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Volume 49, Issue 3
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Yasuhiko TAGO2001 Volume 49 Issue 3 Pages 285-292
Published: September 20, 2001
Released on J-STAGE: January 31, 2011
JOURNAL FREE ACCESSCPUE and body size of the ayu, Plecoglossus altivelis, caught by tomozuri angling and tenkara net (a kind of casting-type gill net), which are the main fishing methods in the Shou River, were examined from 1992 to 1996. The mean CPUE of tenkara net (18 individuals per hour) was 5.3 times as many as that of tomozuri (3.4 i./h.). The CPUE of tenkara net decreased gradually as the fishing season progressed, but that of tomozuri, which was influenced by body size of ayu and water temperature, did not. The CPUE and fishing time of tomozuri did not have a mutual relationship through the season. This means that it is necessary to maintain good fishing grounds for tomozuri at more than a certain level of CPUE to continue tomozuri fishing for many hours. The mean body weight of fish caught by tomozuri (29.8 g) was 1.5 times as large as that by tenkara net (19.3 g). The fish (body weight was more than 25 g) caught by tomozuri accounted for 59.1% of the total, on the other hand, that by tenkara net only equaled 21.7% of the total. It was considered necessary to take these CPUE and body weight into consideration to manage ayu fishing grounds and resources more effectively because tomozuri competes for fishing grounds with tenkara net.View full abstractDownload PDF (1067K) -
Akinori DAN, Toshihiro TAKAGI, Masao OHNO2001 Volume 49 Issue 3 Pages 293-297
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSTwo cultivation techniques applied on Enteromorpha prolifera was carried out in Yoshino River, southern Japan between 6 and 25 November, 1998. The growth of Enteromorpha fronds on culture nets was compared between artificial and natural seeding. Frond number and standing crop in artificial seeding was 3.4 and 4.2 times more than that in natural seeding, respectively. Natural seeding proved to be a more effective method in the cultivation of Enteromorpha due to its ease in handling in the cultivation ground and suitable environmental conditions. On the other hand, artificial seeding is effective only when low salinity reduces the quantity of spores liberated in the cultivation ground. Based on the findings of this study, it is therefore important to select which of the two seeding methods is appropriate for a given environmental condition.View full abstractDownload PDF (2445K) -
Kyoko SHIMAMURA, Mikio NAKAMURA2001 Volume 49 Issue 3 Pages 299-304
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSThe artificial reef of concrete blocks was placed on the sandy silt bottom about 4 m in depth on the coast of the brackish Lake Nakaumi.
A successional survey of animals and plants was carried out on the artificial reef for about two years. Seaweeds have not grown well without Ulva sp. and smaller species during the survey period. Balanus spp. dominated on the artificial reef past three months. Afterward, Mytilus edulis increased and dominated twelve months later. In summer, they died all together. The main animals on the artificial reef were B. spp., M. edulis, Limnoperna fortunei, and Anomia chinensis, which were common species in Lake Nakaumi. The biomass was 24124.5g wet weight/m2 nineteen months later, and after that it had decreased. Brackish fishes gathered to the artificial reef in summer.View full abstractDownload PDF (3183K) -
Ken-ichi YAMAMOTO, Takeshi HANDA2001 Volume 49 Issue 3 Pages 305-309
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSFor the Mediterranean blue mussel, Mytilus galloprovincialis, seasonal changes in the amount of oxygen uptake (Vo2), ventilation volume (Vg), oxygen utilization (U) and gill cilia movement (SP) and the effects of hypoxia on them were examined during winter (12°C), autumn (20°C) and summer (28°C). Under normoxic conditions, Vo2 and Vg were greater in the winter than in the summer. U and SP were smaller in the winter than in the summer. Under hypoxic conditions, each of four respiratory parameters showed similar changes during all the seasons as follows. Vo2 gradually decreased with decreasing oxygen tension. Vg and SP remained constant, while U gradually increased.View full abstractDownload PDF (722K) -
Gen-ichi HOSHIAI, Satoshi KATAYAMA, Nagahira ARAI, Keishiro KARITA, Ze ...2001 Volume 49 Issue 3 Pages 311-316
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSIn order to estimate the activity in cultured ascidian, Halocynthia roretzi, we examined the effects of chemical (MgCl2) stress and followed physical (high temperature) stress on ascidians which had been reared in running water, stagnant water with aeration and without aeration conditions, through the continuous monitoring of squirting.
Mg treatment reduced the squirting of ascidians reared in stagnant condition compared with control ascidian, which had been reared in running water, although they did not show significant difference under running water treatment.
High temperature treatment, followed Mg treatment, increased the squirting of control ascidian. For the others, it transitorily emphasized the squirtings, but decreased and stopped them in several hours. Of the ascidians reared in stagnant condition, the ascidian, which was reared without aeration suffered a severe effect rather than ascidian reared with aeration.
These results suggested that the monitoring of squirting in the chemical and physical stress conditions could evaluate the activity of ascidian.View full abstractDownload PDF (893K) -
Katsuyuki NUMAGUCHI2001 Volume 49 Issue 3 Pages 317-322
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSChanges in the Phyto-pigments (chlorophyll a+phaeo-pigment) in the digestive diverticula of juveniles Japanese pearl oyster, Pinctada fucata martensii, (average whole weight; 3.34 g, n=20), and relationship between feeding concentration of micro-algal diet (Isochrysis aff. galbana (Parke) clone T-Iso) and phyto-pigment content in the digestive diverticula of the pearl oyster juveniles, and glycogen content of adductor muscle of the pearl oyster juveniles were determined. Phaeo-pigment contents in the digestive diverticula were much higher than chlorophyll a. Phyto-pigment content in the digestive diverticula increased after feeding the algal diet, and phyto-pigment contents included in the digestive diverticula reached a maximum 24 hours after feeding of the algal diet. There was a positive correlation between the feeding algal diet concentration and the phyto-pigment contents in the digestive diverticula of the pearl oyster juveniles. Glycogen of the adductor muscle also increased with the increasing feeding algal diet concentration.
These results indicate that phyto-pigment contents included in the digestive diverticula of pearl oyster juvenile might be a good indicator of feeding of algal diets of pearl oyster juveniles.View full abstractDownload PDF (873K) -
Masato MOTEKI, Takeshi ISHIKAWA, Naruki TERAOKA, Hiroshi FUSHIMI2001 Volume 49 Issue 3 Pages 323-328
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSEarly growth and morphological development, yolk and oil globule absorption, and initial feeding were studied in laboratory-reared red sea bream, Pagrus major. Based on energy transition and morphological development, the nutritional transition process was divided into four phases as follows: 1) primordial phase (endogenous) : from hatching to ca. 20 hours after hatching (HAH), 2.1-2.9 mm in total length (TL); 2) organogenesis phase (endogenous): to ca. 20-90 HAH, 2.9-3.4 mm TL; 3) early feeding (mixed feeding to exogenous) : to ca. 90-180 HAH, 3.4-4.1 mm TL; 4) intensified feeding (exogenous): beyond 180 HAH, 4.1 mm TL. In comparison with early stage features of other marine fishes, red sea bream larvae have a relatively short mixed-feeding period, which is disadvantageous for survival. However, a high rate of feeding at exhaustion of endogenous nutrition, a reduced time from initial feeding to 100% feeding, and large larval size at the onset of feeding are considered advantageous features for supporting the nutritional requirements of larvae, allowing a smooth transition from endogenous nutrition to exogenous food sources under rearing conditions.View full abstractDownload PDF (947K) -
Minoru KIHARA, Takashi SAKATA2001 Volume 49 Issue 3 Pages 329-338
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSWe studied metabolism of carp Cyprinus carpio gut microbes by measuring gas productivity and net organic acids production from gut contents of this fish using a 50μl-scale batch culture system. Intestinal contents of the carp reared at 15°C or 25°C were incubated with glucose, lactosucrose, sodium alginate or colloidal chitin, (each 10g/l) at 15°C or 25°C for 12h. Levels of organic acids at 12h of incubation were quantified with HPLC. Types of substrate, rearing and incubation temperature affected the amount of released gas and organic acid production. We detected higher levels of lactic and iso-valeric acids in cultures of gut contents of fish reared at 15°C than those at 25°C did. More succinic, formic and acetic acids were produced in cultures of gut contents reared at 15°C when incubated at 15°C than at 25°C. More amount of lactic acid was produced in cultures with glucose than in those with lactosucrose, colloidal chitin or none. The level of total organic acids was less in cultures with sodium alginate and colloidal chitin than in blank cultures. These results indicated that the hindgut microbes of the carp are able to utilize various saccharides to produce organic acids and rearing temperature of the host fish affects microbial digestion of these saccharides.View full abstractDownload PDF (1525K) -
Keitaro KATO, Ritsuko HAYASHI, Toru KASUYA, Shinji YAMAMOTO, Osamu MUR ...2001 Volume 49 Issue 3 Pages 339-345
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSThe necessary dose and growth stage for oral administration of 17α-methyltestosterone (MT) suitable for induction of all-male groups were investigated in red sea bream, Pagrus major. Oral administration of MT (0.01-1.0 mg MT/kg BW/day) for 16 weeks to 281-day-old meiotic gynogenetic diploids resulted in 100% functional males in the following spawning season. MT treatment (0.1 mg/kg BW/day) to fish of different ages (55, 141, and 893 days after hatching) for 16 weeks induced males, and testicular tissue was observed in the gonads of all MT-treated fish. While functional sperm were obtained from the fish treated with MT from 141 and 893 days-of-age, no sperm was produced in fish treated from 55 days-of-age.View full abstractDownload PDF (1120K) -
Purification, Characterization, Circulating Levels, and Specific IgM Production by the Parasitic Salmincola stellatusNaoshi HIRAMATSU, Haruhisa FUKADA, Makiko KITAMURA, Munetaka SHIMIZU, ...2001 Volume 49 Issue 3 Pages 347-355
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSImmunoglobulin M (IgM) was purified from the serum of Sakhalin taimen (Hucho perryi) by salting-out, ion-exchange chromatography on DEAF-cellulose, and gel filtration on Sepharose 6B. The intact, tetrameric taimen IgM has a mass of 750 kDa with molecular architecture typical of IgM from other salmonids. The molecular weights of heavy (μ) chain and light chains (L) of the IgM monomer were estimated to be 68 kDa and 23 kDa, respectively. Purified taimen IgM was used to raise a specific rabbit antiserum and to develop a single radial immunodiffusion assay for measuring circulating IgM levels. The serum IgM levels in captive, immature or maturing female taimen varied between 1 and 5 mg/ml, showing seasonal changes regardless of fish age, with relatively low levels in spring and conversely high levels in autumn. Production of specific serum IgM to a parasite, Salmincola stellatus, was assessed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting. The parasitized taimen serum could react with protein components of aqueous extracts from the parasite that were blotted on a nitrocellulose membrane after SDS-PAGE, but normal taimen serum did not, indicating that the parasitized fish produced the specific IgM to S. stellatus in the serum.View full abstractDownload PDF (5214K) -
Katsuyuki NUMAGUCHI2001 Volume 49 Issue 3 Pages 357-362
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSThe dietary value of wheat starch and baker's yeast was evaluated on spat (hinge length 3.1 mm), juvenile (shell length 23.4 mm), and adult (shell length 62.1 mm) of pearl oysters, Pinctada fucata martensii. Baker's yeast had no food value for spat and juvenile pearl oysters. Wheat starch also had no food value for spat pearl oysters. However, wheat starch had a significant food value for juvenile pearl oysters. I consider that wheat starch is not a suitable size for feeding of pearl oyster spat, because wheat starch size (15.0μm) is much too large for the spat of pearl oyster. However, pearl oyster juveniles might be able to feed and ingest the wheat starch. Adding wheat starch (42 mg/l) to a low density algal diet was effective for adult pearl oyster growth. Glycogen of the adductor muscle increased by feeding wheat starch added to the microalgal diet.View full abstractDownload PDF (971K) -
Takayuki KOBAYAHSI, Toshio TAKEUCHI, Tomohito SHIMIZU, Daisuke ARAI, S ...2001 Volume 49 Issue 3 Pages 363-368
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSThis experiment was conducted to investigate the effect of eicosapentaenoic acid (EPA)-enriched Artemia on survival rate, carapace width and total days to reach each developmental stage of larval mud crab. A feeding experiment was carried out in one liter polyethylene white beakers, each containing 30 larvae (first stage zoea). Mud crab larvae fed Artemia which contains different levels of EPA (1.0-7.8%) including 0% to trace amount of docosahexaenoic acid (DHA) on a dry basis from the zoea 3 stage.
All treatments showed the same survival rate (p>0.05). However, accelerated EPA in Artemia containing more than 3.6% remarkably increased the rate of mortality caused by the molting failure prior to the megalopa stage. The crab fed Artemia contained 7.8% EPA (plus trace amount of DHA), showed the large carapace width of the first crab compared to the another treatments.
These results suggest that the excess amount of EPA influences the molting of larval mud crab and its range was wider than DHA. On the other hand, EPA has a little effect on the carapace growth of the first crab.View full abstractDownload PDF (775K) -
Hidetsuyo HOSOKAWA, Hiroki KINOSHITA, Toshiro MASUMOTO, Sadao SHIMENO, ...2001 Volume 49 Issue 3 Pages 369-375
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSThe effects of crystalline amino acid supplementation on the utilization of corn gluten and soy protein by yellowtail, Seriola quinqueradiata were studied in a 30-day feeding trial. Fish fed diets in which brown fish meal (BFM) was completely replaced with corn gluten meal (CGM) and/or soy protein concentrate (SPC) showed lower growth rates than fish fed a control BFM diet. Accumulative supplementation of several essential amino acids to each protein source progressively enhanced growth. SPC with lysine and methionine, and CGM plus SPC with lysine and methionine, or with lysine, methionine and tryptophan improved growth to the level of the control group. There were no marked differences in feed efficiency, body composition and nutrient retention between the supplementation and control groups, although blood characteristics and serum components in the supplementation groups were inferior to those in the control group. CGM with lysine, arginine, tryptophan and methionine also showed supplemental effects. Thus, amino acid supplementation is useful for effective utilization of corn gluten and soy protein by yellowtail.View full abstractDownload PDF (1048K) -
Yoshio MATSUDA, Akihiko KAYASHI, Bunji YOSHITOMI, Toshio TAKEUCHI2001 Volume 49 Issue 3 Pages 377-381
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSIn Japan, 24, 000 t of squid liver (SL) is disposed every year as waste derived from food processing industry. Present study was conducted to assess the digestibility of dietary nutrients and the feed performance in extruded pellet (EP) containing 20% raw SL on rainbow trout, Oncorhynchus mykiss.
The control fish weighing 161.5 g on average at the start of the experiment, grew up to 221.6 g on average for 34 days feeding, while the fish fed the experimental diet containing 20% raw SL grew from 165.1 g to 243.5 g on average. Feed efficiency of the control and the fish fed the experimental diet was 0.66 and 0.75, respectively. Also, daily feed intake of the control and the fish fed the experimental diet was 1.6% and 1.8%, respectively. There was no difference in apparent digestibility of dietary protein, lipid and starch between the diets was 92%, 92% and 84%, respectively.
These results indicate that EP containing 20% raw SL can be used for rainbow trout.View full abstractDownload PDF (685K) -
Hidetsuyo HOSOKAWA, Kenro KUROHARA, Toshiro MASUMOTO, Sadao SHIMENO, R ...2001 Volume 49 Issue 3 Pages 383-388
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSIn order to develop a low-fish-meal diet, the utilization of combined alternative protein sources with and without supplemental amino acids by young yellowtail, Seriola quinqueradiata were studied in a 30-day feeding trial. Fish fed extruded pellets in which about 80% of the fish meal had been isonitrogenously and isocalorically replaced with 0-27% of corn gluten meal and/or 0-28% of soy protein concentrate together with fixed amounts of 10% krill meal and 5% blood meal showed comparable growth to those fed the fish meal control diet. Dietary supplementation of several essential amino acids to each combined alternative protein source did not further enhance growth. There were no marked differences in feed efficiency, body composition, nutrient retentions, blood characteristics and serum components between all groups tested. The results indicate that inclusion of an appropriate combination of alternative protein sources enables a significant reduction in the percentage of fish meal in yellowtail diet without the need for amino acid supplementation.View full abstractDownload PDF (954K) -
Keisuke G. TAKAHASHI, Katsuyoshi MORI2001 Volume 49 Issue 3 Pages 389-396
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSThe participation of reactive oxygen intermediates (ROIs) in the killing of ingested bacteria by hemocytes of the Pacific oyster, Crassostrea gigas, has been investigated under aerobic and anaerobic conditions. In the present study, we used five different species as target organisms, i.e., Arthrobacter ramosus, Bacillus subtilis, Deleya pacifica, Escherichia coli, and Micrococcus luteus. In order to measure the ROI-production by the C. gigas hemocytes, we used chemiluminescence (CL). Significant stimulation of the hemocyte-derived CL occurred in response to A. ramosus, whereas no increase in the ROI-generation was observed when the C. gigas hemocytes were exposed to the other four bacterial species. Although the C. gigas hemocytes exerted a phagocytic ability against all the bacterial strains tested, there were no statistical differences in all the bacterial strains under both aerobic and anaerobic conditions. In the anaerobic environment, the intracellular killing percent of A. ramosus by the C. gigas hemocytes significantly decreased to 36.7% when compared with the 66.2% intracellular killing under the aerobic conditions. Contrary to the intracellular killing activity of the C. gigas hemocytes toward the other four bacterial strains, there was no significant difference between the aerobic and anaerobic environments. Intracellular killing of A. ramosus was also repressed by the addition of diphenyleneiodonium (DPI), which is a potent inhibitor of NADPH oxidase.View full abstractDownload PDF (1437K) -
Yasuhiko TAGO2001 Volume 49 Issue 3 Pages 397-404
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSFormation and disappearance of pools, which are very important for the survival of fishes, were investigated during the period from 1997 to 2000 at the middle reaches of the Jinzu and Shou Rivers. These 2 rivers are important as main fishing grounds of ayu, Plecoglossus altivelis, and masu salmon, Oncorhynchus masou, in northern Japan. In the Jinzu River the number of large pools deeper than 2m decreased from eighteen in 1997 to eleven in 2000. Those of the Shou River which numbered five in 1997, decreased to three in 2000. The existence of pools in both rivers was highly unstable during the period; for instance 30 pools were lost and 21 pools were newly formed. The number of pools that remained unchanged during the period was only four in the Jinzu River and none in the Shou River. The pools in the Jinzu River tended to decrease in number. The classification of river-structure type Bb (representing a typical middle-reach type) which is characterized by a combination of riffles and pools could not be found in good condition in both rivers. It is considered that these changes in river character were mainly caused by river conservation works such as bank protections, and they have negatively affected ayu's and masu salmon's living habitats.View full abstractDownload PDF (1183K) -
Hyuma KUDO, Nobuyuki INOGUCHI, Akihiro KIJIMA2001 Volume 49 Issue 3 Pages 405-411
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSAverage time of death was used to determine the heritability of tolerance to high water temperature in rainbow trout.
A narrow sense of heritability for tolerance to high water temperature was calculated as 0.476 by factorial mating system. This indicates a high gentic variablity of the trait in the rainbow trout population surveyed in the present study.
A broad sense of heritability and degree of fluctuation for tolerance to high water temperture calculated from the same mating system shown above are 1.029±0.332 and 0.517±0.189 in the mean respectively.
Degree of fluctuation is directly correlated to broad sense of heritability.
Average of degree of fluctuations is close to a narrow sense of heritability.
Based on these results, an effective selection for high water temperature tolerance might be expected in the population surveyed.View full abstractDownload PDF (928K) -
Tadamitsu IGARI, Norio MATSUMOTO, Kazuo KITAUE2001 Volume 49 Issue 3 Pages 413-414
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSJuvenile green snails were reared at a mariculture institution for 17 to 29 months and released (shell height: 15.1-45.2 mm) on a reef crest and reef slope in two areas of Kagoshima Prefecture (Boma, Tokunoshima and Sohbaru, Isen). The shell growth of recaptured snails was observed. Juveniles grew more than 40 mm in shell height in a single year without any distinct variation between the two areas. This suggests that 30 mm juveniles would mature in two years.View full abstractDownload PDF (261K) -
Daisuke TAHARA, Isao YANO2001 Volume 49 Issue 3 Pages 415-416
Published: September 20, 2001
Released on J-STAGE: October 28, 2010
JOURNAL FREE ACCESSThis study investigated the effect of diets containing ogonori (Gracilaria vermiculophylla) lipid on the growth of kuruma prawn, Penaeus japonicus. In Trial 1 (11.2 g in average body weight), females fed the diets containing 1.7 g ogonori lipid/kg diet exhibited growth rate of 47.1% compared to that of 31.3% fed the control diet which had no ogonori lipid. In Trial 2 (21.0g in average body weight), the growth rates were 7.6% and 9.0% in control and experimental diets groups, respectively. There was no significant difference among the survival of prawn fed the diets containing ogonori lipid and the control diet in both Trials. These results indicate that diets containing ogonori lipid accelerates the growth of kuruma prawn.View full abstractDownload PDF (273K)
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