Distribution and Sexual Reproduction of a Seagrass-bed-inhabiting Actiniarian, Phymanthus strandesi (Cnidaria: Anthozoa: Actiniaria: Phymanthidae), at Hsiao-Liuchiu Island, Taiwan

小琉球產柱形瘤海葵之分布與有性生殖

林明墩(Ming-Doun Lin) ； 陳昭倫(Allen Chao-Lun Chen) ； 方力行(Lee-Sing Fang)

《Zoological Studies》 40卷3期 (2001/07) Pp. 254-261

摘要

從1997年7月到1998年6月在小琉球蛤板海草床區研究柱形瘤海葵的分布與生殖。柱形瘤海葵分布在珊瑚礁岩盤的潮間帶，平均密度為每平方公尺511隻。柱形瘤海葵分布呈現聚集性且與泰來草與蝦草的出現成正相關。柱形瘤海葵為小型雌雄異體的海葵，平均足盤直徑為0.32公分。大部分的柱形瘤海葵為無法辨識性別的個體，其足盤直徑與雄性個體的足盤直徑顯著地小於雌性個體的足盤直徑。雌性個體的平均孕卵數為294個卵，而所釋放成熟卵的卵徑為500到560微米。組織切片檢查柱形瘤海葵每月配子之發育並無明顯的週期性，顯示柱形瘤海葵可能屬於全年生殖的海葵。雖然柱形瘤海葵的個體小且孕卵數低，可是聚集性的分布增加個體的密度，且全年性的配子發育，可以確保柱形瘤海葵有性生殖的成功。

關鍵字

海葵 ； 有性生殖 ； 分布 ； 生殖週期 ； 海草床

並列摘要

Distribution and sexual reproduction of the seagrass-inhabiting actiniarian, Phymanthus strandesi, was investigated at Gerban, Hsiao-Liuchiu, Taiwan from July 1997 to June 1998. P. strandesi was distributed in the shallow intertidal zone of the reef flats with a mean density of 511 individuals/m^2. The distribution pattern of P. strandesi was contagious, and was significantly correlated with the presence of the seagrasses, Thalassia hemprichii and Halodule uninervis. P. strandesi is a small dioecious actiniarian with a mean pedal disc diameter of 0.32 cm. A high proportion of the anemones were sexually indeterminate, whose sizes were significantly smaller than those of both males and females. The mean fecundity of females was 294 eggs/individual. The released eggs were 500 to 560 μm in diameter. Gametogenesis examined by paraffin section showed no distinct developmental pattern among monthly samples, suggesting that P. strandesi might reproduce continuously throughout the year. Although with a small body size and low fecundity, the large eggs, continual gametogenesis, and contagious aggregation in the seagrass bed might ensure the successful sexual reproduction of P. strandesi.

並列關鍵字

Actiniarian ； Sexual reproduction ； Distribution ； Gametogensis ； Seagrass bed