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On the first infection site
Kounosuke TAKAHASHI, Toshio KAWANA
1974 Volume 9 Issue 1 Pages
1-6
Published: September 30, 1974
Released on J-STAGE: February 10, 2010
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A decline of the occurence rate and a change of the initial infection site in 1973
Kounosuke TAKAHASHI, Toshio KAWANA
1974 Volume 9 Issue 1 Pages
7-9
Published: September 30, 1974
Released on J-STAGE: February 10, 2010
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On the mortality occurred under two kinds of experimental conditions, oligotrophy and oligotrophy plus vibration
Katsuyoshi MORI, Yshio SUGAWARA, Kazuomi OBATA
1974 Volume 9 Issue 1 Pages
10-18
Published: September 30, 1974
Released on J-STAGE: February 10, 2010
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Tetsuo TAKAHASHI, Toshio ISHII, Taro AMANO
1974 Volume 9 Issue 1 Pages
19-22
Published: September 30, 1974
Released on J-STAGE: February 10, 2010
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Hironari SUZUMOTO
1974 Volume 9 Issue 1 Pages
23-27
Published: September 30, 1974
Released on J-STAGE: February 10, 2010
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The Western Japan was visited by a heavy drought in summer 1973. In Lake Shinji which communicates with the Sea of Japan by a canal through lake Naka-umi, chlorinity of the waters increased rapidly in July from 23‰ as in an ordinary year to 79‰ and this high chlorinity continued till October. This caused an outbreak of a copepod parasite on crusian carp, Carassius auratus C. The parasite was identified as Caligus orientalis GUSSEV, 1951, which was described on the specimens found on estuarin fishes of the genera Mugil, Limanda Hyprohamphus, Hexagrammus, Sebastodes, and Leuciscus. Infection of this parasite on Carassius auratus was not reported before as far as the present author knows.
Experiments on the tolerance of this species for various chlorinity of water from 0‰ to 18.4‰ revealed that the optimum chlorinity was about 6.4‰ Cl at 2224°C. From this, it is evident that an ascent of chlorinity owing to the drought made this parasite possible to invade Lake Shinji from sea and to infest on a new host, C. auratus, and that exhaustion of the host fish through hypertonic condition make the damage serious.
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Kiyokuni MUROGA, Hiroo SAKKA
1974 Volume 9 Issue 1 Pages
28-30
Published: September 30, 1974
Released on J-STAGE: February 10, 2010
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Morphology and Taxonomy
Kenji NAKAJIMA, Syuzo EGUSA
1974 Volume 9 Issue 1 Pages
31-39
Published: September 30, 1974
Released on J-STAGE: February 10, 2010
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In July, 1973, it was observed that many young carps in many farm ponds in Nagano, Yamagata and Akita prefectures were infected with a kind of cestode belonging to the genus Bothriocephalus. About 100 cestode specimens of different stages were collected from the intestines of 4 fishes (body weight : 20.7-31.6g). Ten of the largest size group among the mature worms obtained were examined morphologically and identified with B. opsariichthydis YAMAGUTI, 1934.
The criteria for identification were as follows.: 1) As regards the shape and the structure of the body, the present species resembled to B. acheilognathi YAMAGUTI, 1934. B. opsariichthydis YAMAGUTI, 1934, B. fluviatilis YAMAGUTI, 1952 and B. gowkongensis YEH, 1955 which had all been found in the cyprinoid fish in Japan and China. 2) The present species differed from B. gowkongensis in the point that the egg was never embryonated when laid. 3) As regards the body length the present species (17.3 cm in average) was rather close to B. opsariichthydis (more than 10 cm long according to YAMAGUTI), but differed from B. acheilognathi (about 8 cm) and B. fluviatilis (2.2 cm). 4) It was thought that B. acheilognati and B. fluviatilis were young stages of B. opsariichthydis.
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Incidence and Histopathology
Kenji NAKAJIMA, Syuzo EGUSA
1974 Volume 9 Issue 1 Pages
40-45
Published: September 30, 1974
Released on J-STAGE: February 10, 2010
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On September 27, 1973, 40 young carps of 4 months old were collected at random from a pond at Shioda in Nagano prefecture and examined for the presence of B. opsariichthydis YAMAGUTI, 1934 in their intestines. Nineteen fishes were found to harbour 1-57 worms (19.7 worms in average). The incidence rate was 47.5%.
The intestine carrying many worms was extremly swollen and the yellowish-white worms inside were observable through the intestinal wall which became thin and trancelucent. Observations of cross sections of the infected intestine revealed that most of the tips of the villi intestinales were seriously destroyed. This destruction was thought to be induced by “a rasp effect” caused by lasting oppression and movement of the strobillae. At the same time, marked congestion was observed in the lamina propria mucosae and the tela submucosa, and coagulated materials including tissue debris were found on the surface of the villi intestinales. Moreover, hemorrhage, hemolysis or vesiculation was found to occur in various parts of the lamina propria mucosae and the tela submucosa.
No deaths were reported from the above-mentioned farm pond, and it was said that affected fish continued to take foods actively, though the histopathological changes of the intestine of infected fish were fairly serious.
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Anthelmintic Effects of Some Chemicals
Kenji NAKAJIMA, Syuzo EGUSA
1974 Volume 9 Issue 1 Pages
46-49
Published: September 30, 1974
Released on J-STAGE: October 26, 2009
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Tissue Levels of Chloramphenicol in Cultured Yellowtail after Oral Administration
Kishio HATAI, Takashi HIRAOKA, Yoshio SAHASHI, Matajuro MATSUSHIMA, Yo ...
1974 Volume 9 Issue 1 Pages
50-70
Published: September 30, 1974
Released on J-STAGE: February 10, 2010
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The absorption and excretion of chloramphenicol (CP)of the cultured yellowtail were studied. The water temperature during the experiment was about 22°C. The average body weight of the cultured yellowtail used in the experiment in which 50 mg.CP/Kg was administered was 307.2 grams and 370 grams in case of 100 mg. CP/Kg. The results obtained are summarized as follows.
1) When dose of 50 mg. CP/Kg was administered orally once to the yellowtails, the blood level of CP reached a maximum of 8.6μg/ml after 8 hours, maintainning a level of 3.1μg/ml even after 48 hours.The spleen level of CP reached a maximum of 20.1μg/g after 4 hours, maintainning a level of 8.6μg/g even after 48 hours. The kidney levels of CP showed the peak of 16.2μg/g after 8 hours. The liver levels of CP showed the peak of 14.1μg/g after 4 hours. The muscle levels of CP showed the peak of 5.4μg/g after 8 hours. The levels of CP in those three tissues became almost undetectable after 48 hours.
2) When 100mg. CP/Kg was administered once orally in the yellowtails, the blood, spleen, kidney, liver and muscle levels of CP were about twice as high as those in case of 50mg. CP/Kg.
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Riichi KUSUDA, Toshio TOYOSHIMA, Jun NISHIOKA
1974 Volume 9 Issue 1 Pages
71-78
Published: September 30, 1974
Released on J-STAGE: February 10, 2010
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During late autumn of 1970 till following early spring, an epizootic occurred among cultured crimson sea breams, Evynnis japonica, in a bay in Kachi Prefecture. The disease was characterized by large ulcerative lesions with hemorrhagic borders on the body surface(Fig.1). Generally a great number of bacteria were found in the blood of moribund fishes.
The causative organisms were gram-negative, nonsporing rods with polar flagella, and usually about 1.8×0.4μin size. On nutrient agar colonies developed within 24 hours at 25°C. They gave positive catalase and oxidase reaction, utilized glucose oxidatively in HUGH-LEIFSON'S medium and reduced nitrate to nitrite. The organisms produced diffusible fluorescin, and were positive to citrate utilization, and liquefaction of gelatin, and negative to indol production and methylred test.
On the basis of the above characteristics, the organism was identified as Pseudomonas fluorescens.
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Junya SHIOSE, Hisatsugu WAKABAYASHI, Masao TOMINAGA, Syuzo EGUSA
1974 Volume 9 Issue 1 Pages
79-83
Published: September 30, 1974
Released on J-STAGE: February 10, 2010
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Teruo MIYAZAKI, Saburoh S. KUBOTA, Toshio ASANO, Yoshitaka TOMIDA
1974 Volume 9 Issue 1 Pages
84-90
Published: September 30, 1974
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Hironari SUZUMOTO
1974 Volume 9 Issue 1 Pages
91-94
Published: September 30, 1974
Released on J-STAGE: February 10, 2010
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Histological Observation and Bathing Effects of Some Chemicals
Kenji NAKAJIMA, Shigeru IZAWA, Syuzo EGUSA
1974 Volume 9 Issue 1 Pages
95-99
Published: September 30, 1974
Released on J-STAGE: October 26, 2009
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1974 Volume 9 Issue 1 Pages
98
Published: 1974
Released on J-STAGE: October 26, 2009
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