Journal of the Faculty of Fisheries and Animal Husbandry, Hiroshima University Volume 15 Issue 1
1976-07-20 発行

Notes on the Dormancy in the Adults of Tigriopus japonicus

Tigriopus japonicus(ハルパクチコイダ橈脚類)成体の休眠生態について
Kasahara, Shogoro
Akiyama, Toshio
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abstract
Experiments have been done on the salinities and temperatures causing dormancy in the adults of Tigriopus japonicus. The results are as follows;
(1) The animals cultured in sea-water media (salinity, 32.5~34‰) at 25℃ and 20~15℃ wholly lie dormant in 8~4℃ and 2~-2℃, respectively.
(2) These dormant animals of both sexes show a revival rate of 80% after being stored at 0℃ for a month.
(3) When the sea water containing the animals is gradually concentrated by evaporation at 23~26℃, all the individuals fall into dormancy at salinities of 130~150‰. At these salinities the dormant animals survive for more than one month at 1~7℃.
(4) The animals fall into dormancy at higher temperatures as the environmental salinity is higher.
(5) Females are slightly more resistant to falling into dormancy than males, either at lower temperatures or at raised salinities.
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The expenses for this study were partially covered by a research grant from the Ministry of Education.