Thesis (Ph. D.)--James Cook University, 2003. / Title from PDF title page (viewed on May 14, 2007). Includes bibliographical references (p. 140-149).

Thesis (Ph.D.) - James Cook University, 2002. / Typescript (photocopy) Bibliography: leaves 123-144.

Thesis (Ph.D.) - James Cook University, 2003. / Typescript (photocopy). Bibliography: leaves 140-149.

Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.

Thesis (Ph. D.)--University of Hawaii at Manoa, 1994. / Includes bibliographical references (leaves 238-258). / Microfiche. / xv, 258 leaves, bound ill., photographs 29 cm

Les espèces coralliennes Acropora palmata (Lamarck, 1816) et A. cervicornis (Lamarck, 1816) ont un rôle majeur en termes de bio-construction et structuration des récifs dans la Caraïbe. Cependant, les populations de ces deux espèces sont en déclin et elles sont maintenant classées en danger critique d’extinction par l’Union Internationale de Conservation de la Nature (UICN). De récentes études principalement menées sur les récifs de la Floride et des Grandes Antilles se sont ainsi intéressé à la structure et à la dynamique des populations de ces espèces, mais le statut génétique des populations des Petites Antilles est moins connu.Le présent sujet a pour but d’étudier l’état des populations des coraux Acropora palmata et A. cervicornis sur les récifs de Guadeloupe et des Petites Antilles et d’élucider les mécanismes qui président à la survie de ces espèces et au recrutement des jeunes coraux. / In the Caribbean, Acropora palmata (Lamarck 1816) and A. cervicornis (Lamarck 1816) are major coral species for reef building. Since the 80’s, these species populations are decreasing and are now classified as critically endangered species by the International Union for Conservation of Nature (IUCN). Recent studies, mainly conducted on the reefs of Florida and the Greater Antilles concerned the structure and the dynamics of Acropora populations, while the genetic status of the populations in the Lesser Antilles remains less studied. The purpose of the study is to determine the status of the coral populations of Acropora palmata and A. cervicornis on reefs of Guadeloupe and Lesser Antilles and to elucidate the mechanisms governing the survival of these species and the recruitment of young corals.

Since the 1980’s, there has been an unprecedented decline in the reef-building Caribbean corals, Acropora cervicornis and A. palmata, which has led to their listing as “threatened” under the U.S Endangered Species Act. Despite this protective status, these Acropora species continue to experience declines primarily attributed to disease, global climate change, and storm damage. Recent evidence suggests the hybrid of these threatened species (A. prolifera) is found at abundances similar to or higher than the parental species at many sites throughout the Caribbean. However, there is still much that is unknown as to how and why hybrids may be increasing in abundance at select sites. In 2007, scientists from NOAA NMFS established 9 permanent transects at three sites in the USVI to quantify fish diversity and coral tissue condition in A. cervicornis thickets. Over the years, they observed that A. prolifera seemed to be increasing in abundance on transects that were once dominated by A. cervicornis. This dataset provided a unique opportunity to investigate whether a shift from a threatened parental species to its hybrid may have occurred. This study has two objectives, (1) to quantify the change in A. cervicornis and A. prolifera percent cover and colony health over a 9-year period, and (2) to compare the genotypic diversity among the three Caribbean acroporids on and near the transects to determine the primary method of propagation, i.e., sexual versus asexual. For this study, I used transect photographs taken in March, July and November 2009, April 2012, and August 2017 to compare intra- and interannual variation in acroporid cover and colony health. Striking losses were observed in A. cervicornis cover between March 2009 and August 2017. At Thatch Cay, A. cervicornis declined from 25.7% to 8.9% between March 2009 and November 2009, but remained stable (10.2%) up to August 2017. Acropora cervicornis cover declined from 13.2% to 0% at Lovango Cay, and from 8.2% to 0% at No-Name Bay. At the one site (No-Name Bay) that A. prolifera was present during the original surveys of the transects, the percent cover remained relatively high and stable over the sample period. At No-Name Bay, A. prolifera percent cover (18.2%) was significantly higher than A. cervicornis (5.4%) by November 2009. It appears that A. prolifera expanded in the habitat left void by the decline in A. cervicornis. The general health of A. cervicornis based on the amount of healthy versus white and pale tissue appeared to decline at all sites between March 2009 and November 2009. To determine if the high percent cover on some transects was derived from asexual propagation or sexual recruitment, 139 tissue samples were collected in 2017 and genotyped using five microsatellite markers. No significant difference in genotypic richness (number of unique genotypes divided by the sample size) was observed among A. cervicornis (0.62), A. prolifera (0.64), and A. palmata (0.68). This suggests that the hybrid colonization is from multiple sexually derived individuals, not just asexual propagation from a rare hybridization event. High genotypic diversity, stable population abundance, and healthier colonies, suggest acroporid hybrids may become the primary habitat building coral of shallow reefs in the U.S. Virgin Islands. Due to considerable differences in morphologies between A. cervicornis and A. prolifera, it is unclear how a shift to the hybrid may affect the organisms that occupy acroporid structure and if the same ecological functions can be fulfilled.

The maximum quantum yield (Fv/Fm), zooxanthellae density, chlorophyll a concentration and protein concentration of non-bleached and bleached colonies of the reef coral Acropora intermedia were measured in inlet of The Third Nuclear Power Plant of Nanwan Bay in southern Taiwan. A significant positive correlation was found between Fv/Fm and chlorophyll a concentration per zooxanthellae of non-bleached colonies. The chlorophyll a concentration per zooxanthellae and zooxanthellae density of non-bleached colonies were lowest in summer, and were significantly negative correlated with total radiant heat and seawater temperature, respectively. This suggests that the seasonal variation exist, and they maybe regulated by seasonal fluctuation of radiation and temperature. The Fv/Fm, chlorophyll a concentration per cm-2, chlorophyll a concentration per zooxanthellae, zooxanthellae density and protein were significantly lower than those of the non-bleached colonies in the bleaching events. However, compared to the non-bleached colonies, zooxanthellae density, chlorophyll a concentration per cm-2 and protein of bleached colonies were increased and significantly higher than those of non-bleached colonies, then decreased to similar level. However, Fv/Fm increased to similar level, but chlorophyll a concentration per zooxanthellae remained lower. It suggests that number of zooxanthellae rapidly increased while remained stable chlorophyll a concentration during recovery.

Thesis (Ph.D.) - James Cook University, 2003. / Typescript (photocopy) Bibliography: leaves 181-201.

Thesis (Ph.D.) - University of Queensland, 2005. / Includes bibliography.