INTRASPECIFIC VARIATION OF A DOMINANT CARIBBEAN REEF BUILDING CORAL, MONTASTREA-ANNULARIS - GENETIC, BEHAVIORAL AND MORPHOMETRIC ASPECTS

We investigated intraspecific variation of the dominant Caribbean reef building coral Montastrea annularis (Ellis & Solander) in terms of genetic variation (protein electrophoresis), intraspecific interaction and micro/macro morphometry. Our study included 3 sympatric morphotypes, 'Bumpy', 'Massive' and 'Columnar', distinguishable within M annularis populations on the leeward coasts of Curacao and Bonaire (Netherlands Antilles). The genetic study demonstrated 8 polymorphic and 1 monomorphic loci. The mean number of alleles over all loci was 4.7, and the average heterozygosity (H) over all loci examined was high (0.36). One out of 9 taxonomic units showed a significant heterozygote deficiency; the others matched expectation. The M annularis morphotypes showed a significant variation in allele frequencies but no fixed differences were found. The 'Columnar' and 'Bumpy' morphotypes were more similar with a genetic distance of 0.07. The 'Massive' morphotype demonstrated larger genetic distances: 0.13 with 'Columnar' and 0.16 with 'Bumpy'. The 'Bumpy' morphotype was dominant over the other 2 morphotypes in the intraspecific interaction experiments, and 'Massive' was dominant over 'Columnar'. The percentage of interactions was lower in intra-morphic experiments. Of the 22 micro-morphometric parameters examined, 14 showed significant differences between the 3 morphs. In addition the mean number of polyps per cm2 was very different: values ranged from 28.55 for 'Bumpy' to 40.97 for 'Columnar'.