著者

謝 文陽 清水 潮 丸山 芳治

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.55, no.5, pp.853-857, 1989-05-25 (Released:2008-02-29)

参考文献数

13

被引用文献数

3 4

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Nitrogenase activity associated with the seagrass Zostera marina (eelgrass) was examined by the acetylene-reduction assay method. Most of the rhizome-root complex samples showed significant levels of nitrogenase activity after an initial lag period of 8 to 12 hours under aerobic or anaerobic conditions. However, separated rhizomes and roots rarely showed significant nitrogenase activity. Glucose addition had little effect on the activity of rhizomes but remarkably enhanced the activity of roots, which suggests that heterotrophic nitrogen-fixing bacteria are predominately associated with the roots rather than the rhizomes and also that the rhizome-root complexes show significant nitrogenase activity only when the rhizomes contain adequate energy source the for root-associated nitrogen-fixing bacteria. Most of the root-associated nitrogen-fixing bacteria were probably distributed on the surface and not inside the roots.

著者

佐藤 英雄 中村 中六 日比谷 京

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.28, no.6, pp.579-584, 1962-06-25 (Released:2008-02-29)

参考文献数

12

被引用文献数

19 21

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The processes of sex differentiation and sexual maturation of the eel, Anguilla japonica, were examined. In glass eels, the primordial germ cells standing in a line are found in each of the gonads (Pl. I, Fig. 1). The cells gradually increase in number under about 15cm in total length of the bodies, and steadily increase at 18cm or thereabout (Pl. 1, Fig. 2). The sex may differentiate at this stage, and histological structures of gonads become characteristic in both sexes, while ovaries and testes hardly be distinguished by means of their external appearance until the eels come to about 30cm in total length (Pl. I, Fig. 3 and 4). As they grow longer than some 30cm, the discriminative features of ovaries and testes become appreciable. In view of the observations described above, it is suggested that there is neither “phase of precocious feminization” nor “phase of juvenile hermaphroditism” in A. japonica. In testes of eels less than about 40cm, there may be seen many spermatogonia but no spermatocyte (Pl. I, Fig. 5), and the former gradually increase in number accompanying with body growth (Pl. I, Fig. 6). In silver eels having catadromous nature, a number of spermatocytes are found in testes, but spermatids scarcely ever (Pl. II, Fig. 1). In ovaries of eels ranging in total length from 25cm to 40cm, oogonia and primary oocytes are found intermingling (Pl. II, Fig. 3 and 4). As they grow over about 40cm, oocytes increase fast. In catadromous female fish, the cells develop up to the yolk vesicle stage (Pl. II, Fig, 5). It is generally found that the gonadal maturation of eels advance mostly in autumn and somewhat degenerate in winter, though the seasonal fluctuation in maturation are not so obvious.

著者

藤永 克昭 尾山 康隆

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.73, no.2, pp.256-262, 2007 (Released:2007-04-03)

参考文献数

28

被引用文献数

1 1

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2000 年 4 月から 2001 年 4 月にかけて,北海道のえりもにおいてエゾボラの繁殖を,成熟サイズ,生殖周期や性比の点から検討した。エゾボラの成熟サイズは,雄は殻高 120~130 mm,雌は殻高 150~160 mm であると判断された。エゾボラの主な交尾時期は,2 月から 5 月にかけてであると考えられた。一方,エゾボラの産卵は,3 月から 8 月にかけて行われると推測された。エゾボラの性比は季節によって変化した。エゾボラの殻高組成は雌雄によって相違し,その原因として雌雄の成長の差以外に,雄と雌の死亡率の相違による可能性も考えられた。

著者

立原 一憲 木村 清朗

出版者

日本水産學會

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.54, no.7, pp.1107-1113, 1988

被引用文献数

1 4

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A study on the life history of land-locked ayu <i>Plecoglossus altivelis</i> was made in Lake Ikeda, Kagoshima Prefecture, from 1981 to 1986.<br>Like amphidromous ayu, the life span of the land-locked fish in this lake is usually only one year and most of them die after spawning in autumn. However, a few individuals of land-locked ayu passing over the second winter are found in the lake.<br>The specimens counting 7, 810 of ayu in the lake were collected during this study and 73 of them were thought to be the over-wintered ones, because they had a conspicuous spawning mark on the embeded part of their scales. None of 0⁺ fish had any such scales. The amounts of fat tissue around viscera of mature ayu decreased in the spawning season from early October to late Novermber. Also, the condition factor of ayu caught in November showed very wide range from 0.6 to 1.7. The fish whose condition factor was less than 0.9 had exteremely shrunk stomach without any food, whereas the fish of more than 1.3 in condition factor had normal stomach containing a small amounts of diatoms and blue-green algae. All specimens of 1₊ fish, which were collected after December, had recovered their fat tissue and begun to grow again. Thus, it is suggested that the survival of ayu after spawning season depends on the degree of stomach shrinkage and adequate intake of food. Some of them grew 150mm in standard length or more by the next autumn.<br>The specimens of mature 1⁺ fish which were caught at a spawning ground in October suggests that some of the over-wintered ayu in the lake are able to attain maturity in second spawning season.

著者

栄 研二 海野 徹也 高原 泰彦 荒井 克俊 中川 平介

出版者

日本水産學會

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.62, no.1, pp.46-50, 1996-01-15

参考文献数

14

被引用文献数

2

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Yearling ayu <i>Plecoglossus altivelis</i> collected in June and July from the Ohta River were biologically and biochemically examined in comparison with annual ayu caught in the same area.<br>All the yearling ayu were female. The yearlng ayu were different in size and skin color from the annual ayu, but not different in anatomical parameters such as hepatosomatic index, intraperitoneal fat body ratio, and gonadosomatic index. The ovaries of annual ayu were immature and included chromatin nucleolus and perinucleolus stage eggs, but those of yearling ayu consisted mostly of abortive eggs and a few chromatin nucleolus and perinucleolus stage eggs.<br>The yearling ayu had less muscle protein but more triglycerides than annual ayu. Fatty acid composition of muscle triglycerides in the yearling ayu was not different from that of the annual ayu. Low protein accumulation caused by depression of protein metabolism would affect the viability of yearling ayu after July.

著者

宮入 陽介

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.87, no.5, pp.548, 2021-09-15 (Released:2021-10-01)

参考文献数

1

著者

若菜 博

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.79, no.6, pp.1034-1036, 2013 (Released:2013-11-18)

参考文献数

8

著者

金子 豊二

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.80, no.5, pp.663-669, 2014 (Released:2014-10-01)

参考文献数

20

著者

中野 平二

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.71, no.4, pp.639-644, 2005 (Released:2005-08-24)

参考文献数

5

被引用文献数

1 1

著者

岩崎 敬二

出版者

公益社団法人日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.73, no.6, pp.1121-1124, 2007-11-15

被引用文献数

3

著者

野口 勝明

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.83, no.5, pp.750-753, 2017 (Released:2017-09-20)

参考文献数

16

被引用文献数

2

著者

平山 和次 渡辺 剛志

出版者

日本水産學會

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.39, no.11, pp.1129-1133, 1973

被引用文献数

36

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The nutritional effect of caked yeast still living and of dried marine yeast on the rotifer, <i>Brachionus plicatilis</i>, was examined.<br> Experiments were performed by culturing many individuals in many test tubes, each containing two individuals in the experimental medium. From daily counts of eggs laid and surviving individuals, time intervals from hatching to 50% survival and to peak of fecundity, net reproduction rate, intrinsic rate of population increase and mean generation time were estimated.<br> The results obtained are summarized as follows.<br> 1. Caked yeast still living, <i>Rhodotorula sp.</i> has less nutritional effect on the rotifer than that of the marine <i>Chlorella.</i> However, it seems to be somewhat effective as food for the rotifer.<br> 2. Dried marine yeast itself has little nutritional effect on the rotifer. However, aerobical decomposition can increase the nutritional effect to some extent.<br> 3. The marine yeast added to a diluted <i>Chlorella</i> suspension was very effective as supplementary food for the rotifer. Hence, yeast may be used most effectively as a sup-plementary food in the culture medium when sufficient phytoplankton can not be supplied to the rotifer.

著者

渡部 俊広 TOSHIHIRO WATANABE (独)水産総合研究センター水産工学研究所漁業生産工学部 Fishing Technology Division National Research Institute of Fisheries Engineering Fisheries Research Agency

出版者

日本水産學會

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.71, no.1, pp.16-23, 2005-01-15

参考文献数

32

被引用文献数

9 9

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隠岐諸島西方の海域で,商業ベニズワイガニ籠と円形脱出口をつけた商業籠による長期浸漬(約 6 ヶ月間)漁獲試験を行い,逸失時の商業籠の漁獲サイズ選択性を推定した.選択性曲線は,多項分布の尤度を用いた SELECT モデルによって求めた.商業籠の 50% 選択甲幅は 100.8 mm,選択性スパンは 3.4 mm であった.甲幅 99 mm 以下の個体は,商業籠から脱出できるため,雌についてはゴーストフィッシングが生じる可能性はない.しかし,籠に入った甲幅 103 mm 以上の雄については,籠内に保持されたまま死亡する可能性がある.<br>

著者

松岡 達郎 TATSURO MATSUOKA 鹿児島大学水産学部 Faculty of Fisheries Kagoshima University

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.72, no.5, pp.928-929, 2006-09-15

参考文献数

12

被引用文献数

1

著者

近藤 史崇 岩井 俊治 三浦 智恵美 坂田 潤弥 太田 史 井戸 篤史 入江 奨 岡松 一樹 角正 浩一 三浦 猛

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

pp.16-00030, (Released:2016-11-01)

参考文献数

41

被引用文献数

5 7

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養殖クロマグロに最適な飼料の開発を目指して,EP給餌と生餌給餌の体成長と消化関連因子の比較を行った。EP給餌のクロマグロの体成長は胃のペプシン活性が減少した後に一旦停滞したが,その後,幽門垂の肥大化に伴うプロテアーゼ活性の増加により生餌給餌と同程度に回復した。EPは生餌に比べて難消化であるため胃での滞留時間が長く,消化関連因子(cck, pyy)は生餌より遅れて発現した。成長関連因子(ghrelin)は餌の消化管内での移動に伴って発現が変動し,EP飼料では有意に増加する事が明らかとなった。

著者

吉村 研治 大森 庸子 吉松 隆夫 田中 賢二 石崎 文彬

出版者

日本水産學會

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.62, no.6, pp.897-903, 1996-11-15

参考文献数

6

被引用文献数

7 7

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In a high density culture of rotifer (beyond the levels of 10³ind./m<i>l</i>), the amount of aeration needed to maintain an optimum dissolved oxygen (DO) level increases. In order to investigate the effect of aeration on the population growth of rotifer, a series of experiments were carried out. The S-type rotifer <i>Brachionus rotundiformis</i> was cultured at high density using 10<i>l</i> vessels under different aeration conditions. Air or oxygen gas was introduced into the culture media through two types of sparger which formed different sizes of bubbles, at aeration rates from 0.1 to 2.0vvm. The bubble-size from the two kinds of sparger were estimated from the value of <i>KLa</i> (volumetric oxygen transfer coefficient). When the aeration rate was high or the ceramic sparger that formed smaller bubbles was used, DO in the culture system remained at a high level. However, under these conditions, the growth of the rotifer population was seriously inhibited due to very high aeration rates and small bubbles, possibly as a result of foaming separation. When oxygen gas was introduced into the culture system, the density of rotifer was higher than that when air was introduced. Therefore, it is recommended to introduce high-purity oxygen gas for a high density culture to avoid any growth inhibition and to maintain optimum DO.

著者

木村 昇 秋場 稔

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.37, no.12, pp.1207-1213, 1971-12-25 (Released:2008-02-29)

参考文献数

20

被引用文献数

1 1

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Iron-sulfide blackening of the headspace and liquid parts of tin cans was investi-gated. In the lid and bottom of the C-enameled can, a definite area of iron layer was exposed by scratching the enamel and the tin layers. These cans were filled to 2/3 volume with cysteine solution containing 0 to 4% NaCl at various pH values from 5 to 8. Other cans were 2/3 filled with an extractive of King crab meat containing the cysteine solution. The blackening of the iron surface was observed organoleptically and quantitatively for 6 months at 37°C. In the headspace, the blackening was accelerated by lower pH values and higher concentrations of NaCl. On the contrary, blackening of the liquid parts was remarka-ble at higher pH values and lower concentrations of NaCl. The existence of copper in the crab extractives accelerated the blackening. The acceleration was significant in the liquid part but not in the headspace.

著者

大関 芳沖

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.80, no.1, pp.90, 2014

著者

重田 利拓

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.74, no.5, pp.868-872, 2008 (Released:2008-09-27)

参考文献数

14

被引用文献数

8 6

著者

今井 一郎

出版者

公益社団法人 日本水産学会

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.83, no.3, pp.314-324, 2017 (Released:2017-05-22)

参考文献数

87