For U.S. buyers of Pacific white shrimp, the fourth quarter of 2010 got off to a nerve-wracking start. Prices began trending upward again in mid-September and showed no signs of letting up through mid-October.

A similar situation played out in the second quarter, when prices began increasing steadily in March and didn’t ease up until June. But, midway through the fourth quarter, prices were beginning to stabilize again, as raw material costs overseas finally leveled off, according to one majo…