Regeneration after experimental breakage in the solitary reef coral Fungia granulosa Klunzinger, 1879

As a result of experimental breakage, polyps of the solitary reef coral Fungia granulosa Klunzinger, 1879 formed fragments that fractured either radially along the septa, or perpendicular to the septal edges. Recovery was strongly dependent on fracture orientation, fragment size, and percent breakage. Corals with 51-90% breakage either regenerated very slowly or lost mass and died during the 8 months of the study. In those with 10-50% breakage, both tissue and skeletal regeneration increased with the proportion of the fracture perpendicular to the septa. It appears that only the septal edges at the outer polyp margin and the inner mouth area are able to add skeletal mass, while the sides of the septa are unable to initiate regrowth. Small corals (<50g) with 10-40% breakage recovered much more rapidly than did larger (>50g) individuals (calculated time to regain initial size = 4-10 months for small corals). These rates were at least twice as slow as those known for a colonial coral in the same reef area. Regeneration of the fragments also depended upon the presence of a mouth. Skeletal regrowth began as a fan of septa that radiated from the mouth area and spread along the septal sides. It is concluded that, when broken by disturbance, small individuals can rapidly recover from 10-40% skeletal loss. The ability to regenerate is exhibited by many members of the family Fungiidae, and has developed into autotomy and asexual maintenance of populations in some species.