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What's the Difference Between Marine Protection Atlas and World Database on Protected Areas?

Comparison of the MPAtlas [left] and WDPA [right] maps
Comparison of the MPAtlas [left] and WDPA [right] maps

There are two major databases of global marine protected areas (MPAs), and it is not uncommon that we get asked about the relationship between our Marine Protection Atlas (MPAtlas) and the World Database of Protected Areas (WDPA) – what makes MPAtlas different from the WDPA, and why do we report different statistics? These are important questions, so we wanted to take this opportunity to explain how these datasets are related, and how the MPAtlas draws on WDPA data to more deeply assess the quality of protections alongside the quantity.

The WDPA is the official catalog of marine and terrestrial protected areas; it hosts the largest assembly of global protected area data self-reported by 245 countries around the world. This dataset includes basic information such as location, area, spatial boundaries, governance type, and management authority. The WDPA was created in 1981 through a joint effort between the United Nations Environment Programme World Conservation Monitoring Centre (UNEP-WCMC) and the International Union for Conservation of Nature (IUCN) World Commission on Protected Areas (WCPA).

The WDPA reports the IUCN Protected Area Categories to classify marine protected areas (MPAs) in their database. Categories are assigned based on the primary objectives of the protected area by the governing body that holds authority and responsibility for the area. These internationally recognized categories provide a common classification language and facilitate a global system for defining and recording protected areas.

Category Ia: Strict Nature Reserve

Category Ib: Wilderness Area

Category II: National Park

Category III: Natural Monument or Feature

Category IV: Habitat/Species Management Area

Category V: Protected Landscape/Seascape

Category VI: Protected area with sustainable

use of natural resources

MPAtlas, launched in 2012, is an initiative of Marine Conservation Institute that began as an effort to provide an independent assessment and a more nuanced view of global marine protection by focusing on the subset of MPAs with the strongest regulations on human extraction (no-take) and actual implementation on the water. Without strong protections in place, a marine protected area cannot measurably aid in biodiversity conservation. Our team wanted to pinpoint the quantity of self-reported marine protected areas that met these standards, in order to better inform important global conversations about conservation targets.

Starting in 2021, upon the publication of The MPA Guide, MPAtlas honed this vision by creating a database of science-based MPA assessments. Today, MPAtlas builds upon the WDPA dataset by using science-based frameworks and assessments, such as The MPA Guide, and its precursor the Regulation-Based Classification System (RBCS), to independently categorize and report MPAs and MPA zones based on their Stage of Establishment and Level of Protection. We apply these tools to assess the protection afforded by MPA regulations and identify the conservation outcomes they can expect to deliver for ocean biodiversity and all of us who depend on it. As we continue to assess MPAs across the globe, our dataset will continue to grow.

MPA Guide Regulation Based Classification System
Stage of Establishment Level of Protection Zone Classification
Committed/Proposed Fully Protected 1 No-take/No-go 5 Moderately regulated extraction
Designated Highly Protected 2 No-take/Regulated access 6 Weakly regulated extraction
Implemented Lightly Protected 3 No-take/Unregulated access 7 Very weakly regulated extraction
Actively Managed Minimally Protected 4 Highly regulated extraction 8 Unregulated extraction


The WDPA classifies MPAs based on their IUCN management objectives, while the MPAtlas classifies areas based on determinants of their conservation outcomes. This distinction is important because objectives on paper don’t always match implemented regulations and management, and therefore, the conservation outcomes. Moreover, an MPA is labeled ‘protected’ according to WDPA at the time of legal designation; however, biodiversity is not safeguarded until protections are legally implemented and the MPA is actively managed on the water. By focusing on protection level and resulting conservation outcomes, we identify fully and highly protected areas to provide a more nuanced picture of effective global marine protection. This is why the WDPA reports the percent of global ocean in protected areas while MPAtlas reports the percent of global ocean in fully or highly protected areas.

At first glance differences in the reported statistics from these two databases may seem conflicting, but in reality, the WDPA and MPAtlas actually provide different complementary information about global marine protection. The existence of the two databases allows the WDPA to serve the role of nationally-reported data custodian and the MPAtlas to serve the role of the third-party appraiser. Together, these systems will drive the next conversations about goals for international progress and collaboration in marine conservation.

It is important to note that the information on is constantly being updated and is dependent on feedback from our community for accuracy. We welcome feedback and additional information. Reach out to us at We also request that any use or citation of our data and statistics be time stamped.