This is a good thing, but, there are always ways around stuff and for that reason sanctions don't always work. It does show that there is a "United Front" against them and what they are attempting to do with their underground nuke program.
Maersk Line also holds government defense contracts for their MSC (Military Sealift Command) division that does all kinds of black ops operations like submarine hunters that do nothing but run and drag really long cables through the water listening for and tracking submarine transits points, locations ext.. and they really don't want to screw those contracts up, so they'll play ball and won't want to try and skirt around the blockade.
A growing number of Western companies, especially those in shipping and related businesses, are pulling out of trade with Iran due to the complexities of deals and tougher banking restrictions as the sanctions take hold - and out of fear of losing business elsewhere.
"Iran's commercial shipping sector has suffered a significant hit," said Anthony Skinner of risk analysts Maplecroft.
"Although U.S. and EU sanctions do not target food shipments, importers struggle to acquire letters of credit and transfer funds. I expect current sanctions and the further tightening EU sanctions to sour the appetite of the international commercial shipping sector further."
The United States and the EU have led the sanctions push, hoping to force Iran to halt its nuclear program which they suspect is aimed at making weapons. Tehran says the work is peaceful, but the trade measures are hurting shipping badly.
Data from maritime intelligence publisher IHS Fairplay showed the overall number of vessels calling at Iranian ports in the year to early October was 980. That figure for more than three quarters of this year compares with 2,740 ships for the whole of 2011 and 3,407 for 2010.
Of that total, the number of visits by container ships - which carry consumer goods ranging from foodstuffs and household items to clothing and toys - was 86 so far this year, compared with 273 for the whole of 2011 and 378 in 2010.
The world's top container firm Maersk Line said this week it had stopped port calls to Iran, citing the risk of damaging trade opportunities especially in the United States.
