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Volume 16, Issue 5
Displaying 1-11 of 11 articles from this issue
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S. SUTO1950 Volume 16 Issue 5 Pages 171-174
Published: October 25, 1950
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSPorphyra tenera is edible red alga cultivated in Japan. In late September many twigs of bamboos are set in the sea. “Autumn spores” appear and fix themselves on the twigs and begin to develop. In winter plants grow thick, When spring comes, they decrease and the twigs are taken away. In late spring, some poor plantlets, less than several milimetre so called “summer plantlets” are found here and there, in late summer they are lost in sight.
Carpospores are formed sexually on the winter plants, while monospores are formed asexually on some of the young plants in autumn especially in November and also on summer plantlets.
It remains in doubt, where the autumn spores come from, i.e. whether they are monospores from survived summer plantlets or carpospores rested during spring and summer. To make clear the nature of this autumn spores, diameter of spores and thickness of young sporelings on bamboo twigs were measured in whole year and compared each other. The results are as follows.
1. Monospores from summer plantlets and also from autumn plants are all 15μ in diameter (Fig. 1, C-F). Carpospores in winter are 11μ (Fig. 1, B). Autumn spores are also 11μ. (Fig. 1, A).
2. By thickness, young sporelings can be divided in two groups. Sporelings from monospores in summer and also in late autumn are belong to thicker group (Fig. 3, II & IV) and those from autumn spores in early autumn to thinner group (Fig. 3, I), i.e. the latter must be originated from smaller spores, nothing but carpospores in previous winter.
These results show that, a greater part of the carpospores in winter rest during summer and appear again in early autumn and make crigin of next winter plants. “Summer plantlets” may be in a side road of life history.View full abstractDownload PDF (325K) -
III How many Herrings are produced per IndividualT. KAWANA1950 Volume 16 Issue 5 Pages 175-176
Published: October 25, 1950
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSThe ratio of the number of the young herrings to that of their parents (calculated by the. study of age-composition) is 0.05-4.3, the mean value being ca. 1. Even in those years when plentiful year-classes were produced, the ratio is 2-3. If the number of the parents diminishes, the ratio becomes larger.View full abstractDownload PDF (128K) -
IV Appearance of young Herrings along the Coast of North-eastern Hondo correlated with the Production of the Plentiful Year-classes along the Western Coast of HokkaidoT. KAWANA1950 Volume 16 Issue 5 Pages 177-178
Published: October 25, 1950
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSYoung herrings were taken along the coast of Iwate-ken and Miyagi-ken by set nets exclusively in spring of the year (or, rarely, of the two successive years) following that when unusually plentiful year-classes were produced along the western coast of Hokkaido. In spring following that of the usual production of year-classes along the coast of the latter coast no catch of herring along the former is recorded.View full abstractDownload PDF (90K) -
M. SIMADATE1950 Volume 16 Issue 5 Pages 179-183
Published: October 25, 1950
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSIn Tikuma River, no fish goes up the stream being prevented by dams, so many young “Ayu” (Plecoglossus altivelis) have been transplanted every years.
I investigated on the growth and the development on these samples which caught with weirs at 6 stations, Ueda and it's neighbourhood within 35km. in Tikuma River (Fig. I, Tab. I) in the matured season 1946. The differences were found among these stations on the growth and the development (Tab. 3-5), the growth was inferior, and the development earier at these upper stations, Gozigawara, Otiai and Iwasita; and the growth was superior and the development later at these lower stations, Gosyo, Simonozyo and Simohanga. In each station, these fishes which the growth was relatively superior, the development was later, that would be caused mostly on the temperature of water, but at Gozigawara above all, the growth was the worst, it seems to due on the existence of dam at upper stream and drain at lower stream of the power plant, even if there were other causes.
So the production of Plecoglossus altivelis in this district to increase by transplanting more seedlings in these stations where they thrived, it will be better to carry on such as suit place for live as Gosyo, Simonozyo and Simohanga in the other.View full abstractDownload PDF (334K) -
H. MIYASAKA1950 Volume 16 Issue 5 Pages 184-191
Published: October 25, 1950
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSThe quantities of fisheries resources, chiefly fishes and their foodbeings such as larva of insects, were investigated which flow from Tikuma-River into the passage of the Ueda Branch of the Central Fisheries Station of Japan, and these were collected by an equipp-ment at the entrance of the experimental ponds. And it was concluded that the all resources which flowed down through Tikuma River in conformity with' the volume of water measured by water-meter.
The volume of water flowed into ponds are 30 thousands m3 per day during the time from the last ten days of June to the first ten days of September, 16 thousands m3 from the middle of Sept ?? ber to the last ten days of Octorber, 7 thousands m3 in November, and in which the numbers of fishes 15 thousands, weight of food-beings 21kg. through these period in 1948, and the numbers of fishes 7 thousands, weight of food-beings were 15kg. in 1949. These fishes which flow down into pond were many at the day, and the food-beings were many at the next day of the largest volume of water in river. And there are many fluctuate at the number of fishes or weight of food-beings which flow down into pond, althogh the volume of water were similar from June to September, this is the reason the volume of water are much flactuate in the main stream. The fishes and food-beings were less since the middle of September, it will be these individuals are decreased for the flood, and also is not the season of insects propergation.
Then the number of these fishes were presumed as 4380 thousands in 1948, 4100 thousands in 1949, and food-beings are 6000kg. in 1948, 1698kg. in 1949 which flowed down Tikuma River during above season.
So, it should be considered to prevent these fishes and food-beings from flowing into the water passage such as the conducts for irrigation or hydroelectricity.View full abstractDownload PDF (474K) -
II. On the plankton of Nakano-umi in summer (1949)T. CHIBA1950 Volume 16 Issue 5 Pages 192-194_2
Published: October 25, 1950
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSThis investigation were made in the summer of 1949 in the whole region of Nakano-umi which could not be researched last year. In research of 1948 the plankton species have been found 53, but 85 species were found in this time.
The increase of the plankton seems to be mainly due to the fact that we researched the region of the Japan Sea also.
Zooplankton is superior to phytoplankton in species but less predominant in amount. Diatoms are the most abundant among the phytoplankton, 25 species have been found.
The Copepoda and Cladocera are the most important in the zooplankton of this lake. As the important species we can show the following: Rhizosolenia semispina, Thalassiothrix nitzschioides, Haemiaulus Hauchii, Chaetoceras decipiens, Leptocylindrus danicus, Nitzschia seriata, Ceratium fusus, Pyrophacus horologicum, Oithona nana, Penilia schmackeri, Evadne tergestina. Most of these usually distributed on the coast of Japan Sea.View full abstractDownload PDF (433K) -
The Case when two Homotypic Shoals consisting of Large and Small Individuals met with each otherY. OHSHIMA1950 Volume 16 Issue 5 Pages 195-200
Published: October 25, 1950
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSOn the case when the large and small individuals of fish living in a shoal were brought together into a tank and they aggregated in a new homotypic shoal, does the shoaling keep long or separate? In this paper the author dealt with this problem in the young fish, Plolosus angui'laris. The results were obtained as follows: (1) Aggregation or separation is decided by the size-difference, Δ L, between large and small individuals (see Table 2). (2) Small individuals are responsible for separation. (3) Stability of aggregation or occurence of separation is variable accorging to the ratio in the number of large individuals to small ones. In general, small individuals are more numerous than large ones, aggregation keeps longer and it is more difficult for separation to occur (see Table 5 and 6).View full abstractDownload PDF (385K) -
H. YASUDA1950 Volume 16 Issue 5 Pages 201-204
Published: October 25, 1950
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSThis report inform the result of measurement of the elongation and the contraction of the netting cord, applying periodically and repeatedly the load in order to know the nature of elastic hysteresis of netting cord.View full abstractDownload PDF (246K) -
H. YASUDA, T. SAKAI1950 Volume 16 Issue 5 Pages 205-210
Published: October 25, 1950
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSSome discussions on the fishing season, on the course of migration, on such facts in question and and on problem of the stock of Sardina melanosticta (T and S) are given in this article analysing the reports on the size of the fish catched, sent to us from 174 fishing guild.View full abstractDownload PDF (396K) -
M. SUYAMA, T. TOKUHIRO, Y. SUYAMA1950 Volume 16 Issue 5 Pages 211-214
Published: October 25, 1950
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSRespectively by the xanthydrol method9, 12) and the WEBER-WILSON's method, we have determined the amounts of urea and ammonia (calculated from the amounts of volatile basic nitrogen) in 100 grams of the muscle of shark-fishes as shown in Table 1.
When the muscle of Prionace glauca (LINNÉT) is caused to decay at 35°C, the contents of urea was decreased quickly by linear function and after 48 hours all urea was decomposed by the urease of the bacteria. On the other hand, the formation of ammonia was much slower in the early stage of putrefaction as compared to the ammonia calculated from the decreasing amounts of urea, but was more rapidly in the later stage (Fig. 1). At the room temperature of winter (9±2°C), a similar tendency was observed (Fig. 2).
As demonstrated by YAMASAKI15) and SUMNER16), we assumed that an intermediate product will be formed in the enzymatic hydrolysis of urea, at least in the limit of this experiment.View full abstractDownload PDF (276K) -
S. KOKUBO1950 Volume 16 Issue 5 Pages 215-220
Published: October 25, 1950
Released on J-STAGE: February 29, 2008
JOURNAL FREE ACCESSThe ecology of Calanus plumchrus and Calanus cristatus of Japan Sea and Mutsu Bay was studied and compared. These two Copepods are regular frequenters of Mutsu Bay, and migrates from Japan Sea into Mutsu Bay during April- May. The present result, however, seems to show that at the time of the present collection (March 18th, 1950) C. plumchrus has been accomodated yet in great depth in Japan Sea, whereas C. cristatus already began upward migration, the migration of the latter species seems to take place a little earlier than that of the former.View full abstractDownload PDF (432K)
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