Protected Area, Kiribati. The Channel Islands National Marine Sanctuary in California, USA. The Chagos Marine Protected Area in the Indian Ocean. The Wadden Sea bordering the North Sea in the Netherlands, Germany, and Denmark. Marine protected areas as percentage of territorial waters The following shows a list of countries and their marine protected areas as percentage of their territorial waters (click "show" to expand). Assessment Managers and scientists use geographic information systems and remote sensing to map and analyze MPAs. NOAA Coastal Services Center compiled an "Inventory of GIS-Based Decision-Support Tools for MPAs". The report focuses on GIS tools with the highest utility for MPA processes. Remote sensing uses advances in aerial photography image capture, pop-up archival satellite tags, satellite imagery, acoustic data, and radar imagery. Mathematical models that seek to reflect the complexity of the natural setting may assist in planning harvesting strategies and sustaining fishing grounds. Other techniques such as on-site monitoring sensors, crowdsensing via local people, research and sampling endeavors, autonomous ships and underwater robots (UAV) could also be used and developed. Such data can then be used for assessing marine protection-quality and -extents. In 2021, 43 expert scientists published the first scientific framework version that – via integration, review, clarifications and standardization – enables coherent evaluation of levels of protection of marine protected areas and serve as a guide for improving, planning and monitoring these such as in efforts towards the 30%-protection-goal of the "Global Deal For Nature" and the UN's Sustainable Development Goal 14. Coral reefs Coral reef systems have been in decline worldwide. Causes include overfishing, pollution and ocean acidification. As of 2013 30% of the world's reefs were severely damaged. Approximately 60% will be lost by 2030 without enhanced protection. Marine reserves with "no take zones" are the most effective form of protection. Only about 0.01% of the world's coral reefs are inside effective MPAs. Fish MPAs can be an effective tool to maintain fish populations; see refuge (ecology). The general concept is to create overpopulation within the MPA. The fish expand into the surrounding areas to reduce crowding, increasing the population of unprotected areas. This helps support local fisheries in the surrounding area, while maintaining a healthy population within the MPA. Such MPAs are most commonly used for coral reef ecosystems. One example is at Goat Island Bay in New Zealand, established in 1977. Research gathered at Goat Bay documented the spillover