Mackerel economics

this is a funny story about how prisons use fish as currency

Mackerel is hot in prisons in the U.S., but not so much anywhere else, says Mark Muntz, president of Global Source, which imports fillets of the oily, dark-fleshed fish from Asian canneries. Mr. Muntz says he's tried marketing mackerel to discount retailers. "We've even tried 99-cent stores," he says. "It never has done very well at all, regardless of the retailer, but it's very popular in the prisons."

There are other threats to the mackerel economy, says Mr. Linder, of Power Commissary. "There are shortages world-wide, in terms of the catch," he says. Combined with the weak dollar, that's led to a surging mack. Now, he says, a pouch of mackerel sells for more than $1 in most commissaries.