MEPS 351:129-138 (2007)  -  DOI: https://doi.org/10.3354/meps07150

Synchronized spawning of abalone Haliotis diversicolor triggered by typhoon events in Sagami Bay, Japan

Toshihiro Onitsuka1,*, Tomohiko Kawamura1, Toyomitsu Horii 2, Naoyuki Takiguchi3, Hideki Takami4, Yoshiro Watanabe1

1Ocean Research Institute, The University of Tokyo, 1-15-1 Minamidai, Nakano-ku, Tokyo 164–8639, Japan
2National Research Institute of Fisheries Science, Fisheries Research Agency, 6-31-1 Nagai, Yokosuka 238–0316, Kanagawa, Japan
3Fisheries Division, Environment and Agriculture Department, Kanagawa Prefectural Government, 1 Nihon-odori, Naka-ku, Yokohama, Kanagawa 231–8588, Japan
4Tohoku National Fisheries Research Institute, Fisheries Research Agency, 3-27-5 Shinhamacho, Shiogama, Miyagi 958, Japan

ABSTRACT: To elucidate the external cues triggering spawning of Haliotis diversicolor, changes in the gonads of adults and the occurrence of newly settled post-larvae were monitored from 2001 to 2004 in Sagami Bay, Japan. The gonad index (GI) and gonad somatic index (GSI) of both sexes began to increase between April and June 2002, peaked in September, and then decreased significantly by early October. In other years, GI and GSI were significantly lower in autumn. Between June and September in each year, almost all females had a mature ovary and most were capable of spawning, but the occurrence of newly settled post-larvae (<500 µm in shell length) was strictly limited to the periods just after typhoons passed through the study area. The GI and GSI of both sexes also decreased significantly only after typhoon events. Although mature adults experienced various changes in seawater temperature, tidal height and lunar phase during the survey periods, evidence of spawning was observed only after typhoon events. There were no specific trends in seawater temperature and lunar phase before newly settled post-larvae were collected. Our results suggest that spawning of H. diversicolor is strongly associated with typhoon events. Most individuals had an immature ovary just after the passage of a typhoon. However, 1 mo after spawning, most individuals had a mature ovary with a high GI, suggesting that H. diversicolor requires an interval of about 1 mo between successive spawning events.


KEY WORDS: Synchronous epidemic spawning · Spawning cue · Typhoon · Abalone · Haliotis diversicolor · Post-larvae · Maturation


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Cite this article as: Onitsuka T, Kawamura T, Horii T, Takiguchi N, Takami H, Watanabe Y (2007) Synchronized spawning of abalone Haliotis diversicolor triggered by typhoon events in Sagami Bay, Japan. Mar Ecol Prog Ser 351:129-138. https://doi.org/10.3354/meps07150

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