Aquaculture Science
Online ISSN : 2185-0194
Print ISSN : 0371-4217
ISSN-L : 0371-4217
Volume 53, Issue 1
Displaying 1-15 of 15 articles from this issue
  • Masahiko KOISO, Hiroshi KUWADA, Akinori HINO
    2005 Volume 53 Issue 1 Pages 1-5
    Published: March 20, 2005
    Released on J-STAGE: March 09, 2010
    JOURNAL FREE ACCESS
    Neonates of the rotifer Brachionus plicatilis were exposed to 3, 6, 9 and 12 hours' starvation after hatch, and evaluated the effects on survival rate, life-history parameters, biological minimum size and egg size under the provision of Chlorella as food. Short- period starvation for 3-12 hours induced the decline of survival rate and the reduction in biological minimum size. In addition to those phenomena, the delay of the first spawning was observed proportionally to the starvation period, which implies that the development of a reproductive organ was induced by the commencement of feeding. In spite of the proportional reduction in biological minimum size, egg size had no relation to the starvation period, which shows that somatic growth and egg formation were regulated independently in the rotifer. Even it is short, starvation should be avoided in mass culture of the rotifer in order to prevent both reduction in animal size and survival rate.
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  • Kazuhiro OKADA, Morio NISHIMURA, Nagahisa UKI
    2005 Volume 53 Issue 1 Pages 7-14
    Published: March 20, 2005
    Released on J-STAGE: March 09, 2010
    JOURNAL FREE ACCESS
    This experiment was conducted to evaluate the effectiveness of a newly designed rearing method using 10 kl raceway tanks in juvenile abalone, Haliotis gigantea, in large scale production. Two different size groups (4.9±0.4 and 6.4±0.5mm in mean shell length ±SD) of juveniles feeding on diatoms were removed from settlement plates, and then the scattered seed rearing method was used at two stock densities of approximately 2, 500 and 1, 800 individuals per square meter for each size. Juveniles were fed on artificial diet once every four days over a period of seven months, eliminating the need for routine cleaning by siphon; instead fecal material from juveniles was carried away through drainage after strong aeration of the tank water. Survival rates in all groups were higher than 95%, and feed efficiency was the same between experimental groups, ranging from 78 to 80%. Total weight gain was 3, 420-3, 760% in the smaller groups and 2, 470-2, 800% in the bigger groups. Abalones growing under lower stock densities showed higher weight gain and grew significantly faster than those in the higher density groups. These results show that the rearing method we developed is effective for juvenile abalone, H.gigantea, with a mean shell length of 5 mm or greater, and to achieve optimum growth the maximum stock density should be less than 2, 000 individuals per square meter.
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  • Tsuneo MAEDA, Ryo TSUJIMOTO
    2005 Volume 53 Issue 1 Pages 15-22
    Published: March 20, 2005
    Released on J-STAGE: March 09, 2010
    JOURNAL FREE ACCESS
    To clarify the growth and intermolt period in the red snow crab Chionoecetes japonicus, 3 male and 15 female immature crabs were collected from Toyama Bay, the Japan Sea, from July 1999 to July 2002, and were reared in the laboratory until 2 February 2004. A total of 39 molts were observed during the rearing experiment; in the maximum case, a crab molted 6 times during a period of 4.5 years. Carapace width (CW) growth increment increased with body size in the molts of both male and female juvenile crabs, whereas it remained unchanged regardless of body size in the female crab's terminal molt. Moreover, the liner regression line between premolt and postmolt CW differed between juvenile and terminal molts in females, which might suggest that the growth pattern changed at maturation. A liner relationship was exhibited between the premolt CW (Ln) and intermolt period (IP) and is described by the equation: IP (days) = 4.773Ln (mm) + 147.3; r2 = 0.737, P < 0.001, n = 21.
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  • Atsushi ITO, Taichi KOYANO, Yuki OKAMOTO, Masao OHNO, Satoshi WADA
    2005 Volume 53 Issue 1 Pages 23-30
    Published: March 20, 2005
    Released on J-STAGE: March 09, 2010
    JOURNAL FREE ACCESS
    Settlement of puerulus Postlarvae of Japanese spiny lobster Panulirus japonicus was investigated using seaweed-like collectors at a seawall in Uranouchi Inlet, Tosa Bay, Japan. Developmental stage of collected pueruli differed in soaking time of collectors. Late stage pueruli were not collected after one day soaking to compare with longer soaking days, indicating that pueruli might not move around before metamorphosis. In field and laboratory experiments on color preference for artificial seaweed, pueruli did not show consistent preference on color, indicating that puerulus postlarvae do not choose settlement site by color. Timing of metamorphosis from puerulus postlarvae to juvenile was not affected by shelter, indicating that post settled pueruli could not delay metamorphosis.
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  • Eun-Jeong PARK, Megumu TAKAHASHI, Yukihiro KITADE, Hajime YASUI, Naots ...
    2005 Volume 53 Issue 1 Pages 31-40
    Published: March 20, 2005
    Released on J-STAGE: March 09, 2010
    JOURNAL FREE ACCESS
    Polymorphisms of the three strains TU-1 (wild type), TU-2 (green type) and TUH-25 (red type) inPorphyra yezoensis were investigated using cultured monospores and cleaved amplified polymorphic sequence (CAPS) analysis of gametophytes in each strain. Comparison of early developmental characters of monospores, such as the size, cell number at the first longitudinal cell division, and change of the cell number of germlings over time, indicated that these characters are useful for phenotypic classification of the three strains. In the CAPS analysis using 19 PCR primer pairs and 22 restriction endonucleases, no length polymorphism in the restriction fragments was detected among the three strains of P. yezoensis examined. These results suggest that a distinctive phenotypic character in early developmental stage of monospore is not always associated with a genetic polymorphism. Therefore, the three strains may be too close genetically, and not applicable to a linkage analysis of P. yezoensis using CAPS markers employed herein.
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  • Hideshi SEKI, Akira SUZUKI, Rie KUSHIBIKI, Hideo MARUYAMA
    2005 Volume 53 Issue 1 Pages 41-46
    Published: March 20, 2005
    Released on J-STAGE: March 09, 2010
    JOURNAL FREE ACCESS
    A fundamental study of the continuous foam separation of uneaten fish feed with a new biodegradable surfactant, methylated egg albumin (MeOA), was carried out. Pulverized fish feed particles with a mean diameter of 0.1 mm was used as a model system in this study. Continuous foam separation experiments were conducted at different mass flow rates of the feed particles, MeOA, and bubble surface production rates. A continuous foam separation model considering the adsorption of McOA and the feed particles to bubble surfaces was applied to explain the experimental results. The experimentally determined fractional removal of the feed particles agreed well with the values predicted by the model. The result showed that the fractional removal of feed particles can be predicted by the model with four basic operational parameters; mass flow rates of the feed particles and MeOA, bubble surface production rate, and volumetric flow rate of the water drained.
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  • Hideshi SEKI, Akira SUZUKI, Ako NIWA
    2005 Volume 53 Issue 1 Pages 47-51
    Published: March 20, 2005
    Released on J-STAGE: March 09, 2010
    JOURNAL FREE ACCESS
    This paper presents a model describing the light dependent growth of microalgae. This model is based on the assumption that the light intensity dependence of specific growth rate follows an Arrhenius-type relationship. The specific growth rate of microalgae is expressed as the product of an Arrhenius-type equation and the Monod equation. The model was applied to describe the photo-autotorophic growth of a green microalga Chlorella fusca var. vacuolata at different light intensities and nitrate concentrations. The model successfully described the effects of light intensity and nitrate concentration on the specific growth rate of the microalga. Our model expressed the sigmoidal light intensity dependence of specific growth rate at low light intensity.
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  • Keisuke G. TAKAHASHI, Hidekazu YANAI, Kiyokuni MUROGA, Katsuyoshi MORI
    2005 Volume 53 Issue 1 Pages 53-59
    Published: March 20, 2005
    Released on J-STAGE: March 09, 2010
    JOURNAL FREE ACCESS
    Hemocytes from the Japanese rock oyster Crassostrea nippona and the Pacific oyster C. gigas were divided into 5 types (Types A to E) based on the microscopic observation of specimens stained with May-Grünwald and Giemsa. Of these 5 types, Types A, B and E were agranular and Types C and D were granular hemocytes in both species. In vitro phagocytic experiments using hemocytes of these two oyster species collected monthly through a year (September, 2002 to August, 2003) against zymosan revealed that Types C, D and E had high, Type B had low, and Type A had no phagocytic activities through the year, although phagocytic activities of the three types of hemocytes (C, D and E) became lower in the post-spawning season from October to November. When compared collectively between granular (C and D) and agranular (B and E) phagocytes, granulocytes played more important role in phagocytosis than agranulocytes. These morphological features and phagocytic activities of the two species of oysters were quite similar to each other, but when exposed to lower temperatures and salinities, lower phagocytic activities were exhibited in the Japanese rock oyster than the Pacific oyster, reflecting the difference in ecological nature of the two species.
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  • Kaname ONO, Yuriko YANO
    2005 Volume 53 Issue 1 Pages 61-66
    Published: March 20, 2005
    Released on J-STAGE: March 09, 2010
    JOURNAL FREE ACCESS
    This research examines the effects of mixtures of synthetic surfactants (C14EO14, C18F1EO14, Tween80, C14FA and Oleyl EO20) on red-tide causing organisms and red sea bream. Surfactant (1 to 50 ppm) was added to media containing Chattonella marina or Heterocapsa circularisquama and examined every 30 minutes for swimming, immobile, and lysed cells for a total of 2 hours. The lowest concentration to immobolize or lyse the cells (LC50, 2h) was calculated. The LC50 (24h) of surfactants was also calculated for the ichthytoxicity of red sea bream juveniles. The LC50 (2h) of C14EO14, C18F1E014 and Tween80 for C. marina was 1, 5 and 20 ppm, respectively; and for C14FA and Oleyl EO20, it was 30 ppm. Conversely with respect to H. circularisquama, approximately 30% of the cells showed sings of deformation at concentration of 50 ppm, Ichthyotoxicity (LC50, 24h) for Tween80 was the strongest at 55 ppm, the other surfactants were ichthyotoxic from 125 to 150 ppm.
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  • Ken-ichi YAMAMOTO, Takeshi HANDA, Kenji FUJIMOTO
    2005 Volume 53 Issue 1 Pages 67-74
    Published: March 20, 2005
    Released on J-STAGE: March 09, 2010
    JOURNAL FREE ACCESS
    The difference in the ventilation in the respiratory tree among Red, Blue and Black (color pattern) of the Japanese common sea cucumber, Apostichopus japonicus was examined with rising water temperature from acclimation temperature (28, 22 and 12°C) . In Red, Blue and Black, ventilation volume (Vg), ventilation frequency (Vf), exhalation and inhalation volume per one stroke (Vst-ex and Vst-in) and inhalation frequency per one cycle of Vf (If/Vf) remained almost constant at 28°C, even if the water temperature rose. At 22°C and 12°C, If/Vf remained almost constant, but Vg, Vf, Vst-ex and Vst in increased with rising water temperature. From these results, it was clear that there was no difference among Red, Blue and Black with regard to changes in the ventilation parameters with rising water temperature. However, the tolerance of Red to high-temperature was lower than those of Blue and Black.
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  • Hiroyuki ICHINOSE, Koki TOKUDA, Takashi KUDO, Yukio AGATSUMA
    2005 Volume 53 Issue 1 Pages 75-82
    Published: March 20, 2005
    Released on J-STAGE: March 09, 2010
    JOURNAL FREE ACCESS
    To discriminate hatchery-raised and reseeded sea urchins Strongylocentyotus intermedius from the wild ones in shallow waters in Wakkanai, northern Hokkaido, the structural characteristics of one year-aged rings in the charred fifth genital plates and the maximum width were examined. The one year-aged rings of reseeded sea urchins with ALC marking fertilized in August were located adjacently to the clear ring in the center of the genital plates and the maximum widths were significantly wider than those of wild ones. The widths of the sea urchins collected in four reseeded sites were discriminated into two normal distributions with the modes of ca. 500μm and 800-900μm, corresponding to wild and reseeded sea urchins, respectively. It is demonstrated that hatchery-raised S. intermedius reseeded at >13 mm test diameter is allowed discrimination from wild ones by the structural characteristics of the one year aged ring and the wide maximum width.
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  • Naoyuki SUGURO
    2005 Volume 53 Issue 1 Pages 83-90
    Published: March 20, 2005
    Released on J-STAGE: March 09, 2010
    JOURNAL FREE ACCESS
    Lefua echigonia is a freshwater fish traditionally found in satoyama (countryside worked by human activity) areas of Japan. Its numbers are declining, however, owing to a deterioration of its habitat environment. At the Kanagawa Prefecture Fisheries Research Institute, scientists have successfully developed seed production technology by inducing natural spawning, then raising larvae under circulating filtration. The present study was conducted to determine how many parental fishes and spawning bed should be used to maximize seed production. The study vial conducted using 36-litre glass tanks and 2-ton fibreglass reinforced polyester (FRP) tanks. In the glass tanks, I varied the number of parental fish released in each tank and induced natural spawning to determine the ideal number of parental fishes. Eggs were most numerous in test sections containing one male and one female. I also found that this species is a multiple spawner, the spawning season lasts two months, and a single female can spawn more than 1, 500 eggs during spawning season. To determine how many parental fishes should be used to maximize seed production in 2 t FRP tanks, I placed 20, 40 and 60 fish (half males and half females) into different tanks, and induced natural spawning. The highest number of hatched larvae produced per parental fish, occurred in the tank with 40 fish. Next, I placed 40 fish (20 males and 20 females) into three FRP tanks containing different numbers of artificial spawning beds (2, 3 and 4) . I varied the strains of parental fishes, testing three times in each case, and compared the number of hatched larvae. The highest number of larvae was obtained in the tank with 4 spawning beds. This tank also had the highest number of hatched larvae per spawning bed. These results show that the increasing the number of artificial spawning beds can increase the number of eggs spawned.
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  • Tadamitsu IGARI, Hiromi NISHI, Yoshihisa KAMINO, Norio MATSUMOTO, Nori ...
    2005 Volume 53 Issue 1 Pages 91-92
    Published: March 20, 2005
    Released on J-STAGE: March 09, 2010
    JOURNAL FREE ACCESS
    The transmission period of the unidentified filtrable causative agent of amyotrophia in the juvenile Japanese black abalone Haliotis discus discus was examined. The juvenile abalones reared in ultraviolet irradiated sea water were exposed to non-UV treated sea water for 10 days in different dates (January 18-28, January 29-February 8, February 9-19 or February 19-, in 2002) . They were sampled for observations of the typical histopathological changes of amyotrophia in April and May. The histopathological changes were observed in the groups of abalones exposed to non-UV treated sea water after February 9, but no changes in the groups exposed from January 18-28 or January 29-February 8. From the results, it was suggested that the transmission of amyotrophia via rearing sea water occurred during a particular period from the late winter to the early spring in Kagoshima Prefecture.
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  • Kazutoshi OKAMOTO, Satoshi ATSUMI, Hajime MATSUYAMA
    2005 Volume 53 Issue 1 Pages 93-94
    Published: March 20, 2005
    Released on J-STAGE: March 09, 2010
    JOURNAL FREE ACCESS
    In order to obtain information on early life history and larval rearing conditions of the deep sea red crab Chaceon granulatus, one hundred 1st zoeae of this crab were reared under laboratory conditions. It has been succeeded in rearing this crab from the 1st zoeal stage to the juvenile stage, 5.1 mm in carapace width. The number of successful moltings to the 2nd, 3rd, and 4th zoea, megalopa and juvenile crab were 40, 38, 36, 28 and 2 individuals, respectively. After hatching, it took 81 to 92 days to reach the juvenile stage. The average numbers of days spent in the 1st, 2nd, 3rd, and 4th zoea stages and the megalopa stage were 11.2, 8.5, 8.8, 12.0 and 46, respectively. It was found that maintenance of a good rearing environment and a sufficient quantity of bait were important for rearing the crabs to the juvenile stage.
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  • Takanobu GOTO, Tomoko TAKAHASHI, Takumi KAIMASU, Shusaku TAKAGI, Akihi ...
    2005 Volume 53 Issue 1 Pages 95-96
    Published: March 20, 2005
    Released on J-STAGE: March 09, 2010
    JOURNAL FREE ACCESS
    Distribution of cystathionine γ-lyase activity was studied in fish. Liver homogenates were incubated with L homoserine at 25°C for 60 min, and 2-oxobutyrate formed by the enzymic reaction was determined and defined as the enzyme activity. Fish enzymes showed the maximum activities when the reactions were performed at pH 8.9 with Tris-HCl buffer. The highest enzyme activity was observed in smelt fish followed by that in yellowtail, and the lowest activity was found in carp. Addition of DL-propargylglycine or L-cysteine into the reaction mixtures inhibited 2-oxobutyrate productions, but the inhibition manners of cysteine were different among the examined species.
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