Bulletin of the Plankton Society of Japan
Online ISSN : 2434-0839
Print ISSN : 0387-8961
Original Papers
Occurrence of planktonic larvae of manila clam Ruditapes philippinarum in Ariake Bay: Characteristic of spatial and temporal variation among the populations
Akiko MichiyamaAkihiko FujiiKyohei YamadaTomoki UmedaJunji TakadaJunichi UchikawaMasaya HosodaHiroshi YamaguchiYukihiko Matsuyama
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2022 Volume 69 Issue 2 Pages 83-92


In Ariake Bay, catches of the manila clam Ruditapes philippinarum have decreased considerably due to the low rate of larval return to adult habitats, shrinkage of larval networks among each local population, and shortening of the occurrence period of larvae. In this study, we examined the seasonal and annual occurrence trends of planktonic clam larvae and the environmental factors related to the quantity of larvae based on surveys conducted in the Ariake Sea between 2015 and 2018. In the Ariake Sea, emergence peaks with population densities of more than 1,000 m−3 individuals occurred during the spring and fall spawning seasons. In spring, the peak onset often occurred between late April and May, but trends also varied from year to year. In autumn, the peak period was observed at approximately the same time every year, from mid-October to November. The peak emergence of plankton larvae was thought to be related to water temperature.

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© 2022 The Plankton Society of Japan
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