Marine protected areas (MPAs) are important tools for protecting ocean ecosystems and biodiversity. They create zones where natural coastal and ocean environments are protected from human activities that can harm them, such as pollution, unsustainable fishing practices, boating, and other disturbances. Well-designed and well-managed MPAs can effectively conserve marine habitats and wildlife. Here are some examples of MPAs and evidence of their effectiveness:

The Great Barrier Reef Marine Park (GBRMP) in Australia is a great example of a large and effective MPA network. Established in 1975, it is over 344,400 km2 in size, making it the largest MPA in the world. Protection in no-take zones within the GBRMP has allowed species targeted by fishing, such as groupers and snappers, to increase in abundance and size. It has also led to increases in biodiversity, with studies finding as much as 30% more fish species in protected zones. Coral cover is also increasing within protected areas, making the GBRMP’s reefs more resilient to climate change impacts like bleaching. Increased biodiversity and abundance in no-take zones provide spillover benefits to surrounding fished areas as well.

The Florida Keys National Marine Sanctuary in the United States was designated in 1990 to protect the delicate coral reef ecosystem in the Florida Keys. Research has shown clear benefits from the protections put in place. Fish abundance inside protected zones is often five to ten times higher compared to fished areas. Larger, older fish are found inside protected areas, which enhances reproduction. The density of lobsters, a heavily fished species, has increased by over 500% inside protected zones. Coral cover has increased by 20-30% in protected areas over two decades as well. The MPA system has clearly enhanced the Florida Keys coral reefs’ ecological health and resilience.

The Apo Island Reserve in the Philippines was established in 1977 and has become a global model for community-based coast management. Research found that from 1998 to 2008, the fish biomass inside the reserve increased by 268% and average fish size grew by 29%. Reef limestone and live hard coral cover also increased significantly. Crucially, nearby fishing villages have seen beneficial economic impacts from the reserve’s spillover effects. It has improved food security and income generation for many local communities. This demonstrates how MPAs can protect biodiversity, aid resource sustainability, and support local economies all at once when communities are engaged.

Some large offshore MPAs have also proven remarkably effective. The Papahānaumokuākea Marine National Monument, established in 2006 off Hawaii’s Northwestern Hawaiian Islands, protects 582,578 square miles of remote coral reefs and seabirds. With limited human use and climate change impacts, reefs have remained pristine and biodiversity is high relative to more populated regions. Green sea turtle and monk seal populations have increased significantly within monument boundaries over the last two decades. The Chagos Marine Protected Area in the Indian Ocean is the world’s largest no-take marine reserve at 210,000 square miles. Surveys have found highly abundant marine life inside, with fish being 30% larger and over 700% more plentiful compared to fished areas. Such offshore protected zones shelter marine ecosystems and species from threats over vast expanses of ocean.

While the impacts of MPAs can vary depending on factors like the level of enforcement, the research and first-hand accounts above provide clear and compelling evidence that protected areas conserve marine environments and biodiversity when properly established and managed. From the individual reserve to networks as large as entire atolls and archipelagos, MPAs protect habitats, foster marine population increases, safeguard ecosystem services, and demonstrate balanced approaches to ocean resource management when aligned with community needs. With over 15,000 of the world’s estimated 22,000 coral reefs now threatened by climate change, pollution, and overfishing, strengthening of marine protected areas continues to be a priority strategy worldwide for ocean conservation and long-term sustainability.