A modified cannulation technique to collect urine from Salmo gairdneri was shown in comparison with the original method. The intraperitoneal injection of the bovine somatotropic hormone followed a remarkable increase of chloride excretion of the urine in Salmo gairdneri.

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Ten kinds of trawl gears which are used by six stern trawlers ranging from 100 to 3000 gross tonnage were experimented on hydraulic resistance of gears. The resistance of net itself is estimated theoretically by subtracting the resistance of otter board, warps and hand rope from the total resistance of gears as illustrated in Tables 2 and 3.
It can be said that the resistance R (kg) of a trawl net composed of six seams net is approximately expressed as follows. (Fig. 4)
R=kabd/lv²
a=The maximum breadth of net body without shrinkage (dotted line seen in the Fig. 3) (meter)
b=The maximum length of trawl net without shrinkage (meter)
d/l=The average value of ratio: d, diameter of net twine: l, length of each mesh bar at side panel 1-7 section (Fig. 3)
k=Resistance coefficient
v=Towing speed (m/sec)
From the Fig. 4, the value of k, coefficient of resistance, can be read as 8 when there are no catch inside the net, but it takes about twice value as much as the above one when there are some fishes of about 1.5 tons which are gilled in the meshes of the net.

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An experimental study on the influence of changes in chlorinity on the haematological characteristics of Sebastiscus marmoratus was carried out with the hope that these might reveal ecological factors controlling the distribution of these fish in the sea. Two males and females (Table 1) were hooked in the vicinity of Nagasaki on September 19, 1963 and were kept in circulating sea water in a plastic tank (80×51×100cm) from September 19 to November 19, and in a concrete tank (75×71×130cm) from November 20 to August 25, 1964. The pH values of water in the latter tank were maintained within a range of 7.70-7.85. The chlorinity of the water was increased or decreased by adding ordinary salt or fresh water. The chlorini-ties used and the periods of acclimation are shown in Table 2.
The blood was withdrawn from the Cuvierian duct of each fish following an acclimation period of at least three days with a 0.5 - 0.7ml syringe. Heparin (0.2mg/ml) was added to prevent coagulation of the blood. To minimize differences in the blood elements dependant on the time of day, all samples were taken between 9 and 11 a.m. KURODA's micro-measurement method was used to determine the moisture content of blood. A copper sulphate solution ad-justed from 1.022 to 1.050 with intervals of 0.002 was used as a standard in ascertaining the specific gravity of blood. After the separation of sera with a hand centrifuge, measurements of the serum protein were carried out with a Hitachi refractometer. The number of nucleated erythrocytes was counted with a Bürker-Türk counting cell after dilution with Hayem solution. The chlorinity was determined by titration using the KNUDSEN's method. Several species of shrimp caught by trawl in the neighboring waters were used as food throughout the course of study. In this way, chemical changes in the diet were minimal.
1. In the experiments with considerably lower (8.22-8.34‰) or higher (22.31-22.47‰) chlorinities than that in the natural habitat (17.60-17.72‰) of S. marmoratus, the entire body surface of each specimen was covered was covered by a transparent mucous film. This seemed to regulate the osmotic mechanism against extreme changes in salinity. Feeding activities and swimming movements were markedly decreased. Indeed, there was scarcely any movement at all. These chlorinity values, therefore, appear to indicate the approximate upper or lower limits of chlorinity tolerance for this species.
2. No correlation was observed between the moisture content of blood and changes in chlorinity (Table 3, Fig. 1) or between the fluctuation of the quantity of serum protein and the chlorinity (Table 3, Fig. 1). On the other hand, a very high positive correlation was found between the specific gravity of the blood and the chlorinity of the water (Table 3, Figs. 1 and 2).
Thus the specific gravity of blood increased with increasing, or decreased with decreasing chlorinity in the water, but a negative correlation was clearly found between the specific gravi-ty and the moisture content of blood (Table 4, Fig. 3). Consequently, these relations may indicate that the chlorinity changes in the fishes' habitat would cause physiological readjust-ment of the moisture content of blood.
3. When the fishes were kept in more or less saline water than that of their natural habitat, a positive correlation was found between the specific gravity and the serum protein of blood. The interrelation between the serum protein and the moisture content of blood was, however, negative with one exception (Table 4).
4. When S. marmoratus was not subjected to any change in the chlorinity of the water, i.e. they were kept in natural sea water, the correlation coefficients calculated for three blood elements were conspicuously higher than those obtained for specimens reared with the water of abnormal chlorinities (Table 5, Figs. 4 and 5).

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L-response of the S-potentials, which is considered as an indicator of luminosity sensation, was used to study the relationship between the amplitude and the intensity of illumination. The intensity to produce a half of the maximum amplitude was measured in five species. The intensities thus obtained were higher in the order of mullet, carp, goldfish, sting-ray and neko-shark. The latency of returning phase at the cessation of the stimulus was found to be shorter in the same order as above.
These results were discussed in reference to ecological aspects of fishes. It is concluded that the five fishes used in this study adapt themselves to the brighter environment in the order of mullet, carp, goldfish, sting-ray and neko-shark.

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Biological study of Chaetognatha has a considerably long history. Chaetognatha is im-portant macro zooplankton as indicator of water mass, and is considered to be playing an important role as the feed for fish.
The present author had an opportunity to go through the Chaetognatha samples collected in the Harima-nada in the eastern part of Seto Inland Sea and in Osaka Bay from April, 1965 to March, 1966. The results obtained are as follows:
1) S. crassa was the most numerous species in the samples, and occurred nearly all through the year with maximum numbers in August. This species was numerically followed by S. enflata which appeared in great numbers in a period from September to December. S. bedoti and S. minima were the species which appeared sparsely in the samples, (See Table 1 and Fig. 2)
2) S. enflata was first seen in the beginning of July in 1965 in the southern part of Osaka Bay, and from that time on this species extended its distribution area northward in the bay. Up to the beginning of September the distribution front reached as far as the center part of the Harima-nada through Akashi Strait. After showing a little more expansion toward December, the population indicated falling tendency in January, and finally disappeared from the area in February. (See Fig. 3)
3) In the Harima-nada and Osaka Bay S. enflata was distributed mainly in the area with transparency of 5 to 10m. and seemed to be densely populated in the area of great transparen-cy. While no specimen was collected in the water mass with its transparency being less than 2m. (See Fig. 5)

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The enzymatic properties of hepatic glucose-6-phosphatase in fishes were investigated, and the results obtained were as follows:
1. Glucose-6-phosphatase, catalyzing specific hydrolysis of glucose-6-phosphate, was found in the liver of flying fish and yellow-tail. Its optimum pH and temperature lay at pH 6.0 and 40°C, respectively.
2. As a result of study on intracellular distribution of the enzyme, the highest specific activity was found in “Heavy microsome fraction”, in which 35% of the total activity was found.
3. The enzyme activity was rapidly decreased by preincubation at pH 4.0 ?? 5.5, but relatively stable at pH 7.5.
4. Apparent Michaelis constant was 3.6×10^-3M.
5. The enzyme activity was scarcely inhibited by glucose and inorganic phosphate at the low concentration, but considerably at the high concentration of glucose. Other hexoses and pentoses did not inhibit so much as glucose.
6. The enzyme activity was strongly inhibited by Mo⁶⁺, Hg⁺⁺, and Cu⁺⁺ at 10^-2 ?? 10^-3M, but neither stimulated nor inhibited by Ca⁺⁺ and Mg⁺⁺.

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Levels of glucose-6-phosphatase (G6Pase) activity in various fishes were investigated, and the results obtained were as follows:
1. The highest level of G6Pase activity in fish organs was found in liver, and low levels in kidney, digestive tract, pyloric caecum, and dark meat. But the enzyme was not detected in heart tissue and ordinary meat.
2. In the tested condition, the livers of marine or migratory fishes showed higher G6Pase activity than those of fresh-water or non-migratory fishes, respectively.

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The bactericidal effect of furylfuramide [2-2(furyl)-3-(5-nitro-2-furyl) acrylamide; FF], a newly permitted food preservative in Japan has been examined. And results obtained may be summarized as follows:
1. Bactericidal effects of FF and nitrofurazone (NFS) were compared each other by the official phenol coefficient method⁴⁾. S. typhi was killed off with FF at a dilution equivalent 1:10, 000 in 5 minutes which corresponded to 120 in terms of phenol coefficient number. To the contrary, NFS with 1:5, 000 dilution exhibited almost no killing effect on the same test organism in 120 minutes (Tables 1 to 3).
2. Bactericidal activities of FF and NFS against E. coli and Staph. aureus were measured at their growing stage in the nutrient broth containing varying concentrations of each of the drugs and exposed for different period of time. As shown in Fig. 1, E. coli was killed off with more than 0.2 ppm of FF, and Staph. aureus with more than 1.6 ppm of the drug within 6 hours of incubation. To the contrary, no marked killing effect could be seen with NFS even at 200 ppm (Fig. 2).
3. Similar bactericidal effects on the growing stage of E. coli and Staph. aureus were noted with FF which had been added to the tuna flesh infusion, however, the efficacy was slightly lowered as compared with that observed in the nutrient broth (Fig. 3).

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The wide distribution of Vibrio parahaemolyticus in coastal sea area has been reported by several workers in Japan. However, concerning the density of the organisms in sea water, no information has been given because of the lack of suitable method for their enumeration. A selective agar medium was deviced for this investigation and designated as AAC medium had the composition as shown in Table 1. Majority of V. parahaemolyticus utilizes arabinose as a carbon source and produces typical yellow colonies on AAC medium at 42°C, whereas most of closely related species can produce only greenish minute colonies and furthermore, the growth of usual marine flora can be inhibited.
After appropriate quantities of water sample were filtered through millipore filters, the filters were incubated on the AAC medium for 16-24 hours at 42°C. All typical yellow col-onies appeared on the filters were counted as colonies of V. parahaemolyticus.
A certain number of the typical colonies were picked at random from each millipore filter and the isolates were subjected to certain microscopic and biological examination for V. parahaemolyticus. In this investigation approximately 89 per cent of the isolates tested were proved to be V. parahaemolyticus as shown in Table 6. Using this procedure, the numbers of the organisms in pelagic and coastal sea waters, and estuarine waters were determined. None of the organism was isolated in the pelagic sea water samples even with 1000ml volume of them. On the other hand, it was revealed that coastal sea waters or estuarine waters con-tain 10⁰-10⁵ of V. parahaemolyticus per 1000ml in summer season.

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To establish the relation between ‘greening’ and TMAO concentration in raw fish, 108 albacores were examined. The results obtained are as follows:
1. The marked, uneven distribution of TMAO in the body muscle is observed and the highest level is always found in the tail end muscle.
2. Albacores containing TMAO-N lower than 8mg% in their tail end muscle do not show ‘greening’ when cooked.
3. At the TMAO-N level above 13mg%, most of the cooked loins take on ‘green’ color and degree of ‘greenness’ is roughly proportional to TMAO concentration in the raw muscle.
4. In the intermediate range from 8 to 13mg%, the ‘greening’ occurs at random.

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In the previous papers, it was reported that the fish muscle could be significantly lowered in freshness by autolysis rather than by bactrerial action during ice storage, and that post mortem changes of biochemical substances, especially of degradation products of ATP, should be more precisely elucidated in connection with freshness, as had already been shown by sever-al authors. From this point of view, the present communication deals with the changes in the concentration of free ribose and glucose in the plaice muscle during the ice storage.
At first, the recovery tests for added ribose and glucose were performed using the paper chromatographic determination method proposed by JONES. The recoveries were 51-74 per cent for ribose and 70-80 per cent for glucose, even when the aqueous solution of sugar was used as the sample (Table 1). On the other hand, the recovery percentage of 92 for ribose and 94 for glucose was obtained with the extract of muscle by applying FERNELL's method for simultaneous determination of pentose and hexose (Table 2). In this experiment inter-fering substances such as amino acids and nucleotides were removed according to JONES' de-scription.
The ribose content of plaice muscle increased almost linearly during the ice storage, and did not show any symptom of decrease even after 17 days' storage examined here (Fig. 1). It might be supposed that bacterial activity was not so high as to induce a significant decrease in ribose content, although the muscle was already much lowered in freshness at that time. And there was observed the stoichiometric relation between ribose and hypoxanthine accumu-lated during the ice storage (Fig. 2). Glucose was significantly increased for the first 9 days of storage and thereafter was gradually decreased.

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