Transportation and warehousing sectors are poised to first feel the pinch, with a broader economic fallout expected if the strike drags on.

U.S. ports from Maine to Texas shut down Tuesday when the union representing about 45,000 dockworkers went on strike for the first time since 1977. A lengthy shutdown could raise prices on goods around the country and potentially cause shortages and price increases at big and small retailers alike as the holiday shopping season — along with a tight presidential election — approaches.