To maintain the balance between immigration and extinction rates we need to ensure a steady source of recruits (eggs, larvae, and juveniles) to replenish stressed areas.

• Large reefs may be self-replenishing, because their size allows portions of reefs damaged by bleaching, slumping (collapse of the reef slope), storm surges, freshwater flooding, crown-of-thorns starfish, or other stresses, to be replenished by recruits from undamaged parts of the same reef. Such large reefs are mosaics of patches in different stages of community recovery and development.
  
  
• Therefore, as a general guideline, fewer large coral reef MPAs are preferable to a greater number of smaller ones.
  
  
• However, if these are embedded in a larger management area, there may be distinct advantages in having a number of small, strictly protected areas established to protect pockets of high resistance and resilience to bleaching (and other valuable assets, such as fish spawning aggregation sites).