What is Marine Protected Area?

Legal Definition
Marine protected areas (MPA) are protected areas of seas, oceans, estuaries or large lakes. MPAs restrict human activity for a conservation purpose, typically to protect natural or cultural resources. Such marine resources are protected by local, state, territorial, native, regional, national, or international authorities and differ substantially among and between nations. This variation includes different limitations on development, fishing practices, fishing seasons and catch limits, moorings and bans on removing or disrupting marine life. In some situations (such as with the Phoenix Islands Protected Area), MPAs also provide revenue for countries, potentially equal to the income that they would have if they were to grant companies permissions to fish.

On 28 October 2016 in Hobart, Australia, the Convention for the Conservation of Antarctic Marine Living Resources agreed to establish the first Antarctic and largest marine park in the world encompassing 1.55 million km2 (600,000 sq mi) in the Ross Sea. Other large MPAs are in the Indian, Pacific, and Atlantic Oceans in certain exclusive economic zones of Australia and overseas territories of France, the United Kingdom and the United States, with major (990,000 square kilometres (380,000 sq mi) or larger) new or expanded MPAs by these nations since 2012—such as Natural Park of the Coral Sea, Pacific Remote Islands Marine National Monument, Coral Sea Commonwealth Marine Reserve and South Georgia and the South Sandwich Islands Marine Protected Area. When counted with MPAs of all sizes from many other countries, as of August 2016 there are more than 13,650 MPAs, encompassing 2.07% of the world's oceans, with half of that area – encompassing 1.03% of the world's oceans – receiving complete "no-take" designation.
-- Wikipedia