著者

NAOKI KUMAKURA KIYOSHI SAKAI FUMIO TAKASHIMA

出版者

The Japanese Society of Fisheries Science

雑誌

Fisheries science (ISSN:09199268)

巻号頁・発行日

vol.69, no.3, pp.495-504, 2003 (Released:2009-03-31)

参考文献数

37

被引用文献数

9

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The annual reproductive cycle, including the first maturity of ovarian development and plasma levels of testosterone (T) and estradiol-17β (E2), was examined in female Japanese catfish Silurus asotus reared under natural conditions. In addition, the possible period that final oocyte maturation and ovulation can be induced by human chorionic gonadotropin (hCG) injection were investigated. Results showed that female Japanese catfish matured 1 year after hatching under reared conditions. The beginning of vitellogenesis was in March and ovarian development and plasma T and E2 levels peaked in June. Thereafter, the gonadosomatic index gradually decreased to October and regression of oocytes at the tertiary yolk globule stage was observed. Female Japanese catfish could be induced to final oocyte maturation and ovulation by hCG treatment during the period from June to September. In addition, the fertilization rates were relatively high and stable during this period. These results suggest that yearling female Japanese catfish can be used as brood stock for seed production. This is the first study to investigate the annual reproductive cycle in Japanese catfish. These data will provide useful information regarding brood stock management and seed production.

著者

Kaworu Nakamura

出版者

The Japanese Society of Fisheries Science

雑誌

Fisheries science (ISSN:09199268)

巻号頁・発行日

vol.60, no.3, pp.271-274, 1994 (Released:2008-06-30)

参考文献数

10

被引用文献数

3 6

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To prove air breathing, common carps Cyprinus carpio acclimated at 27°C were subjected to the following experiments after a 3 h precooling period in water by decreasing the temperature to 17°C. 1) Each fish with a plugged oesophagus was accommodated in a respiratory chamber connected to gas meters for measurements of concentration changes of O2 and CO2 at 17°C. 2) Each group of five fish was exposed to 17°C air to examine its 100% survival time. Over time, the O2 concentration decreased and that of CO2 increased. The CO2 concentration showed a saturation curve. Mean respiratory rates in the initial period of 1-1.5 h were 51±24.2ml O2 per kg•h and 24±5.8ml CO2 per kg•h. The 100% survival time with a 3 h precooling was 4.5 h. As a conclusion, carp breathe following an incomplete CO2 excretion even in air.

著者

Kazuya Taniguchi Kazuya Kurata Takayoshi Maruzoi Minoru Suzuki

出版者

The Japanese Society of Fisheries Science

雑誌

Fisheries science (ISSN:09199268)

巻号頁・発行日

vol.60, no.6, pp.795-796, 1994 (Released:2008-06-30)

参考文献数

8

被引用文献数

12 42

著者

松川 康夫 張 成年 片山 知史 神尾 光一郎 YASUO MATSUKAWA NARITOSHI CHO SATOSHI KATAYAMA KOICHIRO KAMIO (独)水産総合研究センター中央水産研究所 (独)水産総合研究センター中央水産研究所 (独)水産総合研究センター中央水産研究所 (株)東京久栄 National Research Institute of Fisheries Science Fisheries Research Agency National Research Institute of Fisheries Science Fisheries Research Agency National Research Institute of Fisheries Science Fisheries Research Agency Tokyo Kyuei Co. Ltd.

出版者

The Japanese Society of Fisheries Science

雑誌

日本水産学会誌 = Bulletin of the Japanese Society of Scientific Fisheries (ISSN:00215392)

巻号頁・発行日

vol.74, no.2, pp.137-143, 2008-03-15

参考文献数

60

被引用文献数

8 37

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我が国のアサリRuditapes phillipinarumの総漁獲量は,1960年には10万トンであった。その後,一部に漁場の埋め立てによる減少があったにも関わらず,1982年には14万トンまで増加したが,1984年から激減して,1994年にはわずか3分の1程度(5万トン)になり,その後もこの水準が続いている。著者らはアサリの生態や資源に関する報告を総括し,1984年以降のアサリ漁獲量の激減の主要因を過剰な漁業活動,すなわち親貝と種貝用の稚貝に対する過剰漁獲と結論づけた。それ以外にも,周年の過剰操業による底質擾乱は,稚貝の生残率低下を助長した可能性が高いと考えられる。The annual catch of the Manila clam Ruditapes phillipinarum in Japan increased from 100 thousand tonnes in 1960 to 140 thousand tonnes in 1982. This increase occurred despite a local decrease in coastal fishing grounds due to land reclamation and helped to balance overall production. Since 1984, however, the catch has decreased drastically to only 50 thousand tonnes and has remained at this low level. The authors reviewed published reports relevant to the ecology and resources of Manila clam and concluded that the main factor responsible for the drastic decrease in catch is over-fishing. Over-exploitation of the adults and sub-adults significantly affected and damaged reproduction and source-sink relationships among localities. Disturbance of the clam habitat throughout the year by heavy fishing gear may also be responsible for lowering the survival rate of the juveniles.

著者

川尻 稔

出版者

The Japanese Society of Fisheries Science

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.15, no.4, pp.166-172, 1949

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I Studyed on the influence of the population density of Killie-fish (<i>Oryzias latipes</i> T & S) upon the number of spawn eggs, hatching-rate, and consequentry upon the reproduction. In the present study these fishes were cultured a pail (1 ?? and -1 ?? ) 1, 2 and 4 pairs respectively in 3 glass bowls (diameter 30cm, depth 15cm) filled with 7 L. of water, and were given food daily into each groups at the ratio of 1, 2, 4, and the rearing water of each bowl were changed 2-3 times in a week at the same ratio as above. Their spawned eggs were counts 3-4 times every day, and transfered into each 3 glass bottles (capacity 200cc) which filled water at the above ratio also, and disinfected by 0.5% of formalin solution every 4-5 days, and the fry which hatch out were counted every day. These experiments were carryed on two times in the same way.<br> Putting these results together, the number of eggs spawned one female a day decreases, so, accordingly, the number of eggs spawned one female decreases, and besides the hatch-rate have a tendency of depresses, in proportion to the population density of the fishes increases, and by the accumlation of these factors the rate of reproduction of the fish decreases.<br> Satisfied the equation <i>y=ax^b</i>, where <i>y</i> represents the number of eggs spawned per i female a day, or hatching-rate, <i>x</i> density of population, <i>a</i> and <i>b</i> are the characteristic constants.

著者

安田 秀明

出版者

The Japanese Society of Fisheries Science

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.10, no.5, pp.229-230, 1942

著者

田中 博之

出版者

The Japanese Society of Fisheries Science

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.60, no.4, pp.533-534, 1994

被引用文献数

1 2

著者

山本 勝太郎

出版者

The Japanese Society of Fisheries Science

雑誌

日本水産学会誌 (ISSN:00215392)

巻号頁・発行日

vol.51, no.11, pp.1755-1760, 1985

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To obtain a standard for rope usage, the tensile breaking strength of various ropes tied in ten different kinds of knots has been tested in both dry and wet conditions. The ropes tested were a polyethylene, a polypropylene, a mixed one consisting of polyethylene and vinylone which comprised a 3-strand laid rope, and a polyethylene 8-strand braided rope. The commercial size was 9mm in diameter for all ropes. "Dry condition" means that the knot samples were stored at normal temperature of a room, and "wet condition" means that the knot samples were soaked in water applying a pressure of 2.0kg/cm² for 12h. Results of tests for tensile breaking strength indicated that the optimum number of tucks in an eye splice was 4 tucks for the laid ropes, and 3 tucks for the braided rope. Percentages of the knot strength to the dry one of the eye splice although being somewhat different for both sample conditions and among the kinds of ropes tested, were roughly estimated as follows: 50% for the overhand knot and the single-sheet bend with end return, 55% for the double-sheet bend, 60% for the bowline knot and kakine-musubi and 95% for the short splice. Furthermore, percentages of the knot strength to the dry strength of the unknotted rope, if estimated as 90% for the eye splice, become 45%, 50%, 55% and 85% respectively.

著者

大谷 真紀

出版者

The Japanese Society of Fisheries Science

雑誌

日本水産學會誌 = Bulletin of the Japanese Society of Scientific Fisheries (ISSN:00215392)

巻号頁・発行日

vol.78, no.5, 2012-09-15

著者

Takashi Yada Fuminari Ito

出版者

The Japanese Society of Fisheries Science

雑誌

Fisheries science (ISSN:09199268)

巻号頁・発行日

vol.64, no.5, pp.694-699, 1998 (Released:2008-06-30)

参考文献数

34

被引用文献数

6 6

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Sexual differences in survival and changes in plasma ion levels after transfer from neutral water to acid water prepared with sulfuric acid were examined in medaka Oryzias latipes. In acid water at pH 3.5 and 3.8, survival of female fish was better than male. During exposure to acid water at pH 4.1, there was no mortality in either sex. Male fish showed a transient decrease in the plasma sodium level 24 h after transfer to pH 4.1, whereas there was no change in the female. The plasma level of sulfate was not affected in the female, but a significantly high level was consistently observed during the exposure in the male. In both sexes, the activity of gill Na+, K+-ATPase increased within 24 h after transfer to pH 4.1, and this high level was maintained for 1 month. Treatment with short day-photoperiod (8L:16D) caused a cessation of spawning due to inactivation of the testis and ovary. Transfer to acid water caused a decline in plasma sodium only in male fish, but not in female even under a short photoperiod. These results indicate that female medaka are more tolerant to acidic environment, possibly with a greater osmoregulatory ability than male fish.

著者

Tomoko Seki Toru Taniuchi Hideki Nakano Makoto Shimizu

出版者

The Japanese Society of Fisheries Science

雑誌

Fisheries science (ISSN:09199268)

巻号頁・発行日

vol.64, no.1, pp.14-20, 1998 (Released:2008-06-30)

参考文献数

16

被引用文献数

21 24

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We studied age, growth, and maturity of the oceanic whitetip shark Carcharhinus longimanus in the North Pacific, and the reproduction in the North and South Pacific, captured with tuna longline from Nov. 1967 to Oct. 1995. Vertebral rings were examined from 111 males (precaudal length: 54-172cm) and 114 females (precaudal length: 50-195cm). Minimum and maximum numbers of translucent rings were 0 and 11. Marginal increment analysis suggested annualus deposition occurs during spring. A growth difference between sexes was not found. A von Bertalanfly growth equation combining both sexes was as follows; Lt=244.58×{1-e-0.103×(t+2.698)}Lt was expressed as precaudal length in cm at age t. The reproductive condition was examined from 136 males and 85 females. Maturation was determined to be when precaudal length was between 125 and 135cm for both sexes (4-5 years). The parturition period is extended over a long duration. The birth size was 45-55cm and litter size varied from 1-14 with a mean of approximately six in the North Pacific.

著者

Masataka Satomi Bon Kimura Gen Takahashi Tateo Fujii

出版者

The Japanese Society of Fisheries Science

雑誌

Fisheries science (ISSN:09199268)

巻号頁・発行日

vol.63, no.6, pp.1019-1023, 1997 (Released:2008-06-30)

参考文献数

27

被引用文献数

7 9

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Microbial population in kusaya gravy from Niijima Island was analyzed by grouping of functional characteristics and genetic identification from 16 S rRNA genes (16 S rDNA). Viable conunts in TSSY medium supplemented with 0.1% thioglycolate and 0.3% agar using the MPN method were determined as 1011/ml, which was the highest value compared with previous reports on kusaya gravy. Each of denitrifying, nitrate reducers, sulfate reducers and proteolytic bacteria were estimated as about 109/ml, and starch hydrolyzing and lactic acid producing bacteria were estimated as lessthan 103/ml. Viable counts on TSA medium, which were superior to BPG and B6P6G media, were 108 CFU/ml. The 16 S rDNA were amplified from kusaya gravy by PCR without cultivation of baceria, cloned, and sequenced. Sequence analysis of the cloned partial 16 S rDNA indicated that the major bacteria in kusaya gravy were Bacteroides-Cytophaga group bacteria, wall-less spirochaeta-like bacteria, unidentified bacteria, and so on. The results of genetic identification did not coincide with those of cultural methods; i.e., most of the above bacteria have not been isolated by plate methods so far, and Corynebacterium and Peptococcuceae which were representative organisms in the plate surface method under aerobic or anaerobic conditions, respectively, were not detected by the PCR method. These results indicated that there are diverse organisms which are unknown and unculturable in kusaya gravy.

著者

Takuya Otani Tohru Takahashi Shuhei Matsuura

出版者

The Japanese Society of Fisheries Science

雑誌

Fisheries science (ISSN:09199268)

巻号頁・発行日

vol.62, no.5, pp.670-674, 1996 (Released:2008-06-30)

参考文献数

20

被引用文献数

6 5

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Larvae of the swimming pea crab Tritodynamia horvathi hatched in the laboratory were reared to adult, and were bred successfully. Zoeal larvae were obtained from ovigerous females collected at Yatsushiro Sound, and they were reared on rotifers, Artemia nauplii and artificial diet. Zoeae hatched in April passed through five zoeal stages during 15-22 days, and the duration of the megalopal stage was 5-11 days. First stage crabs reached the fifth crab stage within two months. Ovigerous females first appeared from September 14, 6 days after the first copulation was observed. However, the percentage of ovigerous females over this period was less than 7%. Copulation and ovigerous females were not detected during November to January. After February 8, copulation resumed and ovigerous females appeared again. The percentage of ovigerous females in the latter breeding season reached 78%. When the crabs were swimming in the aquarium, they were constantly moving their maxillipeds in a regular pattern, and fed on Artemia nauplii or powder of pellets. This suggests that the swimming behavior of T. horvathi is not apeculiar behavior restricted to mating as the copulatory swimming recorded in some other pinnotherids, but a behavior for feeding.

著者

塚本 勝巳 河村 知彦 竹内 俊郎

出版者

The Japanese Society of Fisheries Science

雑誌

日本水産學會誌 = Bulletin of the Japanese Society of Scientific Fisheries (ISSN:00215392)

巻号頁・発行日

vol.75, no.3, pp.458-459, 2009-05-15

著者

勝川 俊雄 TOSHIO KATSUKAWA 東京大学海洋研究所 Ocean Research Institute University of Tokyo

出版者

The Japanese Society of Fisheries Science

雑誌

日本水産学会誌 = Bulletin of the Japanese Society of Scientific Fisheries (ISSN:00215392)

巻号頁・発行日

vol.73, no.4, pp.656-659, 2007-07-15

参考文献数

18

被引用文献数

5 3

著者

堀井 善弘 佐伯 拓磨 西村 麻理生 神澤 識大 田中 彰 大泉 宏

出版者

The Japanese Society of Fisheries Science

雑誌

日本水産學會誌 = Bulletin of the Japanese Society of Scientific Fisheries (ISSN:00215392)

巻号頁・発行日

vol.76, no.2, pp.267-268, 2010-03-15

被引用文献数

1 1

著者

NAOHIKO WATANUKI GUNZO KAWAMURA SHOHEI KANEUCHI TORU IWASHITA

出版者

The Japanese Society of Fisheries Science

雑誌

Fisheries science (ISSN:09199268)

巻号頁・発行日

vol.66, no.3, pp.417-423, 2000 (Released:2009-03-31)

参考文献数

21

被引用文献数

21

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The role of vision in the entry of the cuttlefish Sepia esculenta into basket traps was examined in laboratory experiments and by histological examination of the retina. Both entry into the trap and feeding on shore crabs stopped when the tank was completely darkened. The eyes of cuttlefish have a high sensitivity to light. The visual field of cuttlefish was determined by the optical method, based on the assumption that incident light on the pupil from any direction reaches the retina through a refractive lens. The uniocular visual field was found to be 253° on the horizontal plane, and the anterior and posterior binocular visual fields were 86° and 60° respectively. On the retina, areas with especially high visual cell density formed a visual equator slightly above the optical equator. The distribution of the visual cell density indicates no specific visual axis. The visual acuity is 0.36 when estimated from the bait recognition distance and the size of bait during feeding, and 0.89 when determined from the visual cell density at the visual equator and the focal length of the lens. Cuttlefish have far superior visual acuity than fish.

著者

HIROKAZU MATSUDA TAISUKE TAKENOUCHI TAKASHI YAMAKAWA

出版者

The Japanese Society of Fisheries Science

雑誌

Fisheries science (ISSN:09199268)

巻号頁・発行日

vol.69, no.1, pp.124-130, 2003 (Released:2009-03-31)

参考文献数

23

被引用文献数

14

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The timing of molting and metamorphosis was monitored for Panulirus japonicus phyllosoma larvae cultured in the laboratory. Larvae cultured under natural light-dark cycle molted synchronously within approximately 1.0 h before and after sunrise, except for a short period after hatching; the timing of molting changed with time of sunrise. When three artificial light-dark cycles were introduced, larvae molted around the start of lighting, irrespective of the light-dark cycles. In the event of a sudden change in the start or end of lighting, molting was regulated by an endogenous rhythm. The start of lighting had a greater impact on the timing of molting than the end of lighting, suggesting that sunrise is probably the critical signal for phase-setting in molting rhythm. Metamorphosis to the puerulus stage occurred within 0.4 h before and 1.2 h after sunset under a natural light-dark cycle, and the timing of metamorphosis was also changed artificially by regulating the end of lighting.

著者

KATSUYUKI HAMASAKI HIDEYUKI IMAI NOBUHIKO AKIYAMA KYOHEI FUKUNAGA

出版者

The Japanese Society of Fisheries Science

雑誌

Fisheries science (ISSN:09199268)

巻号頁・発行日

vol.70, no.6, pp.988-995, 2004 (Released:2009-03-31)

参考文献数

22

被引用文献数

26

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Females of the swimming crab Portunus trituberculatus were cultured under natural temperature and high temperature (21°C) conditions to examine ovarian development and oviposition from autumn (October) to the beginning of breeding season in the following spring (May). Ovaries developed because of vitellogenesis of oocytes from October to December and their developmental state did not change during the overwintering period from December to March. In spring, from late March to mid May, some ovaries reached prematuration and maturation stages and ovipositions began from mid-late April under natural temperature conditions. Females reared in tanks of high temperature regimes oviposited earlier than those reared in tanks of natural temperatures. The number of days to oviposition tended to decrease with advancement of the beginning times (early February to late April) of culture of females under high temperature regimes; induced ovipositions were achieved more easily with increasing photoperiod from c. 12 h in early February to c. 14 h in late April. Therefore, it is inferred that the temperature and photoperiod are important environmental factors controlling ovarian development and oviposition.

著者

内田 詮三

出版者

The Japanese Society of Fisheries Science

雑誌

日本水産學會誌 = Bulletin of the Japanese Society of Scientific Fisheries (ISSN:00215392)

巻号頁・発行日

vol.76, no.5, 2010-09-15