People stand on a sand berm with a view of anchored container ships which cannot enter the ports of Los Angeles and Long Beach to load and unload cargo because of a strike by the International Longshore and Warehouse Union Local on November 29, 2012 in Seal Beach, Calif. - 

Several container ships are anchored off the coast of southern California today, waiting to get into the ports of Los Angeles and Long Beach. It marks the seventh day of a strike that has crippled the busiest port complex in the country.

L.A.'s mayor Antonio Villaraigosa has called for round-the-clock negotiations to solve the impasse.

So far, most Americans aren't feeling the effects of the strike, according to Julia Coronado, chief economist with BNP Paribas.

"Retailers build up their inventories well in advance of the holiday season, so they've got plenty of goods on hand to sell," she points out. "But clearly if this goes on for another week or two, I think we'll be feeling the effects."

Together, the ports of Los Angeles and Long Beach account for about 40 percent of the goods coming into the U.S., says Coronado. "In fact, we economists track activity at this port to get a sense of global trends in trade."