Effect of Toxopneustes pileolus on the Acropora tumida community in Suruga Bay, Japan
Atobe, T.; Ueno, S. (1999). Effect of Toxopneustes pileolus on the Acropora tumida community in Suruga Bay, Japan. Bull. Inst. Oceanic Res. & Develop., Tokai Univ. 20: 139-145
In: Bulletin of Institute of Oceanic Research and Development. Tokai University. Tokai University. Institute of Oceanic Research and Development: Shimizu. ISSN 0289-680X, more
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| Abstract |
At the ,Acropora tumida community in the Uchiura Coast of Suruga Bay, it is no confirm of recolonization by juvenile settlement of A. tumida. So the reproduction by fragmentation of A. tumida is more important for the sustenance of the community. But the geological characteristics of the sea bottom around the community is sandy frat, the base of reproduction by fragmentation is only dead coral around the community. On this dead coral, Toxopneuste pileolus keep the independent community (ATOBE.UENO, 1998). It has been suggested that these are some interaction between T. pileolus and the community.However, the influence of the heaping and grazing of T. pileolus on the fragmentation of A. tumida, in particular, still remains unclear.Many A. tumida died by the water temperature below 14° from Jan. 1996 to Apr. 1996. The result was that the dead coral area around the community spread. And it was confirmed that the shifting of T. pileolus from the area around the community to the spread dead coral area. The population density (individuals/m², mean ± SD) of T. pileolusin in the expanded area of dead coral increased monthly from Feb. to Dec., reaching 0.66 ± 0.11 by Dec. 1997. The relativity of diameter of T. pileolus to length and number of heaping dead coral showed low values (r = 0.026,0.261). The dead coral and living coral possibly heaped by T. pileolus at the dead coral area were 409.5 and 14.9 pieces/m², respectively (n=17). At the tank test, T. pileolus kept 65% of a heaped dead coral for 3~24 hours (n=51), all individuals irrelevantly heaped the dead coral piece during the day and night (MANN-WHITNEY Utest, p=0.05). It was no confirmed of all individuals that grazed on living coral (n=12). Heaping rate of T. pileolus at the dead coral area in the edge of the A. tumida community was 99% (n=117). For these result, it was suggested that the effect of the heaping of T. pileolus on the fragmentation of A. tumida. |
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