The ocean is barely wild anymore. A map of the wilderness left in global waters shows that only 13 per cent of the ocean remains undisturbed by human activity.
Kendall Jones at The University of Queensland in Australia and his colleagues analysed the effects of 19 human stressors on the seas, which fall into broad categories: fishing, pollution, climate change, and shipping. Transporting vast quantities of goods across the ocean can disturb habitats and pollute the water, and also ferries invasive species throughout the seas. And pollution doesn鈥檛 just include physical contaminants 鈥� light pollution is included in the analysis, as it can affect the habitats of coastal species.
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鈥淲e know that ocean wilderness has unparalleled levels of marine diversity. We mapped some of the last places that you still find big populations of large predators like tuna or sharks,鈥� says Jones. 鈥淭hat biodiversity makes these areas more resilient to climate change, and more successful at recovering from stresses than places that are more degraded.鈥�
Of the 16 ocean realms the team studied, the area with the largest portion of wilderness left is in the South Pacific, which is 88.5 per cent wilderness. Arctic and Antarctic waters are also less disrupted than other ocean areas, though with increasing sea ice loss, that may soon change, Jones says.
In the temperate areas of the Atlantic 鈥� between Europe and North America, and between Africa and South America 鈥� wilderness is almost entirely wiped out, with less than half of one per cent of waters there left undisturbed. Two-thirds of all the ocean wilderness is in international waters, where no one nation has jurisdiction. And of all the wilderness left in coastal areas and the open seas, Jones found that less than 5 per cent is protected.
Their聽map is based on surface area, so it may not take into account how much deep sea wilderness is left. 鈥淚t would be good to emphasise volume rather than area,鈥� says Jesse Ausubel at The Rockefeller University in New York.
Ausubel helped create the Census of Marine Life, a database of聽65,000 species of marine animals and plants across 30 distinct ocean realms. That data could be used to assess the volume of聽water that is still wild, he says, which may be a more accurate measure.
Jones says they didn鈥檛 include plastic pollution in their analysis because they didn鈥檛 have the data for all ocean realms. 鈥淏ut we know plastic pollution is widespread and found even in remote areas. With that, plus climate change, I鈥檇 be surprised if soon there was really anywhere untouched by human influence,鈥� Jones says.
Read more: Giant ocean fish farms to solve food security? There鈥檚 a catch
