Reproduction and Early Life Ecology of Abalone Haliotis diversicolor in Sagami Bay, Japan
Studies on the reproduction and early life ecology of an abalone, Haliotis diversicolor, are reviewed, especially focusing on the results of our recent field and laboratory studies in Sagami Bay, Japan. Our four-year monitoring of the occurrence of newly settled post-larvae and changes in adult gonads clearly indicates that the spawning of H. diversicolor in Sagami Bay was triggered by typhoon events with large-scale storms. The abalone could spawn at least twice in a single spawning season, but required an interval of at least 1 month between spawning events. The proportion of adults releasing gametes and the amount of released eggs/sperms from each individual tended to increase on the spawning events occurring later in a spawning season. Higher mortality rates of post-larvae and early juveniles were detected at places which had greater water turbulences and more frequent stone overturning caused by storms. A storm event caused by a typhoon appears to be a necessary cue triggering the synchronous spawning of H. diversicolor, but the violent water turbulence and overturning of stones caused by storms negatively affect the post-settlement survival. Cohorts experiencing lower seawater temperatures due to the later settlement in the spawning season tended to have a slower growth rate than those experiencing higher temperatures, suggesting the temperature-dependent growth of post-larval H. diversicolor. The timing of typhoon-triggered spawning in H. diversicolor was suggested to be an important factor affecting the growth and survival and eventual recruitment of the abalone.
|作成者||ONITSUKA Toshihiro KAWAMURA Tomohiko HORII Toyomitsu|
|公開者||Japan International Research Center for Agricultural Sciences|
|権利||Japan International Research Center for Agricultural Sciences|