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No to farmed salmon; yes to backyard aquaponics & small fish

I’ve heard whispers of the dirty secrets of farmed fish for a few years now, but my awakening to just how bad things are- at least with some fish and in some places- happened in a local children’s park.

Standing around the swing set at 8am one Saturday morning last month, I began a casual conversation with another parent that quickly evolved from “How old is your son?” to “Salmon farms in Chile are endangering Patagonian ecosystems”.

This father just happened to be scientific coordinator for Patagonia’s only scientific field station and he’d come to Barcelona from Chile to try to attract attention to his research at the World Conservation Congress being held here.

In between runs between the slide and the swings, he gradually painted the picture of life- or marine life- in the Patagonian fjords. He, and his wife, are marine biologists and, excitedly, he explained that they are discovering incredible diversity underwater there.

His wife is an anemone expert, the only one in Chile it seems. She told me if I googled anemone and Chile, her name would come up. Thank goodness, because I would never have remembered the spelling of Verena Häussermann, nor of Günter Försterra (her husband). And from my search, it seems she and her husband have discovered new species of Chilean anemones.

Ironically, while the Chilean fjords are home to the most diversity of species along all of Chile’s long coast, it is also home to most of the country’s salmon farms- at a great price to the local ecosystem.

“Farming penguins in the Rocky Mountains”

Salmon isn’t native to Chile (Salon Magazine says “farming salmon in Chile is a bit like farming penguins in the Rocky Mountains“), but in less than 2 decades, this South American country has become the world’s second largest producer of farmed salmon (after Norway). Last year, these farms- in what has become the country’s second largest industry- brought in $2.2 billion in export revenues.

The problem with this quickly growing industry is it’s incredibly polluting. The feces and food pellets from the caged salmon rob the water of oxygen, killing off surrounding marine life. This isn’t a small problem.

The nutrients and fecal matter from 200,000 farmed salmon is roughly equivalent to the raw sewage generated by 20,000 to 60,000 people. To put this in perspective: it’s estimated that Scotland’s salmon farms, much smaller in size than in Chile, produce more nitrogen waste than the untreated sewage of half the country’s population (or equal to the untreated sewage of 3.2 million people).

Added to all this waste is the problem of disease. Günter explained to me that in Chile the cages are much too close to each other. The crowding not only prevents feces and nutrient pollution from dissipating, but it stresses the fish leading to parasitic, viral and fungal infections.

To fight the chronic disease, Chilean fish farmers use a lot of antibiotics. Chilean Immunology professor Felipe Cabello estimates that Chilean fisheries use 70 to 100 times more antibiotics– some of which are prohibited in the U.S.- than those in Norway.

It turns out all these antibiotics are not only polluting waterways, but they just aren’t powerful enough to hide some very stressed fish. Last spring Chilean salmon suffered an outbreak of infectious salmon anemia (I.S.A.). Exports dropped considerably. And Chilean salmon got a bad name. Some supermarket chains, like Safeway in the U.S., made a point to restrict their purchasing of some Chilean salmon.

Closed-containment recirculation systems

I asked Günter what the solution is. He said for one, they should space the cages further apart, like in Canada where they’re placed every 3 kilometers (1.9 miles).

And of course, he wants fisheries banned from Patagonia’s fjords and instead placed further out to sea.

The World Wildlife Federation (WWF) representative to Chile, David Tecklin, would agree with him. “These lakes are a global treasure and pollution from salmon farming is completely avoidable.”

The WWF solution is to move salmon farms from freshwater lakes to closed-containment recirculation systems on land. While more expensive, they estimate it will only cost about 2% of the value of Chile’s salmon exports of 2006.

The problem with farming salmon anywhere

As I left the park, I was determined to tell everyone to stop eating Chilean salmon- at least until they cleaned things up-, but back home again, I started to read a bit more and I’ve realized that even those countries with better-spaced, nearly antibiotic-free farms have their own set of problems.

In countries like Canada, Norway, the US and the UK, where farmed salmon co-exist with their wild cousins, great damage is being done to wild fish stocks from escaped farmed fish. They compete for spawning and feeding grounds, transmit diseases rampant in caged populations and they inter-breed with wild populations (this genetic contamination makes the wild salmon less able to survive in their natural habitat).

The effects of salmon farming on native populations is frightening. In the first study looking at the problem- released last winter in Science magazine- researchers found that the sea-lice from salmon farms had killed 80% of pink salmon runs on British Columbia’s Broughton Peninsular (Canada).

In 8 years, whole river systems could lose their pink salmon forever.

The Canadian activist group the Sea Shepherd, among others, has taken up the fight against salmon farms. In a recent press release they denounced the entire industry for “causing irreparable damage to marine habitats and…endangering native species of fish”.

I was surprised to read that they were equally critical of farming salmon in closed tanks (like the WWF has proposed for Chile) because “it is simply not possible to produce salmon in a sustainable way. You will never get it into ecological balance.”

Eating lower on the fish chain

The idea that we’re focusing on the wrong fish- salmon production worldwide has tripled since 1980- reminded me of something Brian Halweil, a Worldwatch Institute researcher, had told me a few years ago when I asked him if it was okay to eat farmed fish.

We were talking about a recent report warning that “all the world’s major fish populations… are going to be over-harvested, virtually extinct, by the middle of this century” and Halweil was explaining that eating high on the fish food chain was part of the problem.

By buying the big carnivorous species like salmon and tuna, we’re depleting the supplies of smaller fish like anchovy and herring that are used for their feed. And it takes a lot of small fish to produce these bigger species: about 10 kilograms of fish feed to produce 1 kg of salmon and about 20 kgs to produce 1kg of tuna. As Halweil explains, it’s “an exercise in ‘reducing’ fish to produce fish.”

I asked Halweil when is it okay to buy farmed fish? “Farmed fish in general, is problematic if you’re buying these big carnivorous species. But if you’re buying fish like carp or tilapia that can be raised on vegetable matter, it is much more sustainable. And in fact, it does take a lot of pressure off of the oceans.”

Farming carp with rice in China

Somehow, like so much of our food supply system, fish farming has gone industrial, large scale and high on the food chain, but it doesn’t have to be this way. China has been practicing sustainable aquaculture for 4000 years, by raising carp in ponds integrated with rice farming so the agricultural waste feeds the fish and the fish waste fertilizes the fields.

Fish farms have gotten a bad name, but if done right, they can actually help us clean our water. As Dr. Daniel Pauly, University of British Columbia Professor at the Fisheries Centre, told PBS: “I personally like the idea of shellfish aquaculture. These are animals that stay quiet, they stay where you put them, and they clean up the water. They eat what they have extracted from the water that they clean. You can produce absolutely enormous amounts of food, of wholesome, human food, food for people, in a very small area. Shellfish, in fact, have the potential of feeding humanity, if we go that way.”

He also described tilapia as having the potential to become “the aquatic chicken of the future” because it’s a filter feeder, can be an herbivore and it can be grown in an industrial setting or in your backyard.

Backyard aquaponics: aquaculture + hydroponics

The idea of backyard fish farming may seem far-out, but lately I’ve heard mentioned a few times the idea of backyard aquaponics: aquaculture (growing fish) combined with hydroponics (growing plants in water) for a symbiotic recirculating environment where plant waste becomes fish food and fish waste becomes plant food.

I’m tempted by the idea of putting a system on my terrace (I even checked out the forum on backyardaquaponics.com), but for now I’m trying to limit my fish diet to the bottom of the food chain- which means a lot of fresh sardines in Spain- or to closed-system farm-raised catfish, carp, tilapia and shellfish.

Substituting tuna for tilapia

While it’s unlikely that we’ll all begin getting fish from our backyards anytime soon, it’s possible we can begin to start buying greener fish- substituting tilapia for tuna or shellfish for salmon. Though in a culture where tunafish sandwiches are a staple, we need to ask for a fairly large behavioral shift.

Even my father who tries hard to green his ways has had trouble cutting back on salmon. He grew up catching fish in his nearly backyard- the San Francisco Bay- back in the ’40s and ’50s when there was plenty of fish in the bay.

But times are changing. This year, for the first time in history no one caught salmon in the San Francisco Bay (or no commercial fisherman) because the entire West Coast salmon fishing season was canceled due to a collapsed river system: in the past 6 years, the number of salmon spawning in California’s Sacramento River system has dropped by 94%.

Since my father only buys wild salmon perhaps the rising prices will force him to make this fish a luxury item. Or maybe I need to start suggesting some great shellfish recipes: my mother-in-law’s paella for example.

[** Note on how to pick a sustainable fish:

I just read a comment on the faircompanies interview with Brian Halweil and I realize that this huge dietary shift in the type of fish we eat needs better instructions.

The faircompanies user wrote: “After reading this article i feel more concerned and yet more confused about what fish to actually buy. Can anyone recommend any brands which you can buy from main supermarkets which are better? Or is it best to avoid supermarkets altogether and just go to local fish shop and ask a lot of questions?”

Halweil definitely recommends asking lots of questions at both markets and restaurants. But you can also learn more about which types of fish are more sustainable, the Monterey Bay Aquarium lists an A-Z Seafood Watch guide ranking seafood as either “best choice”, “good alternative” or “avoid”.

In an industry with many exceptions, the reviews are thorough. For example, catfish is listed as such: “U.S. farmed catfish is a best choice because it’s farmed in an ecologically responsible manner. Consumer note: we recommend you look for the country-of-origin label to ensure you’re purchasing U.S. farm-raised catfish instead of imported catfish, like basa and swai, which are sometimes also sold simply as ‘catfish.'”]