Read the Marine Policy paper entitled, "Categorizing global MPAs: A cluster analysis approach"
From the Abstract:
Marine Protected Areas (MPAs) are a widely used and flexible policy tool to help preserve marine biodiversity. They range in size and governance complexity from small communally managed MPAs, to massive MPAs on the High Seas managed by multinational organizations. As of August 2018, the Atlas of Marine Protection (MPAtlas.org) had catalogued information on over 12,000 Marine Protected Areas. We analyzed this global database to determine groups of MPAs whose characteristics best distinguished the diversity of MPA attributes globally, based upon our comprehensive sample.
Read the article here.