One management technique is to create Marine Protected Areas (MPAs) that directly limit human activities such as fishing.
[9] Environmental conditions such as a rise in water temperature inflict stress on the corals causing their symbiont Zooxanthellae to be expelled.
[11] Also known as the "rainforests of the sea," coral reefs cover less than 10% of the ocean yet provide a habitat to over 9 million species, approximately one fourth of all marine life, for food, shelter, and even hunting grounds for predators.
[12][13] Species found on coral reefs include fish, invertebrates, birds, and megafauna such as sharks, sea turtles, and marine mammals.
[14] Coral reefs provide complex structures that buffer the ocean's waves, protecting coastlines from strong currents and nasty storms.
Not only are they critical in preventing the loss of lives, property damage, and erosion, but they also serve as a barrier for harbors and ports that depend on them economically.
[15] Species found in coral ecosystems produce chemical compounds that are used to develop new medicines to treat cancer, arthritis, asthma, heart disease, ulcers, bacterial infections, and viruses.
Antiviral extracts and tonics continue to be studied and toxic compounds such as neurotoxins discovered in coral reefs have proven beneficial as painkillers.
Local economies rely heavily on coral reefs, receiving about $9.6 billion through diving tours, recreational fishing trips, hotels, and restaurants.
Long-term, coral reefs have been recognized as large contributors to the absorption of carbon dioxide emissions which has been an important part of the mitigation of climate change.
[21][22] Localized examples include residential, developmental, agricultural and industrial runoff, sedimentation from land clearing, human sewage and toxic discharges.
Groundings in sand, or even the churning action of propellers, can cause major localized siltation, indirectly killing adjacent corals.
[26] During the 20th century recreational scuba diving was considered to have generally low environmental impact, and was consequently one of the activities permitted in most marine protected areas.
The increase in the popularity of diving and in tourist access to sensitive ecological systems has led to the recognition that the activity can have significant environmental consequences.
The same pleasant sea conditions that allow development of relatively delicate and highly diverse ecologies also attract the greatest number of tourists, including divers who dive infrequently, exclusively on vacation and never fully develop the skills to dive in an environmentally friendly way.
[32] Oftentimes, illegal industrial fishing ships will cast wide nets in the water, capturing large amount of sea life.
Zinc oxide is widely used inorganic UV filters and are mainly incorporated into sunscreen because the larger, size particles usually leave unpleasant white marks on the skin.
Some of the mineral UV filters do get additional coatings such as alumina or incorporated manganese to minimize the formation of free radicals.
Exposure to all tested sunscreen and led to the conclusion that UV filters induce a lytic viral cycle that leads to coral bleaching.
[34] To more accurately document the status of the reef, recently, photogrammetric techniques have been introduced to generate orthophotos of the interested areas either by using consumer drones[35] or by capturing photos with scuba divers.
[42][43] Sediment flux can be reduced in steep watersheds on montane tropical islands in the Hawaiian archipelago by restoring vegetation and controlling invasive species.
[45] In this process, coral gametes are harvested from spawning grounds and grown in a laboratory environment, then replanted when they grow larger.
[49] Many species that are introduced into non-native areas either die out because they are not able to adapt to their new environment fast enough or they do survive but don't alter the ecosystems enough to cause any damage.
[55][56] Due to the large cost and limited success in preventing COTS outbreaks and coral loss, scientists doubt the effectivity of this method.
[55][58] Marine zoning has in previous studies been highly successful in minimizing outbreaks of COTS when it is paired with manual control.
[59][57] Excess nutrients run-off from agricultural land uses (grazing, grain, sugar cane, and horticulture) create phytoplankton blooms in reef waters that can be carried to COTS populations.
MPAs encompass both social and biological objectives, including reef restoration, aesthetics, biodiversity and economic activity.
[60] In some situations, as in Kiribati's Phoenix Islands Protected Area, MPAs provide revenue that is potentially equal to the income they would have generated without controls.
[citation needed] The Parcel de Manuel Luís Marine State Park protects the largest coral reef in the South Atlantic.
[citation needed] Inhabitants of Ahus Island, Manus Province, Papua New Guinea, have followed a generations-old practice of restricting fishing in six areas of their reef lagoon.