A study on early life ecology of abalone species and factors affecting their mortalities in southern Japan

采用野外观察和室内实验相结合的方法，对栖息于日本南部地区的鲍鱼（Haliotis discus discus）、H. madaca、H. gigantea和H. diversicolor)的生殖生物学和早期生命生态学进行了研究。分析和讨论了影响北方鲍鱼（haaliotis discus hannai）招募的因素，北方鲍鱼在早期阶段的繁殖和生态信息比南方鲍鱼多。小鲍鱼的流行产卵似乎与台风事件同步。沉降基质上的沉积物和波浪扰动对幼虫沉降和后期幼虫的初始存活有较大影响。其栖息地的饮食条件和水温会影响幼鱼的生存和生长速度。不同种类的大鲍鱼与不同种类的大鲍鱼的主要食性不同，生境也不同。10月至1月出现南方大型鲍鱼品种，如：discus discus， H. madaca， H. gigantea。然而，没有检测到任何相关的产卵线索。这些大种属的幼虫密度远低于异色夜蛾。由于产卵种群密度低，大鲍鱼的成功繁殖可能受到抑制。研究结果表明，冬季海水温度、成虫产卵密度和后期幼虫的摄食条件是影响大褐家蚕繁殖的主要因素。

The reproductive biology and early life ecology of abalone, Haliotis discus discus, H. madaca, H. gigantea and H. diversicolor, which inhabit in southern area in Japan, were investigated by field observations and laboratory experiments in this study. The factors affecting recruitment of the northern species Haliotis discus hannai, which has more information on its reproduction and ecology in the early life stages than the southern abalone species, were analyzed and discussed.Epidemic spawning of the small abalone Haliotis diversicolor appeared to be synchronously with typhoon events. The larval settlement and initial survival of post-larvae could be strongly influenced by sediment on the settlement substrata and wave disturbance. The dietary conditions and water temperature in their habitats could affect the survival and growth rates of juveniles. The radula development in H. diversicolor was different from that in H. discus hannai, suggesting the main diets and thus habitat of H. diversicolor are different from those of big abalone species.Larvae and post-larvae of big southern abalone species, H. discus discus, H. madaca, H. gigantea, appeared from October to January. However, any associated spawning cues were not detected. Densities of the post-larvae of these big species were much lower than that of H diversicolor. Successful reproduction of the big abalone species may be inhibited due to the low density of their spawning populations.As present major factors affecting recruitment of H. discus hannai, seawater temperature during winter, density of spawning adults, and dietary conditions for post-larvae were suggested.