There are an estimated 2,679 marine protected areas (MPAs) in coral reef areas worldwide, encompassing approximately 27 percent of the world’s coral reefs. For Reefs at Risk Revisited, MPAs in coral reef regions areas rated by regional experts according to their effectiveness level using a 3-point score:

  1. MPAs rated as “effective” were managed sufficiently well that local threats were not undermining natural ecosystem function.
  2. MPAs rated as “partially effective” were managed such that local threats were significantly lower than adjacent non-managed sites, but there may still be some detrimental effects on ecosystem function.
  3. MPAs rated as “not effective” were unmanaged, or management was insufficient to reduce local threats in any meaningful way.