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  • Page | Last updated: 03 Sep 2025
Marine coverage by protected areas

Information on the calculation of the Marine Protected Area Coverage indicator

Biodiversity

Last updated | August 18, 2025

Indicator information

Name

Marine Protected Area Coverage

Unit

Percentage or surface (km2) of a marine area covered by protected areas.

Area of interest

The indicator is distributed through REST services at country and ecoregion level and available in KCBD - Global Biodiversity Data Viewer (GBDV) at country level.

Related targets

biomon-prod-sdg-14
Sustainable Development Goal 14 on life below water
Target 3
Global Biodiversity Framework Target 3

Policy question

How much are marine areas covered by protected areas at the country and ecoregion level? This is a key question for measuring progress on the coverage element of GBF Target 3 of the Convention on Biological Diversity (CBD).

Use and interpretation

The indicator can be used to assess how far countries or ecoregions are from the GBF Target 3 of having 30% of coastal and marine areas covered by well-connected systems of protected areas. Inversely, the information highlights where on the globe additional efforts are most needed in expanding or reinforcing the coverage by protected areas.

We look here both at coastal and continental shelf waters and at surface pelagic waters. In the first case, we use the 232 boundaries provided by the Marine Ecoregions of the World (MEoW) dataset (Spalding et al., 2007). These ecoregions are extending from the coast (intertidal zone) to the 200 m depth contour (extended beyond these waters out by a 5 km buffer). We also use the 37 pelagic provinces of the world (PPOW) developed by Spalding et al. (2012) which go beyond the 200 m depth. These biogeographic classification systems can help ensure that the full range of ecosystems is represented in global and regional conservation and development strategies.

Key caveats

Country boundaries and exclusive economic zones (EEZ) include disputed territories which may contain protected areas. In such cases, protected areas are assigned to all the countries claiming this territory. Note that the designations employed and the materials and maps produced do not imply the expression of any opinion whatsoever on the part of the European Commission concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries.

Protected areas with a reported area and a point but no boundaries are artificially generated using buffers. This approach can underestimate or overestimate the level of protection of an ecoregion as well inaccurate estimates of the elements that are marine or terrestrial when buffered points cover coastal areas. See Visconti et al. (2013) for further discussions. 

Indicator status

Standard indicators of the Global Biodiversity Framework as an indicator to measure PA coverage under GBF Target 3. Published in UNEP-WCMC & IUCN (2016).

Available data and resources

Data

The KCBD Global Biodiversity Data Viewer provides typical metrics such as the amount of protection for each marine ecoregion within a country; the relative contribution that a country is making to the protection of a marine ecoregion worldwide; and the number of different marine ecoregions which fall within a particular protected area.

Update frequency

Planned annually.

Code

The procedure for the computation of the indicator, which currently involves the use of a wide range of software to handle the different steps, is documented in Juffe Bignoli et al. (2024).

Additional guidance from the curators of the World Database on Protected Areas can be found at

https://www.protectedplanet.net/c/calculating-protected-area-coverage

Methodology

We use the GISCO Administrative Units and the Exclusive Economic Zones (EEZ) v9 to compute protected area coverage of countries. PA coverage statistics are also calculated for marine ecoregions because these represent more meaningful entities within which to analyze the ecological representativeness of the global protected area network (Figure 1). The boundaries of the 232 marine ecoregions and 37 pelagic provinces are defined by Spalding et al., 2007, 2012.

Following current practice, the UNESCO Man and Biosphere Reserves are not included in the calculations, as many of their buffer areas do not meet the IUCN’s protected area definition (Watson et al., 2014; UNEP-WMC & IUCN, 2016). PAs that are proposed (but not yet fully designated or established) and PAs recorded as points without a reported area are also excluded. In addition, all overlaps between different PA records are removed from the calculations to avoid double counting.

The procedure for the computation of the marine coverage is described in details in Juffe Bignoli et al. (2024). A GIS analysis is used to obtain the absolute and relative coverage of protected areas at national, regional and global scales.

Example of a global assessment: Protected marine area (PAs and OECMs, % of ecoregion area) for the world’s marine ecoregions as of February 2023.
Figure 1. Example of a global assessment: Protected marine area (PAs and OECMs, % of ecoregion area) for the world’s marine ecoregions as of February 2023.

Input datasets

References

Juffe-Bignoli et al. (2024) Delivering Systematic and Repeatable Area-Based Conservation Assessments: From Global to Local Scales. Land 2024, 13, 1506. https://doi.org/10.3390/land13091506

Lázaro, C., Mandrici, A., Delli, G., Caudullo, G., Bourgoin, C. et al., Challenges in integrating global environmental data with GISCO administrative layers – A GIS perspective, Publications Office of the European Union, 2025. https://dx.doi.org/10.2760/8183010

Spalding, M. D., et al. (2007). Marine Ecoregions of the World: A bioregionalization of coastal and shelf seas. Bioscience, 57, 573–583. https://doi.org/10.1641/B570707

Spalding, M. D., et al. (2012). Pelagic provinces of the world: a biogeographic classification of the world’s surface pelagic waters. Ocean and Coastal Management 60: 19-30. http://dx.doi.org/10.1016/j.ocecoaman.2011.12.016

UNEP-WCMC & IUCN (2016). Protected Planet Report 2016; UNEP-WCMC: Cambridge, UK; IUCN: Gland, Switzerland, 2016. Protected Planet Report 2016

UNEP-WCMC & IUCN (2025). Protected Planet: The World Database on Protected Areas (WDPA) [On-line], [January 2025], Cambridge, UK: UNEP-WCMC and IUCN. www.protectedplanet.net

Visconti, P., et al. (2013). Effects of errors and gaps in spatial data sets on assessment of conservation progress. Conservation Biology, 27, 5: 1000-1010. http://dx.doi.org/10.1111/cobi.12095

Watson, J. E. M., et al. (2014). The performance and potential of protected areas. Nature, 515: 67–73. http://dx.doi.org/10.1038/nature13947