NIPPON SUISAN GAKKAISHI
Online ISSN : 1349-998X
Print ISSN : 0021-5392
ISSN-L : 0021-5392
Volume 76, Issue 6
Displaying 1-50 of 56 articles from this issue
Originals
  • KOH-ICHI FUJIWARA, TAKAHIRO USUKI, SHUICHI KITADA
    Article type: Originals
    2010 Volume 76 Issue 6 Pages 1025-1034
    Published: 2010
    Released on J-STAGE: January 31, 2011
    JOURNAL FREE ACCESS
      Changes in swimming speed of larval and juvenile nigorobuna Carassius auratus grandoculis associated with its growth and exercise training in running water were investigated in order to obtain basic data for considering the effective release strategies for the stock enhancement program in Lake Biwa. As a result, increase in burst speed was observed until approximately 16 mm in standard length (SL). During the juvenile stage (≧16 mm SL), a rapid increase in the cruising speed and a marked increase in the swimming ability were observed. The results strongly indicate that ca. 16 mm SL is an effective criterion for release. Increase of burst speed in larval and/or juvenile nigorobuna by exercise training in running water was observed, but when the fish reared in running water and still water were released in concrete ponds with one or two largemouth bass Micropterus salmoides as a predator and in the natural environment of Lake Biwa, significant differences were not recognized in the survival rates between trained and still water reared fish.
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  • HARUHISA FUKADA, KOHTARO KAWAI, DAIJI TADOKORO, KATSUJI MORIOKA, TOSHI ...
    Article type: Originals
    2010 Volume 76 Issue 6 Pages 1035-1042
    Published: 2010
    Released on J-STAGE: January 31, 2011
    JOURNAL FREE ACCESS
      Bullet tuna Auxis rochei broth is food-processing wastewater obtained after boiling fish and is rich in free amino acids and peptides. To efficiently utilize bullet tuna broth as fish feed, we investigated the effects of bullet tuna broth-supplemented diet on the growth performance in yearling yellowtail Seriola quinqueradiata. Fish meal (FM) and 30% FM-replaced with soybean meal (SBM) diets were used as basal diets. The effects of bullet tuna broth on growth performance were confirmed with or without supplementation to the basal diets (100 mL/kg diet). After 6 weeks of feeding trial, the growth performance (i.e., body weight, weight gain, specific growth rate and feed efficiency) was characterized as FM+Broth diet group>FM diet group>SBM+Broth diet group>SBM diet group. We conclude that supplementation of bullet tuna broth to yearling yellowtail diets improves the growth performance.
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  • YOSUKE NAKAYAMA, KAZUHIKO HIRAMATSU
    Article type: Originals
    2010 Volume 76 Issue 6 Pages 1043-1047
    Published: 2010
    Released on J-STAGE: January 31, 2011
    JOURNAL FREE ACCESS
      The reliability of VPA used for stock assessment for the nine TAC stocks was evaluated using Fisher's information matrix and a profile likelihood confidence interval. The confidence intervals for the stock sizes of the Pacific and the Tsushima stocks of Japanese sardine in 2007 were extremely wide. The results also indicated that the confidence intervals for the Pacific stock of club mackerel and the Pacific and the East China Sea stocks of blue mackerel were wide. Uncertainties in stock size estimates should be considered in stock management. The reliability of stock size estimates should be routinely evaluated using the profile likelihood method which is relatively easy to calculate.
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  • HITOSHI KUBOTA, TADAYUKI SAKAI, TAKAHIDE DOI
    Article type: Originals
    2010 Volume 76 Issue 6 Pages 1048-1055
    Published: 2010
    Released on J-STAGE: January 31, 2011
    JOURNAL FREE ACCESS
      Rotational fishing in mountain streams is a potential inland fisheries management practice for the sustainable exploitation of natural stocks. To evaluate the effects of rotational fishing on enhancement of white-spotted charr and masu salmon stocks, we investigated changes in the abundances of these fishes in two streams where this management practice was applied. Generalized linear mixed models showed that the density of catchable-size (>150 mm) of both species increased during two closed years and three closed years in one stream. In another stream, the density of catchable-size charr did not increase during two closed years. The density of new recruits (≤150 mm) of either species did not increase in either stream, probably because of the effects of environmental fluctuations and time lags for population increase. Our data indicate that the effects of rotational fishing in mountain streams on enhancement of fish stocks differ among streams and fish sizes. Because the short-term closures investigated here resulted in only small increases in population (1-2 individuals/100 m2), stocks may decline rapidly under high fishing pressure during open periods. Accordingly, additional harvest regulations may need to be implemented during open years to sustain the increased abundance resulting from rotational fishing.
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  • MASATO KOBAYASHI, KOICHI OKUZAWA, KIYOSHI SOYANO, KENZO YOSEDA
    Article type: Originals
    2010 Volume 76 Issue 6 Pages 1056-1065
    Published: 2010
    Released on J-STAGE: January 31, 2011
    JOURNAL FREE ACCESS
      In order to reveal the reproductive ecology of captive hawksbill caught from the wild, we investigated the mating and nesting behavior, clutch size, number of clutches and hatching rate from 2006 to 2009. We used a video camera system in order to determine the date and time of mating and nesting. Mean mating duration ranged from 50 to 150 minutes, and the period from mating to the 1st nesting was 29.6±3.4 days. As for nesting, 4 females nested a total of 16 times between 2006 and 2009. Mean clutch size and number of clutches were 135.9±25.2 eggs and 3.5±0.7 clutches, respectively. These results closely correlated with data from wild populations. Hatching rate of captive eggs was markedly lower compared to that of wild eggs. However, the straight carapace length and body weight of hatchlings in captivity were comparable to those of the wild ones.
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  • ATSUSHI OOI, YOUJIRO TAMURA, TSUYOSHI OKAGAKI
    Article type: Originals
    2010 Volume 76 Issue 6 Pages 1066-1072
    Published: 2010
    Released on J-STAGE: January 31, 2011
    JOURNAL FREE ACCESS
      The aim of this study was to clarify the effect of gluconate on heat-induced gelation of myosin. Myosin purified from ordinary muscle of red sea bream Pagrus major was incubated at 80°C and then cooled to make heat-induced gel. The breaking strength of the gel formed with gluconate was 4-6-fold larger than that formed with chloride salt. Scanning microscopy showed that the gel with gluconate had a finer and more regular network structure. Gluconate strongly suppressed the thermal denaturation of myosin, but the effect of the suppression was similar to that in the case of sorbitol. On the other hand, gluconate heightened the gel-melting temperature more effectively than sorbitol. The partial specific volume of myosin in sodium gluconate solution was 0.65 cm3/g, which was much smaller than that in sodium chloride solution (0.71 cm3/g). Furthermore, the values of the adiabatic compressibility of myosin in chloride salt solution were positive, while those in gluconate solution were negative, indicating that gluconate remarkably increased the amount of hydration of myosin. These results suggested that gluconate strengthened intermolecular hydrophobic interactions by changing the water structure around myosin molecules.
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  • MEIKO KIMURA, YOSHINOBU HIRAOKA, TAKASHI KIMIYA, SINTARO IMAMURA, MICH ...
    Article type: Originals
    2010 Volume 76 Issue 6 Pages 1073-1079
    Published: 2010
    Released on J-STAGE: January 31, 2011
    JOURNAL FREE ACCESS
      Trimethylamine-N-oxide (TMAO) content of Pacific saury caught on the high seas in the northwest Pacific Ocean was estimated and its degradation products, trimethylamine (TMA) and dimethylamine (DMA) responsible for characteristic ‘fishy’ odor, were also analyzed during postmortem storage in the frozen state. The TMAO content differed between individual fish and tended to be high in the fish with a large coefficient of fatness. The TMAO content was higher in dark muscle than in ordinary muscle. The amount of TMA hardly increased for up to 12 months during frozen storage at −40°C. At −20°C storage, a great increase of TMA was detected in dark muscle though in ordinary muscle it hardly increased 6 months later, suggesting that the ‘fishy’ odor was mainly derived from dark muscle. The amount of formation of DMA was less than that of TMA in both ordinary and dark muscle during frozen storage.
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Short Papers
Symposium
Ecosystem services of coastal waters, nursery for fishery resources
Mini-Symposia
Quantitative prediction and evaluation models of biological environment parameters
Research activity and ethics of fisheries engineers
Highlights in Fisheries Science Research
Topics
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