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Toru Kobayashi, the late Shozo Fushiki, Koichi Ueno
2009 Volume 57 Issue 3 Pages
361-370
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
JOURNAL
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Physiological changes during exhaustive exercise for 0-15 min and during the recovery process from 6 min exhaustive exercise were compared between triploids and diploids of all female rainbow trout progeny. Before the exhaustive exercise, the hemoglobin content in the spleen of triploid fish was significantly higher than that of diploids. Once the triploid fish was forced to perform exhaustive exercise, the relatively large triploid spleen was reduced to the same size as the diploid spleen until 1 min after the start of exercise. Thus the reduction in ratio of the weight of the triploid spleen with respect to the body weight with exercise was higher than that of the diploid spleen. The red blood corpuscle number significantly increased following the exhaustive exercise in both ploidies, but the ratio of increase was markedly higher in the triploid fish. The physiological recovery of triploid measured in terms of blood components following the exhaustive exercise was delayed by about 30 min compared with the diploid. The triploid fish required a longer time to recover than the diploid. Both the diploid and triploid fish recovered to their normal state 24 hours after the 6-min exhaustive exercise. Thus, it is presumed that triploids require a larger supply of red blood corpuscles to the blood during the exhaustive exercise than diploids, and the ability to supply red blood corpuscles is higher in triploids due to enlargement of the spleen.
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Sohei Kino
2009 Volume 57 Issue 3 Pages
371-382
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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To obtain basic information about propagation for the Chilean sea urchin,
Loxechinus albus, distribution of echinopluteus larvae of this species was investigated from 1986 to 1989 in the eastern coastal waters of Chiloé Island, Chile. Echinopluteus larvae of three sea urchins:
L. albus,
Pseudechinus magellanicus and
Arbacia dufresnei were observed in the waters. The larva of
L. albus was distinguished from the other two species mainly by the difference in skeletal rod structure. The larvae of this species were observed for almost a year, and the 4-armed larvae appeared mainly from November to January. The metamorphic larvae were observed only once in October 1988 in Hueihue in the investigation period. The number of larval appearance in the southern waters was larger than that in the northern waters.
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Thitiporn Laoprasert, Kenji Yagita, Rieko Shimogawara, Supranee Chin ...
2009 Volume 57 Issue 3 Pages
383-388
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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In 2000, an amoebic infection was found in oscar (
Astronotus ocellatus), a tropical fish, in Thailand. Amoebae isolated from these oscar were classified into the genus
Acanthamoeba. The isolation, morphological identification and biological characteristics of
Acanthamoeba isolated from the affected oscar are described. We investigated the growth of isolates cultured on
Escherichia coli (
E. coli) agar plates under various conditions, and examined the effects of environmental conditions on the growth of trophozoites. Effects of temperature, pH and salinity were examined. The diameters of amoeba colonies in all experimental agar plates were observed and measured daily for 7 days. If amoebae did not grow, survival was confirmed by inoculation onto a new
E. coli agar plate at the end of the experiment. As a result, it was demonstrated that
Acanthamoeba isolated from the oscar could grow at 5 to 45°C, pH 3-11 and 0-10% NaCl. The results of this study indicated that
Acanthamoeba sp. isolated from oscar can grow in a broad range of environmental conditions.
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Md. Shah Alam Sarker, Shuichi Satoh, Seiji Matsumoto, Suguru Sasaki, ...
2009 Volume 57 Issue 3 Pages
389-397
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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Two experiments were conducted to investigate the effects of dietary supplementation of citric acid (CA) and amino acid-chelated trace element (AA-CTE) on growth and excretion of nitrogen and phosphorus in yellowtail fed diets including alternate plant protein sources. This study was conducted under on-site conditions and the test diets contained fishmeal 30-35%, defatted soybean meal 10%, and corn gluten meal 14%. Each net cage of 200 yellowtails was fed one of the diets for 4 months at average water temperature 21°C. The fishmeal-based diet gave the best growth while the alternate proteins diet the lowest. However, the growth of fish increased in CA or AA-CTE supplemented groups demonstrating that their addition to low phosphorus containing plant protein diet improved fish growth and reduced phosphorus excretion. Hence, the use of these compounds in young yellowtail diets can help to partially replace fishmeal with plant protein ingredients and this in turn would enable a reduction in environmental pollution from aquafeeds.
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Chutharat Munchan, Kishio Hatai, Shiyuusaku Takagi, Azumi Yamashita
2009 Volume 57 Issue 3 Pages
399-404
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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Antifungal activities of amphotericin B, fluconazole, 5-fluorocytosine, itraconazole, micafungin, miconazole, terbinafine and voriconazole against four strains of
Ochroconis humicola isolated from fish were tested by the broth microdilution method. Three of these drugs (itraconazole, terbinafine and voriconazole) were effective against all isolates. The most active drug was terbinafine (for liniment) with a MIC (MFC) range of 0.06 to 0.13 (0.0625 to 0.125)μg/
ml. Itraconazole (for oral administration), with a MIC (MFC) range of 0.5 to 2.0 (0.5 to 1.0)μg/
ml, was chosen for in vivo treatment. In vivo treatment with itraconazole of striped jack
Pseudocaranx dentex experimentally infected with
O. humicola was conducted for 50 days. No fish died, but grey to white nodules were found in the visceral membrane, kidney, liver and spleen in the fish. Granulomatous inflammatory reactions were histopathologically found in all fish injected with conidia of
O. humicola NJM 0472. Clinical signs and histopathological findings indicated that itraconazole showed no efficacy for curing the fish infected with
O. humicola.
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Takashi Kikkawa, Motonori Kaku, Takumi Setoguma, Hideaki Kinoshita
2009 Volume 57 Issue 3 Pages
405-409
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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Ontogenetic changes of acute thermal tolerance were investigated in embryonic, larval and juvenile Japanese sea bass,
Lateolabrax japonicus. Samples of 6-14 fish cultured at 16°C were exposed for 15 min to elevated water temperature between 20 and 38°C at ages of 0, 1, 2, 3, 5, 7, 10, 13, 16, 21, 24, 31, 38, 45 and 52 days post-hatch. Median lethal temperatures (TL50) were calculated from the mortalities at 24 h after the thermal exposure. The most susceptible developmental stage was flexion larvae and TL50 was 27.0°C, whereas the most tolerant stage was yolk-sac larvae before the mouth opening (35.0°C).
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Nobukazu Satoh, Toshio Takeuchi
2009 Volume 57 Issue 3 Pages
411-416
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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Estimation of spawning cycle, fecundity, spawning time and ovulation cycle was examined in brown sole
Pseudopleuronectes herzensteini. Three females (TL: 320-370 mm) were reared separately with three males in each 1 m
3 tank. Spawning time was estimated using 22 females (TL: 310 mm) and 22 males (TL: 282 mm) cultured in 8 m
3 aquaria. During the spawning period, females spawned almost everyday with fecundity ranging between 2,174,600 and 4,063,700 per female. Moreover, it was estimated that spawning time in brown sole maintained in tanks would occur from approximately 17:00 to 20:00 likely depends on their ovulation cycle.
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Satoshi Katayama, Seiji Akiyama, Miwako Naganuma, Rena Shibata
2009 Volume 57 Issue 3 Pages
417-422
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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To understand the life history of rabbitfish,
Siganus fuscescens, we examined the age and growth by thoroughly observing otolith sections of the fish caught during 2005 to 2007 in Tateyama Bay, Japan. Standard length (SL) of the rabbitfish (
n=1781) caught by set net fisheries ranged from 83 to 357 mm, and that of additional sample (
n=5) caught using hand net in Oct. 2007 ranged from 35 to 43 mm. Almost all large sized fish over 300 mm in SL were female. Seasonal change in the proportion of aggregation of grooves at the otolith margin showed that this structure was formed once a year from July to Sep. The maximum ages of male and female were estimated to be 13 and 11 years old, respectively. The von Bertalanffy growth equations were significantly different between male and female, and estimated as follows:
SLt = 275 (1-exp(-0.605 (
t-0.361))), for male and
SLt = 298 (1-exp(-0.537 (
t-0.348))), for female, where
SLt is the SL (mm) at
t (year). Growth curves displayed minute gain of SL after age 3 for both sexes. The growth pattern of the rabbitfish is the growth stagnant coincident with sexual maturation.
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Tetsuya Tokuhara, Tomonori Kuwada, Tetsuji Kariya, Ryouji Fujii, Toru ...
2009 Volume 57 Issue 3 Pages
423-428
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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For the purpose of effective management and control for angling of released large size-amago salmon, we examined suitable releasing dates and phase difference between anadromous form smolt and resident form parr in a stream. Tagged smolt and parr were released on three different dates from late February to 1st March in 2006 and 2007. From 1st March when the fishing season of amago salmon was started, we conducted a creel census of anglers. The number of days from releasing to starting had a close relation to angling rate, and fish released on the starting day made the highest angling rate. Our results also indicated as follows, an effective fishing period was very short for releasing large size-amago salmon; angling rate of parr was not less than that of smolt.
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Makoto Yamauchi, Hajime Kimura, Yoshiaki Takahashi, Mikio Noda
2009 Volume 57 Issue 3 Pages
429-435
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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We examined the influence of seaweed,
Ecklonia kurome densities to the feeding behavior of a siganid fish,
Siganus fuscescens. Three kinds of artificial seaweed stocks at densities of 5, 15, and 30 plants/m
2 were prepared and placed in a concrete tank with 20 fish. The fish intensely fed seaweed stocks of 15 and 30 plants/m
2. The fish cut off leaves frequently and many seaweeds dispoused on the tank bottom. However, the fish did not cut off seaweed stock of 5 plants/m
2, and hardly ate them. A large quantity of laminas was scattered on the tank bottom against the seaweed stocks of high densities. Estimated feed consumption in considered scattered laminas was more occurred for seaweed stock of the high densities. The feeding behavior was observed mainly in the circumference of the artificial seaweed stocks, and rare and at random in the central regions. This study suggest that Signid fish intensively feed on
E. kurome living at high density.
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Kohei Fukuda, Masakazu Kondo, Hiroyuki Inagawa, Anan Chongthaleong, ...
2009 Volume 57 Issue 3 Pages
437-447
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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Performance of an immunochromatography kit (IC kit) for detection of the white spot virus in cultured shrimp was evaluated. The IC kit’s virus detection rate was similar to that of the one-step PCR method, but lower than that of the two-step PCR method. The antibody included in the IC kit recognized the white spot virus (WSV) envelope protein VP28, and the assay had a detection limit of 9.9×10
3 viral DNA copies/μ
l. Compared to detection based on gross and histopathological examination, this assay could detect virus even from shrimps without apparent disease signs and also few virus positive cells in the stomach and gills. When infected cultured shrimp from various countries and several other infected crustaceans were tested using the IC kit as well as one-step PCR, the IC kit was proven as a more rapid diagnostic tool.
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Jyoji Go, Kiyohito Nagai, Tsuneo Honjo
2009 Volume 57 Issue 3 Pages
449-453
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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We used a Hall element sensor to measure valve movements of Akoya pearl oysters (
Pinctada fucata). Pearl oysters exposed to hypoxic seawater with a dissolved oxygen concentration (DO) of 1.5 mg/
l had frequent valve movements that were recorded as a sharp spiked pattern, which differed from the pattern of occasional valve movements under normal conditions. When pearl oysters were exposed to hypoxic seawater with a DO of 0.5 mg/
l, we observed the same pattern of frequent valve movements as under a DO of 1.5 mg/
l. In contrast, pearl oysters exposed to hypoxic seawater (DO of 0.5 mg/
l) containing hydrogen sulfide at 0.88 mg/
l had valve movements that were recorded as a trapezoidal pattern. These valve movements were distinguishable from those that occurred under normal and hypoxic seawater conditions. These results indicate that we can specifically detect hypoxic seawater and hypoxic seawater containing hydrogen sulfide through the valve movement patterns of pearl oysters indicated by a Hall element sensor. This technique is therefore available for monitoring for these conditions in aquaculture beds.
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Ryota Miyamoto, Naoyuki Suguro, Kosuke Takaku, Kazumi Hosoya
2009 Volume 57 Issue 3 Pages
455-461
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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Optimal feeding regime, the most suitable food set was investigated for the larvae and juveniles of an Japanese endangered freshwater fish,
Aphyocypris chinensis by rearing experiments. Fertilized eggs were collected by HCG injection, and natural spawning. Newly hatched larvae were stocked into 8 tanks at a density of 50 individuals per tank. In the rearing experiments, four different sets of foods were tested: Sec. I, S-type rotifer (SR) -
Artemia nauplii (AN) - Artificial diet (AD); Sec. II, SR - AD; Sec. III, AN - AD; Sec. IV, AD solely. The larvae and juveniles of
A. chinensis showed high survival rates and favorable growth when the food items include live feed. The survival rate of Sec. III fed with AN was almost equal to that of those fed with SR. Single feeding with AD, always showed the lowest survival rates and the poorest growth. These findings suggested that the larvae and juveniles of
A. chinensis can be reared with a combination of AN and AD, without SR.
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Shinsuke Morioka
2009 Volume 57 Issue 3 Pages
463-468
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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We investigated features of the sagitta, lapillus, and asteriscus in laboratory-reared larvae and juveniles of the climbing perch
Anabas testudineus until 30 days after hatching. The sagittae and lapilli were present at hatching and each had a core, while the asterisci were not present at hatching. Increments in the sagittae were deposited at a rate of 1 increment per day in fish with a body length (BL) less than 14.9 mm, but the increments were barely detectable in marginally notched portions of the sagittae in most of larger specimens than ca. 14.0 mm BL. Increments in the lapilli were deposited at a rate of 1 increment per day and were observable in fish of all sizes used in this study. The asterisci were found with having an ambiguous core in fish with a BL greater than 8.0 mm. In conclusion, the lapillus is the most feasible for age determination in days in this species. From the ages of the wild 0 year-old specimens collected from the rice-fields and reservoirs, we deduced that the breeding of the species occurs mostly all through the year in the region. The age-growth relationship in larvae and juveniles was expressed by Gompertz growth equation; the BL reaches >70 mm during the first 5 months after hatching, and the growth is accelerated by the first 50 days and is decelerated thereafter. This growth pattern indicates that the species is attainable to the maturation size within 5 months.
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Takayuki Fujiwara, Hideo Aoki, Takashi Ishikawa, Takashi Atsumi, Hisay ...
2009 Volume 57 Issue 3 Pages
469-474
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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The aim of the present study was to evaluate the capability of a portable near-infrared spectrophotometer as a simple and nondestructive method to determine the nutritional constituents (glycogen, protein and moisture) closely related to pearl oyster health. The spectra of intact pearl oysters, their soft tissue, and shells were acquired using commercially available equipment with an interactance fiber optics probe. Since the second-derivative spectra of intact samples in the wavelength region of 730 nm to 1000 nm were similar to those of soft tissue, and the shells did not have any particular absorption in the region, the effect of shells on spectra in this region did not appear very strong. Second-derivative spectra in the near-infrared region and multiple regression analysis were used to develop calibration equations for each constituent of soft tissue. Although the protein and moisture determinations using spectra of intact oysters were not as accurate as measurements using spectra of soft tissue, spectra from intact oysters can be used for screening. The calibration equations for glycogen were not accurate, even for the soft tissue measurements. In conclusion, we suggest that portable near-infrared spectrophotometers are suitable for the nondestructive evaluation of pearl oyster health.
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Prasatporn Borisutpeth, Pithai Kanbutra, Chutima Hanjavanit, Kanit ...
2009 Volume 57 Issue 3 Pages
475-482
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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The aim of the current study was to investigate the effects of Thai herbs as anti-fungal agents in Nile tilapia
Oreochromis niloticus eggs in Thai hatcheries. The fungistatic and fungicidal effects of 5 herbs including guava, tamarind, salapeepa, betel pepper and red rose against the fungal species
Saprolegnia diclina,
Achlya sp. and
Aphanomyces invadans were evaluated
in vitro. The effects of guava and betel pepper against fungal hyphae were greater than those of the remaining 3 herbs when the fungi were exposed to each herb for 7 days. At 24 h exposure, guava and betel pepper exhibited fungicidal activity against zoospores of
S. diclina and
Achlya sp. at concentrations of 125 to 250μg/
ml. However, when fertilized and eyed eggs of Nile tilapia were exposed to 125μg/
ml of guava or betel pepper solution, the observed mortality was significantly higher than that of the control group. We conclude that these herbs are not suitable for the control of fungal infection in tilapia eggs at the established fungicidal concentration. However, if zoospore germination can be inhibited at lower concentrations, the herbs may still prove useful as a potential anti-fungal agent.
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Ken-ichi Yamamoto, Takeshi Handa, Masahiro Kayano, Masashi Siraishi
2009 Volume 57 Issue 3 Pages
483-488
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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Ventilation in the respiratory tree of the Japanese common sea cucumber,
Apostichopus japonicus was analyzed by modeling the movements of the aloaca and the coelom as the double-pumping system based on the continuous records of the ventilation volume and the inner pressures of the cloaca and coelom. The sequence of ventilation phases is regarded as follows:
1) The boundary between the respiratory tree and the cloaca is closed. The anus is opened and the sea-water is inhaled into the enlarged cloaca.
2) The cloaca is expanded and the inner pressure of the coelom is elevated. The volume of the coelom is increased by the increasing inner pressure of the coelom.
3) The anus is closed and the boundary is opened. The sea-water is injected from the cloaca into the respiratory tree by contracting the cloaca. The inner pressure of the coelom does not change because the sea-water is simply moved in the coelom.
4) The volume of the coelom is increased with repeating the sequence of ventilation from phase 1 to phase 3 (inhalation) and subsequently the ventilation is temporarily stopped.
5) The inner pressure of the coelom is elevated with increasing the volume of the respiratory tree by repeating inhalation. The anus and the boundary are opened and the sea-water in the respiratory tree and the cloaca is once exhaled by the elastic force of the body wall without the contraction force of the body wall and/or the cloaca.
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Sohei Kino, Kiyotaka Kani
2009 Volume 57 Issue 3 Pages
489-499
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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In order to understand the settlement ecology of the Chilean sea urchin,
Loxechinus albus, PVC collectors were suspended in the water column in eastern coastal waters of Chiloé Island from 1986 to 1988. Three species of juvenile sea urchin,
L. albus,
Pseudechinus magellanicus, and
Arbacia dufresnei, were collected. These were the same species as echinopluteus larvae observed in plankton samples collected during the same period. Seventy-nine juveniles of
L. albus were collected using a collector placed in August and October 1986 in Yaldad. Their size in April 1987 was 1.1-6.5 mm in test diameter. The settlement period estimated from juvenile growth was January. Some collectors sank by the mass attachment of barnacles and washed away by rapid seawater currents.
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Kazumi Nimura, Hiroyuki Noda, Takayuki Hanai, Kazutoshi Okamoto
2009 Volume 57 Issue 3 Pages
501-505
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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The kelp
Eisenia arborea was cultivated from December, 2006 to May, 2007 at the Jitougata fishery port in Makinohara City, Shizuoka, Japan and the growth of sporophytes was examined. It was observed that the sporophytes grew well when cultivated using the Noren method at 1.3-2.3 m depth from December, 2006 to May, 2007. The blade length and width of the sporophytes attained 230 mm and 53 mm at 4 April, 2007; further, no significant differences were observed in the blade length and width when the sporophytes were cultivated at depth of 1.3 or 2.3 m. The blade length of the sporophytes cultivated from 24 January, 2007, has increased to 226 mm by 19 May, 2007. Eventually, the apical parts of these sporophytes eroded, with the blade length reducing to 142 mm at the end of May. It was concluded that it is possible to cultivate
E. arborea from December to May.
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Yasuro Iwashita, Nobuhiro Suzuki, Hiroyuki Matsunari, Tsuyoshi Sugita, ...
2009 Volume 57 Issue 3 Pages
507-512
Published: September 20, 2009
Released on J-STAGE: September 26, 2012
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In rainbow trout,
Oncorhynchus mykiss, fed defatted soybean meal-based diets, increase of chenodeoxycholyltaurine (CDC-T) in the biliary bile as well as histological changes in the liver occurs. To investigate a possible involvement of biliary CDC-T on the occurrence of morphological abnormalities in the liver of rainbow trout fed soybean meal-based diets, histological observations were conducted on fish fed a casein-based semi-purified diet supplemented with CDC-T. A control diet (Cont), and two test diets supplemented with CDC-T at 0.05% (0.05CDC-T) and 0.5% (0.5CDC-T), and a soybean meal-based diet (SBM), were fed to rainbow trout for 6 weeks. The proportions of biliary CDC-T of fish fed diet SBM and diet 0.5CDC-T were higher than fish fed diet Cont. Hepatocytes of fish fed diet 0.05CDC-T seemed normal. However, the hepatocytes of fish fed diet 0.5CDC-T were atrophied, and the hepatic histological features of this group were similar to those found in fish fed diet SBM. These results suggest that increase of biliary CDC-T is probably a responsible factor for the occurrence of histological changes in the liver of rainbow trout fed soybean meal-based diets.
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