This is Scientific American 62nd Science.

I'm Cynthia Graber.

Got a minute?

Londoners love their fish, and according to a new study, in the early 13th century,

they suddenly started importing it from as far away as the Arctic near Norway

the researchers in the journal Antiquity. About the year 1,000 sea fishing increased

significantly in Northern Europe. To see how that increase influenced urban growth,

researchers looked at 95 excavation sites in London,

which included about 3,000 bones from codfish.

Cod are decapitated before being dried for transport, so finding heads meant the fish were local.

And the researchers found that his fish heads appear to decrease in the early 1200's fish tails dramatically increased,

a sign of importation. Examination of the chemical isotopes in the tails match those for fish in waters far to the north,

probably off Norway close to the Arctic, more evidence of import.

The scientists do not know if the rapid switch from local to imported cod happened because local fish weren't as plentiful as the population increased, or if the market became flooded with dried imports from the north.

But these fish tales tell a story of London becoming a growing economic

center and part of a globalizing fish trade.

Thanks for the minute. For Scientific American 60 Second Science, I'm Cynthia Graber.