Mapping the World’s Key Maritime Choke Points Maritime transport is an essential part of international trade—approximately 80% of global merchandise is shipped via sea. Because of its importance, commercial shipping relies on strategic trade routes to move goods efficiently. These waterways are used by thousands of vessels a year—but it’s not always smooth sailing. In fact, there are certain points along these routes that pose a risk to the whole system. Here’s a look at the world’s most vulnerable maritime bottlenecks—also known as choke points—as identified by GIS. What’s a Choke Point?