We investigated intraspecific variation of the dominant C a~i b b e a n 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 C u r a~a o and Bonaire (Netherlands Antilles). The g e n e t~c 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'

A long-term study of the common coral reef spatial competitor Trididemnum solidum (van Name), a benthic colonial asc~dian, showed a 900% increase in densities along the 84 km of fringing reef in Curaqao over 15 yr The pattern of distribution along the coast d~d not change significantly and showed long-term effects of philopatry. This pattern relates to limited dispersal potential and the impact of the clonal ecological strategy of this modular organism. All hard reef substrata were overgrown but between 1978 and 1993 there was a significant increase in the number of ascidian colonies overgrowing dominant scleractinian corals such as Mon tastrea annularis.

We studied the relation between surface lesion regeneration and reproduction in distinct morphotypes of the coral Montastrea annularis (Ellis & Solander). There were significant differences between the rnorphotypes (viz. 'Bumpy', 'Massive' and 'Columnar'; Van Veghel & Bak 1993, Mar. Ecol. Prog. Ser. 92: 255-265). The number of eggs per gonad in polyps adjacent to the lesions was reduced in the Massive and Bumpy morphs but not in the Columnar morph. Fecundity (eggs per polyp) and the number of gonads per polyp were reduced in these areas in all morphs. We found a significantly higher regeneration rate for the Bumpy compared with the other 2 morphotypes. Regeneration rates were similar in the Columnar and Massive morphotypes. Regeneration rates in this study were relatively low, suggesting that regeneration is slower during the reproductive season.

ABSTRACT. We studied reproductive characteristics of 3 Montastrea annularis (EUis & Solander) morphotypes (viz. 'Bumpy', 'Massive' and 'Columnar'; Van Veghel & Bak 1993, Mar. Ecol. Prog. Ser. 92: 255-265) by dissecting about 2450 polyps in the reproductive seasons of 1991 and 1992. Fecundity. number of gonads per polyp, and ferthty were found to be significantly different between the studied morphotypes (ANOVA, p < 0.001), ranking from h g h to low in Bumpy, Massive, and Columnar morphotypes. Gonads as percent of total biomass also varied, but were not sigruficantly different for Bumpy (29.7 %) versus Massive (22.0%) and Columnar (20.9 %) morphotypes. Columnar colonies with interconnected living tissue larger than 50 cm2 were already fully reproductive whereas in other morphotypes fecundity was significantly (ANOVA, p < 0.001) reduced in colonies smaller than 300 cm2. Significant differences (ANOVA, p < 0.05) in fecundity occurred between 2 consecutive years for the Massive morph. On a geographic scale, fecundity of M. annularis populations on Curaqao was 5 to 14 times lower than in Puerto Rico. Coral species with comparable reproductive strategy all had higher fecundities than M, annularis in this study. Fecundity and reproductive traits in M. annularis appear to correlate with colony morphology.