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KMID : 0894520080120030231
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Development & Reproduction
2008 Volume.12 No. 3 p.231 ~ p.241
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Reproductive Cycle and Environmental Factors on the Gonadal Maturation and Egg Breeding of the Freshwater Mitten Crab, Eriocheir japonicus Living in Sumjin River
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Lee Hyun-Kee
Lim Sang-Koo
Kim Dae-Jung
Kim Dae-Hyun
Lee Je-Yong
Kim Myung-Hee
Kim Byung-Ki
Han Chang-Hee
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Abstract
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The present study was designed to clarify aspects of the annual reproductive cycle of the fresh water mitten crab, Eriocheir japonicus inhabiting Sumjin river, and to determine the adequate conditions of temperature, photoperiod and salinity on the gonadal maturation and breeding of adult female crabs. Based on the seasonal changes of GSIs and gonadal histology of adult crabs, the annual reproductive cycle could be divided into 4 periods as follows: previtellogenesis period (from September to October) when GSIs were low value and ovaries had oocytes in previtellogenesis stage and meiotic prophase stage; maturing period (from November to March of the next year) when GSIs increased gradually and ovarian oocytes accumulated yolk globules; spawning period (from April to June) when high value of GSI of female was kept and ovigerous female appeared; resting period (from July to August) when GSIs decreased rapidly, and vitellogenic oocytes degenerated. Gonadal maturation was influenced by water temperature, but not photoperiod and salinity. GSI more increased in experimental regime of 18℃ than that of 10℃ regardless of photoperiod conditions (12L12D and 15L9D). However, in 26℃ regime of both photoperiod conditions, the value of GSI was not changed, and vitellogenic oocytes were not observed. Spawning was considerably influenced by water temperatures and salinities regardless of photoperiods. Vitellogenic female crabs did not spawn at 10℃ in any salinity conditions. However, at 18℃ and 26℃, over a half of rearing female crabs spawned in condition of 30% sea water (salinity 9.6‰) and 60% sea water (salinity 19.2‰), while no female spawned in freshwater condition (salinity 0.0‰).
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KEYWORD
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Freshwater mitten crab, Eriocheir japonicus, Reproductive cycle, Gonadal maturation, Breeding, Temperature, Salinity, Day length
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