Shrimponomics

2007-08-31

in Daily updates, Economics, Science, The environment

Ashley Thorvaldson and Marc Gurstein

Here is an interesting blog post analyzing theories about why people are eating more shrimp than was previously the case. In short, people without training in economics seem to focus more on the demand side than people with such training.

One response that surprised me was “a rise in the number of vegetarians who will eat shrimp.” Now, if you are a vegetarian because you think it is wrong to kill cows and chickens for food, that may be a sensible position. If you are a vegetarian for general reasons of ecological sustainability, it is a lot less valid. As fisheries go, shrimp is one of the worst when it comes to bycatch. The UN Food and Agriculture Organization says that the present shrimp catch is at least 50% above the maximum sustainable level. Shrimp also tends to be collected through a process called bottom trawling: where large steel rollers smash and kill everything on the ocean floor.

Shrimp aquaculture is arguably even worse. There are all the problems attendant to all agriculture – close quarters, disease, harvesting other creatures unsustainably to turn into feed, antibiotics, etc – and then there is the fact that mangrove swamps are ideal for conversion into shrimp farms. The UN Environment Programme estimates that 1/4 of the total destruction of these important ecosystems has been brought about by shrimp farming.

From an ecological standpoint, vegetarianism (and probably veganism) remains a far preferable option, compared to eating meat.

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{ 4 comments… read them below or add one }

Neal September 1, 2007 at 6:02 pm

I think it has become fairly obvious to most people who are paying attention that the rich world needs to seriously reduce consumption of all types of animal-derived foods. However, I’m not so sure that strict veganism is preferable to consumption of small amounts of meat, dairy, seafood, etc. While it is true that fish stocks are overexploited, and modern factory farming of livestock is immensely wasteful, it doesn’t necessarily imply that veganism is the solution to our problems.

The sea feeds so many people, and seafood is such an important source of protein, that to remove seafood from our diets would require the cultivation of a great deal of land to replace fish as sources of fat and protein. While there are crops that can accomplish this–soy, nuts and hempseed spring to mind–eliminating the consumption of seafood on a large scale would require us to clear a huge amount of land to grow crops that have much lower caloric yields than cereals and other staples. To be sure, we should be getting more of our protein from plants, but I’m unsure that this would be sufficent to feed the world in the absence of animal-based foods from both land and sea.

I’m not at all convinced that meat and dairy in general is unsustainable. There exist vast areas of grassland, which while unsuitable for growing crops, can sustainably support large numbers of grazing animals. A switch from industrial feedlots to more traditional pastoral grazing could preserve livestock as a valuable source of meat, dairy, hide, wool, etc, while both improving the conditions in which the animals are kept and freeing productive cropland from being used to grow animal feed.

Another consideration is manure. Cow dung is a good source of fertilizer, fuel for cooking, even paper. If we are going to scale back our use of inorganic fertilizer, as most vegans would probably support, we would have to replace it with something. Animal waste in one form or another (guano, for instance) is probably the best source of nitrogen aside from the Haber Process. The alternative is to abandon the yield gains of the green revolution. I could only speculate how many people this would starve, but the number would almost certainly be in the billions, certainly that high if fish stocks have collapsed, or if seafood is abandoned entirely. The methane cow dung emits can be captured and burned for energy. Most manure plants do this already. Stopping the practice of feeding cows grain will probably do even more to cut down on the vast majority of the methane they emit.

Neal September 1, 2007 at 6:11 pm

Of course, the natural counterpoint to my last paragraph is that the gains from the industrialization of agriculture are so large that we couldn’t possibly dream of abandoning inorganic fertilizer and other fossil fuel intensive techniques without imperiling the worlds food supply. I don’t really know enough about this subject to really have an opinion on the matter.

R.K. September 1, 2007 at 7:48 pm

I think it has become fairly obvious to most people who are paying attention that the rich world needs to seriously reduce consumption of all types of animal-derived foods. However, I’m not so sure that strict veganism is preferable to consumption of small amounts of meat, dairy, seafood, etc.

I agree. Most people will never become vegetarians. Convincing them to cut back on consumption is therefore the best plausible option.

. July 17, 2009 at 4:36 pm

“Today, 90 percent of our shrimp—more than 1 billion pounds a year—come from foreign farms,” writes Jim Carrier in an excellent recent piece in Orion. In Bottomfeeder, Grescoe puts it like this: “The simple fact is, if you’re eating cheap shrimp today, it almost certainly comes from a turbid, pesticide- and antibiotic-filled, virus-laden pond in the tropical climes of one of the world’s poorest nations.” Lest anyone think otherwise, these factory farms generate poverty in the nations that house them, as Grescoe demonstrates; they privatize and cut down highly productive mangrove forests that once sustained fishing communities, leaving fetid dead zones in their wake.

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