Marine Protected Areas (MPAs)
Definition of Marine Protected Areas (MPAs):
The World Conservation Union defined Marine Protected Areas (MPAs) as “any area of the intertidal or subtidal terrain, together with its overlying water and associated flora, fauna, historical and cultural features, which has been reserved by law or other effective means to protect part or the entire enclosed environment”  .
In the USA, Presidential Executive Order 13158 provided a similar definition” any area of the marine environment that has been reserved by Federal, State, territorial, tribal or local laws or regulations to provide lasting protection for part or all of the natural and cultural resources therein.”Another definition states that: “Marine Protected Areas (MPAs) are valuable tools for conserving the nation's natural and cultural marine resources as part of an ecosystem approach to management”. 
This is the common definition for Marine Protected Areas (MPAs), other definitions can be discussed in the article
There are numerous definitions for Marine Protected Areas (MPAs) under which a a wide variety of sites could be considered as MPAs and they are used to manage marine resources. However they often mean different things to different groups of interests within the society. These differences are based mainly on the level of protection they provide.
The main purposes for Marine Protected Areas (MPAs) establishment are:
- to protect a certain species
- restore depleted species
- to benefit fisheries management
- to protect full ecosystems,
- rare and/or critical habitat
- spawning and nursing grounds for fish
- to protect historical sites as shipwrecks and important cultural sites such as aboriginal fishing grounds
There is a range of restrictions in MPAs. The typical ones take the following issues under consideration:
- oil and gas mining
- access for tourism
- ultrasonic devices like sonar (which confuse the guidance system of cetaceans),
- development and construction
Marine reserves offer legal protection against fishing and development. They are considered to be a part of MPAs where they ensure a high but not an absolute level of protection. They are not able to directly protect from regional pollution, climate change, natural disturbance, or human disasters 
Marine reserves and fishery closures are treated as two options to promote ecosystem and species recovery. According to Worm et al. (2006) who reviewed 44 “fully” protected marine reserves and four fisheries closures, found that high variation, species diversity, productivity, resistance and recovery from natural disturbances, and tourism revenue (measured on 138 Caribbean protected areas) increased when were associated with marine protected areas.
The designation of marine reserves seems to be a rare and controversial measure although supported from numerous theoretical and empirical studies  . Over 160 leading marine scientists of the American Association for the Advancement of Science have called on decision-makers to act on the confirmation with urgent effect by setting a fully protected network of marine reserves. The 2003 World Parks Congress suggested that “networks should be extensive and include strictly protected areas that amount to at least 20-30% of each habitat”, while the United Nations Millenium Project demands 10% of the oceans to be covered by marine reserves in the short to medium term, with a long–term aspiration of 30% . In 2020, 7.45 % of the ocean is currently under effective protection worldwide of which 61 % is placed in high seas. However, according to the Marine Protection Atlas, a no-take full protection regime only applied to about 2.7% of the world oceans in 2020. If fact, MPAs appear as one of the main issues in international negotiations on managing of high seas. A network of high seas and coastal MPAs allows to refuge for the increasingly threatened high seas species for example, turtles, dolphins, sharks, whales and some of most precious marine biodiversity, at the same time supporting the recruitment of fish stocks. Additionally the re-evaluation of fishing methods and gear could reduce by-catch and superfluous waste of marine resources.
Natura 2000 network
See the article Marine Protected Areas in Europe.
In the EU, the establishment of the marine Natura 2000 network was delayed due to lack of knowledge and understanding of marine biodiversity in the European waters that are the crucial to establish clear baseline conditions and indicators that will enable monitoring and appropriate management of marine sites. By the end of 2016, 10.8 % of the surface of Europe's seas had been designated as MPAs. The Director General of The World Conservation Union calls for learning on experience of the countries from other parts of the world. IUCN has prepared a revised version of its guidelines for setting up Marine and Coastal Protected Areas, with instructions on institutional set-up, design principles for specific habitats and 25 individual case studies, see .
- IUCN Marine Protected Areas
- Marine Protected Area
- EU Marine Protected Areas
- World atlas of Marine Protected Areas
- World Database Marine Protected Areas
- ↑ IUCN (International Union for the Conservation of Nature and Natural Resources).1994. Guidelines for protected area management categories. IUCN, Gland, Switzerland and Cambridge, UK
- ↑ Kelleher, G. 1999. Guidelines for marine protected areas. International Union for the Conservation of the Nature and Natural Resources, Gland, Switzerland, and Cambridge, UK.
- ↑ http://mpa.gov
- ↑ Jameson, S.C., Tupper, M.H., and Ridley, J. M., 2002. The three screen doors: can marine “protected” areas be effective? Marine Pollution Bulletin 44: 1177-1183
- ↑ Worm, B., Barbier, E.B., Beaumont, N., Duffy, J. E., Folke, C., Halpern, B. S., Jackson, J.B.C., Lotze, H.K., Micheli, F., Palumbi, S.R., Sala, E., Selkoe, K.A., Stachowicz, J.J. and Watson, R.2006. Recent biodiversity loss undermines ocean ecosystem services at all scales. Science 314: 787-790.
- ↑ Johnson, D.R., Funicelli, N.A. and Bohnsack J.A.,1999. The effectiveness of an existing estuarine no-take fish sanctuary within the Kennedy Space Center, Fliorida. North American Journal of Fisheries Management 19: 436-453.
- ↑ Murray, S.N., Ambrose, R.F., Bohnsack, L.A., Botsford, L.W., Carr, M.H., Davis, G.E., Dayton, P.K., Gotshall, D., Gunderson, D.R., Hixon, M.A., Lubchenco J., Mangel, M., MacCall, A., McArdle D.A., Ogden, J.C., Roughgarden, J., Starr, R.M., Tegner, M.J., and Yoklavich, M.M. 1999. No0-take reserves networks: protection for fishery populations and marine ecosystems. Fisheries 24(11):11-25.
- ↑ Halpern, B., 2003. The impact of marine reserves: do reserves work and does reserve size matter? Ecological Applications 13: S117-137.
- ↑ Wilson, J.R., Bradley, D., Phipps, M. and Gleason, M.G. 2020. Beyond protection: Fisheries co-benefits of no-take marine reserves. Marine Policy 122, 104224
- ↑ IUCN European Newsletter. Marine biodiversity. Volume 13/2007.
- ↑ World Database Marine Protected Areas
- ↑ IUCN European Newsletter. Marine biodiversity. Volume 13/2007.
- ↑ https://www.eea.europa.eu/themes/water/europes-seas-and-coasts/assessments/marine-protected-areas