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Volume 43, Issue 2
Displaying 1-16 of 16 articles from this issue
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Osamu MURATA, Shigeru MIYASHITA, Toshiro NASU, Hidemi KUMAI1995 Volume 43 Issue 2 Pages 177-183
Published: March 20, 1995
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSIt is empirically known that the maturation and spawning seasons of the red sea bream from waters around Hong Kong (Hong Kong red sea bream) differs from those of the red sea bream found around Japan (Japanese red sea bream) through. In order to confirm this, a comparative study was made of the growth, maturation, and spawning ecology of the Hong Kong and Japanese red sea breams using broodstock bred selectively in our laboratory. Eggs and sperm were taken from female and male broodstock of both strains red sea bream and artificial insemination was performed. The progenies were reared for a period of 2 years and 2 months, at the end of which the average body weights (g, n=30) of Hong Kong and Japanese strains were 856±235 and 1, 273±186, respectively. This result showed that the Hong Kong red sea bream grows slower (p<0.01) than the Japanese red sea bream. The maturation phases of 3 to 4 year-old fish of both strains were assessed through monthly measurements of the gonadosomatic index it was found that Hong Kong red sea bream of both sexes matured to the stage that they were capable of spawning in November. The male and female Japanese red sea bream, however, began maturation in January and February of the following year, respectively. When Hong Kong red sea bream broodstock were raised under natural conditions in a water tank on land, spawning began in November at a water temperature of 22.0°C and ceased when the temperature fell to 15.2°C in December. Fish could be induced to spawn again later by artificially raising the temperature to 18-20°C. Thus, whereas the Japanese red sea bream spawns only once from spring to summer, when the temperature of the water rises, the Hong Kong red sea bream may spawn twice at both decreasing and increasing water temperature of fall and spring, respectively.View full abstractDownload PDF (2584K) -
Sadao SHIMENO, Takayoshi MIMA, Toshiro MASUMOTO, Hidetsuyo HOSOKAWA, I ...1995 Volume 43 Issue 2 Pages 185-190
Published: March 20, 1995
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSQualitative and quantitative changes in the contents of digesta and serum constituents were investigated in juvenile yellowtail, Seriola quinqueradiata, after feeding a moist pellet diet containing 30% soybean meal (SBMP) . Raw fish (RAWF) and fish meal moist pellet diet (FMMP) were also used as controls. RAWF was effectively digested and considerably large amounts of peptide were observed in the stomach soon after feeding. Also in the intestine, it was efficiently hydrolized and absorbed, resulting in a rapid increase of serum free amino acid concentration. On the other hand, SBMP together with FMMP were scarcely digested in the stomach, and only trace amounts of peptide could be detected within 5h after feeding. Large amounts of insoluble proteins were transported into the intestine, where they were effectively digested under high trypsin activity, showing a high protein digestibility. These results suggest that the raw fish diet is effectively digested in both the stomach and intestine of yellowtail, while moist pellet diets with and without soybean meal pass the stomach without any significant digestion and undergo an active digestion in the intestine.View full abstractDownload PDF (686K) -
Effect of Dietary Moisture Level on the Growth and Feed Performances of Fingerling Japanese FlounderTakeshi YAMAMOTO, Toshio AKIYAMA1995 Volume 43 Issue 2 Pages 191-197
Published: March 20, 1995
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThree feeding experiments were conducted to clarify the suitable moisture level in the diets for three size-classes of fingerling Japanese flounder Paralichthys olivaceus. Experimental diets were prepared to have the same nutrient content on a dry weight basis but different levels (10 to 30%) of dietary moisture. These pelleted diets were fed to satiation to small fish (initial mean weight of 5.6g) and medium fish (15.4g) for 4 weeks at 20°C, and to large fish (57.5g) for 8 weeks at 17-24°C.
Daily feed consumptions of each size of fish on a dry weight basis were not affected by the dietary moisture levels. Feed efficiency of the small fish fed a diet with 20% moisture was significantly higher than that of the fish fed a diet with 10% moisture. In the medium fish, dietary moisture level had no influence on the weight gain and feed efficiency. On the other hand, weight gain and feed efficiency were better in the large fish fed a 10%-moisture diet than those of the fish fed a 30%-moisture diet.
These results suggest that suitable moisture level in the diets for fingerling Japanese flounder change with fish size. Adequate level of moisture content is 20% in diets for small fish, whereas more than 10% moisture would not be required for medium and large fish.View full abstractDownload PDF (707K) -
Seiichi NAGATA, Kenji CHIBA, Takao MATSUNO1995 Volume 43 Issue 2 Pages 199-203
Published: March 20, 1995
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSIn this paper, the effects of growth and feeding habit on the carotenoid pattern of wild and tank-reared young striped mullet were investigated. The results of cultured striped mullet were also analysed in relation to the persence of attaching algae in the culture tank.
The carotenoid pattern in early young fish varied depending on the date and location of capture, but correlated storongly with their developmental stage and feeding habits. The principal carotenoid of the carnivorous early young striped mullet (locally known as “haku”) was tunaxanthin, a reductive metabolic product of astaxanthin from their main food, copepods. On the other hand, that of the herbivorous late young striped mullet (locally known as “oboko”) was diatoxanthin from their food, diatoms. Thus, this shift from tunaxanthin to diatoxanthin well corresponds with metamorphosis from the carnivorous “haku” to the herbivorous “oboko”. The total amount of carotenoids of young striped mullets reared in uncovered sea water tank (with adhesive algae) amounted to two-three times that of fish reard in covered tanks (without adhesive algae) and the amount of diatoxanthin was 10 times higher in the former. In conclusion, the total amount and percentage composition of carotenoids in young striped mullets are remarkably influenced by the presence of adhesive algae in culture tank.View full abstractDownload PDF (461K) -
Maher SAMET, Shigehisa YAMASAKI, Hachiro HIRATA1995 Volume 43 Issue 2 Pages 205-211
Published: March 20, 1995
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSJuveniles of Kuruma prawn, Penaeus japonicus, were fed dry pellet (treatment 1) and minced short-neck clam (treatment 2) separately in a closed culture system to examine the effects of food quality on growth and the environment. Growth of prawn was 121 % and 204 %, respectively in treatments 1 and 2 during the experimental period of 43 days. The food conversion ratio was higher in treatment 1 than in treatment 2. On the final day, total N concentration in the culture medium in treatment 1 was lower than in treatment 2 whereas total P concentration was inverse. N/P ratio was calculated to be 6.1 and 21.7 in treatments 1 and 2, respectively. In the case of organic sediment content, treatment 1 was higher than treatment 2. Nannochloropsis sp. density in the examination of algal growth potential of prawn culture water was higher in treatment 1 than in treatment 2 throughout the experimental period. The highest density of 43.43 × 106 Nannochloropsi sp. cells/ml was obtained with the prawn culture water taken at the 4th week. On the other hand, Chaetoceros calcitrans reached a lower density, 11.63 × 106 cells/ml at the maximum, showing little difference between treatments 1 and 2.View full abstractDownload PDF (698K) -
Shusaku KADOWAKI, Yoshiaki TANAKA1995 Volume 43 Issue 2 Pages 213-217
Published: March 20, 1995
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe light intensity in water decreases exponentially with depth and it is usually estimated by the equation as Iz=Io⋅e-k⋅z, in which Iz is the intensity at z. Io is intensity at the surface, and k is extinction coefficient (m-1) in water. The extinction coefficient is affected by presence of dissolved and suspended substances. In this study, this relation is shown by the equation k=ko+α (SSchl) + β (SSdet) in which k is the total apparent extinciion coefficient, ko is the light extinction of water with no suspended solids, SSchl is the phytoplankton concentration (g⋅m-3), SSdet is concentration of suspended substances other than phytoplankton (g⋅m-3), and α and β are constant (m3⋅g-1⋅m-1) . SSchl, and SSdet be computed by using the following equations: SSchl=250 (chl-a) in brown water, SSchl= 150 (chl-a) in green water, and SSdet=SS-SSchl in which chl-a is chlorophyll-a concentration (g⋅m-3) and SS is the total concentration of suspended substances. Field work to gain data on water quality was performed in kuruma prawn culture ponds of Kumamoto Prefecture. The α value obtained from analysis of experimental data is 0.091 and 0.15 in brown and green waters, respectively. The values of β and ko were found to be 0.060 and 0.076, respectively, regardless of the color of the water. Concerning with k values, mean occupation rates of SSchl and SSdet per SS are 59.6 ± 18.3 % and 35.9 ± 17.1 %, respectively. The ratio of ko + β (SSdet) per k is 40.4 % in kuruma prawn ponds, and this result was shown to be higher value than 2-16 % in offshore waters obtained by Riley's works. From these results, the extinction coefficient was calculated by the above equation and experimental data. A comparison of the observed and calculated coefficients yielded a satisfactory result.View full abstractDownload PDF (526K) -
Susumu SEGAWA1995 Volume 43 Issue 2 Pages 219-224
Published: March 20, 1995
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe effects of temperature change on oxygen consumption and ammonia excretion were investigated in young disk abalone, Nordotis discus discus between 11.0-49.8 mm in shell length (0.12-12, 92 g in total wet weight) . Animals previously maintained at 16.5 °C were exposed to two series of thermal regimes, e.g., falls to 15, 10, and 5 °C and rises to 20, 25, and 30 °C, at a rate of 1 °C per hour. Measurements were performed after an acclimation period of 6 hours at the desired temperatures. The rates of oxygen consumption (R) and ammonia excretion (E) of the abalone increased linearly with an increase in body weight (W) following the equation R (or E ) = a Wb in each experimental temperature. The a value of oxygen consumption increased slightly but a steadily between 5-25 °C, whereas the b value was relatively constant between 10-25 °C (Q10 = 1.49) . In contrast, both a and b values for ammonia excretion changed markedly with temperature. Thus, oxygen consumption, which reflects the basic metabolism of the abalone, remains relatively stable, whereas, the ammonia excretion, which reflects the catabolism, is directly affected by changes in environmental factors such as temperature.View full abstractDownload PDF (652K) -
Yushi UCHIMURA, Tomonori HIRATA, Shunnosuke ABE1995 Volume 43 Issue 2 Pages 225-228
Published: March 20, 1995
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSCompared with diploid pearl oyster, although mortality of the triploids was 10 % higher, the pearl size was bigger and the quality was higher, except for some cases.View full abstractDownload PDF (400K) -
Miyuki TSUSHIMA, Shiro ITO, Itsuro KAWAHARA, Takao MATSUNO1995 Volume 43 Issue 2 Pages 229-235
Published: March 20, 1995
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThis study investigated the carotenoid profiles in the gonads of wild sea cucumber Stichopus japonicas from both red and green types and in cultured individuals of the green type, with the following results:
1. The carotenoid profiles of the gonads of the red and green types were quite similar to each other. The major carotenoids were canthaxanthin (30-60%) and (3S, 3'S) -astaxanthin (12-20%), whereas β-carotene, β-echinenone, 4'-hydroxy-β-echinenone, canthaxanthin, phoenicoxanthin, zeaxanthin, 4-ketozeaxanthin, 7, 8-didehydroastaxanthin, 7, 8, 7', 8'-tetradehydroastaxanthin, astaxanthin, alloxanthin, and pectenolone were found in varied amounts.
2. The net carotenoid content of the gonads increased with enlargement of the gonadal index. With increasing gonadal index, the percentage compositions of β-carotene, β-echinenone, and canthaxanthin decreased, while those of phoenicoxanthin and astaxanthin increased.
3. Expermental feeding of sea cucumber (green type from Oomura bay, Kyushu) with sea weed (containing β-carotene) showed an increase in the contents of β-carotene, β-echinenone, 4'-hydroxy-β-echinenone, canthaxanthin of the gonads in comparison to unfed controls.
4. Taking into consideration the experimental results of (2) and (3) described above, the following possible oxidative metabolic pathway of β-carotene has been postulated: β-corotene→ β-echinenone →4'-hydroxy-β-echinenone→canthaxanthin→phoenicoxanthin→astaxanthin.View full abstractDownload PDF (673K) -
Itsuro KAWAHARA, Shigeru HIROSE, Shiro ITO, Yukio MIYAZAKI, Hitoshi KI ...1995 Volume 43 Issue 2 Pages 237-241
Published: March 20, 1995
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSLarvae of sea urchin Pseudocentrotus depressus were induced to settle and metamorphose by exposure to sea water supplemented with KCl. The larvae responded to KCl within 10 min at KCl concentrations of 32-100 mM and within 60 min at 18 mM at 20°C. Response was completed in 60 min at KCl concentrations of 32-100 mM. Addition of 10, 18, 32, 56 and 100 mM KCl induced 7, 20, 53, 53 and 100% metamorphosis, respectively. However, the juveniles induced by KCl concentration higher than 32 mM could not settle normally. Production of 100% normally settling juveniles was obtained by a brief exposure (5 min) to 100 mM KCl added sea water followed by immediate transfer to untreated sea water. This procedure was effective in a wide range of sea water temperature (14-26°C) .View full abstractDownload PDF (542K) -
Shigehisa YAMASAKI, Hachiro HIRATA1995 Volume 43 Issue 2 Pages 243-247
Published: March 20, 1995
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSOxygen consumption rate of Nannochloropsis sp. was measured under darkness, during which cell division takes place. Nannochloropsis sp. was cultured in a flexible transparent plastic bag without air for six days, renewing the culture every morning. Density was adjusted to 2×106 cells/ml at every renewal of the culture medium. The culture was agitated gently by magnetic stirrer. Light was provided at 195 μmol/m2/sec and 13L : 11D (07: 00 on, 20: 00 off) . Temperature was 25°C. On the sixth day, partial pressure of oxygen (PO2) in the culture medium and cell volume were determined throughout the dark period.
PO2 at the standard temperature of 37°C was 198 mmHg on average at 20: 00. It decreased rapidly just after 20: 00 and then leveled off at around 02: 00, when cell division was completed. PO2 at 02: 00 was 139 mmHg on average. Between 02: 00 and 07: 00, extremely low decreasing of PO2 was obtained. PO2 during the period was 137.3±0.8 and 139.6±1.0 mmHg on average and SD in the first and second trials, respectively. From these results, it was concluded that oxygen consumption rate of Nannochloropsis sp. was highest at the time of peak cell division and thereafter decreased gradually toward completion of cell division. After cell division, oxygen was maintained at a very low level.View full abstractDownload PDF (516K) -
Shotaro OHYA, Toshikazu SHIMIZU, Yoshiaki HORIKAWA, Shin'ichi YAMAMOTO1995 Volume 43 Issue 2 Pages 249-251
Published: March 20, 1995
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSChanges in body weight of female broodstock of amago salmon, Oncorhynchus rhodurus, were measured before and after ovulation. Three groups of four females were randomly selected on October 14 around 2-3 weeks before the usual time of peak incidence of ovulation among our broodstock and fasted from the next day. Body weight was individually assessed every day from October 15, 20 and 25 in the A, B and C groups, respectively.
Females in the A group initially showed a steep weight loss but regained weight between 1-5 days before and a day after ovulation. Subsequent weight losses became steep again from 4 to 10 days after ovulation. The B and C groups showed similar weight changes as the A group before ovulation. However, after ovulation, fish in the B and C groups increased their body weight with and without a temporary weight loss, respectively. Moreover, some fish in the B and C groups died in a few days after ovulation.
The mean period elapsed since the initiation of measurements until the occurence of ovulation followed the order A (8.5 days) > B (6.0) > C (5.25), whereas the period elapsed the time of selection of the fish followed the inverse order A (8.5) < B (11.0) < C (15.25) . These results suggest that stress resulting from handling accelerates the ovulation of amago salmon.View full abstractDownload PDF (300K) -
[in Japanese]1995 Volume 43 Issue 2 Pages 253-262
Published: March 20, 1995
Released on J-STAGE: March 09, 2010
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Fuminori Endo1995 Volume 43 Issue 2 Pages 263-267
Published: March 20, 1995
Released on J-STAGE: March 09, 2010
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[in Japanese]1995 Volume 43 Issue 2 Pages 269-272
Published: March 20, 1995
Released on J-STAGE: March 09, 2010
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Tatsuo Tsuzaki1995 Volume 43 Issue 2 Pages 273-276
Published: March 20, 1995
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSDownload PDF (411K)
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