Comparative study on origin and formation of lunar-synchronized spawning in reef fish

为了阐明珊瑚鱼月同步产卵活动的起源和形成，研究了印度尼西亚中爪哇热带珊瑚礁鱼类的年生殖周期和产卵节律。大多数研究都是使用兔鱼进行的，因为在日本冲绳的亚热带珊瑚礁也进行了类似的研究。在每月从珊瑚礁采集或从渔民处购买的鱼类中，大多数鱼类都有明确的生殖季节，发生在由干到湿或由湿到干的季节转换前后。在繁殖季节，根据农历周期每周采集一次鱼，以了解产卵节律。因此，在繁殖季节，兔鱼物种重复了与月球有关的产卵。例如，金色的兔子鱼，Siganus guttatus，在上弦月左右发育性腺并产卵。对印度尼西亚中爪哇和日本冲绳与月球有关的产卵活动进行比较，发现金兔鱼在相同的月相（上弦月）左右产卵。本研究表明，鱼每年的繁殖季节，这是密切相关的区域环境和相同的线索，从月球被用作同步产卵在任何地区的Zeitgeber。

In order to clarify origin and formation of lunar-synchronized spawning activities in reef fish, annual reproductive cycle and spawning rhythm of fish inhabiting tropical coral reefs in Central Java, Indonesia were examined. Most studies were carried out using rabbitfish, because similar studies have been conducted in sub-tropical coral reefs in Okinawa, Japan. When the fish were monthly collected from coral reef or purchased from fishermen, most fish had definite reproductive seasons, which occurred around changing season from dry to wet or from wet to dry. During the reproductive season, the fish were collected weekly according to lunar periodicity in order to know spawning rhythm. As a result, rabbitfish species repeated a lunar-related spawnings during the reproductive season. For example, the golden rabbitfish, Siganus guttatus, developed the gonads toward and spawned around the first quarter moon. Comparison of lunar-related spawning activity between Central Java, Indonesia and Okinawa, Japan, revealed that the golden rabbitfish spawned around the same lunar phase (the first quarter moon). The present study suggest that the fish have annual reproductive season which is closely related to regional environments and that the same cues from the moon are used as Zeitgeber for synchronized spawning in any regions.