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Volume 31, Issue 4
Displaying 1-11 of 11 articles from this issue
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Yoh-ichi TAKAHASHI, Jyun HIROKAWA, Atushi KUMAGAI1983 Volume 31 Issue 4 Pages 167-172
Published: March 25, 1984
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSAs a fundamental studies on the seedling of Pacific herring, Clupea pallasi, the methods of egg-taking and incubation were examined.
Matured brood fish were caught by gill net or set net in bay of Mangoku-ura, Miyagi Prefecture. Ova were stripped by hand massage and inseminated with minced testis. Artificial insemination were carried out 3 times during the spawning season from December 1982 to January 1983.
Fertilized eggs were dispersed on the nest made of saran-net (1 mm streched mesh) with wooden frame. The rate of eyed eggs and hatching were examined under different conditions. The results are summarized as follows :
1) It is important to disperse the eggs uniformly on the nest; recommendable density was 30 to 40 eggs per cm2.
2) The eggs incubated at 10°C (10.5-12.7°C) or 15°C (13.5-15.0°C) were normally developed and hatched. The rate of eyed eggs was more higher at 20°C (13.5-19.7 °C), while the rate of hatching was higher at 10°C and 15°C. The viability of the larvae was weak at 20°C and a half of them died until 2 to 3 days.
3) Temperature-day degree from fertilization to hatching was given following parabolic expression :
D (days) =278.35T-1.315 (°C) (r=0.995)
4) Temperature-day degree from fertilization to eyed stage was 75 D° at each temperature. After eyed stage, however, the temperature-day degree until hatching was different and varied from 115 to 145 D°.
5) There was a close relationship between the rate of fertilization and the time after death of brood fish. The rate was decreased suddenly when the time passed over 6 hours.View full abstractDownload PDF (738K) -
[in Japanese]1983 Volume 31 Issue 4 Pages 173-177
Published: March 25, 1984
Released on J-STAGE: September 07, 2010
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Ryuzo FUKAO, Akiko ENOMOTO, Nobuko KUBOTA, Kinji KURAWAKA1983 Volume 31 Issue 4 Pages 178-190
Published: March 25, 1984
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSThreestriped tigerfish, Terapon jarbua is relatively small among the free-swimming estuarine fishes in Japan. They are abundant and widely distributed. A large number of juveniles can be collected easily because of their gregarious habit at the water edge.
The culture of T. jarbua has been conducted in our laboratory with the view of exploiting the fish species for bioassay to toxicity. Two kinds of mortality were observed in the course of the culture. In the early fall of the years 1980 and 1981, juveniles were collected at the mouth of the Sagami River. Mass mortality occurred in 1980 after 10 to 20 days from beginning of culture. This might result from some physiological dysfunction caused by the feeding on fish meats and ceased by the feeding on other items (opossum shrimp, brineshrimp nauplii, euphausia, and veneriid clam) than fish meats. The physiological dysfunction was believed to be associated with the composition of lipids contained in the foods, fish meats, because the incidence of fatty liver was high in the died fishes. After a while, the scale-eating habits were developed and then the dead fishes resulted from the loss of their scales by autopredation frequently occurred since they exceed 5 cm in total length. In the present case, peculiarly, the fishes attained rather good growth were apt to suffer autopredation. Judging from the fluctuations in dissolved oxygen concentration of the culture sea water, the activity of scaleeating habits was appeared to be the most intensive just after the lights-out. The autopredation is believed to be prevented from by lowering culture density of fishes and simultaneously by setting the ration appropreately as they grow. Thus, the tigerfish could supply for the bioassay like toxicity tests from the laboratory stock all the year round.View full abstractDownload PDF (8513K) -
Vibrio-Aeromonas Group Bacteria Isolated from the Gastrointestine of Tilapia FishHaruo SUGITA, Taizo SAKATA, Yuzaburo ISHIDA, Yoshiaki DEGUCHI, Hajime ...1983 Volume 31 Issue 4 Pages 191-195
Published: March 25, 1984
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSNinety seven strains of the bacteria belonging to Vibrio-Aeromonas group, isolated from the gastrointestine of tilapia Sarotherodon niloticus, were examined on 57 taxonomic characteristics. All strains were gram-negative asporogenous rods and sensitive to vibrio static compound (O/129), and were able to ferment glucose without gas production and to utilize ammonium and glucose as nitrogen and carbon source. Oxidase and catalase were produced and macromolecular substances such as gelatin, casein, starch, chitin, esculin, tributyrin and lecithin were not hydrolyzed. Decarboxylases of lysin, ornithin and arginine were produced. From the above results all strains were identified as Plesiomonas shigelloides, which were divided into 2 types based on ability to utilize inositol and mannose.View full abstractDownload PDF (422K) -
[in Japanese]1983 Volume 31 Issue 4 Pages 196-199
Published: March 25, 1984
Released on J-STAGE: September 07, 2010
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[in Japanese], [in Japanese]1983 Volume 31 Issue 4 Pages 200-203
Published: March 25, 1984
Released on J-STAGE: September 07, 2010
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[in Japanese]1983 Volume 31 Issue 4 Pages 204-213
Published: March 25, 1984
Released on J-STAGE: September 07, 2010
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[in Japanese]1983 Volume 31 Issue 4 Pages 214-219
Published: March 25, 1984
Released on J-STAGE: September 07, 2010
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[in Japanese]1983 Volume 31 Issue 4 Pages 220-221
Published: March 25, 1984
Released on J-STAGE: September 07, 2010
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[in Japanese]1983 Volume 31 Issue 4 Pages 222-226
Published: March 25, 1984
Released on J-STAGE: September 07, 2010
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[in Japanese]1983 Volume 31 Issue 4 Pages 227-232
Published: March 25, 1984
Released on J-STAGE: September 07, 2010
JOURNAL FREE ACCESSDownload PDF (347K)
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