Volatile acid and indol were determined as to the judgment of quality for the cured whale meat from Antarctic waters. The analytical results are well agreed with organoleptic examination and the to correlation between volatile acid and volatile basic nitrogen is also significantly confirmed (Correlation coefficient was 0.85). This fact will be reasonably explained that the amount of volatile acid corresponds to that of ammonia nitrogen as the result of deamination of amino acids.
It was disclosed by Behrens method that in the post-spoilage of the cured meat, lower volatile acid such as formic possesses major part among total acids, while higher acid like iso-valeric is encountered in the cured meat of fancy grade. Thus, in addition to quantitative determination, it will be necessary to detect each volatile acid, especially formic acid, as effective method for the inspection of cured whale meat.
Indol test can be also recommended as serviceable way for evaluating spoilage of the cured meat.

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Paper chromatographic isolation of individual volatile acid in the spoiled Cured whale meat was made according to the method of Fink and Fink (1949). About 450 mgms of total volatile acids were obtained from 350g of sample and converted to mixed esters of the acids, then the esters were synthetized to Potassium hydroxamates. A drop of this hydroxamates in methyl alcohol solution was deyeloped by n-butyl alcohol on one-dimensional filter paper. Saturated Fecl₈ solution (in butylalcohol) is sprayed on the paper after development is completed. As Rf values of dark purple spot are agreed with that reported by Fink and Fink, the writers assumed the existence of butylic, propionic, acetic and formc acid in the sample (Fig. 1) and this result is also proved by Behrens' petrograplic microscopic method.

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Distribution of free amino acids in fish muscle was examined by means of paper partition chromatographic method. The type of amino acid in the muscle, which was tested immediately after killed, differs markedly with species of fish; namely, flesh rich in muscle pigment such as tunny fish or sardine is characterized by its histidine content, besides those belonging to white meat, like as sole or barracuda is lacking for free histidine. It is conceivable that the presence of this amino acid will effect to the palatability of fish meat, for example, yellow tail fish is known as one of the most tasty flesh; the result of paperchromatogram shows the presence of histidine.
Special reference will be paid for the occurrence of proline in squid muscle. Probably sweet taste experienced for the flesh squid of cuttle fish is affected by the presence of this amino acid.
The kind of amino acid fo and in hydrolysates of various fish meat cannot be distinguished each other, nevertheless, in the stage of spoilage some peculiarity was observed. As progress of decomposition usually more basic amino acids become to appear than the case of fresh state.
It is noteworthy that free proline in the squid muscle disappears after 2 or 3 days' spoilage, explanation for this phenomenon is not yet approached, however, it will be expected that this amino acid serves as important factor for mutual oxidation and reduction in the break-down of other amino acid co-existing in the muscle.
It was also found that shark meat is more difficult to generate free amino acid than other teleost fishes by spoilage, and perhaps the shark protein may be spared by the expense of urea which is highly contained in the meat, and is saved from bacterial attack.

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The methods hither-to presented for estimating the freshness of fish-flesh have made use of either organoleptical, bacteriological, physical or chemical principle. Of these, the chemical method has been widely used because of its reliability³⁾. Recently, certain simple and feasible chemical methods have been reported by Amano¹⁾, and Mori²⁾. All of these methods naturally require certain amounts of flesh to be tesed. It will certainly by practical, however, if it is possible to estimate the freshness of the flesh by examining a certain part of fish other than the flesh. An attempt has, accordingly, been made to estimate the freshness of the flesh by determining the catalase activity of the gill. The results obtained can be summarized as follows.
1) Nearly no change in catalase activity of the gill has been observed during the progress of lowering in freshness of the fish when the homogenized gill has been used for the estimathion. This implies that the catalase activity of the bacteria which propagates on the gill, may by negligibly small.
2) A remarkable increase, however, in catalase activity with the increase in the volatile base of the flesh has been noticed when the gill has been used for the estimation without homogenizing it.
3) A preliminary experiment has been made of the estimation of the catalase acitvity by a manometric apparatus..
4) So far as the kinds of fish have been examined, an almost similar value in the catalase activity of the gill has been obtained at the time when the flesh contains 30mg of the volatile basic nitrogen per cent of the flesh.

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A further elaboration has been made of the apparatus for estimating the catalase activity of the gill by the manometric method, From the practical point of view, the catalase activity can be expressed as the reading of the mercury manometer at three minutes after mixing 400mg sample gill with 5cc 3% hydrogen peroxide.
On exposing the gill to toluene vapor, on one hand, and water vapor, on the other, for 72 hours at 30°C., it has been shown that the increase in catalase activity of the gill with the lowering of the freshness is due to the decomposition of surface layer of the gill, the catalase-rich tissue being exposed to hydrogen peroxide. An intimate correlation between the catalase activity of the gill and the amount of the volatile basic nitrogen has been found when these two estimations have been made on the carp stored at 30°C. after being killed by stabbing a needle into the brain tissue.

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The swelling of fish muscle immersed in acid solution was observed.
(1) The maximum value of swelling (muscle of Ommastrephes sloani pacificus) is shown in the solution of PH=1.8-2.0
(2) In acid solution of various pH values the water content of the muscle immersed and the amount of nitrogen dissolved from it change in the same tendency with the degree of the swelling.
(3) The ionic strength of acid has an important effect upon the swelling of muscle.
(4) In the muscle protein of Ommastrephes sloani pacificus the isoelectric point is pH=3.5 ?? 4.0 and in that of Cyprinus carpio it is pH=4.2.

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In the process of putrefaction of shark muscle, the step is generally found ro exist on the ammonia-developing curve that shows the unthoroughl decomposition of urea to ammonia. In the present paper, we observed it to be responsible for setting of shark muscles during storage.

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On measuring the amount of urea contained in muscles and different parts of elasmobranchiate fishes, we obtained the results as shown in Table 1 and 2. And since we have observed developing of urea in their minced muscles during storage, we presume that Krebs's “Ornithine Cycle” is proceeding in dead shark muscles.

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With a view to sterilization of food to which is transmitted with electric current, we observed on the quantum developmeut of chlorite and chlorate from the sodium chloride solution when it is electrolysed by direct current.

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we studied the distribution of the proteolytic enzyme in the body of sardine and confirmed the existence of the proteolytic enzyme in pyloric caeca, stomaca and muscle but intestine.
The optimum PH of the proteolytic enzyme in the pyloric caeca was about 8.5 and the opt-imum temperature was about 35°C. The activity of this enzyme was destroyed completely by heating of 95°C for 3 minutes.
From the results obtained by the determination of amino-and non-amino-soluble nitrogens it is assumed that there is only trvpsin-like ferment in the pyloric caeca.

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When a certain copper plate is immersed in water. the amount of copper ion dissolved from it increases proportionally with the lapse of time at the definite hydrogen ion cocentration. and the dissolved amount in acidic side is grater than that in alkaline side within the definite time.
The amount is also influenced by the quality of a copper plate.

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The Japanese are unparalleled as a nation fond of eating fishes and seaweeds. Generally speaki-ng, sea-weeds are indigestible, and their carbohydrate is less digestible than that contained in other foods. Therefore, in utilizing sea-weeds, it is necessary that attention should be paid to that point, and steps taken to correct it and fully utilize the nutrition value of sea-weeds.
Sea-weeds, when used as a fertilizer, should be decomposed in advance to make their abs-orption by crops easy.
For the above purpose, we made this experiment by isolating a certain specific bacillus and inoculating it to sea-weeds. This bacillus is similar to Bacillus subtilis, and in this experiment we used Eisenia bicyclis (Kjellm), Ecklonia cova kjellm, and Laminaria japonica Aresch among phaoephyceae In summer they were left alone at a room temperature of 27-31°C, and in other seasons in an incubator (25°C).Their decomposition was recognized in 5-20days. Decomposition of Laminaria was found to be somewhat inferior to other sea-weeds.
Change in chemical composition and methods of utilization of sea-weeds shall be mentioned in our second report.

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The present study aims to ascertain how the microorganisms play upon the spoilage of “Kamaboko” which does not contain sugars.
After standing for several days at room temperature, when the spoilage takes place, from the substances of the surface the ager plate culture was carried out by the ordinary method.
The number of the colonies of microorganisms grown on petri-dishes was shown in the Table 1.
The classification and the identification of all of these mioro-organisms (excepting yeasts) were made depending upon Bergey's method. The results obtained were as shown in Table 2.
From the results it is evident
1. That “Kamaboko” which does not contain sugars is spoiled principally by the action of microorganisms originated from dusts in air, and that the spoilage little be caused by the bacteria originated from the others, such as water bacteria grow well on media contained large amount of moisture, because these bacteria hardly grow on media contained comparatively less amount of moisture as “Kamaboko”.
2. That “Kamaboko” which does not contain sugars is spoiled principally by the action of Micrococcus belonging to cocci and of non-motile rods among Serratia, Flavobacterium and Achromobacter belonging to non-spore former, but the spore forming rods can have their action to some extent on the spoilage of “Kamaboko” in a hot season.

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The present paper is the supplement of my previous work which has been reported on the microbiology in the spoilage 1, and embodies my observations on the appearance of the growth of the bacteria isolated on the surface of “kamaboko” which does not contain sugars.
It is presumed that the “kamaboko” is spoiled principally by the action of bacteria originated from dusts in air, and that when it is kept in the air which has considerably higher amount of moisture the spoilage takes place principally by the action of spore forming bacilli.

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By the present author it has been reported that the bacterial decomposition of “kamaboko” occurs not only in the exterior but also in the interior and that in the exterior the decomposition takes place by the action of microorganisms originated from dusts in air.
The present study aims to ascertain how the microorganisms play upon the decomposition in the interiot of “Kamaboko”
From the substanes of the interior of spoiled “Kamaboko” the agar plate culture was carried out by the ordinary methed.
The number of the colonies of microorganisms grown on Petri dishes was shown in the Table 1.
The classification and the identification of all of these microorganisms were made depending upon Bergey's method. The results obtained were as shown in the Table 2.
From the results it is clear that the interior of “kamaboko” is decomposed principally by the action of spore forming bacilli originated from soil. It seems that these bacteria presented in the interior of “kamaboko” are supplied from the refined starch which is one of the raw materials.

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In our previous paper, it has been reported that the interior of “Kamaboko” is decomposed principally by the action of spore forming bacilli, and which seem to have been supplied with the starch used as a kind of raw materials, and that tite preservative period of “Kamaboko” appear to be influenced by the degree of the microbiological contamination of the starch used.
But, the microbiological studies of refined starch are still meagre and do not seem to have been reported.
The present paper embodies our observations on kinds and amounts of microorganisms in the refined starch on the market.
Results obtained are as shown in Tables 1-3.
In any one of the starch examined. ca. 10, 000-50, 000 of bacteria per gram are found to exist and the most of them are in mode of, spores. About one half of the spores are those of Bacillus megatherium. The others are classified into 6 kinds belonging Genus Bacillus.
These bacteria presented in the starch clearly seem to have been originated from soil.
Also, from the Table 1 it is evident thatr the content of molds in anyone of the starch exa-mined is nearly the same of or less than that of bacteria in it.
The degree of the microbiological contamination of the refined starch is independent of the grade which is decided by physical and chemical natures.

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As for the agar-decomposing enzyme, previous works (Gran, 1902; Oshima, 1931; Mori, 19-39) have merely been concerned with the existence of such enzyme in some kinds of organisms, and, therefore, our knowledges of this matter are far from being satisfactorily unders tood.
Such being the case, the present author attempted this study from various standpoints in order to clearly made out chemical behaviors of this enzyme in some extent.
In the first place, factors affecting the activity of the enzyme of a kind of marine bacteria Vibrio purpureus were preliminarily studied in the following procedure:
1) A semifluid medium, 0.2 per cent agar, was incubated at 25°C after being inoculated with an active culture of Vibrio purpureus. Afer 96 hours, incubation the culture was filtered by Chamberand's Filter and it was used as the crude preparation of the enzyme.
2) The effects of temperature and pH value on the activity of the crude enzyme preparation described above were studied by estimating the amount of reducing sugar produced or by measuring the decreasing rate of relative viscosity.
The results obtained are illustrated in Fig. 1 and Fig. 2.
From the data it seems very probable that the optimum temperature is at around 40°C and the optimum pH value is approximately 6.0
3) The decomposing process of agar-agar by the crude enzyme preparation was observed by the following method:
Reducing sugar and relative viscosity of the reaction mixture (0.3 per cent agar solution 40 Occ+McIlvaine's buffer solution of pH 6.0 200cc) were determined after various period of reaction at 40°C.
The results obtained are shown in Fig. 3.
The velocity constant of the reacton calculated from this results by using the monomolecular equation was shown in Table I.
From this table it is obvious that the rate process obeys the monomolecular reaction within a certain limited range.
4) The effect of NaCI upon the activity of the enzyme solution which had previously been dialysed in running water for five days dy using the collodion membrane was observed by the usual method.
The results obtained are illustrated in Fig. 4. From the data it was found that the optimum concentration of NaCI for the actvity of the enzyme is nearly 3.5 per cent.

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1. A synthetic medium of the following ? was ? to be suited for the culture (enrichment and isolation) of marine aerobic cellulose-digesting bacteria.
NaNO₃ 0.5g
K₂HPO₄ 1.0g
MgSO₄. 7H₂O 0.5g
FeSO₄. 7H₂O 0.01g
Filterd sea-water 1000.0g
Filter paper a strip (13cm×1cm) in each tube.
2. Seasonal variation of number of aerobic cellulose decomposing bacteria in sea-water (sa-mpled from Maizuru Bay) was observed.
3. Aerobic cellulose-decomposing bacteria which predominated in sea-water in different seas-ons were purely isolated and were classified into 3 species, viz., Vibrio purpureus, Vibrio pu-rpureus var, albus and Cellvibrio flavescens var. marinus, after detailed taxononical studies.
In sea-water the Vibrio predcminated in summer and the Cellvibrio outnumbered the Vibrio in the other seasons.

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The prawn, Pandalus kessleri, is commercially important for canning purpose in East and Notth-Eastern coasts of Hokkaidô. Dealing with a large number of specimens taken monthly from Notsuke Bay and Lake Saroma, a bionomics has been carried out, in which the follow-ing 8 items fundamental for conservation of the prawn were treated, viz., growth, weight-le-ngth relationship, secondary sexual characters, sex-reversal, size and numder of eggs produced, spawning season, larvae, food and digestive organs. Derail account of these items has been set fotth in English on the Journal of the Tokyo University of Fisheries, 38 (1), 1 ?? 26, 1951. Wherefore one would be referred to it.

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Nine species of the Cymothoid Isopoda parasitic in the buccal or abdominal cavity of Japanese fishes are described in this report. They are Codonophilus trigonocephalus (Leach), Rhexanella verrucosa (Schi ?? dte & Meinert), Indusa minabensis n. sp., Cymothoa pulchra Lanchester, C. eremita Brünnich, Livoneca sacciger Richardson, L. samariscii u. sp., Irona melanosticta Schi ?? dte & Meinert, and Ichthyoxenus japonensis Richardson, and are parasitic in due order on Caranx (Longirostrum) delicatissimus (Döderlein), Pagrosomus major(Temminck & Schlegel), Chaunax fimbriatus (Hilgendorf), Diodon holacanthus Linné, Aulopus japonicus (Günther), Synaphobranchus pinnatus (Gronow), Samariscus japonicus Kamohara, Hyporhamphus sajori (Temminck & Schlegel), and Acheilognathus sp. All of them except Ichthyoxenus japonensis, which lives in the abdominal cavity, are discovered from the buccal or branchial cavity of the host. Cymothoa pulchra is recorded for the first time from Japan. The two new species are defined as follows:
Indusa minabensis n. sp.: Female 23mm×13mm, nearly symmetrical and highly convex above. Head triangular, with distinct eyes. Antennae comparatively long and slender; those of the lst pair contiguous at the base, 8-jointed, and the 2nd pair longer being composed of 11-12 joints. Thorax oval in outline; antero-lateral angle of the lst segment not produced, but angular. Lateral parts of all thoracic segments slightly expanded having round post-lateral angle. Epimerae in the 2nd to 7th segments, narrow and linear. Basis of pereiopoda without carina. Abdomen one third as long as body; anterior segments covered by the 7th thoracic segment in lateral regions. Pleotelson more or less circular. Peduncle of uropod somewhat acuminate at inner distal angle; exopodite longer than endopodite. Male 10.5mm×5.0mm, relatively narrower than the female, symmetrical and slightly convex above. Head triangular, with distinct eyes. Both pairs of antennae comparatively longer than in the female, but composed of the same number of joints. Thorax oblong, with narrow epimerae. The lst abdominal segment not covered by the thorax. Pleotelson with margin round but more or less notched.
Livoneca samariscii n. sp.: Represented only by a female. 10.1mm×5.9mm. Body only slightly convex above, asymmetrical having one side more expanded than the other, and with mar-supium vaulted but empty. Head triangular, very little immersed in the thorax, and with dis-tinct eyes. Antennae slender and long; those of the lst pair separated at the base, 8-jointed; the 2nd pair longer and 10-jointed. The lst thoracic segment sinuated in front, having anteriorly curved lateral parts and with angular antero-lateral corner. Other segments directed more or less obliquely backwards in lateral region and with anteriorly arched posterior borders. Epi-merae very narrow, linear, and shorter than lateral margins of segments. Pereiopoda without ca-rina on the basis. Abdomen nearly one third as long as body. The first 5 segments curved anteri-orly; lateral parts of anterior segments covered by the thorax on one side. Pleotelson semicircu-lar, two thirds as long as wide. Basis of uropod angular at inner distal corner; exopodite longer than endopodite. Lamellar maxilliped has anterior margin bearing a few short plumose setae and a palp tipped by 2 hooks.

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The female Erimacrus isenbeckii is somewhat smaller than the male one, and it is due to the fact that the molting and the growth of the female is restricted by the incubation term as long as one year or more. In Chironececetes oplis, the female is remarkably smaller than the male. The female crab neither molts nor grows after the first maturing, and there occurs a remarkable difference in size between the male and the female. In Portunus trituberculatus there is no sexual dimorphism in size, for the incubatoin period of the female is only 2-3 week and the molting of the female is not restricted.

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Two allied species of Phocaenoides are found in the Japan waters. Phocaenoides truei (called “Rikuzeniruka” in Japan) is distributed in the northern region of the pacific coast of Japan and migrate twice in a year. Its spring migration begins in February from south to north, from off Choshi, China prefecture to Kurile Islands. The autumn migration begins in September, from Kurile Island southward to off Fukushima prefectue, or off Choshi, Chiba prefefecture.
The otherspecies, Phocaenoides dalli (called “Kitairuka” or “Ishiiruka” in Japanese) is found mostly in the Japan Sea. They are observed off Tajima, Hyogo Prefecture from the end of February to the middle of May and in the middle of June off Akita Prefecture and from the end of June to the beginning of July along the Hokkaido coast. They have occurred in Ohkotsk Sea in Jul and August and disappeared at the beginning of September. They may probably go down to south of the Japan Sea in the autumn. Both species have definite breeding season as other mammals. In phocaenoides dalli, this season is suspected during the end of June and the beginning of July, abo ?? t one month duration. The reason is that almost specimens of the presnt species, provided with sm ?? ll embryos of 5.5mm in body length, were collected in August in Okhotsk Sea. The copulation therefore must have occured before this season. The delivary period may cotinued about seven to nine months, as for the reason of following facts. The adult with emdryo of 5mm body length was caught commonly in the Okhotsk Sea during the summer from June to August, while the adults collected off Tajima, Japan Sea, during March and April are mostly finished the confinement or with large foetus of 1 meter body length.
The detailed descriptions of the embryos will be made in the Miscellaneous Report of the Faculty of Fisheries, the prefectural University of Mie in near future.

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The composition of the plankton in the Straits of Tsushima is simplest in July. In August and September many species of plankton were found. One hundred and two species of plankton were identified from the samples collected in the Straits of Tsushima during the period from July to September.
In this region the temperate oceanic plankton, such as Ceratocorys horrida, Copilia mirabilis, Ceratium reticulatum f. contortum, Sticholonche zanclea, Haemiaulus Heibergii, Tricodesmium sp., were more abandant than the neretic plankton were only found in South region of the Eastern China Sea.
We are inclined to think that at the Straits of Tsushima the plankton were greatly influenc-ed by the warm currents in summer.

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The genus Petroschmidtia was established by Taranetz and Andriashev (1934:507) for the accommodation of their new species P. albonotata taken from the Okhotsk Sea. In 1941 an another species, P. toyamensis. was added to this genus by Katayama (1941: 593, fig.) based upon a specimen obtained from Toyama Bay. Several specimens of the latter have since been obtained by the sane author (Katayama, 1940:330;1949:73) from Toyama Bay, and off Tsuiyama, Hyogo Prefecture, both in the Japan Sea.
Recently we obtained 25 specimens of the outstanding species identical with P. toyamensis, varying from 100.5 to 402.0mm in total length, from Toyama Bay, and off Tsuiyama, Hyogo prefecture. These were taken at a depth of about 125 fathoms by means of deep-sea trawlers, and they are now deposited in the Fisheries Dept., Faculty of Agr., Kyoto University. Upon careful examination of these specimens we found some remarkable variations between them due to their age and sex. We, therefore, fully treated this fish in order to make out these differen-ces satisfactorily as well as to supplement the rather brief original description of this species.
The genus Petroschmidtia is closely related to Lycodes. a genus of Zoarcidae, and is apparently an off-shoot of that genus. For establishing the genus Petroschmidtia to accommodate P alb-onotata, Taranetz and Andriashev (1934:510) wrote “The genus, Petroschmidtia differs from the genera Lycodes Reinh. and Aprdon Gilb. by the absence of teeth on the vomer as well ac on the palatines and also by the absence of pyloric coeca”. Besides these differences, we found a remarkable difference in structure of pelvic fins between these genera, as it will be seers later on.
The various parts of a body were measured in the same way as the senior writer had done in his previous studies on the scorpaenoid fishes of Japan (Matsubara, 1943:6-7). In the present study we carefully observed the pelvic fins, teeth on jaws and gill-rakers by staining with alizarin red, and clearing with potassium hydroxide.
We wish to express our hearty thanks to Mr. Hachiro Kinoshita of Uozu, Toyama prefecture and prof. Masao Katayama, of Yamaguchi University, for their kindness in supplying us some of the specimens which we used in the present study. Through the courtesy ofthe latter, it has been possible to re-examine the holotype and to make an evaluation of this species. The expenses for pursuing the investigaton of this work were defrayed by a grant of the Ministry of Education.

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In the present instalment 186 individuals of as kate, Raja hollandi Jordan et Richardson, which were taken during three seasons in 1950, were analysed by the same method as given in my previous report, and obtained nearly the same results. Namely, the calcified rings of the centrums are considered as the annual rings of the skate, which should be formed during the winter.

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1 Black croaker can be caught throughout the year, but there are two fishing seasons March to July and October to September, especially we can get a larger quantity in May.
2 The good fishing grounds are divided into three regions-nothern, central and southern and the southern area is the best. (See Fig. 2)
3 The migration, differring in each area and race, is in close connection with oceanic current, namely the northern and southern croakers migrate in the meeting bounds of currents, and the central ones travel in warm current. However, I presume these schools of croaker in the central and southern area migrate and alternate reciprocally their places.
4 The length of fish caught by trawler is 10.5-45.2cm, and the most general size of fish is 19-23cm. Its average length is 22.429±0.056cm. This formation varies according to the fishing ground, sex, season and netting.
5 The lergest fish can be found in the northern fishing ground, and the smallest one in the southern part-the length of fish becomes larger and larger as we advance to the north.
6 The female is 11.7-46.9cm in length, its average length is 22.493±0.093cm-and the, male is 11.2-42.6cm in length, its average length is 22.997±0.094cm, so the female is bigger than the male.
7 The length of fish vary according to each fishing season-the largest in May and June, the next in October and September, and the smallest in August, the next in April. This difference refers to the spawning migration.
8 The length of fish is various in each netting, for school is formed by different ages, sizes, etc.
9 It is presumed that the spawning season continues from April to June.
10 The relative formula of body length (L) and weight (W) is shown as follows: W=0.002 03L^3•40?? The growth rate is high in northern area and in female.
11 The relative formula of body length (Lcm) and ovarian weight (Ogr) is shown as follows O=0.0000154L^5•345
12 When the body length reaches 22-23cm, the number of ova varies from 60, 000 to 550, 000 and it increases in proportion to the length.
13 The water temperature for catch is 12.4-21.8°C, and it is different according to a fishing season. The most favorable temperature for catch being 18.5-20.0°C, and the optimum temperature is 17.5-22.0°C.
14 The fishing depth of water is 45-100 meters, and its proper depth for catch is different in every fishing season; it is deeper in April, October and September, and shallow in May and June.
15 The relation between the moon age and the fishing rate per haul in almost all seasons is concluded as follows: The fishing rate increases at the neap-tide, and decreases at the major tide in Feb., Apr., Aug. and Sept., but the contrary phenomenon is shown in May and June, and this relation does not exist in March and July.
16 Generally speaking, croakers can be abundantly caught in daybreak or twilight, except daytime in October.
17 There is a tendency to find school of black croaker in the benthic region occupied by abundant Macrura and Steroidea.

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(1) The writer got on board from Feb. 18 to March 9, 1948 and investigated ecologically Red Gurnards in the Yellow Sea.
(2) Popularly called Gurnards, Lepidotrigla microptera, form dense schools in the SouthernYellow Sea in winter, and these schools do not migrate to the lower latitude than 32°30'N.
(3) Body length composition was in the range of 9.6-29.6cm and the most abandantly capt-ured individuals measured 13.0-27.0cm in length. Average body length of the female was 19.78±3.24cm, and that of the male was 19.78±2.185cm. The male amount to 56.67% of the whole.
(4) Relation between body length and weight was represented as follows:
w=1.7186L^0.250l
(5) Relation of weight between body and ovary was represented as follows:
EW=0.000006324 BW²⁷⁰¹
Average number of incubation was 140, 000, and diameter of ovum was comparatively sm-all being less than 0.8mm.
(6) In the fishing season body length was various according to depth. Schools of big gurnards have a tendency to travel in deep water and small ones in shallow.
(7) The proper depth for catch was in the range of 65-70m, and the best depth for catch was 69m. And composition of body length of the fish caught in the depth of 65-70m were 20. 10±2.408cm.
(8) Quantative variation of catch according to age of the moon was found. (Fig. 7). Kindsand quantity of bait were also changeable. (Fig. 8).

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The writer have studied on hatching rate of Ioaches' eggs putting them into the water with various degrees of PH controlled by HCL or NaOH
The optimum PH for hatching was found to exist between 6.0 and 7.2 the hatching rate was much higher in the acid water than in the alkaline. The range of PH for hatching lied between 3.8 to 10.0
In the course of experiment the rates of died eggs after fartilization to total died eggs were observed as follows:
In the 1st experiment. 0-3 hours after fertilization……acid side was larger than alkaline side; 3-7 hours after fertilization……alkaline side was larger than acid side; 7-18 hours after fer tilization……acid side was larger than alkaline side.
In the 2nd experiment. 0-4.5 hours after fertilization……acid side was larger than alkaline side; 4.5-8 hours after fertilization……alkaline side was larger than acid side; 8-19 hours after fertilization……acid side was larger than alkaline side.
Malformed fishes were found only in both strong acid and alkaline waters.

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The Present paper embodies my observations on the influence of the foul-water flowing into the Mitaziri Bay from Kiyowa Fermentation, Takara Brewery and Nippon Cellulose Company on the water of the bay. The results obtained are as follows.
(1) It seems that the death of fishes in the Mitaziri Bay is ascribed to the organic matter contained in the foul-water.
(2) The influence of the foul-water is observed in everywhere in the bay, and particularly in the central part of the current tide on the ebb.
(3)The foul-water is remarkably mixed up in upper layer.

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The result, concerning the dominant or characteristic association of the benthos, in the five regions of the East China Sea and the Yellow Sea, is shown in Table ? and Fig. 1.
The relation between the good fishing ground of every valuable fish and the characters of benthos in five region is reported in this paper.
The benthos of A region is occupied by Holothurioidca, Macrura, Brachyura, and white or Yellow croacker-especially bottom fish fauna.
As for dominant and characteristic group, the following relation was found:-Ophiuroidea to Yellow croacker in B region; Asteroidea, Gastropoda to ribbon fish and yellow sea bream in C region; Cephaloda and Tetraxonida to lizard fish and gurnard in D region; Asteroidea to Black croacker in E region.
These valuable fish coincide with the majority of benthos in the superior fishing grounds, but the relation between the food habit of fish and benthic quality is unknown; the result of researches for the environmental factors managed by the majority of benthos was that oceanic current has a considerable influence upon them.

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We studied on the age composition and circulii of the black croaker which were caught in the East China Sea.
As to its age composition, numerous groups of the aged fish are found in the northern area, the less groups in the central area and moderate number of the groups in the southern area.
The survival rate shows the value of 0.698 or 0.668.
We could classify the scales into three types according to the circulii and their compositions differing in the fishing area, namely, percentage of A type circulii is 68% in the central or southern area each, B type is 63% in the northern area, and C type is moderate in every area.
In the fish caught in northern area the growth rate is good and the number of circulii in L₁ and L₂ annual ring is less than those taken in the central and southern area.

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Biological and ecological investigations on the Japanese anchovy caught in the Inland Sea of Yamaguchi prefecture was performed from September, 1945 to September, 1950. The items studied were as follows: (1) body length, body weight, state of gonad, sex ratio, and vertebral counts; (2) relation between the body length and the body weight; (3) change of condition factors; (4) biological minimum size; (5) race investigation basing on the vertebral counts; (6) spawning seasons, and (7) number of eggs. Some considerations on the course of migration were added.

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The body length (L.cm) and the body weight (W.gr)of Paralichthys olivaceus (T.etS) caught in the Inland Sea of Yamaguchi Prefecture may be shown by the formula -W=0.00104L^3•795 The length of body (Lb) and that of the scale (Lc) may be represented as follows:
Lb=11.875Ls+2.297
The results of age estimation obtained from its annual rings are summarized in Table 2.
The number of radii on the scale fluctuates remarkably, but we can see a tendency to increase in number in accordance with the growth of the scale.

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The shrimps are important fishery resources in the Inland Sea of Yamaguchi Prefecture. This paper deals with the size, sex retio and relation between the carapace length and the weight of three kinds of shrimp.

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In some animal associations the number of individuals of each species approximately form a geometrical progression, when the numbers are arranged according to the rank of their numbers of individuals. This phenomenon has been named by Motomura (1932) as “The law of geometrical progression of the population, density.” The empirical formula for the same being;
logy+ax=b, ……(1), where y represents the number of individuals of each species and x the rank of the species according to the number of individuals. Utida (1943) and Motomura (1947) gave a theoretical interpretation for this law, assuming the struggle for existence of animals in the habitat. I have examined statistics of catches of several kinds of fishes and found that if y is replaced by the total weight of catch of each species and x is the rank of the species according to the total weight, the equation (1) holds.

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(1) To describe the relation between the fishing effort and the amount of catch the normal regression coefficient, calculated stochastically, is used in place of catch per unit effort.
(2) A mathematical method for testing the significance of the difference as well as for estimating the ratio of these coefficients is divised.

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Under a certain environment, as the number of immigrant fishes aged a years may be assumed to have a certain upper limit, n, and as the survival. rate, ρ, and the fishing rate, f, may be assumed not to vary, then the next relation may be considered nearly to hold between the number of immigrants, n, and the number of parents, ρ^p-an/1-ρ;
dn=bnn/nd (ρ^p-an/1-ρ),
in case the p-aged female begins the first spawning and any parent bears b immigrants in every year when the population is very poor. By solving this equation, we know that n/n _??_ 1 when b ρ^p-a/1-ρ_??_3
Putting ρ=ρ_??_ when f=o, and putting b ρ^p-a/1-ρ=3, then the maximum value of the fishing rate, f, allowable ro conserve the fish population may be expressed by f=1-ρ/ρ₀. And assuming that the amount of the population is x times its original value, then x=1-ρ₀/1-ρ.

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