Just 13% of the world’s oceans are now free from intense human activities such as fishing, according to a new map of ocean wilderness areas.
The map is part of a study published in the journal Current Biology, which claims that only 55 million square km of the global ocean can still be classified as “wilderness,” out of a total of 500 million square km.
The researchers say that there is almost no wilderness left in coastal seas, where human activities are most intense. Much of the remaining marine wilderness is clustered around the poles or near remote Pacific island nations with low populations.
Humans rely on the ocean for food, livelihoods, and almost three-quarters of atmospheric oxygen. We use the ocean for the vast majority of global trade, and more than 2.8 billion people rely on seafood as an important protein source.
Earth’s ocean wilderness areas are home to unparalleled levels of marine life and are some of the only places where large predators are still found in historical numbers. Top predators such as sharks and tuna depend on these areas, as their slow reproduction rates make them particularly susceptible to decline even at mild levels of fishing.
The researchers say that even the strictest, best-managed marine reserves cannot sustain the same levels of wildlife diversity as wilderness areas. This is either because reserves are too small, or because human activities in neighboring areas impact wildlife as soon as they swim outside of reserve boundaries. According to the researchers, only 4.9% of marine wilderness is currently within marine protected areas.
For more, including an outline of the biggest threats, and proposed protections, click here.