Passive Restoration & MPAs

When disturbances to coral reefs are identified, the first step in management is to reduce or eliminate the threat. With many disturbances such as erosion or over-fishing, after the threat has been removed, then the reef can be left to recover on its own.

This has been one of the leading theories in coral reef management between the 1970s to the early 2000s, and the vast majority of funding allocated to coral reef management has gone into implementing Marine Protected Areas (MPAs).

Marine Protected Areas

MPAs are areas for which special rules and regulations have been established that limit or close the use of the area to various destructive industries such as fishing, mining, tourism, or development.


For an MPA to be effective, many factors need to be considered, and often years of research and planning alongside both managers and community members are required.

One of the most challenging tasks for community-based managers is to get support from all the stakeholders involved and implement measures that protect marine resources but still allow for food production and other economic interests. If a consensus on MPA creation can be reached and marine regulations and zoning created, then the next obstacle to success is enforcement, which sometimes can cost millions of dollars annually.

Requirements for success in MPAs

If implemented and enforced correctly, an MPA can reduce reef decline and, in limited cases, even increase reef health, abundance, or diversity. But, this process is highly complex, and to be effective, there are some fundamental factors or requirements which must be met:

  1. The measures implemented must stop the threats being experienced. For example, closing off a reef to economic use that is being depleted due to declining water quality from activities on land will not lead to a successful outcome. 
  2. Most stakeholders must agree to the measures and comply with closure or limited-use zones. For example, if fishing is still occurring in or around a closed site, then the balance of the reef will not be restored by the measures.
  3. There must be adequate physical structure remaining and enough reproductively viable animals in the local region to repopulate the marginalized area. For example, if a reef has been reduced to rubble by blast fishing or is recruitment limited (coral larvae settlement is lower than mortality of mature colonies), then closing the area will not lead to regrowth or return of historically present coral species.

Focusing on the three fundamental factors above, it is clear how difficult creating effective MPAs can be. For example, in 2020, it was found that 86% of the MPAs in Europe/Uk still allow destructive fishing practices.

Indeed, despite the hundreds of millions of dollars invested over the last few decades into MPA’s around the world, very few reefs are protected, and most of those protected are ineffective at increasing coral coverage. A 2006 study by Mora et al., estimated that globally only about 18.7% of reefs are protected by MPAs, and only about 0.01% of the world’s reefs are in MPAs found to have ‘low-risk’. Even more alarming, several studies conducted between 2008-2010 found that coral coverage declined more rapidly in protected areas than adjacent non-protected areas.

For more context about why MPAs fail, check out the video below (about 12 minutes).

Although MPAs are a vital first step in reef management, it is today more evident that they are not a solution on their own. Other activities and programs must be implemented alongside zoning, limited use, or no-take regulations to manage reefs for long-term sustainability and survival effectively.

More and more, it is becoming apparent that protection on its own will not prevent reef decline, and many reefs are so depleted or isolated that recovery cannot occur without intervention in the form of active coral restoration.