Devin Ellsworth

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One Fish, Two Fish, No Fish

I was recently at a friend’s house having a discussion about food.  This is surprising because I never do this.  And by never I of course mean this is the only thing I do with friends.  But either way, we were talking about vegetarian diets, and the subject of fish came up, and I said “well technically I still eat fish so I am not a full vegetarian,” to which she replied, “oh but fish are the worst!  You of all people should know that.”  This comment certainly got me thinking, and I figured this issue should be addressed.  Are fish really the worst for the environment?  That is a bold claim.

To me, determining what is the worst for the environment when it comes to food depends a lot on your criteria.  The first and foremost of the criteria, for me, is greenhouse gas emissions (GHGs).  Climate change is problem numero uno, and is the most common motivator for a reduction in diet impact.  I think it is reasonable then to look at the GHG impact of our food first.  According to a study done at Carnegie Mellon, fish gets lumped into the same category as chicken and eggs when it comes to climate impact.  I have included a graph from that study below that summarizes the GHG impact of various food categories.  (For purposes of this discussion, I will use fish to mean all seafood)

The first thing one notices on this graph is that red meat is just atrocious.  Interestingly enough, however, because of the sheer impact of cows, dairy actually is a very close second place.  After that we have produce, cereals, and chicken/fish/eggs, all right around the same level.  Technically, then, cutting out dairy is a more important step than cutting out chicken.  However, while I find it hard to cut out some dairy (cheese) I don’t see myself going back to eating chicken regardless.  But anyway, back to my main point.  Fish.

Based on this study, the GHG impact of seafood is relatively low.  This makes sense.  Most of the impact of cow production comes from methane emitted from the animal itself, and the vast quantities of corn we need to grow to feed such large animals.  Fish are (for the most part) wild caught, meaning they are out there in the oceans living their lives as they are supposed to, eating food naturally occurring in their ecosystem.  No human input.  The only climate impact of that food, then, comes from fuel burned on the ships, and transportation, which is no more intensive than any other food.  Once the food gets on the truck, its all the same.  A truck is a truck, and miles are miles; doesn’t matter what it is carrying.  So, from a GHG, climate perspective, fish are actually a relatively good choice.

Now, I am not naive, and I know that this is not what my friend was speaking of.  Fish have huge problems of their own.  Those problems come into play when one considers sustainability.  While there are many benefits to an animal that is caught in the wild, including health benefits, there are also many potential drawbacks.  A farmer raising cattle for beef will never drive that population to extinction, because if demand increases he will simply clear more land, and raise more cattle.  However, when demand increases on a natural population of animals, as is happening with seafood, due to rising human populations, nature can’t find more ocean or create more food.  There is a limit.  And, for the VAST majority of fisheries, we are harvesting far more animals than nature is putting back.  This is unsustainable.  It is the definition of unsustainable.

Likewise, many fishing techniques have other negative environmental impacts.  Shrimp are either farmed or wild caught, both of which have immense problems.  With farmed shrimp, large mangrove forests are cleared to make room, decimating local ecosystems.  Wild caught shrimp are captured by scraping the ocean floor, producing an immense amount of bycatch, and leveling everything in the path of the net.  The practice of catching tuna often produces bycatch that includes dolphins and sea turtles.  Salmon are now farmed in Chile, where again local aquatic ecosystems are decimated to make room for these farms, and the fish are being taught to eat corn, of all things.  And these are just a few of the many examples.

So there are many reasons to avoid seafood, and reasons to believe it is the worst for the environment.  I try to eat only sustainable fish, but even that has issues.  I carry in my wallet a guide from the Monterey Bay Aquarium, that lists various fisheries in three categories: green list (most sustainable), yellow, and red.  Yet the other day I examined the card in more detail and found that only five of the 21 fisheries on the “good” list were certified as sustainable by the Marine Stewardship Council.  FIVE.  And there are 21 fish on the good list, and equal numbers on the yellow and red lists.  That means that even the best fisheries are still not harvesting sustainably.  There was a report that came out a few years ago that found that at current rates of consumption, ALL seafood would go commercially extinct by the year 2054.  That means NO seafood that we know today would be left.  Some people took that to mean “eat it while you can.”  I take that to mean stop eating it as much as we do.

I don’t feel that I will stop eating fish all together.  I really love sushi, and get a hankering every once in awhile.  And the past three summers working on Cape Cod have been impossible to avoid seafood.  It provides me with a good alternative if I am out to eat and there are no good vegetarian options.  And, like it or not, seafood is quite healthy.  However, I have stopped buying and preparing it at home, and will continue with that.  And I am now probably only eating seafood once a month.  And of course, any time I do choose to eat seafood, I do my best to at least use the green list, or even better to use the 5 sustainable fisheries I know of.

So, worst for the environment?  It depends on your priorities.  However, it can be agreed that like everything else we eat, there are complex issues involved, and the impact is greater than zero.  And equally true, understanding the production of this food only helps inform and guide us to better, more sustainable choices.  But I want to know what you think.  Do you eat fish?  What do you feel about their environmental impact?  Are they the worst in your book?


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Farming fish in enclosed aquaponics systems has the greatest potential for being the most eco-friendly protein source. In aquaculture systems with waterways flowing through them, fish effluent can become significant pollution the way runoff from farm fields can. But aquaponics solves this by creating a closed loop system that feeds the fish waste to agricultural plants, which also eliminates the need for additional fertilizer.

The main inputs to aquaponics systems that could harm the environment are the need for water pumps to continuously circulate the water and, in greenhouse systems, the need for a heat source. But water pumping and other electrical needs can be provided by alternative energy sources and the water can also be pumped directly with a windmill.

Adding vermiculture (the processing of food waste using worms or larvae) not only can provide food for fish and great soil additives for the plants, but it can also provide enough heat for greenhouse systems even in the winter in cold climates. If the food waste for vermiculture is collected from local restaurants and grocery stores, then the fish food, worms and larvae which feeds on the food waste, would be from a sustainable source. Also, tons of waste would be diverted form landfills every year.

And the animals raised in an aquaponics system are by no means limited to fish: giant freshwater prawn, escargot snails, tiger shrimp, crayfish, and any other edible freshwater animal can be raised along with the fish.

Though the chart cited in the post lumps fish with poultry and eggs, I would seriously doubt that the researchers were taking into account systems like aquaponics that could make fish, and the fruits and vegetables raised with them, the most eco-friendly choices.

So I am a Marine Biologist of sorts, and have spent the last three years working on fishing boats monitoring catches under the employ of NOAA. So I thought I might weigh in on some of the issues brought up. I did my best to quote primary literature, some from memory, but do the research if you’re interested in any of this. First off something like 15-30 % percent of the worlds population (almost exclusively the third world) depends on fish for protein in their diet. It is the cheapest way to get protein to those in need. That being said the global fish industry is anything but simple. As can be expected the US and Japan top the list for total seafood consumption. And most of the fish that developing countries eat comes from the third world I believe its 80%. So fish will always be an important part of our diets. I will give a couple examples of some of the different issues involved in eating fish what is sustainable and where you find more information. Please feel free to email me with any specific questions.

SUSTAINABLITY GUIDES: Good carbon footprint data is hard to come by and most seafood lists don’t include it in their listings of sustainability. This is true of the MSC; it doesn’t do an adequate job of doing true cradle to grave analysis. That being said DO use seafood guides to your advantage. ANY Local aquarium will have the best list for you, usually on their websites. I.E. Boston’s New England Aquarium for those living in the northeast. Buying local is preferable as always. For example while living in Gloucester ma I was able to buy Atlantic Cod from my local market that was caught off Iceland than packaged in Norway, than brought to the US, while earlier in the day I was on a local boat that was only 25 feet long that went 15 miles off the coast and it landed 1000 lbs of the SAME fish. Here we see the same fish with drastically different carbon footprints.

OCEAN ACIDIFICATION. This is F’n important!! This is the meaner and more destructive bastard child of climate change. Basically the increased rate of co2 input into the atmosphere has greatly increased the rate of co2 uptake in the oceans. Which since pre-industrialized times has increased the oceans acidity such that currently it is 30%!!! Higher. This increased acidity makes it harder for shelled organisms to incorporate calcium carbonate into their shells. This has negative implications for all shellfish and coral. But more importantly on the complete restructuring of basic marine food webs as primary producers and consumers who incorporate calcium in their in bodies will die out. Not to be all doom and gloom, there are solutions to this problem, but please inform yourself more about this issue, I feel it is underrepresented

SHRIMP. We get most of our shrimp in the US from Southeast Asia, Thailand in particular. This is mostly done by farming, however farming often resorts to trawling to replenish juveniles from wild populations. Shrimp trawling in the US is much cleaner, because gear modifications are getting better all the time. The industry encourages devices that reduce bycatch because it increases the value of their product and decreases the amount of labor involved. From personal experience I can tell you that the Maine shrimpers have very low bycatch. They actually have a processing problem. I.e. there are not enough companies with the production ability to handle the amount of shrimp that can be caught. With the BP spill in gulf limiting shrimp production in the US heavily, I would encourage buying New England shrimp.

The fishing Industry is HEAVILY Regulated In the US, (albeit not always correctly, true ECOSYSTEM MANAGEMENT, has taken a while to be implemented. Emphasis has been on maintaining specific biomass levels for specific species, with little importance given to ecosystem viability and species interactions. For example SPINY DOGFISH: this species has been excessively targeted esp. in Europe, where it has collapsed as an ecologically important species. It is listed as vulnerable by the IUCN. But it may be that Over fishing of other fishes in our part of the Atlantic accompanied by harsh restrictions on landings of dogfish have given it an edge locally where this sub population replaces stocks that were once abundant. Because it is a common bycatch species I would lobby for a possible reduction in the very small landing quota on this species and larger market incentives.

This brings to my next suggestion on seafood, investigate ALTERNATIVE FISHES. Not to be confused with rare species. In the states we like our animals in well-presented fillet form, and rarely eat anything whole, or that resembles the animal from which it came. Because of this the most profitable fishes in New England are the large ground fishes, cod, haddock, Pollock, Hakes, Monkfish (tails), and large flounder species. But these are not your only options. Try eating locally caught herring, or squid. Skate wings I would encourage exploring. It may be that the skate complex actually responds positively (population increase) to disturbances caused by trawl fishing. This is a theory of mine that needs more research. But they are an underutilized commonly caught bycatch species.

BYCATCH is any marine organisms that are caught that don’t make it to market. Bycatch falls into several categories. Regulations: commercially viable animals are not allowed to be kept because of quotas in place, size restrictions, or lack of permits. Quality: gear damage, scavenger damage (which ranges from seals and sharks, to hagfish and copepods), diseased or unhealthy fish. Depending on the gear type and fishery there also non-commercially viable species: It may be that they are edible, but the boat can’t find a buyer or there is no market to sell to. Alternatively they may not catch enough to make it economically feasible to bring it in. Finally there is catch all “other” category. Here we see rare fishes, inedible organisms, and incidental takes. Incidental takes are marine mammals, birds, and turtles. Survivability of bycatch depends on the resilience of the organism, when and where it was caught, and the gear it was caught in. yes fishing does kill large mammals and birds but on the flip side, the process of gutting at sea increase bird populations, and seals have learned how to steal fish out of gillnets. Ironically they are attracted to these nets because fishermen are required to attach high frequency pingers, which minimize the amount of small cetaceans (in this case harbor porpoises) that are killed. With different GEAR TYPES we get different consequences, while trawls and active gear are relatively less selective and disturb bottom organisms, gill nets and other fixed gears tend to catch or entangle more mammals and birds.

INVASIVE SPECIES. Most people know of lion fish, or zebra fish it is the pretty stripped and frilled poisonous fish seen in aquariums, a variety of these fishes are native in the tropical pacific In the last ten years or so, through unknown means (most likely people releasing them from their aquariums). They have become established along the Atlantic coast. they are a fish predator that is having negative impacts on local fishes. It turns out they are also quite tasty. It is on the market now and as long as you can finds someone to prepared it right (the spines are quite poisonous, but not ever eaten unless you normally eat fish fins), I would encourage eating this.

SUSTAINABLE FISHERIES: they do exist. The scallop fishery is an example in New England. Scallops are dredged from a variety of rotating closed areas that only open to fishermen after the scallops are allowed to grow to maturity. The most commonly caught bycatch is this fishery is yellowtail flounder. Currently the fishing industry has implemented a feed back system that inter connects all the independent boats such that the mangers a get a real-time view of where the yellow tail is and what size scallops are being caught across an entire scallop area, the mangers than inform fishing boats and they can avoid the areas of yellowtail concentration and concentrate on adult scallops.

FISH FARMING: Tilapia is an algae eating fish that is growing in popularity and market presence. You can easily grow its food with little nutrient and energy input in adjacent tanks and than feed the Tilapia. It is a rather bland but nutritious white meat. This is the most sustainable fish on the market by far. Most fish farming requires upper level predators to be feed fishmeal, which is ground up fish caught by traditional means, not efficient or sustainable. However the FDA recently approved a variety of genetically engineered salmon that grows quicker and requires less food than traditionally farmed salmon.

All and all I discourage the eating of BIG FISHES, for the most part they tend to be top trophic level marine predators with cosmopolitan ranges, which make them hard to manage and globally important. For example Japan had an “experimental” fishery for bluefin, whose landings were not required to be reported. The problem was that the landings were substantial and greatly undermined the southern pacific population.

Eating fish is a complicated global issue. I recommend that you find out what fishes are most available in your community and to you. Than do the research on where and how they are caught. Than do your own cost benefit analysis.

Thanks for the comments!

Actually it was this study that sort of helped me make the final push into being a vegetarian over 2 years ago, so this is something that has been with me for awhile. But you are correct that GHG emissions are not the only part of the equation. Granted they are a huge part, and are a very measurable value of sustainability. But, like you said, vegetables are actually worse than chicken, according to this study, so that’s not the whole of it.

However, I think there are a couple of potential issues that your comment raises. I think both points I will address may have been unintentional on your part, so I address them with that caveat.

I should clarify my feelings about vegetarian, or restrictive, diets. While environmental concerns were the spark that led me to this diet, I absolutely, 100% love being vegetarian, and do not in any way miss meat. That is a shocking statement, considering where I came from (an avid meat-eating midwesterner). I absolutely appreciate that my diet has a much lower environmental impact, and my goal is to find the diet with the least impact that works for me, but I love it. But I think that right there is the point. Find the diet that makes the least impact, that works for you. There are many joys to being a vegetarian, and many reasons for going veg (environmental, animal rights, health – a big one). But it is not for everyone, and that is not my goal to try to get everyone to restrict their diet. Nor does it mean that the only way to care about food and sustainability is to not eat meat.

But, this statement is unequivocally true – we eat too much meat in this country. Some restriction is necessary. Not of entire categories, not for everyone, but virtually EVERYONE in America is eating too much meat, at an unsustainable level. So my goal is not to see everyone in America become vegetarian (though that would solve a lot of problems, but I am not naive), but rather to see everyone in America learn to eat less meat. That, is much closer to a sustainable solution. And practical too, theoretically at least.

So again, while not everyone can restrict their diet, I do not think it is necessary for the conscientious few to cut everything out to make up for the average America who doesn’t care. The problem is too large for that to work. Instead, everyone is responsible for their own carbon footprint, and eating a more sustainable diet is probably the most important, and easiest, way to reduce that impact.

I am not a huge fan of most seafood. Perhaps an artifact of living my whole life in the Midwest, but I don’t buy much seafood at all. Maybe one fish a year or so. As a result, the sustainability of fishing only comes to mind when I come across an article in National Geographic or something. When I do find these articles, I feel the same way I do whenever I find out humans are effing up some part of nature – pissed off. Though I have to admit, it is probably easier to get upset about something that I can so easily distance myself from.

I love how you have started to look for a way to quantify your rationale for cutting certain foods out of your diet. Clearly GHG emissions cannot be your only standard, as evidenced by the seafood issue, and by the fact that grains and vegetables are worse for the atmosphere than chicken, eggs, fish, candy or soda. To be honest, I am skeptical of the whole practice of completely cutting foods out of one’s diet. All foods can have their place if they are produced properly and consumed on a sustainable scale on the population level. I think we need to reach a place where EVERYONE is eating in a moderate and responsible way, rather than a place where the conscientious fraction of society goes to dietary extremes to try to compensate for the less responsible fraction of society – I fear that is not a sustainable social solution to the food production problem. This is a complex and interconnected issue though. Much more will have to be written and discussed.

I recently stopped eating fish again. I don’t think they are the worst but it’s pretty freaky to think how much it’s effin’ up the ecosystem to fish on the scale that we do in this high-tech age. I remember reading a study a few years back from Science magazine that said if we go the rate we’re going the oceans will be totally devoid of fish in a few decades. You should also see the movie The End of the Line if you’re interested (which I know you are). 🙂