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Hiroshima-shi, Japan

Suzuki G.,Seikai National Fisheries Research Institute | Arakaki S.,Seikai National Fisheries Research Institute | Arakaki S.,Kyushu University | Suzuki K.,Daikure Co. | And 2 more authors.
Fisheries Science | Year: 2012

In situ larval seeding is a low-cost technique that is currently under development for the large-scale restoration of coral populations. One problem that still needs to be solved is the preparation of coral larvae for seeding, i. e., how many larvae are required to restore a certain area? In this study, we focused on the relationship between the numbers of larvae, settlers, and survivors for three months post-settlement to determine the optimal larval seeding density. A comparison of three different larval densities (low, middle, and high) indicated that the number of settlers was proportional to the larval density, suggesting that settler density is determined by the number of larvae supplied. However, the survival rate of settlers on high-density plates was much lower than the corresponding rates on low- or middle-density plates during the first month after settlement. Moreover, most of the seeded corals had not survived on the low-density plates at three months after settlement. Therefore, the middle larval density (i. e., 5000 larvae m -2) appears to be optimal for seeding on grid plates. © 2012 The Japanese Society of Fisheries Science. Source


Suzuki G.,Seikai National Fisheries Research Institute | Yamashita H.,Seikai National Fisheries Research Institute | Kai S.,Seikai National Fisheries Research Institute | Hayashibara T.,Seikai National Fisheries Research Institute | And 5 more authors.
Marine Ecology Progress Series | Year: 2013

ABSTRACT: For corals that establish symbioses with dinoflagellate Symbiodinium spp. at the larval stage or later through horizontal transmission, the ecological significance of the early uptake of algal symbionts remains unknown. It has been hypothesized that early uptake of symbionts is an advantage for long-distance dispersal. Here, we tested the hypothesis that early acquisition of symbionts enhances post-settlement survival. We used a cultured strain of clade A Symbiodinium that was isolated from wild Acropora spat as the algal symbiont. Symbiotic and aposymbiotic Acropora larvae were prepared in the laboratory and settled on experimental plates in the field. The survival of settlers was monitored for 15 mo. Our results showed that more larval-stage settlers harbouring symbionts survived than those without, even when there was no difference in the initial density of settled larvae. We analysed the Symbiodinium clades harboured by the corals at 1 mo after settlement, and found that clade A was less abundant in the corals that grew from aposymbiotic larvae than in those that developed from symbiotic larvae. There was also a marked difference in coral survival between aposymbiotic and symbiotic larvae over this period. The higher survival rate of 'early uptake' corals was more pronounced on shaded plates. These results suggest that the early uptake of specific symbionts enhances post-settlement survival in dark places such as reef crevices, which are sites commonly settled by coral larvae.© Inter-Research 2013. www.int-res.com. Source


Suzuki G.,Seikai National Fisheries Research Institute | Kai S.,Seikai National Fisheries Research Institute | Yamashita H.,Seikai National Fisheries Research Institute | Suzuki K.,Daikure Co. | And 2 more authors.
Marine Pollution Bulletin | Year: 2011

The initial factors that cause a decline in the survival of in situ settled corals remain poorly understood. In this study, we demonstrated through field experiments that the design of artificial grid plates may influence the initial survival of Acropora corals, with narrower grids being the most effective. In fact, grid plates with a 2.5-cm mesh presented the highest recorded survival rate (14%) at 6months after settlement (representing approximately 50 corals per 0.25m 2 of plate). This is the first study where such high survival rates, matching those of cultures under aquarium conditions, were obtained in the field without using additional protective measures, such as guard nets against fish grazing after seeding. Therefore, our results provide a foundation for establishing new and effective coral restoration techniques for larval seeding, in parallel to clarifying the details of the early life stages of reef-building corals. © 2011 Elsevier Ltd. Source

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