MEPS 146:91-99 (1997)  -  doi:10.3354/meps146091

Predicting regeneration of physical damage on a reef-building coral by regeneration capacity and lesion shape

Meesters EH, Pauchli W, Bak RPM

We present a relationship that predicts regeneration of physical damage on reef-building corals as a function of regeneration capacity and lesion shape. The great abundance of lesions on colonies in the field and the characteristics of the regeneration process indicate that the ability of corals to regenerate damage is limited. Regeneration, the extension of new coral tissue over a damaged area, slows down exponentially. We hypothesized that regeneration is a function of (1) a species specific regeneration capacity and (2) the amount of tissue that directly borders a lesion. A corollary is that there should be a maximum amount of tissue that can be recovered for a certain amount of border. Consequently, there is a maximum lesion size that can be completely regenerated by the surrounding tissue depending on the shape of the lesion. We studied the regeneration process in field experiments and made circular lesions of 4 different size classes (83, 183, 243 and 406 mm2) on colonies of the main reef-building coral of the Caribbean, Montastreaannularis. Lesion size decreased rapidly at the onset of the regeneration process but the rate of regeneration slowed to zero and the curve representing lesion size with time approached an asymptote. This asymptote represents the size of the area which is not recovered by the regenerating tissue at the end of the regeneration process. The value of this asymptote increased with increasing lesion area, indicating limited regeneration capacity. Larger lesions regenerated more tissue than smaller lesions, but this difference was absent when the regenerated surface area was standardized to initial lesion perimeter. This indicates that the lesion perimeter is the primary factor determining the amount of area that will be regenerated. M.annularis could regenerate a maximum of 4.7 mm2 of new tissue per mm of lesion perimeter length. Circular lesions larger than 130 mm2 will not be regenerated. The dependence of regeneration on lesion perimeter results in lesion shape being of major importance for the degree of regeneration of physical damage (e.g. long narrow lesions may be closed, while circular lesions of much smaller size may never be closed). A relationship is presented that predicts percentage regeneration on the basis of lesion shape, with shape being defined as the ratio of initial lesion surface area to initial perimeter length. This function predicts regeneration of physical damage in M. annularis for any size and shape of lesion.

Regeneration · Lesions · Shape · Size · Damage · Corals · Restoration · Patch

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