Global and regional priorities for marine biodiversity protection

The ocean holds much of the planet's biodiversity, yet < 4% of the ocean is within protected areas. On land, the protecting of areas with low biodiversity and under little threat, rather than biodiversity hotspots, is a well-known problem. Prudence suggests that we not repeat this pattern in the ocean. Here we assessed patterns of global marine biodiversity by evaluating the protections of 4352 species for which geographic ranges are known, and mapping priority areas using an index that considers species vulnerability, coverage by marine protected areas (MPAs), and human impacts. Species have, on average, only 3.6% of their range protected. Moreover, species of conservation concern (threatened, small-ranged, and data deficient) have less protection than species on average. Only 5 nations currently protect 10% or more of their exclusive economic zone (EEZ) as strict Marine Reserves (IUCN category I-IV) in accord with the 2020 Aichi Biodiversity Targets. One nation by itself, Australia, accounts for 65% of the global area of Marine Reserves. The Coral Triangle is the clear and dominant global priority for biodiversity, but we identify additional global and regional priorities in each ocean basin. As an example, we show that for the United States, the Marianas and Samoan Islands are the top marine conservation priorities. Despite recent advances, the world has yet to protect most of the area and species that need it. Where to protect those species, however, is increasingly clear.