Havana announced a sharp increase in customs duties to take effect in August . . . duties on items valued at more than $50 will increase 100 to 200 percent . . . “miscellaneus items” shipped through airports, ports and the mail also face new fees . . . all shipments weighing more than seven pounds will pay $4.50 per pound instead of the 25 cents per pound they currently pay . . . the high duties counter economic modernization implemented by Raul Castro since he took office in 2008 . . . the moves appear aimed at protecting government-run stores that are threatened by growing small businesses flourishing under Raul Castro’s reforms . . . the new taxes are likely to increase prices and cause shortages on the island.