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Osame TABETA, Takakazu OZAWA
1979 Volume 45 Issue 9 Pages
1069-1073
Published: September 25, 1979
Released on J-STAGE: February 29, 2008
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Five specimens of anguillid leptocephali were collected in the eastern Indian Ocean by the T. S. Kagoshima Maru, Faculty of Fisheries, Kagoshima University, in May 1977. Close examination revealed that four of the larvae were the short-finned eel,
Anguilla bicolor bicolor McClelland, and one was the long-finned eel,
A. nebulosa nebulosa McClelland. This is the second record from the sea after the collection by the Dana expedition in September-November 1929. The capture location of the larvae extends the distributional range of the eels in the Indian Ocean.
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Hiroshi SHINOMIYA, Michiyuki MIYAUCHI
1979 Volume 45 Issue 9 Pages
1075-1080
Published: September 25, 1979
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This paper presents a mathematical method to get the optimum speed of tuna long line fishing boats which are usually designed by modification of a type ship. Through heoretical processes, the mathematical model for this purpose was constructed as follows:
V≅2ν
n/
k3 (1)
C≅2η
M/3
f1k1D2/3k33 (2)
V4+4
V3-
C=0 (3)
Here, ν
n is optimum navigating speed,
k3 is coefficient of navigating days, 1-η is ratio of calling days to navigating days,
M is ship cost except fuel oil cost per day, f
1 is fuel cost per unit weight,
D is average displacement and k
3 is coefficient of navigating days.
From the basic values of each parameter, the basic
C and ν
n are calculated, which were denoted as
C0 and
V0, respectively. Then, corresponding curve of
C/
C0:
V/
V0 was made. Thus, by using this curve, the values of
V and ν
n may be obtained easily, based on the values of
C for the desired value of any parameter.
Parameters, the effects of which were shown in curves, should be determined severely by means of statistical disposal of actual data. Applying it to actually operated boats, this model was proved to have generality and effectiveness.
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Tetsuya SHIMAMURA, Hideo SOEDA
1979 Volume 45 Issue 9 Pages
1081-1084
Published: September 25, 1979
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This paper deals with the problem of decrease in the fishing efficiency as soaking time of gear increased over a certain limit, and with the fishing effect where the soaking time zone of gear shifted.
The results are as follows:
1. It was estimated from the results of various examinations of factors in tuna longline fishing that decrease in the fishing efficiency as soaking time of gear increased over a certain limit, was caused by change of the original setting form when the tuna longline settled under the sea.
2. No clear differeuce of fishing effect of Bigeye tuna and Yellow-fin tuna was recognized by X
2 test (5% level of significance) when soaking time zone of gear shifted.
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Preparatory Observation of Fish Amount
Mineo OKAMOTO, Toshiro KUROKI, Tohru MURAI
1979 Volume 45 Issue 9 Pages
1085-1090
Published: September 25, 1979
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To find out the environmental ecology and the gathering factor of fishes near artificial reefs, an automatic underwater camera with fisheye lens was developed. This could be set on the sea floor, and take 250 photographs lit by an electronic flash at every 30 or 60 minutes. At the artificial reefs off Sarushima Island near Yokosuka, where diving research was completed as mentioned in the previous paper, observation studies were continued using automatic underwater camera and self-recording current meter. As the results, some phenomena concerning
Sebastes inermis, “Mebaru” in Japanese, superior near these artificial reefs were found to be as follows.
(1)
Sebastes inermis showed two-peak shaped behavioral characters in one day in its appearance on the photograph.
(2) In 92% of the appearances, observation point corresponded to the artificial reef's upper side or near the tidal current.
(3) In 85% of the above case,
Sebastes inermis was seen to face the current.
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Influence of Oil Pollution on Population Density of Hydrocarbon-oxidizing Bacteria
Masatada MURAKAMI, Hiroaki FUJISAWA, Takehiko MANABE
1979 Volume 45 Issue 9 Pages
1091-1098
Published: September 25, 1979
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It has been reported that the population density of some hydrocarbon-oxidizing bacteria was high in the oil-polluted area of the Seto Inland Sea caused by the Mizushima Oil Refinery Accident. On the other hand, little has been known as yet of the influences of environmental factors on the density of bacterial population.
The present paper dealt statistically with the data collected from the above-mentioned area in the four seasons for the purpose of clarifying the influences of several environmental factors on the density of hydrocarbon-oxidizing bacteria groups A and B (both groups are facultative hydrocarbon oxidizers, the former is counted in an organic nitrogen medium, the latter is counted in an inorganic nitrogen medium) as well as of heterotrophic bacteria in seawater and in bottom sediments. And then the group composition (heterotrophs, hydrocarbon oxidizer groups A and B) in the oil-polluted area and the control area was examined in the principal component analysis.
The results obtained can be summarized as follows:
1. In seawater, a significant correlation could be found between the oil content and the population density of hydrocarbon-oxidizing bacteria group A. The same was true of the density of both of group B and heterotrophic bacteria. lt is, therefore, presumed that the density of these groups of bacteria depends largely on oil pollutants.
2. The significance test of partial regression coefficients of a multiple linear regression equation in seawater of the oil-polluted area showed that the population density of heterotrophic bacteria (d
h) increased with √19-Cl (Cl: chlorinity in ‰) and with log d
p (d
p: oil content in ppm).
3. Though the population density of group A (d
a) was higher than that of group B (d
b) and showed a marked increase just after the oil spill accident, the results of variance analysis showed that closer was the correlation of d
b to d
p than that of d
a to d
p at all seasons.
4. In bottom sediments, the ratio of log d
b to log d
h in the polluted area was higher than that in the control area. Therefore, it can be said that this ratio may be one of the suitable indices for oil pollution.
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Relations between Several Environmental Conditions and Population Density of Hydrocarbon-oxidizing Bacteria in Seawater of the Oil-polluted Waters and Characterization of Group Composition of Bacteria
Hiroaki FUJISAWA, Masatada MURAKAMI, Takehiko MANABE
1979 Volume 45 Issue 9 Pages
1099-1107
Published: September 25, 1979
Released on J-STAGE: February 29, 2008
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Accurate information on the relations between the environmental conditions and the population density of hydrocarbon-oxidizing bacteria is indispensable to clarify the self-purificalion in the oil-polluted areas. In spite of the above-mentioned importance, little has been known of them, as yet.
To clarify the influence of the environmental conditions on the population density of heterotrophic bacteria, hydrocarbon-oxidizing bacteria groups A (d
a) and B (d
b) in seawater of the coastal waters of the different grades of oil pollution, the following areas were chosen: Iwakuni waters (off oil industrial plants), Bisan Seto (one year after the Mizushima Oil Refinery Accident) and Hibiki Nada (slightly polluted area as control). The following factors were measured as the environmental conditions: oil content (d
p), chlorinity, COD and water temparature. And various relations of the density of these bacterial groups to these conditions were statistically estimated.
It may be given as a conclusion of the linear regression analysis that the density of bacteria is clearly affected by the environmental conditions, as indicated by the highly significant coefficients.
Further analyses were conducted by the multiple linear equation in which the areas were used as the dummy variables. And it was found that the dummy variables in the relations of the density of groups A and B with oil content were insignificant. Therefore, the difference in respective areas was not recognized in the relations, and the relations were respectively expressed in the following equations.
log d
a=3.34+1.35log d
p log d
b=2.17+1.36log d
p The group compositions of bacteria in respective areas were examined in the principal component analysis. And it was found that the accumulated proportions in z
1 (size factor) and z
2 (shape factor) were about 86 and 96%, respectively. This fact means that the group composition in these respective areas can be characterized by the distribution figure of scores on axes of z
1 and z
2.
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Akiyoshi KAMATANI
1979 Volume 45 Issue 9 Pages
1109-1114
Published: September 25, 1979
Released on J-STAGE: February 29, 2008
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Bio-elements (C, N, P and Si) in suspended matter and sediments have been studied together with reactive silicate and phosphate in seawater from Tokyo Bay. The seasonal variation of reactive silicate exhibited higher amplitude than that of reactive phosphate. Organic-C and-N contents in the sediments were higher than those of the averaged oceanic sediments, but the phosphorus content was the same level with that of the oceanic sediment. The mean ratio of the bio-elements in suspended matter was calculated to be P:N:C:Si=1:18.8:137:22.6 (atoms). In the sediment it was P:N:C=1:7.6:73.6, but the ratios of N and C to the rest of the phosphorus, which was obtained by substracting the fractions combined with Ca, Al and Fe from the total amount of phosphorus, was found to approach to those of the suspended matter. During the period when stratification developed, about 80% of organic matter produced was estimated to be decomposed in the surface water. A considerable amount of suspended matter in winter season, was considered to be ascribed to the resuspension from the deposited sediment and/or to the debris of organic matter.
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Hiromasa YOSHIKAWA, Mikio OGURI
1979 Volume 45 Issue 9 Pages
1115-1121
Published: September 25, 1979
Released on J-STAGE: February 29, 2008
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This report deals with the gradient of sex differentiation and the interaction between the germ cells and the somatic cells of the developing testes in the medaka,
Oryzias latipes. Interstitial cell, used as a criterion for the differentiation of somatic elements of testes, was detected for the first time at 9.0mm stage, while germ cell in meiosis, used as a criterion for germinal elements, was at 11.5mm stage. According to YAMAMOTO, there was an antero-posterior gradient in the sex differentiation of the medaka. In the present investigation, however, such a gradient was not recognizable. The present investigation revealed that interstitial cell was always found at the very vicinity of the parts where the germ cell in meiosis was observable and that the differentiation of somatic cells into interstitial cells occurred at the stage earlier than that of spermatogonia into spermatocytes. Accordingly, it seems that interstitial cells induce the transformation from spermatogonia to spermatocytes.
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Effect of Clay Particles on the Fluctuation of Nutrient Contents in the Estuary
Akihiko SHIROTA
1979 Volume 45 Issue 9 Pages
1123-1128
Published: September 25, 1979
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The relationship between particulate suspensions and nutrient contents in estuary water is not well known. In the estuary where turbidity is high, fluctuation of nutrient contents in a half tidal period is usually large, and it is sometimes observed that the lower the salinity, the lower is the nutrient contents. It seems conceivable that this phenomenon may be caused by the suspenped matter in the estuary.
In this study, to clarify the idea mentioned above, salinity, phosphate-phosphorus, current velocity and turbidity at the same station were determined every one hour for a half tidal period, and the examination on X-ray diffraction of sediment at the mouth of the Chikugo river was carried out.
The results obtained were as follows.
1) Particulate suspensions and bottom sediment in the estuary were composed of montmorillonite and illite clay which has strong properties of floc formation.
2) Fluctuations of PO
4-P during the stagnant period at ebb tide were much larger than those at flood.
3) Percentage removal of PO
4-P from the estuarine water by the addition of pure montmorillonite clay was in the range of 75-99%.
From these results, it was presumed that particulate suspensions of clay minerals play an important role on the large fluctuation of nutrient contents in the estuary.
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Turbidity as an Index of Water Masses in the Estuary
Akihiko SHIROTA
1979 Volume 45 Issue 9 Pages
1129-1135
Published: September 25, 1979
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The relationship between turbidity and temperature-salinity relation in the estuary is not well known, although the turbidity has been used as an index of water masses in the field of optics in the ocean science from space by the remote sensing.
In this paper, in order to clarify whether the turbidity can be used as an index of water masses in the estuary or not, distribution of the turbidity change by standing water samples for one minute at 400 nm wave length in an absorption cell was compared with the pattern of the area by T-S diagrams in a half tidal period, at all stations of 56 fishing boats anchored in the inner area of the Ariake Sea.
The results obtained are as follows.
1) Turbidity change reached a maximum after one minute from the beginning of deterurination for standing water samples. Therefore, the turbidity change after one minute was indicated as the turbidity.
2) It was found that the difference of water masses in the coastal and offshore side divided by the line showing 0.001 of turbidity change is in complete agreement with the pattern of the area by T-S diagrams in a half tidal period of all stations.
Therefore, it can be concluded that the turbidity change could be used as an index of water masses in the estuary.
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Seasonal variations of Hydrographic conditions
Tatsuaki MAEDA, Toyomi TAKAHASHI, Motokazu UENO
1979 Volume 45 Issue 9 Pages
1137-1142
Published: September 25, 1979
Released on J-STAGE: February 29, 2008
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In the previous papers, the distribution and migration in feeding and spawning seasons of adult Alaska po11ack,
Theragra chalcogramma (PALLAS), in the adjacent waters of the Funka Bay, Hokkaido were examined.
However, the relationship between the habits of adult Alaska pollack and environmental conditions throughout the year is not clear. For this reason, the authors investigated water temperature, salinity, food organisms and biological factors of fish once a month from February 1974 to February 1975 six definite stations.
This paper deals with the examination of the seasonal variations of water mass in this area.
1. The Tsugaru warm current (salinity more than 33.8‰ as an indicates of presence) enters this area through the mid-water layer in June and occupies the widest sphere in November. In December the current falls off and disappears in January.
2. The surface layer water of the Oyashio current (salinity less than 33.2‰) occupies most of the surface and mid-water layers in February and gradually declines from March. In June this water is thrust toward the coastal area by the inflow of the Tsugaru warm current and almost disappears in November.
3. The bottom layer water of the Oyashio current (temperature less than 3.5°C and salinity less than 33, 7‰) occupies about 200-450m in depth near the bottom in February, but the range gradually decreases with the inflow of the Tsugaru warm current and shows the minimum range during December and January.
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Hisahiko WATANABE, Hiroshi HASEGAWA, Rikuo TAKAI
1979 Volume 45 Issue 9 Pages
1143-1146
Published: September 25, 1979
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Electrocoagulation of water soluble fish protein by a continuous flow method without any coagulant was studied. The pH value of the anolyte at steady state operation, pH
s, plays an important role in the design and/or operation of equipment. The factors which affect pH
s are the protein concentration of feed liquid, flow rate of anolyte, and electric current. A function which correlates these factors was determined experimentally by use of a simple model of coagulation. A nomograph for estimation of the current required to maintain the anolyte at a selected pH
s value was given.
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On the Seasonal Variation of Mud and its Control
Kaoru MITSUHASHI
1979 Volume 45 Issue 9 Pages
1147-1150
Published: September 25, 1979
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In a intermittently aerated lagoon, in which a high rate of removal of nitrogen had been observed, a seasonal variation of mud on the bottom was investigated using a new mud sounder which consisted of ultraviolet lamps and a blueprint marker. The volume of mud ranged between 35 and 132m
3. The mud increased in winter and decreased in spring. The total amount of nitrogen found in the mud and mixed liquor was large in winter and spring and small in summer and autumn.
To control the increase of mud in winter, a treatment test was done for shallow lagoon water conditions. The results were that the volume of mud was maintained almost constant, the total amount of nitrogen found did not increase, and the rate of nitrogen removal remained high.
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Effect of Docosahexaenoic Acid on Growth
Akio KANAZAWA, Shin-ichi TESHIMA, Shigeru TOKIWA, Mitsu KAYAMA, Minoru ...
1979 Volume 45 Issue 9 Pages
1151-1153
Published: September 25, 1979
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The effect of docosahexaenoic acid (22:6ω3) on the growth of prawn,
Penaeus japonicus, was studied by using a purified diet during a 60-day feeding period. The prawn fed diets containing oleic acid alone or medium chain triglycerides (MCT) showed poor growth. The addition of 1% levels of linoleic acid (18:2ω6) or linolenic acid (18:3ω3) to the diet containing 4% MCT improved the weight gain. The supplementary effect of 22:6ω3 was the highest among the three acids. These results indicate that 22:6ω3 is more effective as an essential fatty acid than 18:2ω6 or 18:3ω3.
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Hiroyuki NODA, Hideomi AMANO, Fusao OHTA, Yoshishige HORIGUCHI
1979 Volume 45 Issue 9 Pages
1155-1162
Published: September 25, 1979
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The effect of amino acids was examined in cufing “akagusare”, or red rot disease, of the layer
Porphyra spp. Among the amino acids tested, histidine, methionine, and tyrosine were found effective: the infected layer recovered when treated for 23days with mineral-enriched seawater containing each amino acid at a level of 10ppm.
Histidine showed the highest activity against the causative fungi. The time of recovery for an infected layer was shortened to 12h when the level of histidine was increased to 100ppm. Moreover, the treated layer was prevented from reinfection with the fungi, and freed from the disease for at least 2 weeks.
In a similar experiment in natural environment, histidine was also found to cure, or protest against disease, the young bud, young frond, and thallus of the layer.
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Hiroyuki NODA, Hideomi AMANO, Fusao OHTA, Yoshishige HORIGUCHI
1979 Volume 45 Issue 9 Pages
1163-1167
Published: September 25, 1979
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These experiments elucidated the mechanism involved in the activity of histidine in curing “akagusare”, or red rot disease, of the layer
Porphyra yezoensis. The infected frond was cultured in seawater containing histidine or some amino acids for reference. The bacterial flora on the frond and its chemical constituents were analysed.
Results showed that
Flavobacterium was the most predominant, followed by
Alcaligenes, irrespective of the added amino acid and of the length of treatment. In the histidine-treated frond, the levels of photosynthetic pigments such as chlorophyll, phycoerythrin and phycocyanin, and of free amino acids were increased significantly.
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Yoshihisa FUJIO, Yasunari KATO
1979 Volume 45 Issue 9 Pages
1169-1178
Published: September 25, 1979
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Starch gel electrophoresis was carried out to survey the genetic variation among species of fish as a foundation for more extensive and detail studies. Variation in average level of genetic variation among taxonomic groups of fish was observed. Estimate for the fish as whole was 0.194±0.023 in the proportion of polymorphic loci and 0.059±0.007 in the mean individual heterozygosity.
The correlation of the proportion of polymorphic loci with the mean individual heterozygosity was observed and the relationship was found to be linear. The calculated regression line was near to the theroretical relationship on the basis of the neutral theory of protein polymorphisms. Thus, it may be concluded that variation in average level of heterozygosity among taxonomic groups of fish reflected difference in effective population size.
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Syuichi SAKAMOTO, Akira ETO, Masayuki FURUICHI, Yasuo YONE
1979 Volume 45 Issue 9 Pages
1179-1183
Published: September 25, 1979
Released on J-STAGE: February 29, 2008
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This study was conducted to formulate a purified test diet for yellowtail,
Seriola quinqueradiatla. Yellowtail fingerlings were fed on a purified diet or a diet of minced jack mackerel over a 60 day period. At the end of the feeding trial, anatomico-pathological and histopathological examinations of the tissues, hematological examinations, and chemical analyses of the dorsal muscle, liver, and vertebrae were performed. Significant differences were recognized between the two groups in appetite, growth rate, and other factors, and the jack mackerel group were found superior to those of the purified diet group. However, the low mortality and comparatively high feed efficiency indicate that a purified test diet for yellowtail can be established after adequate modification of the present diet.
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Kunio KOBAYASHI, Nobuo NAKAMURA
1979 Volume 45 Issue 9 Pages
1185-1188
Published: September 25, 1979
Released on J-STAGE: February 29, 2008
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A study has been made to demonstrate the contribution of the branchial, renal, and biliary routes to the PCP excretion in goldfish,
Carassius auratus, and also to determine the importance of the sulfate and glucuronide conjugations as the detoxification mechanisms for PCP in the fish.
The amounts of PCP excreted from the branchial, renal, and biliary routes corresponded to approximately 52, 24, and 22% of the total amount of PCP (approx. 5μmol) excreted by the fish (av. 68g) for 24h after 24-h exposure to 0.1ppm PCP. The excretion of PCP from the body surface was negligibly small compared with that from the above three routes.
Approximately 30% of the PCP excreted from the gills was in a free-form, whereas almost all the PCP excreted in both of the bile and urine was in a conjugated-form. The total amount of the sulfate conjugate excreted in the surrounding water and the urine was ca. 3μmol, while that of the glucuronide in the bile was ca. 1μmol.
However, a considerable amount of the PCP-glucuronide in the bile was hydrolyzed by the intestinal mucus of fish. This indicates that the glucuronide conjugation is not so important as compared with the sulfate conjugation to eliminate PCP from the fish body, because the PCP released from the glucuronide in the intestine must be reabsorbed there.
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Masayo OKUZUMI, Hiroshi NAKAIZUMI, Hiroyuki KOIKE
1979 Volume 45 Issue 9 Pages
1189-1194
Published: September 25, 1979
Released on J-STAGE: February 29, 2008
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The present study was undertaken to analyse the bacterial flora of culture-oysters and of the silt accumulating on their shells. All the oysters were taken from two different areas of Hiroshima Bay during July and November, 1973, and the following January.
Enumeration and isolation of bacteria were conducted with a smear plate method using 50 percent seawater agar medium. Identification was based chiefly on the scheme of SHEWAN et al.
The generic composition of bacterial flora of the oysters differed from that of the marine water; that is, a very large portion of the isolates from the oysters consisted of genus
Vibrio with no seasonal variation observed, while in the marine water pseudomonads were predominant. The ratio of psychrophilic vibrios to mesophilic ones, all isolated from the oyster samples, varied with the three seasons.
The bacterial flora of the silt was also composed mainly of vibrios, which were usually the same kind as those of the oysters.
The generic composition of the flora of commercial shucked oysters collected from some department stores in Tokyo in December, 1974, and the following January, was very similar to that of the culture-oysters.
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Tateo FUJII
1979 Volume 45 Issue 9 Pages
1195
Published: September 25, 1979
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Takao MATSUNO, Hisako MATSUTAKA, Masaaki KATSUYAMA, Seiichi NAGATA
1979 Volume 45 Issue 9 Pages
1197
Published: September 25, 1979
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