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Volume 9 (1940 - 1941･･･
- Issue 6 Pages 225-
- Issue 5 Pages 181-
- Issue 4 Pages 133-
- Issue 3 Pages 91-
- Issue 2 Pages 47-
- Issue 1 Pages 1-
Volume 9, Issue 5
Displaying 1-9 of 9 articles from this issue
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VI. Fishing Gear in Relation to the Current Prevailing on the Fishing GroundHideaki MIYAMOTO1941 Volume 9 Issue 5 Pages 181-184
Published: January 25, 1941
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSPercentage frequency distribution of the current velocities observed at several fishing ground was shown in Fig 1, in which the shaded parts represent the percentage of the cases where the net could not be hauled. Fig. 2 shows the relation between the median Mi of the current velocity and the current velocity, c.v., above which the shaded part in Fig. 1. exceeds half the height of the frequency curve. In Fig. 2, the numbers attached to the marks give the ratio of the shaded to the total area under the frequency curves in Fig. 1. The said ratio is the greater, the greater the median Mi, for a certain value of c. v., while the same is the smaller, the greater the value of c. v., if Mi is nearly the same.View full abstractDownload PDF (203K) -
Toradirô SAITÔ1941 Volume 9 Issue 5 Pages 185-190
Published: January 25, 1941
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSThe deformation of the net which is fixed to the sea bottom for fishing ‘Tara’ in Tugaru district and tension on the lines supporting the net were studied with models which were constructed according to TAUTI'S principles. Effects of the current to which the net is subjected were experimented with respect to both directions and speed of the current.View full abstractDownload PDF (1807K) -
Husao SIMIZU1941 Volume 9 Issue 5 Pages 191-197
Published: January 25, 1941
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSExperiments were made with a model of an improved type of the sea bottom fixed nets used for fishing “Tara” in Aomori Pref. The form of the net, such as the width of the entrance, the slope of the leading to the end etc. were examined under various currents to which the net is subject, varying in both direction and speed. Equillibrium between the floating and sinking forces acting on the net, the maximum current up to which the net can be fixed by the sinkers, and tension on the lines which connect the net to the sinkers were made clear so as to enable us to test the materials to be used.View full abstractDownload PDF (2818K) -
Yositada TAKENOUTI1941 Volume 9 Issue 5 Pages 198-200
Published: January 25, 1941
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSA method for estimating the ultimate population of adult fish, when the equilibrium between catch and recruitment due to liberation is attained, was developed. The method was applied to fishing of Himemasu (Oncorhynclaus adonis (JORDAN et MC GREGOR)) in Lake Towada, with slight modification, which was inevitable owing to the lack of complete statistics.View full abstractDownload PDF (169K) -
Kiyohide MIYOSI1941 Volume 9 Issue 5 Pages 201-202
Published: January 25, 1941
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSPrevious to 1931, the trawl fishing grounds were confined mainly to the Yellow and the East China Seas. Taking the catch records by the trawlers in those seas as the basis, the present author estimates the stock of sea breams in the past.View full abstractDownload PDF (119K) -
Hideaki YASUDA1941 Volume 9 Issue 5 Pages 203-207
Published: January 25, 1941
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSDouble rings can often recognized on the scales of “Ayu”, Plecoglossus altivelis TEMMINCK et SCHLEGEL, under a year. Inner ring (Fig. 1:I) appears in March, when the fish becomes about 6cm in length, while outer one (Fig. 1:II), in July when the body-length ranges from 11 to 15cm (Fig. 4, 6). Appearance of these rings can be attributed to the change in food taken by the fish from animals to plants, for the inner ring, and to the sexual maturity of the fish, for the outer ring.
Outer ring has two structural types A-type detectable by the intersection of pairs of excentrically formed circuli and B-type, by the narrowed width between successive concentric circuli (Fig. 1: A, B). Either of the two types appears with different relative frequency in the different parts of the fish-body (Fig. 2). The said frequency calculated with the scales taken either from every or from a certain definite part of the body shows local difference, i. e. it has seemingly close relation to the forest zones through which the home river flows. A-type as well as the total of A and B types appears frequently in the fish from tropical or subtropi-cal forest regions, while B-type alone has the larger frequency with flush from temperate forest region (Fig. 3).View full abstractDownload PDF (959K) -
Mituyo OKADA1941 Volume 9 Issue 5 Pages 208-210
Published: January 25, 1941
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSTemperature-time relations of rectangular food cans, as observed by ITANI-ITÔ and ITANI-TAWA, were studied by, applying theory of heat conduction. Tentative as it is, coefficient of external heat transmission was determined.View full abstractDownload PDF (171K) -
Nobuhiko OBARA1941 Volume 9 Issue 5 Pages 211-214
Published: January 25, 1941
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSThe writer has investigated the diffusing process of the fluvial mater which is poured to the heart of Simoda Bay. The fluvial water advances and is shifted to the comparatively separatel area on account of wind direction in situ, in stead of spreading all over the bay surface. But when wind velocity is weaker, the brackish water zone is localized to the west part of the bay against wind owing to the counter-clockwise current which is proper in this bay. The writer has recognized an apparent relationship between deficient salinity at the river mouth and flowing distance of the fluviatile water which is emitted far in the offing.View full abstractDownload PDF (264K) -
Seiji KOKUBO, Teruyoshi KAWMURA1941 Volume 9 Issue 5 Pages 215-224
Published: January 25, 1941
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSThree lakes, among the Zy ?? niko lake group in Aomori Prefecture, Japan, have been studied in relation to their limnological conditions. Observations showed that at the beginning of the summer, the hypolimnions of Lake Koikuti and Lake Oike show marked poildlo or dichotomous stratification of temperature. The present study proved these stratifications to be due to the effect of underground feeding. Such stratifications are, however, subjected to change into the direct stratification by August. The dissolved oxyg ?? n in the hypolimnion of these lakes shows distinct stratification from as early as mid May, thus exhibiting marked anerobic condition from this afterwards. In Lake Otikuti, the depth of which is about 21 meters, the anerobic layer measures 10 meters in thickness.View full abstractDownload PDF (635K)
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