Voranop Viyakarn

Optimal dietary levels of lecithin and cholesterol for black tiger prawn Penaeus monodon larvae and postlarvae

Abstract The effect of lecithin and cholesterol on growth and survival of larval and postlarval Penaeus monodon was evaluated using semi-purified diets containing four levels of lecithin (0.0, 0.5, 1.0 and 1.5%) and three levels of cholesterol (0.0, 0.5 and 1.0%). Three early stages (zoeal, mysid and postlarval) of P. monodon were fed the experimental diets. Growth and survival of shrimp fed diets containing 1.0 and 1.5% lecithin were not significantly different ( P >0.05) but these groups had significantly greater growth and survival than those fed 0.0 and 0.5% lecithin diets. Shrimp fed diets containing 1.0% cholesterol had significantly greater ( P P. monodon . During a low salinity stress test, PL-15 shrimp fed diets containing 1.0% cholesterol had significantly greater ( P

Patterns of coral damage associated with the 2004 Indian Ocean tsunami at Mu Ko Similan Marine National Park, Thailand

On 26 December 2004, a severe earthquake in Sumatra caused a series of tsunami waves to strike southwestern coastal areas of Thailand. In this study, we investigated the patterns of tsunami‐related damage to coral reefs at Mu Ko Similan Marine National Park. The results showed that the percent of damaged corals ranged from 7.2% to 39.7% of the total live coral cover, and the intensity of the coral damage was high at depths deeper than 10 metres at most study sites. In addition, massive and tabulate coral forms were the most susceptible to tsunami damage. The surveys also revealed that a high degree of coral damage occurred where the reef slope gradually dropped away from the shoreline. Therefore, coral communities and coastal profiles can be major factors influencing the movement of the currents generated by the tsunami and consequently may affect the pattern of coral damage by the tsunami.

Development of Cryopreservation Techniques for Gorgonian (Junceella juncea) Oocytes through Vitrification.

Gorgonian corals are slowly declining due to human interaction and environmental impacts. Cryopreservation of gorgonian corals is an ex-situ method of conservation, ensuring future reproduction. The present study assessed the vitrification properties of cryoprotectant (CPT) mixtures using the cryotop, cryoloop and open pulled straw (OPS) cryopereservation methods prior to experimentation on gorgonian (Junceella juncea) oocytes. Investigations of the equilibration and vitrification solutions’ (ES and VS) effect on oocytes throughout different incubation periods were conducted. The cryotop method was found to be the most successful in ensuring vitrification. The most favourable VS was composed of propylene glycol (PG), ethylene glycol (EG) and methanol with concentrations of 3.5M, 1.5M and 2M respectively. Experiments were performed using the cryotop method to cryopreserve Junceella juncea oocytes using VS2, the solution had the least impact on oocytes at 5°C rather than at 26°C. The success of the vitrification procedures was determined by adenosine triphosphate (ATP) levels in cooled-thaw oocytes and the highest viability obtained from the present study was 76.6 ± 6.2%. This study provides information regarding gorgonian corals’ tolerance and viability throughout vitrification to further advance the vitrification protocol on whip corals.

Membrane Lipid Phase Transition Behavior of Oocytes from Three Gorgonian Corals in Relation to Chilling Injury

The lipid phase transition (LPT) from the fluid liquid crystalline phase to the more rigid gel structure phase that occurs upon exposure to low temperatures can affect physical structure and function of cellular membranes. This study set out to investigate the membrane phase behavior of oocytes of three gorgonian corals; Junceela fragilis, J. juncea and Ellisella robusta,at different developmental stages after exposure to reduced temperatures. Oocytes were chilled to 5°C for 48, 96 or 144 h, and the LPT temperature (LPTT) was determined with Fourier Transform Infrared (FTIR) spectroscopy. The J. fragilis oocytes had a higher LPTT (∼23.0–23.7°C) than those of J. juncea and E. robusta oocytes (approximately 18.3–20.3°C). Upon chilling for 96 h at 5°C, the LPTTs of J. juncea and E. robusta oocytes in the early (18.0±1.0 and 18.3±0.6°C, respectively) and late (17.3±0.6 and 17.7±1.2°C, respectively) stages were significantly lower than those of J. fragilis oocytes (20.3±2.1 and 19.3±1.5°C for the early and late stages, respectively). The LPTTs of early stage gorgonian oocytes was significantly lower than those of late stage oocytes. These results suggest that the LPT of three gorgonian oocytes at different developmental stages may have been influenced by the phospholipid composition of their plasma membranes, which could have implications for their low temperature resistance.

Amphipods Associated with Codium Species in Korea

A comparison was made of amphipod assemblages on different species of the green alga, Codium both from a protected marine area and from a disturbed area. In addition, a laboratory experiment was conducted to determine habitat selection by amphipods. A total of five species of amphipods was found on Codium species. Amphipods were more abundant in the protected marine area; however, high numbers of amphipod species occurred on Codium fragile where that was a fouling organism in the disturbed area. The results from the experiment showed that amphipods preferred C. fragile as their habitat over any of the other species of Codium. The formation of canopies, the morphology of the plant species, and amphipod morphology, are all likely to influence the distribution and habitat selection by amphipods. Se compararon los ensambles de anfipodos en diferentes especies de Codium, en un area marina protegida y en otra alterada. Adicionalmente, se llevo a cabo un experimento de laboratorio para determinar la seleccion del habitat efectuada por los anfipodos. Un total de cinco especies de anfipodos se encontraron en las especie Codium. Los anfipodos fueron mas abundantes en el area protegida; sin embargo, un numero alto de especies de anfipodos ocurrieron en un Codium fragile contaminado en el area alterada. Los resultados del experimento mostraron que los anfipodos prefirieron el C. fragile como su habitat mas que cualquier otra especie de Codium. La formacion de colonias de especies, la morfologia de la planta y la morfologia de los anfipodos son, probablemente, los factores que influyen en los anfipodos para la seleccion de su habitat.

A tunicate from a Thai coral reef: a potential source of new anticancer compounds

Tunicates have attracted attention as potential sources of anti-cancer compounds (Wright et al. 1990; Scotto 2002). In Thailand, a colonial tunicate has been found on coral reefs by Suwanborirux et al. (2002). Subsequent identification by Teruaki Nishikawa showed this to be Ecteinascidia thurstoni Herdman, 1891 (Fig. 1). A group of alkaloids, the Ecteinascidins (Et), including Et 770 and Et 786, have been isolated with very high yields from E. thurstoni pretreated with potassium cyanide. These extracts exhibited potent cytotoxic activity against cancer cells of breast, lung, colorectal, and nasopharyngeal tissues (Suwanborirux et al. 2002). This tunicate is now only found in one reef area at 1–3 m depth in Phuket Province, southern Thailand, on the Andaman Sea coast. The zooid ranges between 0.8 and 1.2 cm in height. The highest density and abundance of this tunicate is in March, July, and November each year. Analysis of stomach contents of the tunicate revealed the presence of the diatoms Navicula, Nitzschia and Thalassiosira, and dinofla-

New coral community on a breakwater in Thailand

In 1995, an 800 m long breakwater, composed of granite rocks (sizes between 1 and 8 m), was constructed to create a new military harbor at the Royal Thai Navy, Sattahip, Chonburi Province, Thailand (Fig. 1). Prior to construction, most corals were transplanted from the area to other islands, which were located ~1.2 km southwest of the breakwater. In 2002–2007, surveys of coral diversity were conducted at the breakwater and islands around the harbor areas. Line transects surveys showed that coral cover ranged between 40% and 70% (Fig. 2). Surprisingly, diversity of corals on the breakwater was as high as those at the surrounding islands. A total of 67 species of scleractinian corals and 9 genera of gorgonians were found. Acropora was the most dominant genus. In contrast, fish surveys revealed that only 17 species were found in the breakwater area, compared to more than 32 fish species occurring at natural reefs in islands nearby. High coral diversity has also been found on breakwaters in other countries (Omori and Fujiwara 2004; Wen et al. 2007). To determine the possible causes of high coral diversity at this breakwater, sources of coral larvae and direction of currents were investigated. The results from a simulation model (two-dimensional hydrodynamic model) of trajectory drogue indicated that during periods of coral spawning, the current flowed out of Ko Khram (located 1.2 km northwest of the breakwater) to the breakwater. The current patterns and the larval drift pattern suggest that coral larvae dispersed from Ko Khram to the breakwater and that colonization of these coral larvae formed the new coral community in the area. Spawning of Acropora spp. was first observed in February 2004 at the breakwater. Subsequently, spawning of corals at the breakwater has occurred each year from January to March.

Feeding behaviors of three tropical scleractinian corals in captivity

This study examined the capture rates and prey digestion of three corals species in two genera (Acropora and Pocillopora) found dominantly in Thailand and the Federated States of Micronesia using Artemia salina nauplii as a food source. In addition, feeding during day and night times of corals was investigated. Results showed that all three coral species, namely, Acropora millepora, Acropora nobilis, and Pocillopora damicornis captured and consumed A. salina nauplii under both light and dark conditions. The capture rates of the three species ranged between 0.44 and 2.39 individuals/polyp/12 h. The results also showed complete digestions of A. salina nauplii by A. millepora and A. nobilis after 2 h, whereas P. damicornis took 2.5 h to complete the prey digestion. Even though feeding corals with Artemia is not a novel implication since this is widely used, the results of optimum daily feeding frequency of corals by Artemia may be applied for optimum corals growth and survival in captivity or aquarium.

Ultrastructural observation of oocytes in six types of stony corals

In this study, the ultrastructure of the oocytes of 6 types of scleractinian corals was observed by transmission electron microscopy (TEM). Moreover, histological and ultrastructural analyses were performed to improve our understanding of the organelles involved in coral oocyte formation. In all 6 stony coral species, the microvilli were tubular and directly grew from the surface of the oocyte membrane; yolk bodies, lipid granules, and cortical alveoli accounted for most of the volume inside the oocytes, suggesting that they are associated with energy storage and buoyancy. Clear differences were observed in the size of yolk bodies and lipid granules in the oocytes of the 6 stony coral species, which occupied approximately 55%-80% of the inner space of the oocytes. Galaxea fascicularis exhibited the largest lipid granule volume, but the oocytes contained only an average number of 12.45 lipid granules per unit area. Only Montipora incrassata oocytes contained symbiotic algae. The smallest size and proportion of lipid granules in M. incrassata oocytes may be attributed to the presence of symbiotic algae and large yolk bodies, which may help oocytes produce energy and function as a nutritional source. This study is crucial for improving the understanding of the basic biology of coral reproduction, and the ensuing datasets is critical for conservation-oriented studies seeking to cryopreserve corals during these times of dramatic global climate change.

Effects of Temperature and Salinity on Survival Rate of Cultured Corals and Photosynthetic Efficiency of Zooxanthellae in Coral Tissues

This study investigated the effects of temperature and salinity on growth, survival, and photosynthetic efficiency of three coral species, namely, Pocillopora damicornis, Acropora millepora and Platygyra sinensis of different ages (6 and 18 months old). The experimental corals were cultivated via sexual propagation. Colonies were exposed to 5 different temperatures (18, 23, 28, 33, and 38°C) and 5 different salinities (22, 27, 32, 37, and 42 psu). Results showed that temperature significantly affected photosynthetic efficiency (Fv/Fm) (p < 0.05) compared to salinity. The maximum quantum yield of corals decreased ranging from 5% to 100% when these corals were exposed to different temperatures and salinities. Temperature also significantly affected coral growth and survival. However, corals exposed to changes in salinity showed higher survivorship than those exposed to changes in temperature. Results in this study also showed that corals of different ages and of different species did not display the same physiological responses to changes in environmental conditions. Thus, the ability of corals to tolerate salinity and temperature stresses depends on several factors.