Tuna long lines as shown in Table 1 were weared down by the rotating drum in water tank as shown in Fig. 1. The coefficient of friction was calculated with the records of reading of spring balance S and hanging weight W. Breaking test on the lines 50cm in lengths, chucks interval, and the measurement of their diameters were done by using the samples, wearing of various durations.
The results obtained are as follows;-
The value of the coefficient of friction decreases with the increase of the duration, and finally it approaches a certain limiting value (Fig. 2, and Table 2). When the breaking strengths of the lines under the initial condition and abraded one are denoted T₀ and T, the diameter under both conditions γ₀ and γ respectively, the values of T/T₀ and γ/γ₀ have the same tendency in the case of the values of the coefficient of friction (Figs. 2 and 3). The values of T/To decrease with the increase of its diameter (Fig. 5).

抄録全体を表示

The Zostera growing area seems to be a suitable field for marine fish-community studies, since it is semi-closed especially for small sized fish which can be easily collected. In the Zostera area of Matsushima Bay, Miyagi Prefecture, it was revealed by the seine collections repeatedly made during the warm seasons of 1959 that the young of Japanese sting-fish, Sebastes inermis, “Mebaru”, is a dominant species inhabited. A fish group was confined within the fish frequently occurred with the dominant species and named as the “Mebaru” community, which is to be regarded as a trunk in the structure of fish production system in the Zostera area.
Each fish belonging to the “Mebaru” community shifts slightly its composition of food item, sharing subtly the food substances produced in the Zostera area as shown in Fig 2. This type of food segregation suggests that each fish lives competing with each other for foods, resulting in a selective feeding. Ecological order for feeding among predators would be measured in terms of the order in the ecological niche of their preys. At present, an ecological order among fish constituting the “Mebaru” community was presented as to be in the following series ;—Pseudoblennius cottoides > Hexagrammos otakii > Sebastes inermis > Enedrias nebulosus > Chaenogobius murorana > Aboma lactipes > Fugu niphobles > Tridentiger trigonocephalus > Acanthogobius flavimanus.
The dominant species, Sebastes inermis, living in the Zostera area seems to be limited its feeding activity by Pseudoblennius cottoides and Hexagrammos otakii and also seems to suffer from diminutions of food supply reduced by Enedrias nebulosus and Chaenogobius murorana.

抄録全体を表示

From 1957 to 1959 1, 005 adult mackerel were tagged on the coast of Oki islands during May and June, and the following results were obtained.
1) From these tagged fish, 106 were returned up to now, the recovery ratio amounted to 10.6%. Eighty percent of recovered mackerel were fished with the purse seine nets (Tables 1, 2; Fig. 2).
2) The majority of recaptures were made to the north of tagging point, and collective recaptures were often seen at the Point Saruyama on Noto Peninsula, but no tagged fish passed over Noto Peninsula (Fig. 4). Nevertheless, 20% of returned fish moved at least 200 miles.
3) Seventy eight percent of recoveries were made within 90 days after releasing, 17% were during between 91 to 270 days and 5% were thereafter.
4) The recoveries were frequently reported near the edge of continental shelf where offshore water converged and the areas of topographic stationary eddies such as Oki Straight, Wakasa Bay and the coast of the Point Saruyama. Eighty percent of recaptures were made in the latter areas. (Figs. 3, 4)
5) The recovery terms of those recaptured at the edges of continental shelf coincided well with the recovery terms of drifting bottles, but the recaptures in the eddy areas were often made after longer terms comparing with those of drifting bottle (Fig. 6).
6) The mackerel populations may be separated into two groups: “passing group” and “staying group”, and migrations of both groups seemed to be controlled by the movements of water masses, being no recaptures in the year of 1957 (Fig. 5).
7) Mackerel in the western Japan Sea seems to migrate as far north to the Point Saruyama on Noto Peninsula.

抄録全体を表示

The taiwa'ainoko, Stolephorus zollingeri (BLEEKER) was distributed in the waters around and south of middle Japan. The species was mainly found in the areas under the influence of the Kuroshio Current. A few specimens were also collected in the Suruga Bay, Enshû Nada and western part of the Seto Inland Sea. This fish is a rare anchovy, but still seems to show itself as an indicator species representing the environmental conditions of the important neritic-pelagic fishes.

抄録全体を表示

The present study covers the relationship between seasonal changes of the price and the amount of catch of important neritic-pelagic fishes landed on the Pacific coast of Honshu in 1958. The Pacific coast of Honshu is divided into Sanriku District extending from Aomori to Fukushima prefectures, Kanto District from Ibaraki to Shizuoka prefectures and Kinki District inclusive of Aichi and Mie prefectures. The data used for the present study have been obtained from governmental statistics on amount and price of catch for such species as the sardine, anchovy, mackerels, common squid, pampanos and yellowtail.
According to Fig. 1 prepared for this study, the following points of interest have been obtained:
1) The price of neritic-pelagic fishes under study rised in winter and lowered in summer. This seasonal fluctuation in price was the most remarkable for the yellowtail.
2) It is suggested that amount and price of catch were correlated negatively for the five species except sardine. The correlation coefficient at less than one percent level for the mackerels in Sanriku and Kinki Districts, and at less than five percent level for the yellowtail in Sanriku District (Table 1).
3) The negative relationship between the amount and price of catch was the most remarkable in Sanriku District, where the processing and transportation facilities have been the least developed.
4) The amount and price of catch as well as the fishing activity were related mutually in many commercial fisheries. As far the data under study are concerned, however, the price did not remarkably lower in spite of increase of catch. Therefore, it may be assumed that the catch statistics reflect the stock sizes of the fishes under discussion.

抄録全体を表示

An erroneous operation in integrating ∫λ³/1-λdλ of Formula 2 of the previous paper (Vol. 26 No. 5, p. 498 of this bulletin) being pointed out by GENSYO, Formula 3, A/κι_∞³=|λ+1/2λ²+1/3λ³|^λ_•5 was now replaced by A/κι_∞³=ln1/1-λ-λ-λ²/2-λ³/3.
While the former corresponds to a linear relation, the latter is a relation representable as a curve as shown in Fig. 1.
In this paper it is verified that the theory already presented in Formula 1 of the first paper can be well supported by the data from actual measurements as shown in Figs. 2 & 3.
Hence we have the following relation between the vitamin A contents of fishes, A, and the ratio of the body-length, λ
A=κι_∞³[ln1/1-λ-λ-λ²/2-λ³/3]………………………………(3') where ι_∞ means the maximum body-length, of the species, λ=ι|ι_∞, and κ is a constant.
This paper deals also with the value of κ of several kinds of fishes, calculated from Formula 3 and Fig. 2 and tabulated in Table 1. The values of κ for a definite species (e.g. ABURAGAREI ^?? ) are independent of fishing ground, season and depth, those calculated from the formulae and Fig. 3 being presented in Table 2.
^?? Athresthes evermanni JORDAN & STARKS

抄録全体を表示

Fluorescent spectrum and flavor were investigated on the sugar-amino acid systems in 0.1M phosphate buffer, pH 6.5, which were autoclaved for 90 minutes at 113°C.
Fluorescence of the system consisted of light of shorter wavelengths than 620mμ and showed the maximum intensity at ca. 480mμ. These were similar to that of unsaturated (hetoro) cyclic nitrogenous compounds which are commonly used as fluorescent whitening agents. Amino acids having unsaturated ring, tryptophan, phenylalaine, and histidine, produced strong fluorescence by the reaction with sugar. Lysine and arginine which yield intense color and fluorescence were also supposed to form unsaturated compounds. On the other hand, imino acids with saturated ring formed little color and fluorescence. Neither color nor fluorescence was produced with aspartic and glutamic acids.
The sugar-amino acid systems produced flavors by heat in parallel with their browning. The produced flavors were generally cocsidered to be underiable for foods with a few exception.

抄録全体を表示

The browning reaction of glucose-lysine system was studied to explain the accelerating mechanism of the reacting by phosphate or borate.
Intensities of color, fluorescence and ultraviolet absorption of the system increased in parallel with each other. Decrease of fluorescence did not occur even though the browning reaction was extended. The fluorescence of the system was supposed to be due to not only precursor of brown pigment but final products of the reaction.
Ultraviolet absorption spectrum of the system containing phosphate differed from the one containing borate. Borate induced the loss of the reducing power of glucose in the absence of lysine.
It was considered that phosphate may accelerate the browning reaction by its simple catalytic action. On the contrary, borate may possibly accelerate the reaction through the formation of its complex with sugar. One of the possible way of the reaction induced by borate is aldehyde formation by opening of pyranose ring, and another way is ketose (sorbose) formation.

抄録全体を表示

Fish culture industry for Salmo irideus GIBBONS has made a rapid progress with export of the frozen products increasing at such a rate as from 323 metric tons 1955 to 955 tons in 1958. Little information, however, is available at hand in regard to chemical properties of lipids of this species. The authors have carried out a survey on the lipids of wild rainbow trout with an expectation that the data would be useful in improving the method of procesing and the feed in culture for this fish.
The fish used were caught by a gill net in Chuzenji Lake on May 27, 1961, and transported with ice to our laboratory in Tokyo. Body length, weight of the samples, and their visceral organs were examined (Table 1). Lipids were extracted respectively from liver, kidney, pyloric caeca, head, fatty tissue in abdominal cavity, and edible portion. Unsaponifiable matter was separated from fatty acid (Table 2 and Fig. 1). Mixed fatty acid of each portion remained within the range from 142 to 155 of iodine value and from 1.4600 to 1.4630 of reflex index at 40°C. As far as saturated and unsaturated acids concerned, however, liver oil was found to be different in composition from oil of other parts (Table 3 and Fig. 3). Among the samples from neck, middle, and tail regions of the dorsal muscle, the middle had a higher oil content, the oil being lower in reflex index that from other body parts. No positive relation, however, could be observed between the oil content and iodine value of the oil for any corresponding part of the muscle, for the latter varied from 105 to 137 according to a region as well as to the individual fish examined (Table 4 and Fig. 4).

抄録全体を表示

Material and method As white muscle fish, carp, red sea-bream, goby were used, and yellowtail and mackerel as red muscle fish. Fish were killed in two different ways: one group was put to instant death by beheading, and the other was left for several hours in air and then beheaded.
A portion of muscle was taken from each fish and subjected to experiments immediately after death, while other portions of muscle were taken after storing for 24 and 70-90 hrs. at ca. 3°C and used as samples in rigor and post-rigor, respectively.
Results
1. Extractability. Amount of the extracted myosins (obtained by blending with 0.6M KCl for 2min., followed by centrifugation, and diluting to μ=0.05) was rather greater in rigor than pre-rigor or post-rigor, regardless of species or lethal conditions of fish (Fig. 1).
2. Salting-out curves. Salting-out curves suggested that actomyosin is dominant and almost the only component of myosin fraction from any of the sea fish used, at any post-mortem phase (Fig. 2-5). With red sea-bream and goby, no significant difference in salting-out pattern was observed between fish put to instant death and those killed after struggle (Figs. 2, 3). In some cases, small peaks were observed besides the major peak of actomyosin. But the reproducibility in such peaks was substantially less than that obtained for actomyosin peak.
It seems that there exist some distinct types in the salting-out curve (S-C curve) according to species and conditions of fish. Most of the sea fish used, especially those killed instantly, gave a typical sharp drop as curve (a) in Fig. 13, while different types of curve were obtained from carp tested in different seasons (Fig. 13).
3. Viscometric behaviors. In white muscle fish which were put to instant death, intrinsic viscosity, [η]_{c→0 ?? →0}, of myosin fraction was found to increase in the following order with respect to the post mortem phase: pre-rigor < in rigor < post rigor (Figs. 6, 8). However, when the fish were killed after struggle, intrinsic viscosity remained almost unchanged in the course of time after death (Figs. 7, 9). Anomaly of viscosity (velocity gradient dependence of viscosity) decreased progressively with the course of post-mortem change, regardless of lethal conditions of fish.
In red muscle fish put to instant death, intrinsic viscosity decreased so far as to 0.5-0.2 after the muscle passed into rigor. Anomaly of viscosity was, in general, weaker compared with the case of white muscle fish, and was hardly appreciable after onset of rigor, within the concentration range tested (Figs. 10, 11).

抄録全体を表示

On eight stages of development of rainbow trout eggs as mentioned in Table 1, moisture, ash, total nitrogen, total lipid, acetone soluble and insoluble lipid were determined. Unsaponifiable matter, acid value, iodine value and mean molecular equivalent of fatty acid in the acetone soluble lipid were determined.
Results were;
(1) Variation of chemical compositions in the developing stages were practically equal to the SUYAMA's results (This journal Vol. 23, 785, 1958.)
(2) Decrease in acetone insoluble lipid during the developing process were found larger before hatching stage than after that stage. On the contrary acetone soluble lipid decreased after hatching stage more considerably than before that stage.
(3) Together with the development, the content of free fatty acid increased. The in-crease was remarkable on the last stage of the development.
(4) Iodine value of acetone soluble lipid were once decreased and then increased gradually.

抄録全体を表示

It has already been described in the previous paper¹⁾ that the conventional method of alkali digestion can not always be regarded as a satisfactory means of obtaining vitamin oil from viscera of aquatic animals because the operative simplicity of this method is usually canceled by its failure in giving any good yield when applied to raw materials containing vitamin A at high concentrations but as dissolved in small quantities of oil.
In the present work, hereupon, several methods are presented and examined of their actual effects, wherein it is planned that the above-mentioned type of defect incidental to the conventional alkali digestion may be evaded and accordingly that vitamin A extraction may be carried out with an improved yield by employing some organic solvents as extractant. The method presented and the results thereby attained are outlined as follows;
1) Examining a method presented as an improvement of the conventional alkali digestion and consisting of extracting previously' alkali-digested viscera with benzene or petroleum ben-zine in place of picking-up oil, the results shown in Tables 1 and 2 were obtained. This method proved not only as able to be easily carried out without causing any serious reduction in the yield of vitamin A but also to allow vitamin oil to be obtained in a state of high vitamin A unit as it is relieved from the otherwise dilution of vitamin A due to the preserve of picking-up oil.
2) Examining a method comprising subjecting a raw viscera previously curtailed by centrifugation in its water content but remaining still moist to multiple extractions with hot alcohol, the results shown in Table 3 were obtained. As confirmed from these data, the use of alcohol as a solvent behaving with different strengths in dissolving fatty acids, neutral oils, vitamin A and etc., respectively, enables an oil fraction having a high acid value to be preferentially and hence separately extracted leaving a vitamin oil fraction behind which can afterwards be extracted as substantially freed from acid impurities and appreciably enriched with vitamin A, the yield of vitamin A being also able to amount in total to quite a satisfactory value.
3) Examing a few methods somewhat different from one another as regards the procedure of preparing ground samples of viscera but mutually analogous in respect of the nonpolarity of the solvents used as extractant for vitamin A, the results shown in Tables 4 and 5 were obtained. These results demonstrate that the method comprising subjecting raw material viscera previously dehydrated in vacuum to extraction with petroleum ether is able to be carried out with high yields of vitamin A and gives promise of its effective application on an industrial scale.
4) In carrying out the above-mentioned type of nonpolar solvent extraction with n-hexane as extractant on an industrial scale, vitamin oil was successfully obtained always with a satisfactory yield (see Tables 6 and 7). The high yield of vitamin A invariably attained in this industrial examination manifests that this method of multiple extraction with non-polar solvent is truly free from said type of drawback encounted in the conventional alkali digestion. Further, by comparing this solvent extraction method with the alkali digestion method in respect of financial productivity for vitamin A (see Table 8), it was confirmed that the solvent extraction method can make a very effective process in the industrial field of vitamin A production.

抄録全体を表示