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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Gametogenesis and Spawning of Solenastrea bournoni and Stephanocoenia intersepta and the Fecundity of Four Common Transplanted Coral Species Offshore, Southeast Florida.

Lueg, Jenna R. 01 August 2011 (has links)
Restoration efforts are being implemented in many of the world’s coral reefs due to damages from anthropogenic sources such as ship groundings and anchor damage. One restoration technique involves attempts to save dislodged and fragmented coral colonies by transplanting them back to damage sites. Research has shown that survivorship and growth of transplanted colonies is comparable to that of natural, control colonies. What remains unknown is to what extent transplantation affects the ecological success and reproduction of dislodged and fragmented coral colonies. The purpose of this study was twofold. Reproduction and spawning information is sparse for S. intersepta and Solenastrea bournoni, so the first purpose was to describe gamete development of these two species and assess correlations between environmental dynamics and spawning of each species. Tissue samples were collected throughout Broward County, Florida and processed for histological examination. Gametes were counted, and development was assessed. For S. intersepta and S. bournoni, late stage oocyte abundance was compared with environmental factors of mean daily water temperatures at depth, lunar phase, semidiurnal tides and solar insolation for correlative evidence to predict future spawning events. Findings indicated that both S. bournoni and S. intersepta are gonochoric broadcast spawners. Solenastrea bournoni spawns annually after the full moon in September when sea temperatures are at a maximum. Stephanocoenia intersepta spawns annually after the full moon of August or September, depending on the timing of the full moon. The second purpose was to determine if previously transplanted Porites astreoides, Montastraea cavernosa, Siderastrea siderea and Stephanocoenia intersepta corals produce gametes and spawn similarly to naturally occurring colonies and to address the issue of transplantation as a suitable resource management tool to aid in reef recovery for future coral generations. Results indicated no significant difference in fecundity between transplants and controls of M. cavernosa, S. siderea or S. intersepta. A significant difference was found in fecundity between P. astreoides transplants and controls, but it is thought that it is due to a difference in depth of collected samples. Overall, this study shows that transplantation of coral colonies after damage and fragmentation events does not have adverse effects on the long-term fecundity of coral colonies.
2

Coral Propagation: A Growth and Survival Comparison among Six Scleractinian Boulder Corals Employing In Situ and Ex Situ Nursery Techniques

Crossett, Daniel James 25 January 2013 (has links)
Knowledge of effective reef restoration techniques are necessary in this age of worldwide coral reef decline. Coral transplantation is a restoration technique employed after natural (i.e. hurricanes) and anthropogenic (i.e. vessel groundings) physical disturbance events. The study was conducted to compare the efficacy of propagating small colony fragments in laboratory and field conditions in terms of survival and growth. Fragment growth and survival were assessed for six scleractinian boulder corals common to Florida and Caribbean reefs: Montastraea annularis, M. cavernosa, Diploria clivosa, Siderastrea siderea, S. radians and Dichocoenia stokesii. Broken coral colonies were salvaged from vessel grounding sites and marine debris, fragmented into pucks and secured to travertine tiles. One hundred and fifty-three coral colony fragments were cultivated in an ex situ laboratory nursery and 133 coral colony fragments were cultivated in an in situ field nursery and monitored for 13 months. Survival of all colonies was 94%, with 98% survival in the laboratory treatment and 89% survival in the field treatment. Complete colony mortality was documented in three S. radians colonies, all in the laboratory treatment. All colony loss in the field treatment was due to colony pucks being detached from the tiles. Overall mean percent change in colony tissue area from initial to final monitoring events was calculated to determine growth. Across species, growth was greater in the laboratory treatment (76 ± 4 % SEM) in comparison to the field treatment (27 ± 5 % SEM). Positive growth was observed in D. clivosa, D. stokesii, M. annularis, M. cavernosa and S. siderea in the laboratory treatment. In the field treatment, D. clivosa, M. annularis and M. cavernosa were the only species that exhibited positive growth. Negative growth was observed in both the laboratory and field treatments for S. radians. In conclusion, colonies propagated in the ex situ nursery (laboratory treatment) had higher growth and survival than colonies propagated in the in situ nursery (field treatment). A critical acclimation period accomplished through the use of stable laboratory conditions will produce healthier, more secure coral colonies that may be used to repopulate disturbed reef sites.

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