who are math-challenged, 353K tons in the U.S. is over 700 million pounds, and that's only 15% of worldwide consumption),

(b) The huge amount of food needed to produce a pound of salable salmon (4-5 pounds of food per pound of meat, so multiply that 700M pounds by 4-5),

(c) The huge amount of waste meat produced (since half of each fish is not used for food, the waste equals the amount used for food, i.e., another 700M pounds in the U.S. alone), and

(d) The cost pressures of being in such a competitive business, 

... do you really suppose that all salmon farmers are going to the trouble and expense of shipping their butchering waste off to trout farmers?  How many do you suppose are quietly feeding the waste back into the feed supply for their next crop of salmon?  Then think about where Mad Cow disease came from -- feeding animal waste from sheep processing to cows ...  It's only a matter of time before this provides yet another source of prions in the food supply.

If that weren't bad enough, this practice is also concentrating the toxins already proved to be in the farmed salmon food supply, with each successive generation -- by the same mechanism that causes certain apex-predator species of tuna to have high concentrations of mercury.

Chloe Neild
Chloe Neild

An article on the impact of salmon farming that doesn't mention sea lice? Sea lice are a serious problem in salmon farms, and pose a serious threat to vulnerable young salmon smolts that migrate past them. Research shows sea lice cause up to a 50% decrease in wild salmon returns. Wild salmon and sea trout populations have plummeted in areas near salmon farms causing devastation to angling industries as well as wild life.

And, the problem does not stop there. The pesticides (sometimes referred to as vetinary medicines to try and avoid stigma) used to kill sea lice on salmon farms are toxic to many aquatic species in particular valuable crustaceans like shrimp, prawn, lobster and crab, as well as fish fry for other commercial stocks. This should come as no surprise they kill crustaceans as sea lice are copepod crustaceans themselves. To make matters yet worse, research is showing increasing sea lice resistance to chemicals and farmers using every increasing quantities in a desperate bid to stay on top of the problem. The industry itself acknowledges this as being the biggest issue in salmon farming today. The result for inshore fishermen and potters is their catches plummet and the economic viability of their traditional jobs dwindles.

Then there's the biological pollution to add to the above mentioned chemical pollution. Fish faeces (and when you have millions of fish in a farm that quantities are considerable) and waste food. The resulting nutrient enrichment exacerbates naturally occurring harmful algal booms, posing problems for any nearby shellfish industries (mussels, scallops, oysters etc..).

Overall water quality plummets, and sea beds (benthic communities) become dead.

Wildlife is also put at risk. Many protected species are attracted to salmon farms. Many many seals are shot each year in Scotland by salmon farmers. Protected sea birds, otters, cetaceans and other species get caught in nets.

The salmon farming industry always argues that they create jobs in remote coastal regions. But this needs closer examination. Firstly, this classic media spin tactic is used to divert attention from the environmental impact. Worse still, it is not true. For in many areas salmon farming could result in a net loss of jobs, as fishermen, potters, shellfisheries, angling based industries, tourism and marine leisure businesses close operations.

This article comes across as advertising for the WWF's Aquaculture Stewardship Council (which aims to be the equivalent of the Marine Stewardship Council certification system for wild caught fish). Yet the ASC has been deeply controversial.

To suggest open cage salmon farming at sea is sustainable is madness. I am very surprised to see such an article in a magazine such as the National Geographic that I'd always believed thoroughly researched their content.

Henrik Lomholt
Henrik Lomholt

Please get your facts strait.

The salmon farming industry get meaner and meaner, not greener.

They pollute like hell, they produce socalled salmon stuffed with pesticides and other chemicals.

On top of that, they are og severe danger to the wild salmon, because of the way they spread lice into the waters, and the deceases they cause.

So think twice, before you publish an article like this.

Henrik M. Lomholt

Henrik Lomholt
Henrik Lomholt

Please get your facts strait.

The salmon farming industry get meaner and meaner, not greener.

They pollute like hell, they produce socalled salmon stuffed with pesticides and other chemicals.

On top of that, they are og severe danger to the wild salmon, because of the way they spread lice into the waters, and the deceases they cause.

So think twice, before you publish an article like this.

Henrik M. Lomholt

Arthur Sevestre
Arthur Sevestre

@Jim Quinn  

The last thing we need to do is to make more food so there can be more people. It is generally accepted in biology that population size of any animal, plant, and any other organism is mostly dependent on the amount of available food. Unless another factor limits the population, an increase in food will lead to an increase in population, and a decrease in food will lead to a decrease in population. The only species that isn't accepted for is humans. Civilised humans, to be exact. Somehow it is common knowledge that human population grows and only then needs more food, because otherwise humans will starve. Biologically that is a nonsensical idea. You can't have 7 billion humans if there isn't enough food to feed them. In fact, there clearly isn't merely enough food to feed 7 billion; there is even enough food to still let human population grow more or less exponentially. All that growth is only possible if there is enough food to make human bodies out of. Sure enough the food isn't distributed fairly, but producing more food is not going to help one iota there. The only thing which is helped by growing more food is that the global corporate food industry and the corporations which directly and indirectly contribute and profit from that will become ever wealthier and more powerful.

I wrote a long article about this some time ago:

Arthur Sevestre
Arthur Sevestre

@Jim Quinn

I'd say the exact opposite: there is no proof of genetic engineering being safe, and many scientists agree on that (I'm one of them, and where I studied biology many others were, too).

So where is the proof you allude to which proves that GM salmon is safe? How long has it been studied? Who by? Who funded the projects? How is 'safe' defined? Depending on the answer to those questions, you could make science claim that roughly everything is safe.

Charlotte Lenox
Charlotte Lenox

@Chloe Neild Everything you've mentioned are definite concerns, and line up with all of the self-study I have been doing in marine biology and ecology (along with personal observation as I was born and raised in Alaska, and have done a fair amount of fishing and eating what I caught). Throughout this article I have been wondering about British Columbia's situation in particular, as I first learned of it from Alexandra Morton, and the damage the farms were causing to the wild fish stocks and seals that the resident and transient orcas depend upon. I don't think fish farms will ever go away, so trying to clean up the ones that exist is a step in a better direction, but at the same time I feel seriously conflicted about their existence.

Human populations are growing and will continue to grow unchecked (I've heard peak estimates of 9-12 billion before it "levels off"). I'm seriously dismayed by this, and feel sick at heart knowing I might live to see this happen. Human population growth is enormously destructive, and the root of so many if not all environmental problems. Granted, all species cause some destruction to their environment, because there isn't a free meal to be had. It's just that evolution has fine-tuned the give-and-take over millions of years, and humans have stepped outside of this control to a degree with the development of agriculture (artificially increasing the productivity of an area at severe cost), and thus population explosion. I don't think we should ever get back to a perfect give-and-take situation as that would likely require humans returning to the hunter/gatherer stage. But our situation doesn't have to be as bad as it is now.

Increasing any food production, including fish farm output, means human population will continue to grow. No one, however, wants to face the ugly truth of such growth, but sooner or later, we will have to face it. And figure out how to control it if we want to prevent a mass plant/animal extinction on this planet, one potentially worse than the Permian. Wild fish stocks are just some of the species already suffering tremendously because of us. Thousands of other species are suffering and will suffer as humans destroy more habitat to make more room for offspring this planet doesn't want. How on earth are we going to face all of this? We're not talking thousands of years--we're talking mere decades, if scientific data is accurate.

I'm truly frightened for our future. Believe me, I want hope to exist. I want things to improve. I want to find out that my assumptions are wrong, that my data is bad, and that our situation isn't nearly as hopeless as it seems.

James Owen
James Owen

@Chloe Neild  You are right to highlight the biological pollution and sea lice issue. In Scotland, this is a problem that has had serious consequences for wild salmonid populations along the west coast, and as sea lice develop resistance to drugs which are supposed to combat these parasites, salmon farmers are having to take increasingly desperate measures, including pumping millions of litres of hydrogen peroxide into the sea, as recently reported in the Scottish media. Despite this, latest figures from the Scottish Salmon Producers Organisation show that sea lice concentrations are out of control in nearly half of areas for which there is data. If Scotland is any guide, "sustainable salmon farming" is an oxymoron. 

Jim Quinn
Jim Quinn

@Henrik Lomholt  All agriculture is destructive.   Agriculture has destroyed more habitat than all other forms of human activity combined.

The question isn't whether salmon farming is destructive.  It absolutely is.   The argument in its favor is that improved methods are less destructive than old methods - including fishing, which is the most destructive of all. 

Arthur Sevestre
Arthur Sevestre

@Charlotte Lenox Charlotte, what would be bad about going back to being hunter gatherers? What negative sides to that do you see?

It's the only way of life for humans which has ever been truly sustainable. Every other way has been more or less unsustainble. It follows, I'm convinced, that it's either going to be hunter gatherer (where a certain kind of agriculture, albeit it not the totalitarian kind we have come to know as the only kind of agriculture possible, is definitely possible), or death to the planet.

Arthur Sevestre
Arthur Sevestre

@Jim Quinn @Henrik Lomholt 

Well, that's something at least: salmon farming is destructive. Agreed.

So the best salmon farming as an industry can do is to become less destructive. It will never become a truly sustainable industry. Since when is that good enough? Why do we need so many clever people to devote time to finding ways to make our actions destroy the world just a tad smaller when they could also devote their time to thinking about and working on ways which are not destructive at all? Ways which
will once again make humans as harmless as a snake, shark, or mosquito? Ways which will see humans once more as a contributing and valuable part of the community of all life?

Settling for just a bit less bad is utterly defeatist. Calling something which has managed to become (or seem!) a bit less destructive 'greener' is misleading at best and pure propaganda at worst. It is like saying that being killed with a knife, compared to with a gun, is human-friendly.


How to Feed Our Growing Planet

  • Feed the World

    Feed the World

    National Geographic explores how we can feed the growing population without overwhelming the planet in our food series.

See blogs, stories, photos, and news »

The Innovators Project

See more innovators »

Latest News Video

See more videos »

See Us on Google Glass

Shop Our Space Collection

  • Be the First to Own <i>Cosmos: A Spacetime Odyssey</i>

    Be the First to Own Cosmos: A Spacetime Odyssey

    The updated companion book to Carl Sagan's Cosmos, featuring a new forward by Neil deGrasse Tyson is now available. Proceeds support our mission programs, which protect species, habitats, and cultures.

Shop Now »