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Volume 46, Issue 4
Displaying 1-21 of 21 articles from this issue
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Kiyokuni MUROGA, Tooru FURUSAWA, Iwao FURUSAWA1998 Volume 46 Issue 4 Pages 473-480
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSEpisode of the disease outbreak, disease signs and histopathology, epizootiology, properties of the causative virus, diagnostic methods, and prophylactic measures of viral nervous necrosis (VNN) in striped jack, Pseudocayanx dentex, were outlined in this review. The first occurrence of VNN in striped jack was recorded in 1989. The causative virus is a non-enveloped, icosahedral virus 25 nm in diameter, containing 2-segmented, non-polyadenylated, positive sense single-stranded RNA. Based on these characteristics, it was determined as a new member of the family Nodaviridae. The same disease has been observed in over 20 marine fish species cultured in Asian and European countries. VNN usually occurs in larval and juvenile fish in hatcheries, however, young or adult groupers, Epinephelus spp. and seabass, Dicentrarchus labrax, are also affected in grow-out farms. Recently the disease in striped jack has been successfully controlled at hatcheries of the Japan Sea-Farming Association where the following prophylactic measures are practised: Health management of spawner candidates, selection of virus-free spawners based on the detection of the virus from gonad by PCR, and disinfection of fertilized eggs with ozone.View full abstractDownload PDF (1438K) -
M. Habibur RAHMAN, M. Afzal HOSSAIN, Kenji KAWAI, M. A. HOSSAIN1998 Volume 46 Issue 4 Pages 481-486
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSSwamps are potential water bodies for expending fish culture in Bangladesh. In order to utilize swamps, their formation, ecology and fish production were investigated. In tropical delta zone, if the part of formal rivers, canals or ponds are not connected with flood water, it will become a swamp. Due to the adaptation of flood control measures in Bangladesh a large number of ponds have been become devoid of their annual flushing with flood water and thus heavily silted. Occurrence of such swamps near human habitation in Bangladesh is very common. After investigation, it was concluded that the ecological conditions of the swamps are suitable for fish culture. The ranges of temperature, pH, dissolved oxygen and free CO2 of swamp waters were 15.0±1.1 to 32.2±0.4°C, 7.43±0.28 to 8.08±0.22, 2.03±0.06 to 4.46±0.29 mg/l and 9.3±0.2 to 19.4±0.4 mg/l, respectively. The fish naturally stocked in swamps (n=16) with areas ranging from 36.3 m2 to 1000 m2 were harvested after 5-months culture. The gross production was 382kg/ha. From the above investigation, it is concluded that the swamp can be utilized for fish culture easily and it may pave a way to expand fish production in Bangladesh.View full abstractDownload PDF (897K) -
Hideaki YAMADA, Yuki ENDO, Tatsuya MUSASHI, Yoh YAMASHITA1998 Volume 46 Issue 4 Pages 487-494
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSWe set up three artificial reefs (5 long×5 wide×2.3m high) at 7 m in depth and another three reefs of the same size at 10 m depth with 40 m distance between each reef, to study the effectiveness of the reefs as nursery areas for juvenile Japanese flounder, Paralichthys olivaceus. Acanthomysis mitsukurii was the dominant species in the mysid community in the study area and comprised 27% of stomach contents of juvenile flounder. However there was no significant difference in mysid abundance between areas immediately adjacent to the reefs (within 0.5m from a reef) and in adjacent control areas (>10m from a reef) . Larval and juvenile anchovy accounted for ca. 70% of flounder stomach contents. Many fish aggregations were detected with an echo sounder around the reefs. We confirmed that most of them were anchovy larvae and juveniles using a small-mesh purse seine catch. We found that reefs set shallower than 10 m depth were likely to be buried due to the unstable bottom conditions. Artificial reefs may function as a nursery for juvenile flounder by acting as a place around which small diet fishes gather at depth deeper than 15 m where the bottom is stable.View full abstractDownload PDF (1189K) -
Shigeaki GORIE, Tetsuya OHTANI1998 Volume 46 Issue 4 Pages 495-501
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe white-spotted conger, which is liable to limit the mesh size of the cod end, is one of the most important fish species caught by the small trawl fishery in Harima-Nada, Seto Inland Sea. Recently, fishery resource management has become more and more important and the protection of under-sized fish is necessary for the effective use of fish resources. In small trawl fishery, one way to protect small-sized fish is to enlarge the mesh size of the cod end. The present study was performed to understand the seasonal changes of length compositions, mesh selectivity, and artificial selectivity in the white-spotted conger. The experiment was carried over one year. In Harima-Nada, a cohort of small size fish occurred in August was caught continuously for nearly a year. Fish over 450 mm were rarely caught in this study. The artificially selected size for landing was over 250 mm. However, since the wholesale price is markedly higher for sizes over 300 mm, enlargement of the mesh size of the cod end is recommended for the future resource control.View full abstractDownload PDF (823K) -
Akinori DAN, Masanori HIRAOKA, Masao OHNO1998 Volume 46 Issue 4 Pages 503-508
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSSynchronous spore formation in the green alga, Enteromorpha pyolifeya, was induced in small excised disks from the materials which had been maintained for 2 days or 5 weeks at 15°C, 20pt salinity and 20 μmol/s/m2 photon flux density (12 h L/12 h D) . The smaller tissue disks released spores after 2-6 days. Maturation and spore release from the tissue disks were induced fast for the 5-week material. The tissue disks of 0.9 mm diameter gave the best performance on maturation. The optimum culture condition for maturation and spore release was at a tissue size of 0.9 mm and a temperature of 20 to 25°C.View full abstractDownload PDF (710K) -
Tomohiko KAWAMURA, Kazumaro OKAMURA, Hideki TAKAMI1998 Volume 46 Issue 4 Pages 509-516
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe marine benthic diatom, Cocconeis scutellum var. payva is one of the most suitable diets for post-larval abalone. Growth of this diatom was examined at (1) various combinations of temperature (10, 15, 20, 25°C) and irradiance (12, 46, 78112, 135μE/m2/s) at 33 PSU salinity, and (2) at various salinities (18, 23, 28, 31, 33, 36, 40, 44 PSU) at 20°C with a 78μE/m2/s and 12: 12 LD cycle. These experiments used modified Jørgensen's medium and ran for 45-55 days. The initial valve length was 16.2±1.2μm for the temperature and irradiance experiment, and 22.0±0.7μm for the salinity experiment. The diatom grew in all conditions. The mean daily growth rate at the exponential phase ranged from 0.26 to 0.55 (divisions/day) . Growth rates were higher at higher temperatures at the same irradiance ≥46μE/m2/s. There were no significant differences in growth rate among temperatures at 12μE/m2/s. No significant differences were observed in growth rate among irradiances ≥46μE/m2/s at the same temperature. Growth rates were significantly lower at 12μE/m2/s than at higher irradiances for temperatures ≥15°C. The optimal growth was observed at 28-40 PSU. The diatom formed a single-layered colony, and stopped growing when it occupied the entire surface area of the culture plate. The cell size appeared to decrease gradually from 34.4 to 9.7±0.5μm in valve length during 130 generations (204 days) . Sexual reproduction was observed at the 95th generation (13.4±1.2μm), during which the valve length restored to 33.8μm.View full abstractDownload PDF (1188K) -
Nagahira ARAI, Keishiro KARITA, Gen-ichi HOSHIAI, Satoshi KATAYAMA, Ze ...1998 Volume 46 Issue 4 Pages 517-521
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSTo examine physiological characteristics of spontaneous squirting in the ascidian, Halocynthia roretzi, a method wchich could monitor changes in intrabranchial pressure continuously for a few weeks was developed. Two types of squirting responses, large and small were observed. They appeared independently and exhibited different circadian rhythms. This method will be useful for clarifying the function and biological rhythm of squirting in the ascidian.View full abstractDownload PDF (655K) -
Ken-ichi YAMAMOTO, Takeshi HANDA, Masatoshi NAKAMURA, Kouichi TAMURA, ...1998 Volume 46 Issue 4 Pages 523-527
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSIn the green mussel, Perna viridis, the amount of oxygen uptake, the ventilation volume, the oxygen utilization were examined by measuring ventilation volume direct, and detecting the gill cilia movement by measuring the moving speed of a small piece of vinyl film (2.0 mm diameter, 0.3 mm thickness) on the gill surface under normoxic and hypoxic conditions at 28.0±0.1°C. Under hypoxic condition, the green mussel maintained the oxygen uptake by increasing the oxygen utilization. And while the moving speed of the piece decreased, the ventilation volume was maintained by being constant. The results indicated that the ventilation volume was not directly regulated by the gill cilia movement.View full abstractDownload PDF (786K) -
Kenji TAKII, Yoshimi KUROMIYA, Motoji NAKAMURA, Hidemi KUMAI, Kazuharu ...1998 Volume 46 Issue 4 Pages 529-534
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSGrouper, Epinephelus septemfasciatus, having a mean body weight of 1, 200g were fed for 71 days on diets with 38, 44, 49 and 54% levels of protein, respectively. The diets were prepared from 80% brown fishmeal and 20% wheat gluten. The daily feeding rate was about the same among the four diet groups. The highest weight gain, feed efficiency and apparent fat retention were obtained in the 49% protein group, while the highest protein efficiency ratio and apparent protein retention were detected in the 44% protein group. Besides that hepatosomatic index and final liver fat content of both 38 and 44% protein groups were lower than those of 49 and 54% protein groups, final proximate compositions of the whole body and liver showed no meaningful differences among the dietary treatments. Comparing the 40% and the 49% protein group, aspartate aminotransferase and alanine aminotransferase activities in liver and cathepsin D and B+L activities in white muscle of the latter were slightly higher than those of the former, but the liver RNA/DNA ratio of the former was higher than the latter. These results indicate that diet protein levels affect on growth performance as well as amino acid and protein metabolisms of grouper. A desirable diet protein level for grouper is 44-49% for the growth performance, and about 44% for amino acid and protein metabolisms.View full abstractDownload PDF (972K) -
Shuichi SATOH, Ryotaro ISHIDA, Toshio TAKEUCHI, Takeshi WATANABE, Tada ...1998 Volume 46 Issue 4 Pages 535-540
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSA feeding experiment was conducted to investigate whether it was necessary to supplement minerals to fish meal based feed for red sea bream or not. Phosphorus (P), magnesium (Mg), zinc (Zn), or manganese (Mn) was excluded respectively from the complete mineral mixture. The mineral mixtures were formulated to the fish meal based experimental diet. The experimental diets were fed to the red sea bream (2.4 g on average) for nine weeks. The growth was lowest in the fish fed the diet without P supplementation, the growth of the fish fed the diet without Zn supplement was significantly lower than the control group. However, influence of excluding Mg or Mn supplementation on the growth was very small. Zn content in vertebrae was lowest in the fish on the diet without Zn supplement, and Mn content in vertebrae was also lowest in the fish on the diet without Mn supplement.
When red sea bream were fed the diet without P, Mg, Mn, or Zn, their growth and mineral composition in carcass were influenced. The results of the experiment suggested that availability of minerals contained in fish meal for red sea bream was not high, and it was necessary to supply minerals even to fish meal based feed.View full abstractDownload PDF (795K) -
Kotaro KIKUCHI, Tomonori SATO, Yoshiaki DEGUCHI1998 Volume 46 Issue 4 Pages 541-546
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSJuvenile fish of 5 g initial body weight were reared with four experimental diets containing glucose, maltose, dextrin, and potato starch, respectively, for 4 weeks at 20°C. Growth and feed efficiency of the cultured fish were higher in the dietary groups with dextrin and potato starch, and tended to decrease in the order of maltose and glucose. Fish of 4 g initial body weight were fed five diets having different ratios of fish meal/potato starch (crude protein, 33 to 53%) for 6 weeks at 20°C. The growth of fish fed the diets containing 44, 50, and 53% of protein were similar to each other, while groups fed diets with 33 and 40% protein grew poorly. Feed efficiency decreased with increasing level of potato starch in the diet, although the protein efficiency ratio was in the same range.View full abstractDownload PDF (853K) -
Toshio TAKEUCHI, Tetsuya HIROTA, Goro YOSHIZAKI, Kiyoshi SAKAI1998 Volume 46 Issue 4 Pages 547-555
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThis experiment was conducted to examine the relationship between the growth performance of tilapia, Oyeochromis niloticus, and the water qualities indicated by ammonium nitrogen, nitrite nitrogen, nitrate nitrogen, etc. Fish weighing 8.6g (total length, 62.8mm) were cultured in recirculating filter tank systems (30 l) with four kinds of filter beds (Bio α, Siporax and Zeolite, all three with coral sands; and an additional Bio α bed without the coral sands) for 70 days at 28°C. During the feeding period, the water quality and feed performance were monitored. The average daily recirculation rate was 98.4% for all the four tank systems. The use of coral sand helped in stabilizing the pH values of the systems during the feeding experiment. All the three types of filter beds with coral sand were effective in nitrifying the ammonia which was excreted from the fish, while the ammonium nitrogen concentration increased to 80.9 mg/ l and pH values decreased to 4.7 in the system without coral sand. However, the tilapia exhibited good growth and high feed efficiency even though the concentrations of ammonium nitrogen or nitrate nitrogen reached 80.9 mg/l or 616 mg/l respectively at the end of feeding experiment. These results demonstrate that tilapia is highly tolerant to adverse water quality and could sustain its growth under such conditions.View full abstractDownload PDF (1209K) -
Takeshi FURUTA, Kotaro KIKUCHI, Nakahiro IWATA, Haruo HONDA1998 Volume 46 Issue 4 Pages 557-562
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSRearing experiment with Japanese flounder, Paralichthys olivaceus, was carried out within a closed recirculating system of 22m3 in total water volume. At the start of the experiment, 2000 flounder of 3.5g in average body weight were introduced to the system and fed a commercial pellet diet to apparent satiation twice daily. Fish grew to an average weight of 480g and had a survival rate of 88% during 337 days. Amount of exchanged seawater was 15m3, yielding a calculated productivity of 23kg fish per cubic meter of seawater used. The experiment was continued to day 533 with 1127 fish of 562g initial average body weight. The average body weight at the end was 851g and survival rate from 337 to 533 days was 71%.
Ammonia-nitrogen concentration within the culture system fluctuated throughout the experiment, especially day 100 to 350, sometimes exceeding 5 mg-N/l. A similar trend was seen in the nitritenitrogen concentration with a peak of 4 mg-N/l. The nitrate concentration decreased during day 220 to 350, even though the system was not equipped with a denitrification unit.View full abstractDownload PDF (788K) -
Haruo SUGITA, Takayuki ISHIGAKI, Daisaku IWAI, Yukiko SUZUKI, Ryuji OK ...1998 Volume 46 Issue 4 Pages 563-568
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSAntibacterial abilities of bacteria were determined for a better understanding of the role of intestinal microflora in coastal fish. Intestinal bacteria were isolated from five of each following species: horse mackerel, Trachurus japonicus, spotnape ponyfish, Leiognathus nuchalis, and red barracuda, Sphyraena pinguis, collected at Enoshima Island, Kanagawa. In the intestinal contents of three coastal fishes, genus Vibrio was the dominant bacterium and accounted for 5-100% of total viable counts ranging from 1.2×104 to 1.3×107 CFU/g. A total of 681 bacteria isolated from the water, sand and fish intestines were examined for their antibacterial abilities against four fish pathogenic bacteria, using the double layer method. Antibacterial producers were accounted for 15.0% of total isolates against Pasteurella piscicida K-III, 1.0% against Enterococcus seniolicida ATCC 49156 and 0.3% against both Vibrio anguillarum ATCC 19264 and Vibrio vulnificus RIMD 2219009. This result reveals that P. piscicida K-III may be much more susceptible than the other three fish pathogens. The growth of P. piscicida K-III was inhibited by 85 isolates of Vibrio spp., six of Acinetobacter spp., four of coryneforms and two of Bacillus spp. These results suggest that an indigenous antibacterial microflora may involve the protection of host fish against pathogenic bacteria to some extent.View full abstractDownload PDF (860K) -
Gen MIMURA, Yasuto KATAYAMA, Xiangrong JI, Jialin XIE, Kenji NAMBA1998 Volume 46 Issue 4 Pages 569-578
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSThe toxic effects of exposure to ozone-exposed seawater and chlorinated seawater were investigated in eggs and larvae aged 3-15 days and juveniles aged 44 days in the setting stage of Japanese flounder, Paralichthys olivaceus. For eggs, the 50% no-hatching concentration of OPO and TRC after 1 min exposure were both about 2.2 mg O3/l. The 24-h LC50 values of OPO and TRC in larvae aged 3-15 days were both 0.02-0.05 mg O3/l. The 24-h LC50 values of OPO and TRC for juveniles aged 44 days in the setting stage were both 0.14-0.15 mg O3/l. Light microscopy of branchial tissues showed detachment of the epithelium of the secondary lamellae after exposure to OPO or TRC. Scanning electron microscopy (SEM) of branchial tissues showed cell swelling and cell destruction of the secondary lamellae after exposure to OPO or TRC. The toxicity of OPO and TRC and damage to branchial tissue caused by OPO and TRC were exactly alike.View full abstractDownload PDF (7304K) -
Gen MIMURA, Takako NAGAMITU, Toshiya NAGASE, Kenji NAMBA1998 Volume 46 Issue 4 Pages 579-587
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSWe tried to quantitate residual oxidants by measuring trihalogenated methanes generated from reacting resorcin with TRO (total residual oxidants) . Our results showed that the residual oxidants in OPO (ozone-produced oxidants) seawater, TRC (total residual chlorine) seawater and electrolyzed seawater were mostly hypobromous acid. When seawater containing hydrogen peroxide or povidone-iodine was treated with resorcin, no trihalogenated methane was detected. In addition, when NaClO was added to seawater diluted 3-30 times with distilled water, both chlorinecontaining and bromine-containing oxidants were detected.
Delayed hatching was observed frequently in Japanese flounder, Paralichthys olivaceus, eggs exposed to OPO Seawater, TRC Seawater or electrolyzed seawater. Occurrence of the delayed hatching increased rapidly when the oxidant concentration increased to 2 mg O3/l or higher. No increment of dead eggs was observed. When the eggs were exposed to seawater containing hydrogen peroxide or povidone-iodine, few delayed hatching of eggs were found. Most of the eggs that failed to hatch died.View full abstractDownload PDF (1422K) -
Ken-ichi WATANABE1998 Volume 46 Issue 4 Pages 589-590
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSBarfin flounder, Verasper moseri, is one of the most endangous fish species in Japan. Since its biological features have hardly been known, such study is urgent. Two fish with ovulated eggs were captured in Akkeshi and Samani of pacific coast of Hokkaido in June 1994 and 1998, respectively. The latter had an enlarged belly dribbling many transparent and opaque eggs; the former had a slackened belly dribbling a small amount of transparent eggs being at the state of right after spawning. This study showed that the barfin flounder could also spawn from spring to early summer in addition to the reported winter. Furthermore, the depths where these fish captured suggested that barfin flounder may spawn at about 35 to 70 m in depth.View full abstractDownload PDF (294K) -
Kiyoshi YOSHIHARA, Takefumi FUKUDA1998 Volume 46 Issue 4 Pages 591-592
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSJack mackerel, Trachurus japonicus, in a fish cage equipped with an underwater lamp for attracting dietary animals, were examined for their stomach contents. The first and maximum peaks of stomach contents appeared 3 and 6 h, respectively, after transfering the fish into the cage. The fact that occurrence of fish larvae (shirasu) in stomach contents increased as time passed, strongly suggests a food selectivity.View full abstractDownload PDF (351K) -
Yukifumi KONAGAYA, Haruo SUGITA, Junji KUMAZAWA, Yoshiaki DEGUCHI1998 Volume 46 Issue 4 Pages 593-594
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSClostridium sp. strain F-8 produced β-N-acetylglucosaminidase (β-G1cNAcase) extracellularlly. The optimal pH of β-G1cNAcase was 6.0, and it was stable at between 6.0 and 7.0. The enzyme had an optimal temperature of 37°C, and was stable at 40°C. These results suggested that the enzyme is well adapted to intestinal environments of host animals.View full abstractDownload PDF (310K) -
1998 Volume 46 Issue 4 Pages 595-614
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSDownload PDF (9506K) -
1998 Volume 46 Issue 4 Pages 615-632
Published: December 20, 1998
Released on J-STAGE: March 09, 2010
JOURNAL FREE ACCESSDownload PDF (2097K)
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