NIPPON SUISAN GAKKAISHI
Online ISSN : 1349-998X
Print ISSN : 0021-5392
ISSN-L : 0021-5392
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Volume 76, Issue 2
Displaying 1-37 of 37 articles from this issue
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  • An evaluation of the ecological features of endangered freshwater fish commonly distributed in Japan
    TAKAHARU NATSUMEDA, TETSUYA TSURUTA, KEI'ICHIRO IGUCHI
    2010 Volume 76 Issue 2 Pages 169-184
    Published: 2010
    Released on J-STAGE: May 13, 2010
    DOIhttps://doi.org/10.2331/suisan.76.169
    JOURNAL FREE ACCESS
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      Based on 20 ecological variables (e.g., stream habitat morphology, body size, longevity, fecundity, mating system, diversity of food at trophic level, and distance from human activities), we evaluated the possibility of common species becoming endangered species in the Red List of the Ministry of Environment, Japan based on the ecological features of native freshwater fish in Japan. Of 109 common species distributed in Japan, 41 species (37.6%) are listed as endangered species. The results of logistic analysis showed that distance from human activities could be used as a valid variable to predict which species are likely to become endangered.
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  • Chemoreception in the abalone Haliotis discus hannai (Ino), and its role in inducing feeding
    KOTARO UCHIDA, GUNZO KAWAMURA, TERUO KASEDOU, TOSHIYUKI ONOUE, MIGUEL ...
    2010 Volume 76 Issue 2 Pages 185-191
    Published: 2010
    Released on J-STAGE: May 13, 2010
    DOIhttps://doi.org/10.2331/suisan.76.185
    JOURNAL FREE ACCESS
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      Putative chemoreceptors in the tentacles and the snout of the abalone Haliotis discus hannai were examined with scanning electron microscopy and light microscopy, and their role in inducing feeding was tested behaviorally. The cephalic, epipodial and mantle tentacles bear papillae with ciliary tufts at their tips. Chemoreceptors with 14-21 ciliated cells were found at high density on the snout. When the tentacles were touched with a bamboo rod or a piece of plastic sheet, the abalone contracted the tentacle stimulated, indicating mechanoreception. The contact of a piece of brown algae Laminaria japonica to any of three tentacles elicited a typical feeding response: shell lifting, pedal sole expansion and lifting, and food seizing with pedal sole. The response disappeared when the algae was separated from the tentacles, indicating that the ciliated cells were contact chemoreceptors as well as mechanoreceptors. A possibility of distant chemoreception was examined in a Y-maze in which seawater flowed over the algae and was directed towards the abalone. The algal stimulant triggered the food searching movement of the abalone which randomly chose both the stimulant containing water from the algal containing side and the control water without stimulant. This implies the possession of distant chemoreception possibly by the osphradium, but the abalone lacks a function to detect the origin of the smell.
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  • Groundfish species composition in the East China and Yellow Seas: a comparison of five surveys in 1986 to 1991
    KEISUKE YAMAMOTO, MUNEHARU TOKIMURA, YOUICHI TSUKAMOTO, HIROMU ZENITAN ...
    2010 Volume 76 Issue 2 Pages 192-203
    Published: 2010
    Released on J-STAGE: May 13, 2010
    DOIhttps://doi.org/10.2331/suisan.76.192
    JOURNAL FREE ACCESS
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      We studied seasonal changes in groundfish species composition in the East China and Yellow Seas. Specimens from five surveys in these areas from 1986 to 1991 were classified into species, weighed and counted. Water temperature and salinity were measured at each survey site with a conductivity-temperature-depth (CTD) profiler. Number of species, species diversity, and abundance per season were calculated for the combined survey area. Groundfishes in the East China and Yellow Seas comprised 334 species from 121 families. The dominant species were Japanese anchovy (Engraulis japonicus), Black scraper (Thamnaconus modestus) and Japanese jack mackerel (Trachurus japonicus). Water temperatures of the bottom layer were higher in autumn than in spring-summer or winter. Salinities of the bottom layer were higher in spring-summer and winter than in autumn. Species richness, species diversity and median values for both number of species and abundance were highest in autumn (October-December). The numbers of species per survey site were greater in the southern East China Sea than in other areas in all seasons.
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  • Removal of cadmium from scallop wastes including mid-gut glands by subcritical water treatment
    SENSHIN UMEKI, SEIJI YOSHII, MASATOSHI SAITO, NORIKO KONMA, MASANORI T ...
    2010 Volume 76 Issue 2 Pages 204-209
    Published: 2010
    Released on J-STAGE: May 13, 2010
    DOIhttps://doi.org/10.2331/suisan.76.204
    JOURNAL FREE ACCESS
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      In order to remove cadmium from scallop wastes including mid-gut glands, a novel process using subcritical water treatment was developed. Crushed scallop organs and pure water were charged in a stainless steel reactor tube with Swagelok caps. The reactor tube was then sealed and immersed in an oil bath adjusted to the prescribed temperatures. Experiments were carried out at temperatures ranging from 90 to 200°C and for reaction times of 10 to 30 min. After 10 minutes of subcritical water treatment at temperatures higher than 150°C, most of the charged samples had decomposed and separated into two parts, liquid and solid phases, and most of the cadmium had concentrated into the solid phase. This phenomenon could be interpreted as that cadmium ions were adsorbed by suspended organic adsorbent materials and settled out. The phenomenon strongly depended on the pH of the samples, and the most appropriate pH value for removal of cadmium was 4.5, which was assumed to be the isoelectric point of the suspended organic adsorbent materials. The weight of the solid phase which contained cadmium decreased to less than 20 mass% in comparison with the raw wet material by centrifugal separation after the treatment at 200°C/10 min. In this case, cadmium concentration in the liquid phase decreased to 10 mass ppb (in 4 times diluted samples) or less without pH control.
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