John Gelb's List: The Economist

• archaeologists have found mounds of oyster shells, known as middens, dating back to 6950BC.
• oysters are not only among the strangest and tastiest creatures in the sea, but as far as the health of marine ecosystems go, they may also be the most important.
• most of the Chesapeake Bay’s oyster operations have been public fisheries rather than aquaculture—anyone with a license could take oysters from state-owned bars, and though size and number limits were set, often they were more honoured in the breach than in the observance. Once a tipping point was reached, oysters were too far apart for enough of their gametes to meet, so the population could not sustain itself. And those few larvae that were lucky enough to live long enough to extend a probing foot too often found only silt. The oyster population in the Chesapeake today stands at just 1% of its pre-1980 levels.

  • reason for disappearance of oysters in Chesapeake Bay
• asn’t just overfishing that depleted the oyster population.

  • see next highlight
• environmental problems: sewage, agricultural run-off and increased burning of fossil fuels, all of which produce large quantities of pollutants, which find their way into the bay.
• no single pollutant does more harm than nitrogen
• Nitrogen thus harms aquatic life in two ways: by allowing phytoplankton to live, it keeps sunlight from reaching underwater plants and grasses, which removes an important source of food and habitat for numerous marine species. And the bacteria that feed on dying phytoplankton use oxygen, leaving less for fish and crabs.

  • nitrogen harm
• “The oyster is pretty particular about what it eats, but it’s not particular about what it filters.” A single oyster can filter about 50 gallons of water per day.

  • benefit of oysters
• A few decades ago, the Chesapeake had enough oysters to filter the entire bay every week: that same task would take its existing population a full year. As an oyster eats plankton, it draws in everything else around it, including nitrogen; what it does not eat it expels into the water as solid pellets of waste, which eventually decompose and bubble up into the atmosphere as nitrogen.
• A pearl actually begins from a parasite adhering to an oyster’s mantle, which is a thin organ that surrounds the inside of its shell. The mantle secretes nacre, or mother-of-pearl, by synthesising calcium carbonate from materials in the water. If a parasite tears off a bit of the mantle and carries it to another part of the oyster’s body, that piece of mantle will still secrete nacre, forming a pearl sac around the parasite, which, over years, turns into what people consider a jewel.

  • how a pearl is formed
• an ideal testing ground for a theory: it is not so much that oysters live in clean water, as that water with an abundance of oysters in it will be clean. In other words, dirty water doesn’t drive away the bivalves; rather a lack of bivalves invites the filth.

  • hypothesis: depleting oysters invites dirty water. oysters no longer there to filter the pollution
• “Oysters aren’t the magic bullet, but they’re an important bullet,”
• farmed oysters, unlike other seafood, suffer no decline in taste. They grow, breed, eat and filter just as they do wild. Indeed, oyster farming is one of the few situations in which both economics and the environment win: any body of water that can support a vibrant oyster industry will almost certainly be cleaner and more vital than one that cannot.

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• Another study in a supermarket some 12% of people spent 90 seconds looking at juices, studying the labels but not selecting any. In supermarket decision-making time, that is forever. This implies that shoppers are very interested in juices as a healthy alternative to carbonated drinks, but are not sure which to buy.
• Deloitte found that customers using fitting rooms convert at a rate of 85% compared with 58% for those that do not do so.
• A third “decoy” item, which is not quite as good as the other two, can make the choice easier and more pleasurable, according to a new study using fMRI carried out by Akshay Rao, a professor of marketing at the University of Minnesota.

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