学术
Locomotor activity rhythm in the Japanese eel Anguilla japonica elvers
DOU Shuozeng[1] TSUKAMOTO Katsumi[2]
[1]Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China [2]Ocean Research Institute, University of Tokyo, Tokyo 164- 8639, Japan
文章出处:
《海洋学报：英文版》-2007年26卷5期 -76-89页
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Locomotor activity rhythm in the Japanese eel Anguilla japonica elvers
Abstract:
Under artificial LD cycles （6, 12, 18 L）, the elvers of Japanese eel, Anguilla japonica, showed a 24 h cycle of locomotor activity rhythm being most active at light transitions ： the eels＇ activity rose to a primary peak after lights-off, followed by a quiescent period during which they buried into the shelters or lying motionlessly on sand for most of the time, and then reached a secondary peak before lights-on. Elvers could resynchronize their activity rhythm with a new photo cycle within 4 d. Moreover, their activity level at dark phase significantly increased as the light period was prolonged ： higher activity levels during shorter dark period. However, the elvers did not display clearly the existence of a circadian rhythm under constant light or dark conditions. The timing of daily activity rhythm evidenced in the Japanese eels may occur through the action of the LD cycles with a weak participation of an endogenous circadian system. In all the LD cycles, over 99% of the activity occurred in the dark phase, indicating that the eels were always nocturnally active no matter what time of day it might be. Under 12 L conditions, the eels＇ activity level and the time outside sand were significantly elevated both at light and dark phases as temperature increased from 10 - 15 to 20 - 25 ℃. The activity rhythm pattern （ i. e. , two peaks occurring around light transitions） did not apparently change among temperatures. However, in contrast with the primary activity peaks immediately after lights-off at 20 and 25 ℃, the timing of the primary peaks at 10 and 15 ℃ showed a latency of a few hours following lights-off, indicating the inhibiting effect of low temperature on the eels＇ activity.[著者文摘]
Key words:
activity rhythm, Japanese eel, light-dark cycle, temperature, zeitgeber
基金资助:
Acknowledgements We thank Drs. Inagaki T, Shinoda A and Aoyama J, 0cean Research Institute, the University of Tokyo, for their technical assistance and helpful advice. This study was supported by an international program from Japan Society for the Promotion of Science （JSPS） and the Ministry of Sciences and Technology of China under contract Nos 2007CB407305 and 2006BAD09A02 .
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