Fragmentation and genotypic diversity of the scleractinian coral Montipora capitata in Kaneohe Bay, Hawaii

The fragmentation and genotypic diversity of Montipora capitata was determined in Kaneohe Bay, Hawaii, using field investigations and allozyme electrophoresis. Two stations were established in the Bay, one in the centre (exposed reef edge, EXPO) and the other at the south end (sheltered lagoonal reef SHEL). Although the number and mean per cent cover of attached colonies did not differ significantly between the two habitats, number and cover of unattached colonies (fragments) were significantly higher at the sheltered habitat. Thirty-seven genotypes were detected in 176 samples using two or three enzyme loci. Although mean genet number did not differ significantly between the two habitats (mean ± SE, 8.2 ± 1.2 and 12.2 ± 1.7 in exposed and sheltered reefs, respectively), lower genetic diversity was detected at SHEL (mean N G :N ± SE, 0.75 ± 0.08 and 0.50 ± 0.06 for EXPO and SHEL, respectively). There was no evidence of strong clonal structure, i.e. many colonies, but few genets. Sexually produced new genets may account for the high genotypic diversity in M. capitata at these two habitats.