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メジナ生殖巣の成熟及び季節的循環に関する研究


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Title: メジナ生殖巣の成熟及び季節的循環に関する研究
Other Titles: Studies on the Maturation and the Seasonal Cycle in the Gonad of Girella punctata
Authors: 水江, 一弘 / 三上, 健彦
Authors (alternative): Mizue, Kazuhiro / Mikami, Takehiko
Issue Date: 31-Jul-1960
Publisher: 長崎大学水産学部
Citation: 長崎大学水産学部研究報告, v.9, pp.18-31; 1960
Abstract: Girella punctata were collected monthly all the year round at Sasebo Bay, and authors studied the maturation and the seasonal cycle of their gonads. 1) The weight of the gonad is highest in May and the decrease and increase of the weight in this month are rapidly. 2) From the variation of the weight of gonad and the observation about the histological sections of gonad, the stage of gonad maturity could be divided into three categories, that is in the testis 1. The resting period……June-November 2. The preparative period for the spermatogenesis……December-April 3. The period of the spermatogenesis and the discharging period of the spermium……May in the ovary 1. The resting period……June-January 2. The growthing period of the oocyte……February-April 3. The fully matured and spawning period……May. 3) The period of the spermatogenesis and the discharging period of the spermium is very short time in comparison with other fishes, and the evidence that Girella punctata is mono-spawning have been presented from the testis. 4) There is a few seminiferous epithelium in the seminiferous tubules, and it is seen in all the year on the histological sections of the testis the spermatogonia has been appeared on the basement membrane for the lumen, and the spermatogonia appears newly after the discharge of the spermium and is not remnants. 5) The testis is small during eleven monthes between June and follwing April but always the abnormal spermatoge nesis has been done in the seminiferous tubules and there are many spermium in the seminiferous tubules, these spermium has no connection with the reproduction and has been digested and absorbed for the nutriment. 6) The spermatogenesis is the syncytium, namly a cyst is formed from a spermatogonia. 7) At the last stage of the spermatogenesis, the secretion is excreted in the cyst, this secretion presents the branchy condition and the many spermium has been supported and maintained at the end of these branches. 8) In the fully matured oocyte the yolk globules do not dissolve and the many oil globules in oocyte grow a large globe and it push out the nucleus to the animal pole. 9) In this fish the oocytes develop rapidly from February untill May and can be divided into two groups in this period, one is a group of the very large oocytes which are spawned in May and other is a group of the very small oocytes which are remained in the ovary on and after June as the remained egges, therefore it is clear that Girella punctata is mono-spawning. 10) After the spawn, it seems that the many remained egges has not been resolved and absorbed and they are existed in the ovary untill the next spawning season. 11) In this fish the number of egges in the ovary are very few in comparison with other fishes, by this fact it is shown that the natural death-rate in the growthing times is very low.
URI: http://hdl.handle.net/10069/31782
ISSN: 05471427
Type: Departmental Bulletin Paper
Text Version: publisher
Appears in Collections:第9号

Citable URI : http://hdl.handle.net/10069/31782

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