Can consumers lead businesses to change? Yes … sometimes.

Americans are convinced that daily consumption decisions are the most powerful mechanism we have for leading businesses to reduce their impact on the environment.

Where we spend our money is a powerful influence for change, but day-to-day consumption is by no means an election in which each dollar is a vote for or against a set of business practices.

I thought this was one of the most interesting conclusions of a book I just read called Four Fish about the depletion of the world’s fishing stocks and what to do about it. The author Paul Greenberg gives a detailed account of how human consumption of fish is increasingly dominated by four species – tuna, salmon, sea bass and cod – as well as all an extensive discussion of the vices and virtues of farming these species.

Greenberg also points out that people concerned about the environmental impact of fish have been given a litany of don’t-eat-this-eat-that-instead instructions that generally leave consumers confused and appear to have little effect on overall production or consumption of those fish.

In contrast, he points to one such effort that did work – a boycott of swordfish that included a coalition of key chefs and well-known restaurants that had the explicit goal of pushing the government to halt fishing in Gulf of Mexico breeding grounds for part of the year. Two years into the campaign US authorities closed swordfish nurseries to fishing, and two years after that the swordfish population had jumped back to historic levels.

Yes, consumers were crucial. But they were not the cause of the improved fish stocks, they indirectly pressured the government to take measures that improved the lot of the swordfish.

Greenberg’s point here is that a focused consumer-backed campaign that pushes authorities to take decisive action cannot be confused with a barrage of isolated “Don’t eat this fish” campaigns. I agree with this, especially since there are so many warnings about every purchase that we make, ranging from where we buy gasoline to what soft-drinks we consume. “Don’t buy from them, they do business in Sudan.” “That place doesn’t serve fair-trade coffee.” “That restaurant serves factory-farmed chicken.”

It’s too easy for so many commandments to get lost in the swirl of “thou shalt nots” that leave even the most civic-minded types confused about what to buy and where. To have a lasting effect, the economic vote-with-your-feet mentality needs to be channeled into focused (and probably limited) campaigns with clear goals.