巻号一覧
4 巻, 6 号
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Ituo KUBO1936 年 4 巻 6 号 p. 361-364
発行日: 1936/03/15
公開日: 2008/02/29
ジャーナル フリーPDF形式でダウンロード (289K) -
Syôkiti KAMIYA1936 年 4 巻 6 号 p. 365-373
発行日: 1936/03/15
公開日: 2008/02/29
ジャーナル フリーPDF形式でダウンロード (515K) -
流動木村 喜之助1936 年 4 巻 6 号 p. 374-384
発行日: 1936/03/15
公開日: 2008/02/29
ジャーナル フリーThe sea-water in this district is nearly at rest in convection period (early October to April of the next year), but after the spring strong current, which was defined in the previous report, strong currents are frequently observed and in the stratification period they are noticed almost every day. In the following lines, the “strong, ” “rather strong” and “weak” currents are termed according to the velocities, above 20cm/sec, 10 to 20cm/sec and below 10cm/sec respectively. The direction of the currents is exclusively north or south, being parallel to the shore of Isle Awasima.
Some accounts on the Velocities of “strong” and “rather strong” currents are given in several figures and tables in the text. The mean velocities of “strong” currents in 1934 and 1935 are as given in the following table:
Year South current North current
1934 42.9cm/sec (mean of 105 observations) 31.3cm/sec (mean of 19 obervations)
1935 34.0 ?? ( ?? ?? 77 ?? ) 28.3 ?? ( ?? ?? 15 ?? )
The current, either north or south, of the velocity above 10cm/sec is continually kept in general for about one and half hours.
In case of “weak” current, north or south, a group of the velocities of about 5cm/sec is the most predominant, but the velocities of 2-3cm/sec form another group in the frequency histogram of the velocity of south “weak” current on the average.
The relation between the time of occurence of “strong” current and tides is not clear. Generally, in the stratification period, “strong” currents happen almost every day with nearly the same time lag as that of tides often for more than ten days, but it sometimes takes place at the same o'clock every day without time lag as tides, and sometimes never occurs for a few days.
In April and May of 1935, the duration T of the maintenance of flow in one sense was 7 hours on the average, but in the summer of the same year the direction of flow was changed more frequently, T attaing its least value of 3.7 hours in August. From September to December 1935, T was almost constantly 4.3-4.5 hours.
The effect of wind on the strength and the direction of current has not yet been studied. But the condition of wind in general is apparently different in the convection and in the stratification periods. In March, especially, the Japanese islands are frequented by conspicuous lines of discontinuity, running from north to south and forwarding to the east. Such a line of discontinuity is accompanied by southerly strong gale in the southern waters off Honsyu, and the spring strong current seemingly begins to occur a week or then days after those strong gales ont he open sea.抄録全体を表示PDF形式でダウンロード (1249K) -
宇田 道隆1936 年 4 巻 6 号 p. 385-390
発行日: 1936/03/15
公開日: 2008/02/29
ジャーナル フリーRecently several investigations have shown that the main fishing ground of “Katuwo, ” Euthynnus rogans (Lesson), in the Pacific region off North-eastern Japan, moves in the zone of temperature 20° to 24°C and is concentrated most abundantly in the region of temperature about 22°C. However, in spite of the same favourable water temperature, the actual distribution of the fishing ground is not uniform but is denser in some regions.
Of the records in 7 years from 1929 to 1935, the writer finds out the following remarkable relation between the locality of the centres of fishing grounds of “Katuwo” and the distribution of water temperature. In summer the fishing centre lies at the northernmost bead of warm current, or is located slightly to the west of it, which forms a convergent cyclonic vortex with northern cold water in the contact zone of the cold and warm waters. Such a region is most conveniently noticed by the steepest temperature gradient between the zones of 15-16°C and of 20-21°C. On the mechanism of such aggregation of shoals, the writer considers that the shoals of “Katuwo” are at first introduced by the invasion of warm current in the region and they are accumulated mechanically by the cyclonic convergent vortex produced between warm and cold current in consequence of the said invasion. The idea previously proposed by the same writer that shoals of “Katuwo” off North-eastern Japan, before they reach the region just stated, migrate keeping pace with the movement of fishing centre, is supported again by the results of the last marking experiment on “Katuwo” carried out in 1935, and also, by the results of investigation on the records of 1932, that the medium size-group appears as the dominant classes of “Katuwo” as in the case of 1933.抄録全体を表示PDF形式でダウンロード (500K) -
宮本 秀明1936 年 4 巻 6 号 p. 391-396
発行日: 1936/03/15
公開日: 2008/02/29
ジャーナル フリーThe original sailing trawl net, of which a model of 1/30 was made for study according to TAUTI'S principle of model net construction, is used in Mikawa Bay. The arrangement of net pieces and the construction of the net are shown in Figs. 1 and 2.
The tension on the net under various pulling speeds estimated from the model experiments coincides with that of the original net as shown in Fig. 3. In the figure the former is, plotted with triangles, while the latter with circles. On the fishing ground in practical case, where the tidal currents exist, the pulling speeds relative to the sea-bottom does not always coincide with those relative to the water. When the tension of the original net was, as shown in Fig. 3, plotted against the pulling speed relative to the water, with different marks for different current velocities, it can be concluded that the tension on the net due to the slip on the seabottom has a constant value of 35 Kgs.
Now let, R and v denote the tension of the net and the pulling speed relative to water, then for the original net we get a relation, R=0.038v2+35 and from the model experiments, R=0.018v2+35. The greater coefficient of v2 obtained for original than for the model net is due to the fact that the original net is pulled through the mud or through muddy water. So, in the figure, the results from model experiments are shown converting the tension of the model net into that of the original by the relation, R=2.1×0.018v2+35.
The form of model net was photographed from above and lateral sides under the pulling speeds which are, if converted into the originals, 1/8, 1/4, and 1/2 miles per hour. Of the reproduced figures in Fig 3, the upper three show the form of net, of which the hight of each of both wings is kept to be 0.5m at its centre.抄録全体を表示PDF形式でダウンロード (1172K) -
菅野 進1936 年 4 巻 6 号 p. 397-406
発行日: 1936/03/15
公開日: 2008/02/29
ジャーナル フリーThe original fixed nets, of which the models were made for study, are used in Kamchatka or fishing salmons. On the experiments two models of both 1/200 of the original nets, of which the net pieces are arranged as shown in Fig. 2 A and A', were made according to TAUTI'S principles of model net construction.
It was known from the experiment, that the sinkers, fixing the net to the bottom slip and the nets float away, when the velocity of current excedes a critical value, which is, if converted into the original, 22/5 mile/hour.
The form of model net ?? under the current in the prevailing directions at the fishing ground were sketched both from above and lateral sides. The sketches are reproduced in Figs. 4A (net A) and A' (net A'), in which the figures in each row from left to right show the form under the current of 0, 1/2, 5/8 and 1 mile/hour, if converted into original, and each of three rows from top to bottom, under the current parallel, 25° inward or 25° outward inclined to the shore.抄録全体を表示PDF形式でダウンロード (607K) -
菅野 進1936 年 4 巻 6 号 p. 407-408
発行日: 1936/03/15
公開日: 2008/02/29
ジャーナル フリーThe catch per net per hour was taken as a measure of the rate of immigration of salmons to Voroskaya fishing ground, West Kamchatka. Daily serial observations of the temperature, salinity and transparency of sea-water were carried out at every mile on a line extending 5 miles from the shore. Salmons were found to immigrate most abundantly to this fishing ground, when the temperature is 10° to 13°C, salinity is less than 29.8‰, and transparency is small near the shore but great in the offing.抄録全体を表示PDF形式でダウンロード (123K) -
佐藤 鉦一1936 年 4 巻 6 号 p. 409-410
発行日: 1936/03/15
公開日: 2008/02/29
ジャーナル フリーCiliary movement of the gill of Ostrea gigas as revealed by the crawling of the gill fragment on Petri's dish was observed in relation to temperature. The mean crawling velocity of the material increases as the temperature goes higher from 1.2°C to 29.2°C, Q10 being 2.71 for 1.2° ?? 12.1°C and 2.20 for 18.8° ?? 29.2°C. But it decreases greatly at temperatures 34.1°C ?? 40.0°C. The figure 1 summarizes the results.抄録全体を表示PDF形式でダウンロード (96K) -
海老名 謙一1936 年 4 巻 6 号 p. 411-414
発行日: 1936/03/15
公開日: 2008/02/29
ジャーナル フリーThe age of 56 specimens of a teleost, Pagrosomus major T. & S., collected from Mito (Pref. lbaraki), Tyôsi, Bôsyû, and Misaki was determined by reading off the number of the annual rings of the scales, and it was found to range from 1 to 26 years. More or less variable in various characters as they are, the material at my disposal may be recognized as representing one category. It appears that the material from these localities are slower in growth than the same species of the fish caught in Inland Sea of Japan. The reader is referred to the accompanying figures for further details.抄録全体を表示PDF形式でダウンロード (190K) -
川口 武男, 清水 淳三, 谷 正二, 由井 十七三1936 年 4 巻 6 号 p. 415-417
発行日: 1936/03/15
公開日: 2008/02/29
ジャーナル フリーThe degree of blackening of the canned crab-meat and that of the blue-meat formation of the same were known to depend on the pH-value, and respective amount of volatile basic nitrogen, copper, iron, and hydrogen sulfide.
As shown in Table 1, no difference was found in pH-valne, amount of volatile basic nitrogen, copper, total sulfur in the examined parts (protopodite, meropodite and propodite of the second to fourth legs), of the examind three individuals, that of iron being the same irrespective of the examined parts, but different in different individuals. On the other hand, the amount off hydrogen sulfide of the meat of protopodite was much more than that of meropodite and of propodite.抄録全体を表示PDF形式でダウンロード (190K)
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