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Volume 49, Issue 1
Displaying 1-19 of 19 articles from this issue
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Mitsuhiro TAKAYAMA, Masamichi YAMAMOTO2001 Volume 49 Issue 1 Pages 1-7
Published: March 20, 2001
Released on J-STAGE: January 31, 2011
JOURNAL FREE ACCESSUpstream migration behavior of Japanese dace, Tyibolodon hakonensis, was investigated at a pool and weir fishway.
Most of the upstream migrating Japanese dace were mature fish of 2 years old, and some immature fish. Upstream migration rate was examined for 7 days in succession, and was found to exceed 50% on day 2. In June and July, the upstream migration rate in 24 hours was found to increase as the discharge volume of the fishway increased.
It was revealed that the water condition for the upstream migration of Japanese dace of 8.4 cm in body length is; water velocity below 100 cm/s, water depth over 15 cm, and water head below 28 cm.
More swimming type was observed than the jumping type. The number of migratory fish reached maximum between 14 : 00 and 16 : 00.
To design fishways suitable for Japanese dace, not only the hydraulic factors, such as discharge volume, but the way Japanese dace utilizes the fishway structures and water movement should be investigated and taken into consideration.View full abstractDownload PDF (1109K) -
Yukihiko SERISAWA, Hideki AKINO, Kazuyo MATSUYAMA, Masao OHNO, Jiro TA ...2001 Volume 49 Issue 1 Pages 9-14
Published: March 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSEcklonia cava populations at Tei, Tosa Bay and Nabeta Bay, Shimoda, Izu Peninsula were compared seasonally from 1995 to 1997 by quadrate sampling. Water temperatures between the two sites differ by 2-4°C on average, with Tei being the warmer site. The mean thallus wet weights at Tei ranged from 60.9 g (January) to 216.2 g (June) and from 329.4 g (January) to 720.5 g (October) in Nabeta Bay. The biomass was low in winter and high from spring to summer in both localities, ranging from 1.9-4.3 kg w.w./m2 at Tei and 4.9-10.7 kg w.w./m2 in Nabeta Bay. The bio-mass was lower at Tei than in Nabeta Bay at all times. The density at Tei ranged from 34-53 ind./m2 (10-19 ind./m2 in plants of 1 year old and over, 16-34 ind./m2 in plants of O year old). At Nabeta Bay the density ranged from 15-40 ind./m2 (12-17 ind./m2 in plants of 1 year old and over, 3-26 ind./m2 in plants of O year old). At Tei, the O-1 y age group was dominant and the 2-3 y age group was rare throughout the year, whilst in Nabeta Bay, the O y age group was dominant from winter to spring, and the 5 y age group was recorded infrequently.View full abstractDownload PDF (942K) -
Yasuhisa KAYANO2001 Volume 49 Issue 1 Pages 15-21
Published: March 20, 2001
Released on J-STAGE: January 31, 2011
JOURNAL FREE ACCESSThe feeding habits of wild and cultured grouper on artificial reefs off the coast of Shiraishijima Island in the central Seto Inland Sea were examined. 195 Epinephelus akaara ranging from 11.1 cm to 32.5 cm total length were caught by gill net. Stomachs of 75.9% of the sample contained food items. The average relative food weight (food weight/fish weight × 100) of the grouper was approximately 1%. There was no significant difference in the composition of the diet between wild and cultured grouper. Although the composition of the diet was no seasonal, predation was slightly size-dependent. The grouper fed mainly on macrura, anomura, brachyura, pisces, or on an artificial diet that was provided by the acoustic sound feeding buoy system. These natural prey items, which colonized the artificial reefs, may be the most important food for the grouper.View full abstractDownload PDF (967K) -
Nobuhiro HATTORI, Shigeru MIYASHITA, Yoshifumi SAWADA, Keitaro KATO, T ...2001 Volume 49 Issue 1 Pages 23-28
Published: March 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSThe volume of lateral muscle, cross-sectional area of red and white fibers, and the number of fibers were examined for artificially hatched Bluefin tuna, Thunnus thynnus orientalis, from juvenile to young adult stage within the size range of 19.5-163.0 mm body length (BL). The red and white muscle volumes increased exponentially with BL. At a size larger than 80.0 mm BL, both the volume increases were significantly accelerated. The proportion of red muscle volume in the total lateral muscle volume slightly increased with BL. The cross-sectional area and the total number of red and white fibers at the point of maximum body height increased in the BL range examined. The small red fibers (<a 100 μm2 in size) of a cross-sectional area gradually disappeared with the growth of BL. In contrast, there existed the white small fibers (200-300 μm2 in size) at all body sizes. Increases of both fiber numbers were approximately accelerated at sizes larger than 85 mm BL. The size of 80-85 mm BL, at which the phase change of muscle development occurred, corresponded to the transitional stage from juvenile to young adult.View full abstractDownload PDF (873K) -
Kamonpan AWAIWANONT2001 Volume 49 Issue 1 Pages 29-34
Published: March 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSThe histology of retinas of three anchovies, namely shorthead anchovy (Encrasicholina heteroloba), Devis' anchovy (E. devisi), and Buccaneer anchovy (E, punctifer) from Thai waters, were examined under light microscopy and scanning electron microscopy. Their retinas were from a light-adapted state. The visual cell layers contained cones and rods as well as apical processes of the pigment epithelium cells. The single layer of cones was arranged in parallel rows. The outer segments of the cone cells were enrolled by the retinal tapetum. Rods were stacked and densely covered by the retinal tapetum of pigment epithelial cells. Three types of tapetum could be recognized; platelets, needles, and crystallites. This retinal tapetum should subserve their visual systems, to become highly adapted for the dim light environment.View full abstractDownload PDF (9478K) -
Tadashi IMAI, Nobuhiko AKIYAMA, Masaya KOSAKA2001 Volume 49 Issue 1 Pages 35-40
Published: March 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSThe salinity assuring Macrobrachium nipponense for surviving up to postlarval stage, and the duration for the development were compared among the three types of freshwater lakes, brackishwater lake and rivers. The larvae of freshwater lake type reached to the postlarval stage even in freshwater, but the survival rate was considerably lower than those reared in the water of 3.3PSU or higher, upper limit of optimum salinity varied from 13.4 to 23.4PSU by the locality. The larvae of river type survived at higher salinity than the freshwater lake type, between 10PSU and 23.4 to 26.7PSU. Also, this type survived in seawater. Allowable salinity for high survival of brack-ishwater lake type ranges from 3.3 to 23.4PSU, similar to that of freshwater lake type. Durations required to moult into the postlarval stage were 15 to 16 days after hatching for the freshwater lake type in the optimal salinity, but longer in freshwater. The freshwater lake type spent shorter duration than river type, 24 to 32 days, but similar to brackishwater lake type, 15 day. These results suggest that the brackishwater and river types adapted to the larval habitat in brackishwater, while the freshwater lake type are on the way adapting to freshwater condition throughout the life.View full abstractDownload PDF (741K) -
Masahiko KOISO, Akinori HINO2001 Volume 49 Issue 1 Pages 41-46
Published: March 20, 2001
Released on J-STAGE: January 31, 2011
JOURNAL FREE ACCESSThe rotifer Brachionus plicatilis was cultured in five salinities (7, 14, 20, 27 and 34 psu). Population growth increased with a decline in salinity, and the daily growth rates at 7, 14 and 20 psu were beyond three times as much as that at 34 psu. The feeding cost for the production of 100 million individuals at 14 and 20 psu dropped to almost half of that at 34 psu. The mean generation time, the spawning interval, and the life span shortened remarkably in low salinities. The percentage of feeding rotifer as an index of hyper salinity tolerance and the nutritive value after 17-hours of enrichment were less when the rotifer was directly transferred from 7 or 14 psu to 34 psu than those when transferred from 20 or 27 psu.
Considering the high population growth and the reduction in feeding cost, rotifer culture in low salinities should be adopted in actual seedling production.View full abstractDownload PDF (1035K) -
Shin-ichi AKIYAMA, Kenji TAKII, Takashi MAOKA, Masao NAKAGAWA, Hisao K ...2001 Volume 49 Issue 1 Pages 47-52
Published: March 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSIn order to progress dietary yeast utilization for red sea bream, Pagrus major, dried eighteen yeasts were prepared for preference and rearing tests. The fish weighing 6.4-10g on initial mean body weights were fed diets including 30% of each yeast to apparent satiation for 7 days. Endomyces lindneri, Rhodotorula rubra and Galactomyces ressii promoted, but Trichosporon cutaneum, Hansenula anomala and Torulopsis candida suppressed the feeding activity of the fish. Saccharomyces cerevisiae, Hansenula silvicola, Kluyveromyces marxianus, Hyphopichia burtonii, Rhodotorula glutinis, Saccharomyces lypolitica, Debaryomyces membranaefaciens, Schizosaccharomyces pombe, Torulopsis aeria, Pichia kluyveri and Saccharomyces ludwigii did not affect on the feeding activity as compared with brown fish meal. The fish weighing 5.0 g on an initial mean body weight were fed diets including 0, 20, and 40% R. rubra as a yeast protein (YP) for 42 days. No significant differences among dietary YP treatments were found in survival, final carcass proximate composition, and gastral organ weight. Daily feed intake, enteral organ weight, and aerobic microbial count of whole gut showed increasing trends with an increase in dietary YP. Otherwise, weight gain, feed efficiency (FE), protein efficiency ratio (PER), apparent protein and fat retentions, and hepato-somatic index, all appeared decreasing trends with an increase in dietary YP. Although, FE and PER of 20 and 40% YP diet groups were lower than 0% YP diet groups. These results suggest that red sea bream appear various degrees of palatability for dietary yeasts and that yeasts are probably available dietary proteins for fish diet.View full abstractDownload PDF (937K) -
Md. Shah ALAM, Shin-ichi TESHIMA, Manabu ISHIKAWA, Shunsuke KOSHIO2001 Volume 49 Issue 1 Pages 53-59
Published: March 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSTwo experiments were conducted to investigate the effects of ursodeoxycholic acid (UDCA) on growth performance and digestive enzyme activities of juvenile red sea bream, Pagrus major. In experiment 1 for growth study, duplicate groups of the juveniles of about 9.01 g in initial body weight were fed a UDCA diet (containing 0.025% UDCA) and a control diet (without UDCA) for 6 weeks. The weight gain of the juveniles fed the UDCA diet tended to be higher than that of the control diet. Total lipids and triglycerides of the whole body were significantly higher in the UDCA diet group than the control. In experiment 2 for enzyme study, triplicate groups of the juveniles of about 9.11 g body weight were fed the UDCA and control diets for 6 weeks, digestive organs were collected every 2 weeks and enzyme (α-amylase, lipase and protease) activities were assayed. The activity of α-amylase for the juveniles fed the UDCA diet tended to increase with the lapse of holding time. But lipase and protease activities of the juveniles fed UDCA diet, were significantly higher than those fed the control diet. The findings of this study indicate that UDCA may promote lipid utilization and nutrient retention by increasing digestive enzyme activities of red sea bream juveniles.View full abstractDownload PDF (1107K) -
Makoto FURUHASHI, Tetsuya UMINO, Naoko YOSHITOME, Heisuke NAKAGAWA, Sh ...2001 Volume 49 Issue 1 Pages 61-66
Published: March 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSAyu Plecoglossus altivelis with 11g initial body weights were reared on two different diets. Growth, feed utilization, characteristics of gut, and the ingestion of nutrients were investigated.
Two experimental diets were prepared, crumbling the extruded pellet produced Diet 1, and Diet 2 was prepared by cutting extruded ingredients into a disk shape. Diet 2 maintained its shape in water and in the fish gut for a long time and gave better results in terms of growth than Diet 1 and there were significant differences in feed efficiency and protein efficiency ratio. The characteristics of gut, such as intestine size, and height of tunica mucosa, and height/intestine diameter ratio were variable in response to dietary types. Fish fed Diet 2 had more muscle protein and but less lipid than fish fed Diet 1.
These findings demonstrate that dietary types affected the characteristics of gut and digestion system in ayu.View full abstractDownload PDF (952K) -
Kenji TAKII, Koji KAWAMURA, Kaori URUSHIHARA, Masahiko HANAYAMA, Motoj ...2001 Volume 49 Issue 1 Pages 67-76
Published: March 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSThe digestive compensation of juvenile tiger puffer, Takifugu rubripes, 43 g and 7 g on an initial mean body weight, for dietary soybean typsin inhibitor (SBTI) and extruded soybean meal (EX-SBM) was estimated by a short-term (25-day) and a long-term (90-day) feeding trial, respectively. In the short-term feeding trial, apparent protein digestibility and final mean body weight decreased with an increase in dietary SBTI levels, 0, 0.6, 3.0, and 6.0 trypsin inhibitor units (TIU) /mg diet. Dietary SBTI conducted smaller enteral digesta but its higher basic proteinase (BP) and SBTI insensitive BP (TI-BP) activities at 6 h after feeding on the final day of the trial. Hepatopancreatic BP and TI-BP activities did not differ among the dietary SBTI treatments at 0, 3 and 6 h after feeding. In the long-term feeding trial, 20% Ex-SBM diet conduced a lower final mean body weight than brown fish meal (BFM) diet. Whereas, in both EX-SBM and BFM diet groups, large-weight gain individuals, weighing about 1.2 times of final mean body weights, indicated higher hepatopancreas-somatic indices and hepatopancreatic BP and TI-BP activities than small-weight gain individuals, weighing about 0.8 times of final mean body weights. Moreover, the higer trend of the indice and hepatopancreatic proteinase activities was obtained in small-weight gain individuals of EX-SBM diet group than those of BFM diet group. These results suggest that tiger puffer confront dietary SBTI to promote proteinase secretion from the hepatopancreas and excrete promptly a part of digesta exceeding their digestive capacity at a relatively early time after feeding. Otherwise, the fish with large hepatopancreas and its high proteinase activities might grow faster and utilize dietary EX-SBM more effectively, as preferential traits for aquaculture seedlings.View full abstractDownload PDF (1359K) -
Ken-ichi SAKAGUCHI, Chan Sun PARK, Makoto KAKINUMA, Hideomi AMAKO2001 Volume 49 Issue 1 Pages 77-83
Published: March 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSIn an attempt to identify conditions effective in suppressing fungal red rot disease in the seaweed Porphyra, acid washes (5 min treatments) were conducted under different regimes of temperature (-5 to 15°C), pH (1.63 to 2.0) and salinity (5 to 25%). After treatment, the seaweed thalli were placed in cultivation tanks (15°C, 2.7% salinity) and monitored for the development of fungal growth. Optimum conditions for treating thalli were found using washes of seawater at high salinity (15%), low pH (1.63) and low temperature (-5°C). After this treatment, thalli grow in the cultivation tanks and showed a slight suppression of red rot disease.
However, this treatment was only marginally more effective than an acid treatment alone (using seawater adjusted to pH 2.0). When densities of fungal zoospores were high, both these treatments were ineffective in suppressing the disease. Instead, an effective sequential treatment was devised. Thalli were acid washed using seawater adjusted to pH 2.0 for 5 min and subjected to a seawater at high salinity (20%) for 5 min 4 days later. This combination of treatments was found to be very effective in suppressing the development of red rot disease in this seaweed.View full abstractDownload PDF (4222K) -
Ken-ichi WATANABE, Mamoru YOSHIMIZU2001 Volume 49 Issue 1 Pages 85-90
Published: March 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSDetection rate of viral nervous necrosis (VNN) virus gene using polymerase chain reaction was investigated. Tested specimens were: just hatched larvae, heads of larvae, eye or brain of juveniles, ovarian fluid and sperm obtained from brood fish. The specimens were mixed with a 10-fold serial dilution of virus solutions prepared from the eyes and brain of the Pacific Cod, Gadus macrocephalus, affected with VNN. For nucleic acid extraction, a comparison was made between 20-proteinase K, SDS- proteinase K, acid guanidium phenol chloroform, Isogen, TRIzol, RNA isolation kit, Catrimox-14, and High Pure Viral Nucleic Acid Kit. Isogen and/or RNA isolation kit showed the highest detection rate. PTC-200 and PJ 480 thermal cyclers were more effective than the PC-700 model. In comparison of reverse transcriptase, AMV, M-MLV, and Super Script II were tested; r Taq or Ex Taq was used as the DNA polymerase. Pairing of Super Script and Ex Taq was most effective. In PCR programs, 3-temperature PCR was more effective than 2-temperature PCR.View full abstractDownload PDF (983K) -
Masaya NIIRO, Hachiro HIRATA2001 Volume 49 Issue 1 Pages 91-96
Published: March 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSIn order to determine the ecological effects of probiotic additive feedings in cultured carp, three probiotic additives, Earth genitor “EG”, Amakusa PX “AP”, and Commercial yogurts“CY” were examined. Relative values of algal growth potential (AGP) against control in “+ EG”, “+ AP”, and “+ CY” groups were observed to be 125%, 120%, and 109%, respectively. Relative values of fecal volume in“+ EG” and “+ CY” groups were 90%, fecal total nitrogen (TN) in “+ EG” group was 95%, and fecal total phosphorus (TP) in “+EG” and “+CY” groups were 79%. The highest elution rates of NH4-N and PO4-P were observed in the “+EG” group. Higher growth rates of carp was obtained in the “+ EG” and “+ CY” groups. Thus, probiotic additive feedings in cultured carp induced the promotion of an ecological cycle in the rearing water.View full abstractDownload PDF (753K) -
Worawut KOEDPRANG, Masamichi NAKAJIMA, Masashi MAITA, Nobuhiko TANIGUC ...2001 Volume 49 Issue 1 Pages 97-102
Published: March 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSFive clonal lines of silver crucian carp were captured from natural habitat and confined in concrete tank for 2 months. Blood was obtained from caudal vein and analyzed using automatically analysis systems. Comparing individual parameters for five clonal lines revealed significant differences of erythrocyte count, hemoglobin, hematocrit, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, triglyceride, urea nitrogen, and total protein, while mean corpuscular volume, glutamic oxaloacetic transaminase, alkaline phosphate, glucose, and total cholesterol were not different. Although, the differences of blood parameters among clonal lines were found, heritability estimates (h2) for all of blood parameters were low in silver crucian carp. Those heritabilities indicated that the changes in blood parameters of silver crucian carp were affected by environment than their genetic factors.View full abstractDownload PDF (972K) -
Yasufumi MADA, Makiko MIYAGAWA, Taiga HAYASHI, Tetsuya UMINO, Katsutos ...2001 Volume 49 Issue 1 Pages 103-112
Published: March 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSTetraploid and tertraploid-triploid mosaic fish were successfully produced in gynogenetically reproducing triploid ginbuna Cayassius langsdoyfii by treating the eggs with various conditions of cold and heat shock after fertilization. Tetraploid fish were detected in the progeny developed from the eggs which were treated by heat shock (40°C, 60s duration) in the period starting from 5 to 95min after fertilization. The heat shock starting from 5 min after fertilization gave 67-100% tetraploidy. The patterns of DNA fingerprinting and RAPD-PCR in the tetraploid and tetraploid-triploid mosaic progeny consisted of all fragments identical to those of the mother triploid ginbuna and additional fragments derived from the father goldfish. Cytological observation on the eggs which were treated by heat shock (40°C, 60s) at 5 min after fertilization suggested that tetraploids are formed by fusing triploid female pronucleus and haploid male pronucleus, which is genetically inactive in triploid iinbuna but active to form male pronucleus by the treatment.
No significant difference was observed in the growth between triploid and tetraploid of 12-month-old fish reared with communal condition. All the triploid progeny examined were female. However, in the tetraploid progeny 10 out of 17 individuals were female, whereas the other 7 individuals were sexually indifferentiated.View full abstractDownload PDF (10836K) -
Conrado G. RENDON, Shigehisa YAMASAKI, Kyaw Moe AUNG2001 Volume 49 Issue 1 Pages 113-114
Published: March 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSPossibility of Tetraselmis tetrathele utilization was tested as a basic food for swimming crab Portunus trituberculatus larval production, culturing the alga in NaHCO3 enrichment medium. The algal density increased significantly by addition of NaHCO3, when it was added at the same concentration as that of natural seawater. In crab larval culture, highest survival rate was 13% at early megalop larval stage. The possibility of larval rearing of this crab was observed with T. tetrathele as a basic food.View full abstractDownload PDF (370K) -
Hideki YASUNOBU2001 Volume 49 Issue 1 Pages 115-116
Published: March 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSPathogenicity of Halocrusticida okinawaensis, the pathogenic fungi of the swimming crab, Portunus trituberculatus, to larvae of five crustacean species (P. trituberculatus, Chionoecetes opilio, Artemia sauna, Charybdis japonica and Crangon cassiope) was examined. All species were infected with H. okinawaensis. Because there were differences in the pathogenicity of H. okinawaensis used in each trial, the susceptibility of the five crustacean species to H. okinawaensis could not be directly compared. Brine shrimp (A. sauna) larvae showed a high susceptibility to H. okinawaensis and therefore, A. sauna can be considered to be an alternative experimental host for this pathogen.View full abstractDownload PDF (302K) -
Yasuhiko TAGO2001 Volume 49 Issue 1 Pages 117-120
Published: March 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSThe number of fly-fishing licenses issued for ayu, Plecoglossus altivelis, which are operated only in the large pools of the Jinzu and Shou Rivers, decreased markedly from 1980 to 1998. On the other hand, the total number of recreational fishermen for ayu, and the number of licenses issued for two types of net and tomozuri which are used mainly at runs, increased during the period. These appeared to well correspond to a decrease in the number of large pools in both rivers. Scale of the juvenile release in recent years expanded several times as high as in 1978 in both rivers. However, the catch in the Jinzu River decreased one half or one thirds, and that only scarcely increased in the Shou River during the period. The relationship between annual catch (y) of ayu and number of licenses (x) for fly-fishing in the Jinzu River during 1988 to 1998 fitted a linear regression equation as expressed by y=- 88.3+0.0827x(r=0.706, p<0.01), suggesting that the decrease in ayu resources is closely related to the changes in reach types of river such as loss of larger pools.View full abstractDownload PDF (651K)
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