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福島県松川浦において，サキグロタマツメタの分布や駆除実態を調査した。その結果，本種が他の水域からのアサリ移植種苗に混入していることを確認した。分布の初記録は 2002 年 5 月にみられ，その後 2004 年にかけて松川浦全域へ拡大した。2004 年から 2010 年にかけてサキグロタマツメタの分布密度は大きく低下しておらず，アサリ食害軽減のためには駆除努力を強化する必要があると考えられた。

小型底びき網漁船における曳網能力の制限下で離着底兼用トロール網を用いるため，現用オッターボードの性能評価を行い，その性能を基準に離着底が可能で，かつ揚抗比のより高いオッターボードを設計・試作して現用オッターボードとの性能比較を行った。模型実験において，操業に用いる迎角における新型オッターボードの抗力係数は現用オッターボードよりも小さく，揚抗比は現用の 1.41 倍となった。また，曳網実験における新型オッターボードの離底時の間隔は，現用の着底時に比べ 1.1～1.2 倍となった。

伊勢湾の機船小型底びき網漁業で使用される 2 つのトロール網とオッターボードの構造を明らかにした。トロール網はいずれも長方形の網地を多用した構造で，製作と修理のし易さおよび網地の合理的な使用に配慮した設計であった。これらの漁具の曳網実験を実施したところ，シャコ対象の網とスズキ対象の網の網高さと漁具抵抗はそれぞれ，1.47～1.79 m と 11.47～16.74 kN および 1.61～1.84 m と 11.56～16.10 kN で，大きな相違は無かった。漁具抵抗の最大値は漁船の曳網能力の上限を反映していると考えられ，漁具改良を行う場合には，漁具抵抗を最大 16.74 kN 程度に抑える必要がある。

A starvation experiment and diet successive sampling were carried out to quantify the diet feeding rhythm and the daily ration of O-group crimson sea bream Evynnis japonica in Shijiki Bay, northwest Kyushu, from June to July in 1981 and 1983. Changes of stomach-contents weight in the starvation study were well applied to both exponential and square root models, with no significant difference in fitness. Evacuation rate of smaller fishes was found greater than that of larger fishes.The diel feeding rhythm was determined by MORISHITA's (ELLIOTT and PERSSON's) method to estimate food consumption using the gastric evacuation rate gained from the starvation experiment. There were three peaks in feeding activity: morning, noon and evening, with the largest peak occurring at noon time. The daily rations were 5.6 and 5.5% of body weight per day in 1981 and 1983 respectively.Clear differences were found in main food organisms and the diel feeding rhythm between the present species and the red sea bream, Pagrus major, a closely related species. The main food of the former was Polychaeta, whereas that of the latter was Gammaridea. The feeding time of day when fishes feed most actively was observed at noon for the former, while at dawn and dusk for the latter. We presumed that these differences would serve to reduce the interspecific competition for limited food resources between two related species cohabiting the same nursery ground.

The spawning and settling periods of Japanese flounder Paralichthys olivaceus (Temminck et Schlegel) were examined in Shijiki Bay and its vicinities in 1986.The start and end of spawning and settlement were estimated from development-temperature relationship of laboratory-reared flounders and developmental stage composition of pelagic larvaeobtained by larva-net surveys in mid March and mid May. These analyses demonstrated that spawning would start from late January and continue until early May, and settlement from early April through early June. The settling period was also confirmed directly by beam-trawl sampling. These evidences revealed that three months of spawning season are reduced to about two months of settling period because while pelagic life is prolonged in the early season, it is shortened in the later season due to increasing water temperatures.During the two months of settling period, a large size distribution in settled flounders would inevitably occur, which would possibly cause cannibalism Furthermore, size at metamorphosis of flounder decreases considerably with increasing water temperature. These factors which are directly related to survival of settling flounders are considered important in analysing recruitment dynamics.

The regular bioassay method for determination of chlortetracycline (CTC) residue in tissues1, 2, 3, 4) presents a difficulty when dealt with many samples for the analysis. Experiences have revealed that such procedures are very tedious as washing and drying of many Petri dishes, the preparation of assay medium in each dish and the standard curve for each set of determination. Attempt has been made, therefore, to simplify the method without sacrificing its accuracy. It was ascertained that routine procedures could be greatly simplified by substituting the Petri dish with glass plate as was reported by GRADY and WILLIAMS1a). It was found that the slope of inhibitory zone size on logarithm of CTC concentration remained constant irrespective of difference in plate and date of the determination. Therefore, the preparation of the standard curve at each determination can be omitted by employing the linear regression line instead when it is calibrated for the difference in zone size for 0.01mcg/cc between the regression line and a sample test plate.

In the course of study on chlortetracycline (CTC)-residue in the antibiotic-treated food, a possibility was presumed that CTC-residue of salt-dried fish might give a lower value probably due to the inactivation of CTC by oxidized oil, or might give a higher value due to the growth inhibition of the assay organism by the presence of sodium chloride in a sample extract. Furthermore, experiences in our laboratory revealed that the inhibitory zone size became smaller in hot season. Therefore, the present study was undertaken to modify the procedure so that the method can deal with such sample possessing salt and fatty acid peroxide and also can give a higher sensitivity even at high room temperature. It was shown that a factor responsible for the inactivation of CTC probably peroxidic free radical occurred markedly when the concentration of acetone was increased. It was observed that when acetone-citrate extractant was employed, salt effect occurred in a sodium chloride concentration range above 2%. It was found that the error due to the presence of salt and the inactivating factor can be removed by employing an aqueous M/50 citrate buffer (pH 5.2) as the extractant of CTC from sample. Assay sensitivity at higher room temperature was increased when the assay plate was refrigerated 30 minutes before and after placing a sample extract into the cylinder.

Data presented here showed that the degradation pattern of varying nucleotides in muscle of wrasse, Pseudolabrus japonicas, kept at 0°C somewhat differed from that of carp1). ATP decreased quite rapidly as compared with that in carp muscle. A complete degradation of ATP occured approximately a three-hour period after slaughter, which corresponded to 1/20 to 1/30 of the time required for ATP degradation in carp muscle. While nearly no rigor mortis was detected in carp muscle during the chill-storage1), a quite marked rigor mortis was detected in the wrasse muscle at three-hour period of storage, accompanied with the rapid disappearance of ATP and the accumulation of considerable amount of AMP. Not much difference was noted between wrasse and carp muscle in the time of maintain-ing of maximal amount of IMP. The time of keeping passable flavor-quality was found about a half the time of incipient spoilage.

In a preceding report3), it was shown that the addition of the viscera-extract of Pecten laqueatus at a 1.7 per cent dry weight basis gave a remarkable growth response of chicks and that APF in the viscera-extract was adsorbed on the activated charcoal from a slightly acidic solution. The present paper deals with a study on the effectiveness of an autolyzed viscera-extract of Atrina Pectinata japonica to the chick growth and the egg production, and further on the fractionation of the growth promoting principle. The results can be summarized as follows. 1. The addition to 100g. of all-vegetable protein ration of a 2.8g. portion of the dried autolyzed viscera and a 0.3g. portion of an activated charcoal adsorbate which is equivalent to 2.8g. of the dried autolyzate, resulted in a slight growth promotion on 35-day old chicks during six-week feeding as contrasted to a negative result obtained on addition of 1.35g. of a non-adsorbed fraction (Table 1). 2. The weight of anterior hypophysis and testis, and the length of humerus and femur increased in a linear proportion to the growth while the weight of thyroid gland inversely pro-portional (Table 2). 3. One-year old hens fed autolyzed viscera at a 2% dry weight basis for 100 days showed an egg production inferior to the control group. This is apparently due to a delay of starting egg production in the experimental group, because when compared as to the egg production of its highest production period (Feb. 7-March 30), a superior egg production in number as well as weight was observed in the experimental group (Table 3). 4. In the case of 5-month old hens fed an all-vegetable protein ration for 3 months prior to the experiment, the supplementation of the autolyzate at a 2% dry weight basis gave a remarka-ble response in egg production (Table 4).

The stability of tetracyclines in muscle tissue at lower temperatures has been studied by WEISER et1), TARR et al2), WALKER and AYRES3), and TOMIYAMA et al 4-6). No concordant results, however, have been reported so far. The present authors studied on factors governing the stability of CTC in mackerel flesh brei, and revealed that two modes of inactivation were involved, namely, one occurred shortly after the addition of CTC, and the other during storage. It was found that the former could be inhibited by the inclusion of chelating agents and the latter by the presence of antioxidants (Tables 2 and 3). These protective substances, however, did not prevent CTC in a buffered solution from deterioration at 100°C (Fig. 1). It was observed that residual CTC after a 3-day icing appeared to become stabilized (Fig. 2). This apparent increase in the stability seems to be due to either antibacterial activity of oxidized CTC or of oxidized oil per se. Data herein reported made it clear that a disagreement among the works above-cited on the stability of CTC in tissues was resulted from a difference among tissues employed by the above cited authors in their ferric iron content and the rate of oxidation of oil in tissues.

TOMIYAMA et al2) reported previously that tylosin could be heat-inactivated both in solution and in tissues by ferric iron and/or autoxidized oil and be prevented from its inactivation by the addition of isoamylgallate and chelating agents. YOKOSEKI et al3), however, pointed out a possibility that the decrease in tylosin on heating various tylosin-containing muscle tissues might be due to the adsorption of tylosin on protein coagulum. The present data clearly indicated that tylosin included in fresh muscle tissue could be inactivated upon heating by the reaction with reducing group(s), most probably sulfhydryl group in situ or formed on heating the tissue (Tables 2, 10 and 11). This type of inactivation was inhibited by the presence of oxidizing agents (Tables 7 and 8). A possibility of leaving some tylosin activity adsorbed on protein coagulum of muscle tissue can be eradicated by the present result showing that an added amount of tylosin was nearly completely recovered in a non-coagulable part of the tissue by heating it with potassium bromate at pH 7 (Table 12).

It has already been shown that the prolongation of storage life of the sardine was obtained by a 30-minute dip in a 10 ppm aureomycin containing brine1). The present paper deals with a similar study of the effectiveness of aureomycin to keeping quality of the mackerel. The results can be summarized as follows: (1) A 1-hour dip in a 10 ppm-aureomycin containing 5% brine at 20°C was effective at 20°C in keeping quality of mackerel 1.7 times longer as judged from volatile base-N, trimethylamine-N and histamine hydrochloride content of the muscle. (2) A 2-hour dip in 5% brine containing 40 ppm-aureomycin at 20°C was found to be effective at 20°C in keeping quality 1.4 times, 2.4 times and 2.6 times longer as judged from volatile base-N, trimethylamine-N and histamine hydrochloride content of the muscle, respectively. A further addition of ascorbic acid at 0.25% level was effective to the inhibition of histamine formation. The treatment of gutted mackerel with the aureomycine-brine was found 2.6 times better in keeping quality than control treated only with brine.

It was reported that a certain cancerous disease of Porphyra tenera was observed in the costal waters of Toko, Nagoya and Fukuyama. This disease was also heavily detected in the waters along the industrial city of Ohmuta. The outbreak of this algal cancer seemed to be always limited in the receiving waters of industrial waste water. From the viewpoint of the diversity of the carcinogenic compounds, and the variety of the pollutants in the waste, there should no doubt be a regional peculiarity in the causal substances of this disease in each of the coastal waters mentioned. In this study, carcinogenic potencies were tested with the waste water taken during the ebb tide of the river Ohmuta, and also with mud deposited on the sea bottom, which was about 1.5km north from the mouth of this river. The tests revealed that the waste water showed poor carcinogenic effect when diluted to a concentration as low as that found in the areas under cultivation where this disease can be easily detected, but the mud induced clearly cancers on the leaves of this alga during a 36 day culture after a single contact for periods ranging from 80 to 320 minutes. Therefore, it is concluded that the cancerous disease of Porphyra tenera should be attributable to suspended solids contained in the sea bottom mud which probably is derived from the Ohmuta river as evidenced from the distribution of nitrogeneous aromatic compounds in the bottom mud.

It was reported by PHILLIPS et al1) and HALVER2) that biotin is an indispensable vitamin for trout and salmon fingerlings which possess rather short intestine. Since biotin can be synthesized by intestinal microflora, it is of interest to study whether or not an oral intake of biotin is essential for such fish as the goldfish possessing rather a long intestine. As judged from the growth response and increase in biotin level of hepatopancreas when biotin was supplemented, it is evident that the goldfish needs the oral intake of biotin. These data (Tables 3 and 4) suggest that the amount of biotin synthesized in the gut was not enough to meet its requirement. Furthermore, it was found that the supplementation of succinyl sulfathiazole to a biotin-deficient group made increase the biotin level of its liver comparable to that of control group with biotin (Table 4). This result indicates that a microfloral change in the gut due to the presence of this cocci-static agent resulted in an increase in biotin supply probably through either a greater biotin synthesis or a decrease in biotin consumption in the gut.

A sextant is indispensable for the determination of boat-position where the sampling or observation is performed for the water pollution research. However, it is difficult to measure angles between terrestrial objects by the sextant within a short time interval and particularly while the boat is moving. Thus, the investigator is so much devoted to the time-consuming measurement by the sextant and the field work has to be finished frequently without satisfaction. The authors, therefore, attempted to apply the terrestrial photogrammetry to locat the boat-position by using a common-type camera in place of a surveying camera which could not be used under a rough weather condition. The use of the common-type camera for measuring angles yielded considerable errors due to the discrepancy between the focal distance of camera-lens and the picture distance proper to the camera employed. In order to reduce such errors the authors proposed equation (1) for calculating the real picture distance, and it was demonstrated that the angles between objects on the picture could be determined with the errors smaller than ±6'30" provided that the real picture distance was utilized. Equations (2), (3), (4), (5) and (6) are presented for the computation of the error of the boat position which corresponds to the space between the real boat-position and the estimated boat-position. Thereby, the magnitude of the error of boat-position in this photogrammetry with a common-type camera was evaluated to vary from 2m to 39m, with the average of 19m. In other words, it can say that the photogrammetry mentioned above possesses such an accuracy that the boat-position can be determined within a circle smaller than 2mm in radius when plotted on a chart with a scale of 1/10, 000 of the natural size.

1) A preparation which is effective in culturing bacteria instead of LIEBIG extract and peptone has been obtained by autolyzing whole fish body. 2) Experiments have shown that it is superior to the usual media when judged from the magnitude of colonies on the plate media and the turbidity of the liquid media 3) The liquid media gave a distinct indol reaction on culturing either E. coli, Staphyl. aureus or Bac. proteus. The liquid media gave the easily perceptible cholera rose reaction after a 6-hour incubation at 37°C. after innoculating Vibrio cholerae in a quantity as minute as 1/100, 000 a loopful bacteria. 4) Corynebacterium diphtheriae was able to grow on a simple two per cent solution of the present preparation with a growth rate two to three times greater than on MARTIN or LOFFLER'S media. The volutin of the bacteria grown on the preparation could be identified without fail on staining. The minimum skin reaction doss of the toxin formed was 0.000001cc. 5) It has been shown that the activity of promoting the growth of bacteria which was displayed by the preparation was in variance with the progress of the autolysis.

A procedure for the nephelometric determination of sulfates has been given in which to a 20-cc sample solution is added 0.5g of a powdered reagent which has newly been adopted in the present method. The reagent is a powdered mixture of 10g of barium chloride, 10g of tartaric•acid, and 80g of sodium chloride. The nephelometlic comparison can safely be of made by diffused light in the laboratroy without using a particular artificial source of light. The menthod can be applied to the determination of from 1.9 to 480mg SO4 per litre. Data are presented showing that the possible accuracy of this method is at least as good as in SHEEN'S method (TABLE I and III). The mean error was about 2.4%, the maximum error about 5.6% (TABLE III).

In the preceding papers of this series, the author dealt with such subjects as (a) systematic separation and identification of the volatile components of various seaweeds, (b) the so-called “tang of the sea”, and the principle of aromatic and odoriferous compounds of seaweeds and (c) pharmacological activity of these volatile components. In the present report, the author discusses the biochemical significance of the volatile constituents and the difference between the volatile constituents of Chlorophyceae, Pheophyceae and Rhodophyceae, bassing on the data hitherto reported as well as those newly presented here. The results obtained are as follows: 1. Dimethylsulfide and acrylic acid are found in Chlorophyceae and some species of Rhodophyceae, but not in Pheophyceae. 2. Higher boiling parts of the fatty acid fraction and the neutral fraction, as well as and the phenolic fraction, do not differ with seaweeds, but the contents of n-valeraldehyde is larger in Pheophyceae than in Chlorophyceae (Fig. 8, Fig. 9). 3. The lower boiling part of the neutral fraction shows difference between Chlorophyceae, Pheophyceae and Rhodophyceae: Furfuryl alcohol is present both in Chlorophyceae and Pheophyceae but not in Rhodophyceae. The alcohol with the Rf 0.21 on the chromatostrip is present only in Rhodophyceae, and the alcohol of Rf 0.35 occurs only in Pheophyceae. 4. The biochemical significance of the compounds which are obtained as volatile constituents is discussed. It should be noted that acrylic acid, which has been detected in Chlorophyceae by gas chromatographic technique (Fig. 6), may be derived to β-alanine by algae in the process of assimilating ammonium, nitrite or nitrate. 5. Of the volatile constituents, dimethylsulfide, benzaldehyde, n-valeraldehyde, α-methylfurfural, furfural, furfuryl alcohol, linalool, geraniol, and 1; 8-cineol are aromatic compounds of seaweed, while methanthiol, trimethylamine, lower boiling part of fatty acids, unsaturated fatty acids, p-cresol are odoriferous compounds.

A considerable effectiveness in prolonging the storage life of the fish fillets has been obtained by a minute dip in minimal concentration of chlortetracycline1, 2). However, no effectiveness for the shrimp has been observed at the concentraton used2). The present study shows that at least a 30-minute immersion in a 5% brine containing 10-20 ppm chlortetracycline is needed for a definite preservative effect on the sardine (Table 1). It has been found that the effectiveness on the keeping quality was increased a little with the increase in the concentration of the antibiotics (Table 2). It is of noteworthy that the brine in which the sardine was immersed was spoiled after one day, whereas the brine with chlortetracycline was judged still passable three days following a dip treatment of the sardine (Table 3). It has also been shown that a 10 ppm solution of chlortetracycline was able to treat the sardine at least by the same amount as its volume without any decrease in the effectiveness (Table 4). An overnight stowage of the sardine in coarsely cracked ice containing 10-20 ppm chlortetracycline followed by a storage at 4-8°C. without the ice has been found effective to prolong the storage life of the sardine as judged organoleptically or by the volatile base-N value (Table 5).

It has been reported that the 24-hr. TLm's of sodium pentachlorophenate (PCP) for fresh water fishes ranged from 0.07 to 0.6 ppm1, 2, 3). No report has been made so far of its toxic effect on marine organisms. The study was undertaken to answer a question whether or not PCP is toxic to organisms in coastal waters. Under a condition of keeping one test organism in 1 to 2 liters of the solution under test at 29°C and of daily renewal of the test solution, the 24-hr and 48-hr TLm's of PCP were found to be 0.09 and 0.08 for “guchi”, Nibea albiflora, 0.40 and 0.25ppm for “warasubo”, Odontamblyopus rubicundus, and 3.4 and 2.3ppm for “shiraebi”, Leander japonicus, respectively, and the 24-hr TLm to be 0.20ppm for eel, Anguilla japonica. The avoidance reactions of “guchi” to PCP in a gradient tank4) showed that the fish could discriminate PCP at level of 0.2 to 0.3ppm.

The OGUR-ROSEN'S method for the determination of RNA and DNA in plants was so modified as to be applicable to the fractionation and determination of acid-soluble phosphates, phospholipids, RNA, DNA and phosphoprotein in marine algae. Major points of the modification are as follows: (1) the extraction of lipid fraction was preceded by that of the acid-soluble fraction, and (2) the E260 value of the PCA extract of RNA was followed up during the extraction until it reached a maximum level.The modified method was employed for the fractionation of RNA and DNA in six species of red algae, three species of grass-green algae and one species of brown algae. The extracted amounts of RNA and DNA were estimated by the absorbance at 260mμ.The RNA and DNA contents of the sample algae on dry basis were 5.3-18.4mg and 0.8-3.8mg per gram, respectively. The results with Porphyra were particularly interesting because of their showing the highest RNA contents among the sample algae.No significant differences in RNA and DNA contents were observed between the normal and tumorous fronds of Porphyra tenera, contrary to the report of higher DNA contents in tumorous lavers by KATAYAMA and FUJIYAMA (1957). The present study of the analytical procedure infers that the high value for DNA presumably resulted from an incomplete extraction of RNA.

TARR1) claimed that CTC was five times as much effective as was OTC in retarding the spoilage of ground flesh. Several studies5, 6, 12) have been reported, however, that the two antibiotics possessed a comparative effectiveness in keeping quality of round fish. The present study deals with the effectiveness of CTC and OTC below a 6-ppm addition in keeping quality of fresh ground flesh at 0°C. It was found that CTC was more effective than OTC and that the difference in the effectiveness varied with the levels of the antibiotics, i.e., higher the levels smaller the difference. A plot of the rate of extension of the storage life against the residue at incipient spoilage showed more marked superiority of CTC to OTC in preservative effect per unit residue.